Print Able Olga 6 User Manual

Welcome to OLGA 6 User ManualThis is the OLGA 6 User Manual. The User Manual includes both information about the OLGA 6 engine and the graphical user interface (GUI). The complete program documentation includes - Release Document for OLGA 6.2 - OLGA 6 User Manual (this document) - OLGA 6 GUI User Manual - OLGA 6 Conversion Guide - Well GUI User Manual - Tutorial - Installation Guide All documents listed above are available from the Start Menu (Start - All Programs - SPT Group - OLGA 6.2 - Documentation). The OLGA 6 User Manual, OLGA 6 GUI User Manual, OLGA 6 Conversion Guide, Wells GUI User Manual and the Tutorial are also available from the Help menu in the GUI). User Manuals for other tools included with the OLGA 6 installation are available from the Help menus in the tools.

Release InformationPlease refer to the Release Document for detailed release information for OLGA 6.2. The Release Document describes changes in OLGA 6.2 relative to OLGA 5 and OLGA 6.1, and should be read by all users of the program. The complete program documentation consists of the OLGA User Manual, OLGA 6 GUI User Manual, OLGA 6 Conversion Guide, Wells GUI User Manual, Tutorial, Installation Guide, and the Release Document. The program is available on PCs with Microsoft Windows operating systems (Windows XP, Windows Vista and Windows 7). Several versions of OLGA may be installed in parallel. Note that you may also run several versions of the engine from one version of the GUI - please refer to the Installation Guide to learn how to configure the GUI for several engines. The support center provides useful information about frequently asked questions and known issues. The support center is available from the SPT Group Support Center Please contact SPT Group if problems or missing functionality are encountered when using OLGA or any of the related tools included in the OLGA software package. E-mail: [email protected] Telephone: +47 6484 4550 Fax: +47 6484 4500 Address: SPT Group AS, P.O. Box 113, N-2027 Kjeller

IntroductionOLGA is the industry standard tool for transient simulation of multiphase petroleum production. The purpose of this manual is to assist the user in the preparation of the input data for an OLGA simulation. In this manual you can find a general introduction to OLGA an overview of the required and the optional input to OLGA. It also describes in some detail different simulation options such as wax deposition, corrosion etc. a detailed description of all input data and the required fluid property tables a description of the output The sample cases presented with the installation of OLGA are intended to illustrate important program options and typical simulation output. A description of the sample cases are also included in this manual. OLGA comes in a basic version with a number of optional modules;FEMTherm, Multiphase Pumps, Corrosion, Wells, Slug Tracking, Wax Deposition, Inhibitor Tracking, Compositional Tracking, Single Component Tuning, Hydrate Kinetics and Complex Fluid. In addition there is a number of additional programs like the OLGA GUI and the FEMThermViewer for preparation of input data and visualisation of results. These optional modules and additional programs are available to the user according to the user's licensing agreement with SPT Group. See also: Background OLGA as a strategic tool OLGA Model Basics How to use in general Graphical User Interface Simulation model Input files Applications Threaded Execution

BackgroundOLGA 6 is the latest version in a continuous development which was started by the Institute for Energy Research (IFE) in 1980. The oil industry started using OLGA in 1984 when Statoil had supported its development for 3 years. Data from the large scale flow loop at SINTEF, and later from the medium scale loop at IFE, were essential for the development of the multiphase flow correlations and also for the validation of OLGA. Oil companies have since then supported the development and provided field data to help manage uncertainty, predominantly within the OLGA Verification and Improvement Project (OVIP). OLGA has been commercially available since the SPT Group started marketing it in 1990. OLGA is used for networks of wells, flowlines and pipelines and process equipment, covering the production system from bottom hole into the production system. OLGA

comes with a steady state pre-processor included which is intended for calculating initial values to the transient simulations, but which also is useful for traditional steady state parameter variations. However, the transient capabilities of OLGA dramatically increase the range of applicability compared with steady state simulators.

OLGA as a strategic tool

OLGA is applied for engineering throughout field life from conceptual studies to support of operations. However the application has been extended to be an integral part of operator training simulators, used for making operating procedures, training of operators and check out of control systems. Further, OLGA is frequently embedded in online systems for monitoring of pipeline conditions and forecasting and planning of operations. OLGA can dynamically interface with all major dynamic process simulators, such as Hysys, DynSim, UniSim, D-SPICE, INDISS and ASSETT. This allows for making integrated engineering simulators and operator training simulators studying the process from bottom hole all the way through the process facility in a single high fidelity model. Note that the OLGA flow correlation has been implemented in all major steady state simulators providing consistent results moving between different simulators.

OLGA Model BasicsOLGA 6 is a three-fluid model, i.e. separate continuity equations are applied for the gas, for the oil (or condensate) and water liquids and also for oil (or condensate) and water droplets. These may be coupled through interfacial mass transfer. Three momentum equations are used; one for each of the continuous liquid phases (oil/condensate and water) and one for the combination of gas with liquid droplets. The velocity of any liquid droplets entrained in the gas phase is given by a slip relation. One mixture energy equation is applied; assuming that all phases are at the same temperature. This yields seven conservation equations to be solved: three for mass, three for momentum, and one for energy. Two basic flow regime classes are recognised ; distributed and separated flow. The former comprises bubble and slug flow [1], the latter stratified and annular mist flow.

Figure A Flow patterns in horizontal flow Transition between the regime classes is determined by the program on the basis of a minimum slip concept combined with additional criteria. To close the system of equations, fluid properties, boundary and initial conditions are required. The equations are linearised and a sequential solution scheme is applied. The pressure and temperature calculations are de-coupled i.e. current pressure is based on previous temperature. The semi-implicit time integration implemented allows for relatively long time steps, orders of magnitudes longer than those of an explicit method (which would be limited by the Courant Friedrich Levy criterion based on the speed of sound). The numerical error is corrected for over a period of time. The error manifests as an error in local fluid volume (as compared to the relevant pipe volume). [1] In standard OLGA a slug unit model is applied which calculates average liquid hold-up and pressure, but which does not give any details about individual slugs. To follow individual slugs through the system the slug tracking module must be applied.

How to use in generalNumericsOLGA applies one global time-step for the time integration and there is an automatic time-step control based on the limitation that a fluid particle should not spend less than one time-step on passing through any numerical section length of a pipe (the Courant Friedrich Levy (CFL) criterion based on the fluid velocity). The user controls the time integration by specifying simulation period in time, time-step parameters such as initial time-step and maximum and minimum time-step values. The latter overrules the automatic control. There is also an option for using the second-derivative of pressure as a time step controlling criterion. Some functions in OLGA, e.g. slug-tracking, take control of the time-stepping in order to ensure a successful simulation. The spatial integration is performed on a user-defined grid. There are tools available to facilitate the gridding. There are no formal limitations on the numerical section lengths, but it is considered good practice to keep all neighbour section length ratios between 0.5 and 2:

0.5 Dxi/Dxi+1 2 for all iAdditionally it is recommended that each pipe should have at least two sections. Due to the numerical solution scheme, OLGA is particularly well suited for simulating rather slow mass flow transients. This is important for the simulation of long transport lines and thermal calculations, where typical simulation times in the range of hours to several days, and sometimes years, will require long time steps, to obtain efficient use of the computer. OLGA is also being used successfully for fast transients such as water hammer and pressure surges in general. Certain precautions w.r.t. spatial grid and time-stepping may be needed in order to keep the numerical error within acceptable limits. Since OLGA not accounts for pipe elasticity the calculated pressure peaks should be conservative. The de-coupling of temperature from pressure would normally give a pressure wave propagation velocity in gas which would be about 15% too low. However, in OLGA 6 a quasi implicit correction of temperature reduces this error considerably. Critical flow calculations are performed in the OLGA valve model, only. A valve with cross section equal to the pipe should then be positioned on e.g. a pipe outlet if choked flow is expected.

TemperatureOLGA is particularly well suited for sophisticated thermal simulations. Since OLGA is one-dimensional (calculates along the pipe axis) any 2 and 3-dimensional effects must be modelled explicitly. The basic OLGA thermal model calculates the inner wall heat transfer coefficient. The built-in correlations are valid for natural- and forced convection and also for the transition between them. Flow pattern is accounted for. The user may specify pipe walls with material properties, including emissivity to account for radiation, and must give the ambient properties, i.e. temperature and heat transfer coefficient. Based on this the fluid temperature is calculated. Special features like Annulus, Solid- and Fluid bundles make it possible to simulate very complex structures of pipe-in-pipe and parallel pipes within structures of various solid materials. Taking into account that temperature is calculated along the pipes one obtains a combination of two-dimensional convective heat transfer within 3dimensional heat conducting structures. Solid bundle cross section of 4 vertical tubes within rock neighbour tubes are 2.5 m apart. The black "line" is a temperature iso-line. One clearly sees how the area between the tubes is subject to inter-tube heating.

Initial ConditionsThe requirement for initial conditions is a fundamental difference between a transient and a steady state model, e.g. the results of a steady state calculation may serve as the initial condition (at t=0 ) for a transient simulation. With OLGA the user decides, and later specifies in the input, whether the simulation is to start from a user defined condition (for instance a specific shut-in condition), or from a steady state multiphase flowing situation calculated by the program. The steady state pre-processor in OLGA can be used to provide good initial values for most production situation. In addition, the user may specify the initial condition in detail, for example for a shut-in system, by defining the initial values for pressures, temperatures, mass flow and gas fractions. Tools for interpolation are available, for filling in the initial values in all numerical sections of the system. Finally, the restart capability may be used to start a simulation from conditions saved during a previous simulation.

Boundary ConditionsThe boundary conditions define the interface between the simulated system and its surroundings and they are crucial to the relevance to any type of simulations. For a network of pipelines and wells there are several options available, but basically flow rate or pressure, in addition to temperature and gas-liquid ratio must be specified at each flow path inlet and outlet boundary (at least one pressure must be given). The boundary conditions, e.g. a pressure, can be given as time series to model a certain transient situation.

Moreover, the ambient temperature along the flow paths and ambient heat transfer coefficient (film heat transfer resistance) must be specified and OLGA provides a number of options for this, including water and air velocity profiles and seasonal variations of temperature. Inflow from reservoirs to well-bores define the most important boundary in a petroleum production network. In addition to various well-inflow correlations and options OLGA comes with an implicit coupling facility to the OLGA Rocx module which is a complete 3-D, 3-phase reservoir simulator. Separators, pumps, compressors and valves, all with controllers, can be modelled to improve the relevance of the outlet boundaries.

Fluid propertiesThe necessary fluid properties (gas/liquid mass fraction, densities, viscosities, enthalpies etc.) are normally assumed to be functions of temperature and pressure only, and have to be supplied by the user as tables in a special input file. Thus, the total composition of the multiphase mixture is assumed to be constant both in time and space for a given part of the network. The user may specify different fluid property tables for each flow path, but has to ensure that a realistic fluid composition has been used to make a table for a flow path with a fluid mixture coming from two or more pipeline branches merging upstream.

It is also possible to perform simulations using Compositional Tracking, where the basic information on the chemical components is provided in a separate text file and then OLGA calculates the fluid properties internally with PVT routines provided by Calsep A/S. This means that the total composition may vary both in time and space, and that no special considerations are needed for the downstream system. Special models are also available for tracking hydrate inhibitors like MEG and methanol. The numerical solution of the OLGA model is generally able to handle multi component fluid systems but will normally have problems with single component systems or systems with a very narrow phase envelope.

RheologyThe standard OLGA flow models assume a Newtonian rheology (viscosities are well defined fluid characteristics). Dispersions and non-Newtonian behavior are quite common in petroleum production and OLGA provides several semi-empirical models to account for more complex rheologies. In some cases the model takes care of the rheology with a minimum of user interference (e.g. for oil-water dispersions and also for waxy oils). For other systems the user needs to specify the various parameters for such fluids to describe e.g. Bingham or power law non-Newtonian behavior.

NetworkIn OLGA the network comprises flow paths coupled with nodes which have a volume. General networks with closed loops can then be modelled, see below. The flow paths have a user defined direction but the flow is invariant to direction as such and any fluid phase may flow co-currently or counter-currently with respect to the predefined direction at any time and position. Pipe-bends are not accounted for as such (except for differences in static head). The user may apply pressure loss coefficients at boundaries between numerical sections. Equipment is positioned on the flow path usually on a pipe-boundary. However, the separator in OLGA is a network component similar to a node. Controllers are specified as integral parts of the simulation model and they have their own network formalism.

Threaded ExecutionPipe sections belonging to the same branch may be updated in parallel. Suppose a branch has 100 sections, and that two threads are available to the OLGA engine:

Section 1 and section 51 will be updated simultaneously, then section 2 and section 52 are updated, and so on. Depending on the computer hardware, this method can drastically reduce the time OLGA takes to advance one time-step. Normally, you do not need to change the default settings of neither OLGA nor your operating system. Parallel updating of segments is usually activated in the OLGA engine if your PC supports it.

Controlling the degree of parallelismThe Windows operating system decides how many threads will be used. If your PC is equipped with a quad-core CPU, typically four threads will be simultaneously running to update four sections in parallel. Is your CPU a single-core Intel Xeon processor with "hyper-threading" (HT), probably two engine threads will be used. It is possible to overrule the choice of the operating system by setting the environment variable OMP_NUM_THREADS; use Windows' Control Panel to do this. However, the preferred way to change the degree of parallelisation is do so from the OLGA menu system. Setting the value here takes precedence over the OMP_NUM_THREADS environment variable. A situation where you might want to reduce the number of threads, arise if you execute parametric studies. Given that your license permits, it would be preferable to spend the CPU's cores on simultaneous simulations, rather than on speeding up each simulation in the study. Another situation could be when you don't want OLGA to consume all your computing power, e.g., if you want to write a report while OLGA is working. Most large cases will benefit from the parallelisation. Still, please note that some of your PC's cache memory will be used for forking and joining the threads, and doing the necessary book-keeping. As a consequence, special cases will run faster with a single engine thread.

Parallel speed-upThe parallelisation encompasses heat calculations in section walls, updating fluid properties and flashing, and, most importantly, calls to the flow model which decides friction factors, liquid holdup and the flow regime. If the flow model calculations dominate the overall simulation, the utilization of the CPUs is most efficient.

Monitoring the OLGA processThe Task Manager can be used to check how OLGA loads your CPU. When the number of engine threads equals the number of cores (or equals two on a single core HTCPU) you should see the CPU usage being clearly over fifty percent when OLGA is simulating. In the Task Manager's list of processes it is possible to view the number of threads for each process. With 1 engine thread, it uses a total of 5 threads in batch mode, and 8 threads while running under control of the GUI. With 2 engine threads allowed, the task manager would display 6 threads for a batch run and 9 threads for a GUI run; with 4 engine threads the total number of threads would be 8 and 11, respectively.

ApplicationsWhen the resources become more scarce and complicated to get to careful design and optimisation of the entire production system is vital for investments and revenues. The dimensions and layout of wells and pipelines must be optimised for variable operational windows defined by changing reservoir properties and limitations given by environment and processing facilities. OLGA is being used for design and engineering, mapping of operational limits and to establish operational procedures. OLGA is also used for safety analysis to assess the consequences of equipment malfunctions and operational failures. REFERENCES contains a list of papers describing the OLGA model and its applications.

Design and EngineeringOLGA is a powerful instrument for the design engineer when considering different concepts for hydrocarbon production and transport - whether it is new developments or modifications of existing installations. OLGA should be used in the various design phases i.e. Conceptual, FEED [2] and detailed design and the following issues should be addressed: Design Sizes of tubing and pipes Insulation and coverage Inhibitors for hydrate / wax Liquid inventory management / pigging Slug mitigation Processing capacity (Integrated simulation) Focus on maximizing the production window during field life Initial Mid-life Tail Accuracy / Uncertainty management Input accuracy Parameter sensitivity Risk and Safety Normally the engineering challenge becomes more severe when accounting for tail-end production with reduced pressure, increasing water-cut and gas-oil ratio. This increase the slugging potential while fluid temperature reduces which in turn increase the need for inhibitors and the operational window is generally reduced.

Operation

OLGA should be used to establish Operational procedures and limitations Emergency procedures Contingency plans OLGA is also a very useful tool for operator training Training in flow assurance in general Practicing operational procedures Initial start up preparations When systems become more complex and critical e.g. with long and deep Flow lines/risers, start-up situations need to be forecasted on a short-term basis and OLGA is regularly being used for assistance at start-up. Some typical operational events suitable for OLGA simulations are discussed below.

Pipeline shut-downIf the flow in a pipeline for some reason has to be shut down, different procedures may be investigated. The dynamics during the shut-down can be studied as well as the final conditions in the pipe. The liquid content is of interest as well as the temperature evolution in the fluid at rest since the walls may cool the fluid below a critical temperature where hydrates may start to form.

Pipeline blow-downOne of the primary strategies for hydrate prevention in case of a pipeline shut-down is to blow down. The primary aim to reduce the pipeline pressure below the pressure where hydrates can form. Main effect that can be studied are the liquid and gas rates during the blow-down, the time required and the final pressure.

Pipeline start-upThe initial conditions of a pipeline to be started is either specified by the user or defined by a restart from a shut-down case. The start-up simulation can determine the evolution of any accumulated liquid slugs in the system. A start-up procedure is often sought whereby any terrain slugging is minimised or altogether avoided. The slug tracking module is very useful in this regard. In a network case a strategy for the start-up procedure of several merging flow lines could be particularly important.

Change in productionSometimes the production level or type of fluid will change during the lifetime of a reservoir. The modification of the liquid properties due to the presence of water, is one of the important effects accounted for in OLGA. A controlled change in the production rate or an injection of another fluid are important cases to be simulated. Of particular interest is the dynamics of network interactions e.g. how the transport line operation is affected by flow rate changes in one of several merging flow lines.

Process equipmentProcess equipment can be used to regulate or control the varying flow conditions in a multi-phase flow line. This is of special interest in cases where slugging is to be avoided. The process equipment simulated in OLGA includes critical- and sub-critical chokes with fixed or controlled openings, check-valves, compressors with speed and antisurge controllers, separators, heat exchangers, pumps and mass sources and sinks.

Pipeline piggingOLGA can simulate the pigging of a pipeline. A user specified pig may be inserted in the pipeline in OLGA at any time and place. Any liquid slugs that are created by the pig along the pipeline can be followed in time. Of special interest is the determination of the size and velocity of a liquid slug leaving the system ahead of a pig that has been inserted into a shut-down flow line.

Hydrate controlHydrate prevention and control are important for flow assurance. Passive and active control strategies can be investigated: Passive control is mainly achieved by proper insulation while there are several options for active control which can be simulated with OLGA: Bundles, electrical heating, inhibition by additives like MEG.

Wax depositionIn many production systems wax would tend to deposit on the pipe wall during production. The wax deposition depends on the fluid composition and temperature. OLGA can model wax deposition as function of time and location along the pipeline.

TuningEven if the OLGA models are sophisticated models made for conceptual studies and engineering will be based on input and assumptions which are not 100% relevant for operations. Therefore OLGA is equipped with a tuning module which can be used on-line and off-line to modify input parameters and also critical model parameters to match field data.

Wells- Flow stability e.g. permanent or temporary slugging, rate changes - Artificial lift for production optimization - Shut-in/start-up - water cut limit for natural flow - Cross flow between layers under static conditions - WAG injection - Horizontal wells / Smart wells - Well Clean-up and Kick-off - Well Testing - Well control and Work-over Solutions

Safety AnalysisSafety analysis is an important field of application of OLGA. OLGA is capable of describing propagation of pressure fronts. For such cases the time step can be limited by the velocity of sound across the shortest pipe section. OLGA may be useful for safety analysis in the design phase of a pipeline project, such as the positioning of valves, regulation equipment, measuring devices, etc. Critical ranges in pipe monitoring equipment may be estimated and emergency procedures investigated.

Consequence analysis of possible accidents is another interesting application. The state of the pipeline after a specified pipe rupture or after a failure in any process equipment can be determined using OLGA. Simulations with OLGA can also be of help when defining strategies for accident management, e.g. well killing by fluid injection. Finally it should be mentioned that the OLGA model is well suited for use with simulators designed for particular pipelines and process systems. Apart from safety analysis and monitoring, such simulators are powerful instruments in the training of operators. [2] Front End Engineering and Design

Input filesThe OLGA simulator uses text files for describing the simulation model: .opi; generated and used by the OLGA GUI .inp; input format used by OLGA 5 and earlier versions .key; input format used by OLGA The .key format has been introduced as the new input file format for the OLGA engine. The OLGA GUI will automatically generate files in this format (with the extension .genkey). The .key format reflects the network model described in the simulation model and should be the preferred format. In addition to the simulation file, OLGA handles input in several other formats as described in Data files.

Simulation descriptionThe input keywords are organised in Logical sections, with Case level at the top, followed by the various network components and then the connections at the end.

Case levelCase level is defined as the global keywords specified outside of the network components and connections. Case level keywords can be found in the CaseDefinition, Library, FA-models and Output sections. The following keywords must or can be defined at Case level: CaseDefinition; CASE, FILES, INTEGRATION, OPTIONS, DTCONTROL, RESTART Library; MATERIAL, WALL, SHAPE, TABLE, DRILLINGFLUID, HYDRATECURVE Compositional; COMPOPTIONS, FEED, BLACKOILOPTIONS, BLACKOILCOMPONENT, BLACKOILFEED, SINGLEOPTIONS FA-models; CORROSION, FLUID, WATEROPTIONS, SLUGTRACKING, TUNING, SLUGTUNING Output; OUTPUT, TREND, PROFILE, PLOT, OUTPUTDATA, TRENDDATA, PROFILEDATA Drilling; TOOLJOINT CASE PROJECT="OLGA Manual", TITLE="Example case", AUTHOR="SPT Group AS" INTEGRATION STARTTIME=0, ENDTIME=7200, DTSTART=0.1, MINDT=0.1, MAXDT=5 FILES PVTFILE=fluid.tab MATERIAL LABEL=MAT-1, DENSITY=0.785E+04, CAPACITY=0.5E+03, CONDUCTIVITY=0.5E+02 WALL LABEL=WALL-1, THICKNESS=(0.9000E-02, 0.2E-01), MATERIAL=(MAT-1, MAT-1)

Network componentsThe network components are the major building blocks in the simulation network. Each network component is enclosed within start (NETWORKCOMPONENT) and end (ENDNETWORKCOMPONENT) tags as shown below. Each data group belonging to this network component will be written within these tags. NETWORKCOMPONENT TYPE=FlowPath, TAG=FP_BRAN ... ENDNETWORKCOMPONENT The following network component keywords can be specified (see links for further details on each component): FlowComponent;FLOWPATH, NODE ProcessEquipment;PHASESPLITNODE, SEPARATOR Controller;CONTROLLER ThermalComponent;ANNULUS, FLUIDBUNDLE, SOLIDBUNDLE FLOWPATHPiping

The flowpath can be divided into several pipes, which can have an inclination varying from the other pipes in the flowpath. Each pipe can again be divided into sections as described above. All sections defined within the same pipe must have the same diameter and inclination. Each pipe in the system can also have a pipe wall consisting of layers of different materials. The following keywords are used for Piping: BRANCH; Defines geometry and fluid labels. GEOMETRY; Defines starting point for flowpath. PIPE; Specifies end point or length and elevation of a pipe. Further discretization, diameter, inner surface roughness, and wall name are specified. POSITION; Defines a named position for reference in other keywords. BRANCH LABEL=BRAN-1, GEOMETRY=GEOM-1, FLUID=1 GEOMETRY LABEL=GEOM-1 PIPE LABEL=PIPE-1, DIAMETER=0.12, ROUGHNESS=0.28E-04, NSEGMENT=4, LENGTH=0.4E+03, ELEVATION=0, WALL=WALL-1Boundary&Initialconditions

For the solution of the flow equations, all relevant boundary conditions must be specified for all points in the system where mass flow into or out of the system. Initial

conditions at start up and parameters used for calculating heat transfer must also be specified. The following keywords are used for Boundary & Initial conditions: HEATTRANSFER; Definition of the heat transfer parameters. INITIALCONDITION; Defines initial values for flow, pressure, temperature and holdup. INITIALCONDITIONS is not required when a steady state calculation is performed. NEARWELLSOURCE; Defines a near-wellbore source used together with OLGA Rocx. SOURCE; Defines a mass source with name, position, and data necessary for calculating the mass flow into or out of the system. The source flow can be given by a time series or determined by a controller. WELL; Defines a well with name, position and flow characteristics. HEATTRANSFER PIPE=ALL, HAMBIENT=6.5, TAMBIENT=6, HMININNERWALL=0.5E+03 SOURCE LABEL=SOUR-1-1, PIPE=1, SECTION=1, TIME=0, TEMPERATURE=62, GASFRACTION=-1, TOTALWATERFRACTION=-1, PRESSURE=70 bara, DIAMETER=0.12, SOURCETYPE=PRESSUREDRIVENProcess Equipment

In order to obtain a realistic simulation of a pipeline system, it is normally required to include some process equipment in the simulation. OLGA supports a broad range of different types of process equipment, as shown below. It should be noted that the steady state preprocessor ignores the process equipment marked with (*) in the list below. The following keywords are used for Process equipment: CHECKVALVE (*); Defines name, position and allowed flow direction for a check valve. COMPRESSOR (*); Defines name, position and operating characteristics of a compressor. HEATEXCHANGER; Defines name, position and characteristic data for a heat exchanger. LOSS; Defines name, position and values for local pressure loss coefficients. LEAK; Defines the position of a leak in the system with leak area and back pressure. The leak can also be connected to another flowpath to simulate gas lift etc. PUMP (*); Defines name, type and characteristic data for a pump. TRANSMITTER (*); Defines a transmitter position. VALVE; Defines name, position and characteristic data for a choke or a valve. VALVE LABEL=CHOKE-1-1, PIPE=PIPE-1, SECTIONBOUNDARY=4, DIAMETER=0.12, CD=0.7, TIME=0, OPENING=1.0Output

OLGA provides several output methods for plotting simulation results. The following keywords are used for Output: OUTPUT(DATA); Defines variable names, position and time for printed output. PLOT; Defines variable names and time intervals for writing of data to the OLGA viewer file. PROFILE(DATA); Defines variable names and time intervals for writing of data to the profile plot file. TREND(DATA); Defines variable names and time intervals for writing of data to the trend plot file. TRENDDATA PIPE=1, SECTION=1, VARIABLE=(PT bara, TM, HOLHL, HOLWT) PROFILEDATA VARIABLE=(GT, GG, GL) NODEBoundary&Initialconditions

PARAMETERS; A collection keyword for all node keys. This keyword is hidden in the GUI.Output

OLGA provides several output methods for plotting simulation results. The following keywords are used for Output: OUTPUTDATA; Defines variable names, position and time for printed output. TRENDDATA; Defines variable names and time intervals for writing of data to the trend plot file. NETWORKCOMPONENT TYPE=Node, TAG=NODE_INLET PARAMETERS LABEL=INLET, TYPE=CLOSED ENDNETWORKCOMPONENT NETWORKCOMPONENT TYPE=Node, TAG=NODE_OUTLET PARAMETERS LABEL=OUTLET, GASFRACTION=-1, PRESSURE=50 bara, TEMPERATURE=32, TIME=0, TOTALWATERFRACTION=-1, TYPE=PRESSURE, FLUID=1 ENDNETWORKCOMPONENT PHASESPLITNODEBoundary&Initialconditions

PARAMETERS; A collection keyword for all phase split node keys. This keyword is hidden in the GUI.Output

OLGA provides several output methods for plotting simulation results. The following keywords are used for Output: OUTPUTDATA; Defines variable names, position and time for printed output. TRENDDATA; Defines variable names and time intervals for writing of data to the trend plot file. SEPARATORBoundary&Initialconditions

PARAMETERS; A collection keyword for all separator keys. This keyword is hidden in the GUI.Output

OLGA provides several output methods for plotting simulation results. The following keywords are used for Output: OUTPUTDATA; Defines variable names, position and time for printed output. TRENDDATA; Defines variable names and time intervals for writing of data to the trend plot file. CONTROLLERBoundary&Initialconditions

PARAMETERS; A collection keyword for all controller keys. This keyword is hidden in the GUI.Output

OLGA provides several output methods for plotting simulation results. The following keywords are used for Output: OUTPUTDATA; Defines variable names, position and time for printed output. TRENDDATA; Defines variable names and time intervals for writing of data to the trend plot file. NETWORKCOMPONENT TYPE=ManualController, TAG=SetPoint-1 PARAMETERS SETPOINT=(2:0.1,2:0.2,0.3), TIME=(0,2000,2010,4000,4010) s, STROKETIME=0.0, MAXCHANGE=1.0 ENDNETWORKCOMPONENT ANNULUSInitialconditions

PARAMETERS; A collection keyword for all annulus keys. This keyword is hidden in the GUI.AmbientConditions

AMBIENTDATA; A collection keyword for specifying the Annulus ambient conditions.AnnulusComponents

COMPONENT; A component to place within the annulus definition.Output

PROFILEDATA; Defines variable names and time intervals for writing of data to the profile plot file. TRENDDATA; Defines variable names and time intervals for writing of data to the trend plot file. FLUIDBUNDLEInitialconditions

PARAMETERS; A collection keyword for all fluid bundle keys. This keyword is hidden in the GUI.AmbientConditions

AMBIENTDATA; A collection keyword for specifying the fluid bundle ambient conditions.BundleComponents

COMPONENT; A component to place within the fluid bundle definition.Output

PROFILEDATA; Defines variable names and time intervals for writing of data to the profile plot file. TRENDDATA; Defines variable names and time intervals for writing of data to the trend plot file. SOLIDBUNDLEInitialconditions

PARAMETERS; A collection keyword for all solid bundle keys. This keyword is hidden in the GUI.AmbientConditions

AMBIENTDATA; A collection keyword for specifying the solid bundle ambient conditions.BundleComponents

COMPONENT; A component to place within the solid bundle definition.Output

PROFILEDATA; Defines variable names and time intervals for writing of data to the profile plot file. TRENDDATA; Defines variable names and time intervals for writing of data to the trend plot file.

ConnectionsThe CONNECTION keyword is used to couple network components, such as a node and a flowpath. Each flowpath has an inlet and an outlet terminal that can be connected to a node terminal. Boundary nodes (i.e. CLOSED, MASSFLOW, PRESSURE) has one terminal, while internal nodes has an arbitrary number of terminals where flowpaths can be connected to. CONNECTION TERMINALS = (FP_BRAN INLET, NODE_INLET FLOWTERM_1) CONNECTION TERMINALS = (FP_BRAN OUTLET, NODE_OUTLET FLOWTERM_1) Separator and PhaseSplitNode has special handling of terminals.

The CONNECTION keyword is also used for coupling signal components. CONNECTION TERMINALS = (FP_BRAN SOUR-1-1@INPSIG, SETPOINT-1 OUTSIG_1) See also connecting the controllers for more information.

Example fileThe keyword examples shown above can be combined to an OLGA .key file. CASE PROJECT="OLGA Manual", TITLE="Example case", AUTHOR="SPT Group AS" INTEGRATION STARTTIME=0, ENDTIME=7200, DTSTART=0.1, MINDT=0.1, MAXDT=5 FILES PVTFILE=fluid.tab MATERIAL LABEL=MAT-1, DENSITY=0.785E+04, CAPACITY=0.5E+03, CONDUCTIVITY=0.5E+02 WALL LABEL=WALL-1, THICKNESS=(0.9000E-02, 0.2E-01), MATERIAL=(MAT-1, MAT-1) NETWORKCOMPONENT TYPE=FlowPath, TAG=FP_BRAN BRANCH LABEL=BRAN-1, GEOMETRY=GEOM-1, FLUID=1 GEOMETRY LABEL=GEOM-1 PIPE LABEL=PIPE-1, DIAMETER=0.12, ROUGHNESS=0.28E-04, NSEGMENT=4, LENGTH=0.4E+03, ELEVATION=0, WALL=WALL-1 HEATTRANSFER PIPE=ALL, HAMBIENT=6.5, TAMBIENT=6, HMININNERWALL=0.5E+03 SOURCE LABEL=SOUR-1-1, PIPE=1, SECTION=1, TIME=0, TEMPERATURE=62, GASFRACTION=-1, TOTALWATERFRACTION=-1, PRESSURE=70 bara, DIAMETER=0.12, SOURCETYPE=PRESSUREDRIVEN VALVE LABEL=CHOKE-1-1, PIPE=PIPE-1, SECTIONBOUNDARY=4, DIAMETER=0.12, CD=0.7, TIME=0, OPENING=1.0 TRENDDATA PIPE=1, SECTION=1, VARIABLE=(PT bara, TM, HOLHL, HOLWT) PROFILEDATA VARIABLE=(GT, GG, GL) ENDNETWORKCOMPONENT NETWORKCOMPONENT TYPE=Node, TAG=NODE_INLET PARAMETERS LABEL=INLET, TYPE=CLOSED ENDNETWORKCOMPONENT NETWORKCOMPONENT TYPE=Node, TAG=NODE_OUTLET PARAMETERS LABEL=OUTLET, GASFRACTION=-1, PRESSURE=50 bara, TEMPERATURE=32, TIME=0, TOTALWATERFRACTION=-1, TYPE=PRESSURE, FLUID=1 ENDNETWORKCOMPONENT NETWORKCOMPONENT TYPE=ManualController, TAG=SetPoint-1 PARAMETERS SETPOINT=(2:0.1,2:0.2,0.3), TIME=(0,2000,2010,4000,4010) s, STROKETIME=0.0, MAXCHANGE=1.0 ENDNETWORKCOMPONENT CONNECTION TERMINALS = (FP_BRAN INLET, NODE_INLET FLOWTERM_1) CONNECTION TERMINALS = (FP_BRAN OUTLET, NODE_OUTLET FLOWTERM_1) CONNECTION TERMINALS = (FP_BRAN SOUR-1-1@INPSIG, SETPOINT-1 OUTSIG_1) ENDCASE

Simulation modelAn OLGA simulation is controlled by defining a set of data groups consisting of a keyword followed by a list of keys with appropriate values. Each data group can be seen as either a simulation object, information object, or administration object. Logical sections The different keywords are divided into logical sections: CaseDefinition; administration objects for simulation control Library; information objects referenced in one or more simulation objects Controller; controller simulation objects FlowComponent; network simulation objects Boundary&InitialConditions; simulation objects for flow in and out of flowpath ProcessEquipment; simulation objects for flow manipulation ThermalComponent; thermal simulation objects FA-models; administration objects for flow assurance models Compositional; administration and information objects for component tracking Output; administration objects for output generation Drilling; drilling simulation object OLGA Well; OLGA Well simulation object

Network modelA simulation model is then created by combining several simulation objects to form a simulation network, where information objects can be used within the simulation objects and the administration objects control various parts of the simulation. The simulation objects can again reference both information and administration objects. The network objects can be of the following types: Flowpath; the pipeline which the fluid mix flows through Node; a boundary condition or connection point for 2 or more flowpaths Separator; a special node model that can separate the fluid into single phases Controller; objects that perform supervision and automatic adjustments of other parts of the simulation network Thermal; objects for ambient heat conditions The simulation model can handle a network of diverging and converging flowpaths. Each flow path consists of a sequence of pipes and each pipe is divided into sections (i.e. control volumes). These sections correspond to the spatial mesh discretization in the numerical model. The staggered spatial mesh applies flow variables (e.g. velocity, mass flow, flux) at section boundaries and volume variables (e.g. pressure, temperature, mass, volume fractions) as average values in the middle of the section.

The figure below shows a flow path divided into 5 sections.

Each flowpath must start and end at a node, and there are currently three different kinds of nodes available: Terminal; boundary node for specifying boundary conditions Internal; for coupling flowpaths (e.g. split or merge) Crossover; hybrid node for creating a closed-loop network The figure below shows a simple simulation network consisting of three flowpaths and four nodes.

The flowpath is the main component in the simulation network, and can also contain other simulation objects (e.g. process equipment, not shown in the figure above). It is also possible to describe the simulation model with a text file. See Input files for further descriptions.

IntroductionWith OLGA 5 a new graphical user interface (GUI) was introduced that replaced the OLGA 2000 GUI. OLGA 6 uses the same GUI as OLGA 5 with some additional features. The main new features in the OLGA 6 GUI are: Plot configurations (variables, colours, etc) may be saved as templates for easy recreation of plots Graphical configuration of signal network (controllers) New graphical configuration of Bundles New utility for running cases in batch (without having to start the GUI) The main new features of the OLGA 5 GUI compared with the OLGA 2000 GUI are: Graphical configuration and visualization of complex networks with Drag and drop Graphical copy paste Automatic detection and classification of internal nodes Positive flow direction can be indicated on flow path Pressure boundary nodes are distinguished Network coupling table with configuration capability Design time verification of model and listing missing items Errors are detected while the model is created Action buttons for missing items GEOMETRY Editor with spreadsheet type input Copy directly from Excel Both XY and Length-Elevation input are displayed. Automatic Sectioning without simplification Direct access to simplification procedure with new angle distribution details Automatic inversion of pipe profiles which facilitates e.g. annular models

New Plotting Functions Select variables from a complete list with descriptions Make your own standard sets of variables with units Within a graph - copy directly to and from Excel Spreadsheet type input and visualization of input series New Parametric study function New RESTART function Context sensitive help

New ProjectA new project is defined by: Select File/New/Project Ctrl+Shift+N Click the New Case icon

or New Project at the base of the Start Page.

When starting a new project a new folder can optionally be created by checking the Create folder box.

New caseA new case is defined in one of the following ways: Select File/New/Case (you will be taken into a dialog to create a new project if not already done) Ctrl+N Click the New Case icon Then, the window below appears:

Enter a case name (or use default), fill in location (or use default) and select template. OLGA Case File. This generates an empty case. OLGA Basic Case. This generates a complete basic case. Ready for simulation. OLGA Network case. This generates a complete basic case with an internal merge node.

Open existing caseYou may open an existing Project, an existing OLGA case or an existing OLGA 2000 case (*.inp). If you open an existing case after you have opened or created a project the case will be added to the project. However, if you open an existing case without having a project, a project with the case name is created. You should save this project immediately. Open project Select either of these: Select File/Open/Project Ctrl+Shift+o and open a file with extension .opp. Open case Select either of these: Select File/Open/Case Ctrl+o Click the Open Case icon and open a file with extension .opi, .key or .inp.

Start pageWhen opening the OLGA graphical user interface the Start page will appear. The central window contains a list of recent projects and the date when they were last modified. A project can be opened by double clicking on the case name. A new project can be started from the New Project button at the bottom of the screen.

See also Moving windows, Hot keys, Moving view in 3D, Menus, Toolbars or Properties and settings

Model view

The Model View is used for navigation between the objects of the system. The objects are ordered hierarchically with a Project on top comprising one or more cases. A case contains Case Definitions, Libraries, Output, Network Connections and Network Components. Case Definitions describe information common to the whole system simulated. Network Components describe the properties of the flow network (currently either a node or a flow path). Libraries contain keywords that can be accessed globally (for instance Material and Wall). Output contains global output definitions, such as plotting intervals for trend, profile and output. FA-models contains input to flow assurance models. Compositional has input to the compositional model. Advanced thermal contains input to the FEMTherm and bundle models and input to annulus calculations.

When selecting an object in the project explorer, the object is made active and its properties may be edited in the Properties view. The model view contains input for all cases in the project. Switching between the different cases is done by clicking on the file name in model view.


File viewThe File View shows the input files of the project. By right clicking on a file the file can be removed or opened. If the file is a .opi-file (case-file) you get the option to open it as a text file. The text file is the OLGA 6 .keyformat which resembles the OLGA 2000 inp-format. You may edit the key-file, save it and then reopen the case from the edited key fileby selecting 'reload from text file'

See alsoMoving windows, Hot keys, Moving view in 3D, Menus, Toolbars or Properties and settings

Component view

Simulation objects may be fetched from the Components window by Drag&Drop onto the Graphical Editor. Only objects available at the network level presented are available. This means that e.g. process equipment can be introduced this way only when the Flowpath is open.


Property editorThe Properties window is a common interface to all simulation objects (keywords). Here the objects are defined setting values on the different keys. The left column gives the property name (currently the key name), the right its value. Units may be altered as shown in the figure. By default the value will update when the unit is changed. To keep the value: Press the Shift key while changing the unit. When a property is selected, a description is shown in the field at the bottom. Values may be inserted by typing or by selecting one or several values presented by the interface. The colours of the keys are the following meaning: Black : Key can be given but not required. Red : Key required. Grey : Key can not be given. Note that the colours will change as input is given. As an example: Two keys are mutually exclusive and one of them must be given. Both will then initially be red (required). When a value is given for one of the keys its colour will change to black (key is given and no more input required for that key) while the other key will turn grey (can not be given).

Some keywords have a special property page to make the process of entering data easier. These property pages can be accessed through the property editor button at the top bar of the property editor window.


Network viewBelow you see a snapshot from the GUI with the template case Case0 loaded. All the windows are described in the following sections. The windows may be moved around (outside or inside the frame) and may be docked as described in Moving windows .

Click left button on canvas and use mouse wheel to zoom in/out

The central view in the figure above shows the Network view with its Graphical editor functions. Zooming in and out is done by the mouse wheel. Moving the mouse while the left mouse button is held down will move the layout within the window. Pressing Q adjusts the graphical view to the frames. Holding Shift and pressing Q zooms out in steps. Focus is shifted away from selected objects by pointing to the background while holding down the Shift key. Nodes and flow lines are drawn schematically. Network components (Nodes and Flowpaths) can be dragged into this view from the Components window. Sources,

Pressure boundaries and Process equipment are visible and their properties may be entered or modified by selecting the object (left-click) and filling in their "Properties. In the figure the properties of the NODE OUTLET are shown to the right.

The window above is the 2-dimensional Flowpath view which shows one Flowpath at the time. The functions for "moving" the graph are the same as for the Network view, see flowpath view for more details. You can drag equipment to the canvas from the Process Equipment Components on the left. When e.g. a valve is dropped on the canvas it "attach" to the middle of the Flowpath as illustrated below. The actual position and other data for the valve can be entered in the Properties window for the Valve which now is in focus (to the right). By entering the data e.g. the PIPE and SECTIONBOUNDARY the valve will take its specified position on the Flowpath.

Each graphic view has its own tab and if you click on the Case0-tab (see below) you get back to the Network view.

We shall show how you make a new Flowpath: Start with dragging a Node from the Components window and drop it on the canvas, see above.

Then you make a new Flowpath by following the instructions in the drawing below:

The new Node and Flowpath also appears in the Model View window, see below:

An alternative method for adding a Flowpath. Select the Components window

Select a FLOWPATH and drag it to the canvas. Then drag a new node to the canvas.

Then do as illustrated below.

Re-configure the network:

Connecting Nodes and Flowpaths can be done as follows: Point to the red dot at one end of a Flowpath (the red dot indicates that this end of the Flowpath is not connected). Hold down the right mouse button, initially pointing to the blue square that has appeared at the end of the Flowpath. Move the mouse pointer to the Node which the Flowpath should be connected to and release. Select connect from the pop-up box that appears. The dot at the end of the Flowpath turns green, indicating that a connection is established. Alternatively: Right-click on the view background and select Network Connections. Select the "from-to" nodes for each Flowpath and click OK. The network should appear as specified.

Select Red dot on Flowpath

Right-click within the blue square and move pointer towards NODE_0. Select Connect to and release mouse button.

Do the same with the other end of the Flowpath.

Disconnect a Flowpath from a Node by left-clicking on the Flowpath and then point to the green dot at the end of the Flowpath. Hold down the left mouse button while moving the end of the Flowpath away from the node and release. The dot at the end of the Flowpath should now be red, indicating that it is not connected.

Left-click on Flowpath, select green dot (left-click) and drag endpoint away from Node.

Right-click while pointing to an object in the Network view brings up various menus depending on the object: - Add : Add items to the network object. - Verify : Checks input file and reports errors and missing input in the output window. - Copy : Copy selected item. - Paste : Past the copied item onto the currently selected item. - Delete : Delete selected object. - Properties : Starts property editor for selected object. For a Flowpath this would be to Geometry Editor while for other items it would typically be a time series editor. For example: pointing to a Flowpath gives the alternatives below.

Text labels in the Network view (which reside in their separate text boxes) can be rotated and scaled in addition to moved (except those for Flowpaths). Move is the default edit mode. You can either select the edit mode on the toolbar

or you can type one of the following letters to change the edit mode for the selected text box.

s:

Scale: (left-click in the triangle and drag while keeping the mouse button down)

r:

Rotate: (left-click in the sector and drag horizontally)

m:

Move: (left-click in the square and drag)

You can add fixed points on a Flowpath by pressing Ctrl while double-clicking anywhere on it. A fixed point, indicated by a small square, appears on the Flowpath.

The fixed points can be moved to shape the Flowpath (this does not change the actual geometry of the Flowpath).

More points are added by repeating the Ctrl double clicking. You remove the fixed points by Ctrl double click within its blue square. Right-click in the Network view activates a menu with the following items:

Copy as picture: Network Connections:

A "Case.jpg" file with the Network view is copied to the folder where the project resides. Opens the network overview/connection window

Network plot allows for a quasi-animated plotting of profiles in the Network view.

Configure:

Allows for (re)configuration of e.g. colours and line interpolation.

3D View described in Moving view in 3D . Show directions Direction arrows are displayed on each Flowpath.

Changes to 3D view as


Flowpath viewThe actual profile of the geometry may be viewed by opening the Flow path; double click FLOWPATH in the Model View. This opens a new tab in the Graphical Editor

showing the selected flow path only (including equipment). In the Flowpath view equipment may be added by drag and drop from the Components window (the available components are now the ones that are located on a specific Flowpath).

Focus an object by a left mouse click to bring up the Property editor, and the properties of the object can be entered or modified.

Focus is shifted away from selected objects by pointing to the background while holding down the Shift key. Zooming in and out is done by the mouse wheel and moving the mouse while the left mouse button is held down will move the layout within the window.


Connection viewThe connection view is used for showing connections for a single component or all connections in a case. The connection view can also be used to create new connections. The connection view has two modes. The above figure shows connections for a selected component. When a component is selected, all terminals for the component is shown in left column in the view. The column "Connected NC" shows the name of the network component which is connected. The column "Connected terminal" shows which terminal is used on the connected network component. In a signal connection a variable is given. This variable is shown in the column "Variable". Creating a new connection for a selected component: 1. Select a network component from the column "Connected NC". Only network components with compatible terminals are shown in the list of available network components. 2. Select a terminal on the component from the column "Connected Terminal". After selecting a terminal, the connection is made. 3. Select a variable (only for signal connections) from the column "Variable". The other mode is for showing all connections in the case. In this mode it is easier to see the direction of the signals (see figure below) Creating a new connection when showing all connections: 1. Select a network component in the column "From". 2. Select the out-signal (terminal) from this component in the column "Out". 3. Select a network component to receive the signal in the column "To". 4. Select the in-signal (terminal) in the column "In" 5. Select a variable (only for Transmitters) from the column "Variable".

Output windowThe output window (not to be confused with the OUTPUT keyword/OUTPUT File) gives information about the state of the cases, modeling and simulations. The information comes out three categories:

Error messages (and task list) : Cannot simulate o Errors in input o Errors from initialization phase o Errors during simulation o List of incomplete keywords. o Click on the symbol to go to the incomplete keyword. Warnings - : The simulation may still be performed [1] Information o Simulator state changes o Progress during simulation

o

Any messages during simulation (info previously directed to DOS window)

The windows can be cleared from the context menu (right click). Text can be copied: Mark text Right click and copy

Which Output categories are active are indicated by the "orange" background around the category names in the top bar of the output window. A left mouse click on the text will activate and deactivate.

By default the output from the active case is shown. Output from other cases is selected from the pull-down menu at the top of the output window.

[1] Warnings from the OLGA interpretation of fluid files which takes place when the simulation has started are categorized as Information


Time series editorInput keys that have time series can be edited in a time series editor. The time series editor is accessed through the properties for the relevant keyword.

If there are several independent time-varying parameters within one keyword the graph of these can be displayed by checking them in the graph legend (which shows the minimum necessary input parameters).

You can insert columns in the spreadsheet by right-clicking on a column-header, see below.

Selecting "cancel" nullifies all actions performed within the time series editor.

A trick: to fill in the same value for several time points: enter the value in the column for the last time-point and then enter.


PlottingTrend and profile plot output as defined by the user can be viewed during and after simulation. The plotting buttons on the top menu will show red lines when plot files are available for the active case.

TREND Plot PROFILE Plot Plot PVT file Multi-case plotting General features of the plotting tool Export/import data


Active case trend plotSelect trend plot with the buttons in the top menu. Trend plot gives you the menu below. Select the variables you want to plot. Move the selection over to the upper right hand side window where you may change units. Click OK to see the graph.

The default time unit for a Trend plot is Seconds which you change at the lower left.

Active case profile plotYou select the profile button and then select variable(s) to plot:

You may now "play-back" the profile plot, either by dragging the slide or by clicking the green triangle. You may also freeze a curve by clicking the "needle"

button.

You get a frozen curve each time you click it. You "un-freeze" by disable the needle profiles simultaneously, but the speed will of course depend on your PC-capacity.

. The play-back is stopped by clicking the blue square. You may play-back several

Fluid propertiesYou can use the plot-tool to plot fluid-properties. Select PVT file plot with the buttons in the top menu (.tab). You then select the property or properties you want to see and proceed as usual.

You may use the freeze-function as for profile plots. You click the nail and then the green triangle. You repeat clicking the nail to freeze more curves. The default x-axis is temperature. You can change this by moving the column header fields in the right-hand side window to locate the "X-Axis" field (which is in the far right position by default) and select Pressure instead of Temperature.

Multi-case plottingIt is possible to plot results from several cases/projects simultaneously. For example you can plot data from all the cases in your project (use the Plot Project button in the select variables dialog), the in-active as well as the one active. You can open several results files by the Tools -> Plot menu (select several files, either trend (.tlp) or profile (.plt) or from within the plot tool itself by adding files, see below. You plot as for single cases.

Note that for profile plots where different plotting intervals have been used in the different files the profile closest to the selected time will be used and no interpolation is currently applied.

Some general features of the plotting toolThe plotting tool is a quite sophisticated program and you have access to several functions for modifying your graph Add/remove data to plot: o Right click and select Dataset /Select or o Menu Options/Select Plot Variables View values: Right click and select Track values For profile plots: select plot time point with slider at bottom right Collapse/expand axes: Right click and select o Axes/Collapse all or o Axes/Expand all Display legend: Right click and select Show legend Modify settings o Right click and select Configuration (window as below) or o Menu Options/Configuration Zoom: o o o Select upper left corner with left mouse button Drag to lower right corner while holding button Release

Un-zoom: Do as for zoom, but drag to the left (any start and end point works) Zoom in/zoom out/un-zoom buttons are also available

Export/import data to/from MS ExcelExport data: In the Select variable dialog, mark the variables that you want to export and then press the Export button. The marked variable data are then copied to the clipboard and can easily be pasted into MS Excel. Some examples are shown below. Paste from Excel: Select data columns in and select copy. In Plot window right click and select Dataset->Paste. Trend:

All the variables marked in the selection dialog are copied to separate columns in the Excel-worksheet. Profile:

When exporting profile variables, there are some options. First, choose the points in time that are of interest. Secondly, choose the output grouping. On time copies the variables sorted on time, while the On variable option copies the variables sorted on variables. See examples below:

Showing data sorted on time

Showing data sorted on variable

Parametric StudiesParametric studies are defined through Tools-Studies, where new studies can be added or previously performed studies reopened.

The input screen for parametric studies is shown below.

The number of parameters is given in the field labelled "#Parameters. At present studies can only be performed on the local machine, but the number of simultaneous simulation can be given (#Parallel simulations). This can be useful for machines with multiple processors or multithreading.

The quick way to enter an equidistant parameter variation is given below:

Right-click in MASSFLOW below and select Set Value(s)

Set the e.g. the values below:

This results in the definition of 4 cases ready for running. You may save the study by clicking OK. The study is saved in a separate folder together with the Project/Case.

Click Run Study and observe the progress:

For more information on XY-plot and Matrix see the Tutorial (accessed from the Help menu).

Geometry editorActivating Enter a new profile Edit Geometries Edit the table Edit the graph Check angle distribution Filter the data Complete the data Define sectioning Use the new geometry Menus Limitations


ActivatingPipeline profiles are edited in the Geometry Editor. The tool can be started like this: Tools/Geometry Editor (opens with only default data) or Select the Property page for the active geometry (opens with data for the selected geometry)

You may also select FLOWPATH (or GEOMETRY) in the Model-View and right click and then select Properties:

You will now see this graph of the default geometry for the single branch template:

Enter a new profileYou can work with an existing profile in the .xy-format by File/Import and opening the relevant xy-file with the browser (e.g. Profile-A.xy - this Geometry is given below).

You should save this new Geometry with a new label while in the Geometry Editor (e.g. GEOM-A. The saved geometry file has the extension .geo:

You must also give the new Geometry relevant sections, diameters, roughness and walls. How to do this is described below. You can also copy directly from an Excel worksheet: Open the Geometry Editor and select File New. You will get a new Geometry with one pipe and default values as given below. The geometry is now presented in a tabular format and you can toggle between this and the graphic format by clicking on the relevant tab.

Open the Excel-file with your profile-data, select the X-Y columns and copy.

Select the Start Point 0, 0 in the Geometry Editor with the default geometry open and then Paste. You will get the question below. Answer yes and the data will be pasted directly over to your open geometry.

Please observe that if your excel geometry contains fewer pipes than the one you paste over you must delete the obsolete pipes. You can now save this Geometry (e.g. GEOM-B) and use it for one or several Flowpaths in any model. First you must of course complete it with sections, diameters etc., see below.

Edit GeometriesWhen opening the Geometry Editor you have seen that two views are available i.e. the graph of the profile and a table of pipes. The two windows can be viewed simultaneously by selecting the e.g. plot tab and drag it towards the bottom of the window (as has been done below).

See alsoEdit the table Edit the graph Check angle distribution Filter the data Complete the data Define sectioning Use the new geometry

Edit the tableNew pipes are added, renamed or deleted, by right-clicking in the Pipe column and selecting the relevant action.

X and Y in the table give the data for the end point of the pipe. Changing Length-Elevation affects X-Y and vice-versa. Units are changed by right clicking in the title cell (e.g. r;Diameter [m]) and selecting a unit.

Edit the graphYou can also edit the Geometry by the following actions under the Actions menu:

Normal (no change) A: Add a point M: Move a point D: Delete a point

Restrictions on the graphic editor can be imposed (Actions -> Restrictions):

X Fixed (X remains fixed, Y can be changed) X Bound (Point X-value can not be moved upstream or downstream neighbors) Y Fixed (Y remains fixed, X can be changed) Y Bound (Point Y-value can not be moved above or below neighbors) Recursive (all points downstream will follow the point that is being moved)

Check angle distributionYou can check the angle distribution of a Geometry by selecting Tools -> Check angle distribution. You can see the angle groups that are used by right clicking when in the output window from the angle distribution calculation. You can also change the angel groups. The colour of the bars and the % values in the output window indicate the difference between the average angle of the pipes within a group and the mean value of the angle group. Green (and a low % deviation) means a good relevance of the angle group. The % value is a numerically calculated standard deviation divided by half of the angle group span.

Filter the dataSelect Tools/Filter. You have two options: a Box filter or a preservation of angle distribution / total flowpath length (the algorithm is identical to the one used in the OLGA

2000 Grid Generator). Box filter: This filter is more relevant for removing relatively small disturbances from a pipeline survey. Enter the horizontal sample distance and the vertical sample height. These values define a moving rectangle (a box) within which all data points will be filtered out. The filtered data appear as a new geometry which may be further filtered/edited. Angel distribution: Enter the maximum pipe length that shall be used to filter the profile while maintaining the angle distribution and the total pipe length. When filtering has been completed it is a good idea to compare the angle distributions of the original geometry and the filtered ones. The filter with the best reproduction of the original geometry should be used keeping in mind that the angel groups should be representative.

Complete the dataYou may want to open the e.g. GEOM-A.geo file. All fields except the r;Length of sections are editable directly, and copy/paste may be used for single cells. The "Length of sections" has its own input support-tools In contrast to OLGA2000 all Pipes must have a Diameter, a Roughness and a Wall (if relevant). You can use copy-paste functions to achieve this. If defined in the OLGA case, walls may be selected from the drop down menu. Within the Graph window the profile may be edited activating either of the four menu functions (found under Actions -> Graphical):

Define sectioningThe pipe sectioning can be performed in two ways: 1. 2. Manually enter number of sections in the r;# Sections column. This gives you equally long sections for a given pipe. If you double click in the Length of Section list you enter a tool to distribute sections of various lengths over the pipe-length.

Change (the nominal) no of sections to 3 and enter 4.75 m in Section 1 and click OK.

You get 2 sections of 4.75 m and 1 0f 4.64214 m.

The main rule is that the tool ensures that you get a sum of sections which is equal to the pipe length. Moreover, open section lengths mean that you repeat the value above. The "remaining of total" is the total pipe length minus length accumulated over the section lengths specified (including the open ones).

If you double-click in the Length of Sections field again

You get the window below and you see that the remaining now is very close to zero.

To start over again you can set # of sections to 0. 3. Use the discretization tool (Tools/Discretize). Then all pipes are given the same selected number of sections.

Use the new geometryA new geometry may be imported to a case as follows: Open the geometry files you want to use (you can open them from the Geometry editor or in explorer) Right click on FLOWPATH or Piping in the Model View, select r;Exchange Geometry and pick the desired geometry. If you use the same Geometry file for several branches you must re-label the Geometries afterwards to secure that the labels are genuine. You can also exchange geometries between flow paths in the same case. Select the flow path and its Property Page of the Geometry you want to distribute to other flow paths. Then you select the flow paths that you want to import to and select Exchange Geometry. Select FLOWPATH and click on Properties. This opens the Geometry GEOM-1_2

Select destination FLOWPATH and click on Exchange Geometries and then on GEOM-1_2.

MenusThe Geometry Editor features the following menus: File New Import Open Close Save Save As Print Print Preview Print Setup Send Exit Edit Undo Cut Copy Paste Configure View Standard Restrictions Graph Status Bar Labels Actions Graphical Normal/Add/Move/Delete Restrictions X Fixed/X Bound/Y Fixed/Y Bound/Recursive Tools Angle groups Check Angle Distribution Check section lengths calculate the length ratio of adjoining sections. Discretize Automatic pipe sectioning (all equal) Filter Filter data Reset Pipe Labels Use default pipe labeling Reverse geometry Creates a geometry that is the mirror image of the original geometry (in x-direction). Window New window New window with active data (works on same data set) New window Select graph or table representation New Horizontal Tab Group New Vertical Tab Group More Windows Help Help Topics Not implemented About Geometry Version Information New geometry Import xy-data Open geometry file (*.geo) Close geometry Save geometry Save geometry as new file Print active window

Configure graph window

LimitationsThe following important limitation applies: 1. For export to Excel, dot (r;.) must be selected as decimal separator for Excel

Moving windowsWindows may be hidden and re-opened through the view menu. They may be detached from the frame (floating) and may be docked again by moving the window to the border of the frame. Double click on a floating window to move it back to the last docked position. In the picture below the blue area indicates where the window will end up if dropped at the current location. If the cursor is moved over one of the arrows towards the edge of the screen the window will dock on the corresponding border of the frame. If dropped on one of the four arrows in the centre of the screen the window will dock towards the corresponding side of the frame of the pipeline schematic window. Double clicking on the top bar of a docked window makes it float and double clicking on the top bar of a floating window makes it dock.

Hot keysCtrl+z z Leftshift+z Mouse wheel Delete Undo Enable zoom in graphical editor; mark area with mouse Enable un-zoom in graphical editor; mark area with mouse Zoom in or out in graphical editor Deletes object

Moving view in 3DThe following illustration shows how to navigate the camera in fly mode. In Orbit Mode left mouse button + moving the mouse will make the camera orbit around the pivot point. If you release the left mouse button you can use the key combinations to move around. Camera maneuvering: Mouse wheel Arrows Right shift Left shift Left mouse button Zoom in/out Move camera in/out/left/right Move up Move down (or: Insert move down) No selection: Rotate camera Network selected: Rotate network (see below)

Camera Movement Speed Slow to Fast Keys 1 9 Rotate/Move/Scale Rotate Move Scale Select object + key R+ left mouse button + move mouse Select object + key M + left mouse button + move mouse Select object + key S + left mouse button + move mouse

Scene View Shortcuts Fly Mode Key F Orbit Mode Key O Field of View Mouse wheel, or key Z + left mouse button + mark area, or key Z + left mouse click (zoom in) Left Shift + key Z + left mouse click (zoom out) Space Deselect interaction mode Escape Deselect objects Q (in 2D View) Zoom to extent Delete [Del] Delete selected object.

Graphic ConfigurationThe graphical layout of individual flow paths can be changed through the Graphical configuration dialog. The choices made her will affect only the selected flow path.

If one want to change the layout of all the flow paths, this can be done in Tools -> Options ->Graphics.

MenusFileNew > Project... New > Case... Open > Project... Open > Case... Save Case Save Case As... Duplicate Case... Save Project Close Project Print... Print Preview Print setup... Recent projects Recent cases Exit Create new project Create new case Open project Open case Save case Save a new case Makes a copy of the selected case Save project Close (and save) project Disabled Disabled List of projects recently opened List of cases recently opened Exit

EditStandard windows commands Undo Redo Cut Copy Paste Paste special...

Disabled Disabled

ViewSelect what windows and toolbars to be visible.

ProjectAdd New Item... Add Existing Item... Project Dependencies Close Project Same as New Case Open an existing file e.g. an .opi file Option to specify the dependencies between the cases

SimulationRun Stop Pause Start simulation (Start simulation in batch- messages from simulation are sent to the Output window) Stop simulation. Returns to initial state Pause simulation. Simulation may be resumed (Not implemented for OLGA).

Run Project Run Batch Run Project Batch

Start to run all cases in a project in a given order Start simulation in a DOS-control window. Start to run all cases in a project in a DOS-control window

ToolsThe tools available are listed below.

WindowsStandard windows operations.

HelpHelp topics GUI Manual Tutorial About OLGA OLGA User Manual Opens OLGA GUI USer Manual (pdf). Starts OLGA 6 Tutorial Release information

ToolbarsStandard

New case Open case Save Save Project Copy Paste Undo Redo Model view Property editor Components File view Output view Connection view

Saves Case

Disabled

Simulate

Run Stop Pause Run Batch Verify

Start simulation Stop simulation. Returns to initial state. Disabled Run batch in DOS window Verify case

Plot

Plot current trend plot Plot current profile plot Plot current PVT file View current Output File

Layout

Fit window Move Moves a graphic object Scale Scales an object Rotate Rotates an object Circular For systems with defined Grid Nodes placed in grid Hierarchical type 1 Hierarchy Hierarchical type 2 Hierarchy Radial For systems with defined center V Layout algorithm direction is vertical. H Layout algorithm direction is horizontal. Layout of equipment Toggle between relative and sequential layout of inline equipment Snap to grid Toggle snap to grid

Properties and settingsThe overall simulator settings are specified under Tools->Options; making it possible to work with different simulation engines under the same GUI (this includes OLGA 2000 versions as long as it accepts the keywords you actually use). Settings under the General tab are: My Project locations: Location where file dialogs will open. Show start page at start-up: If applied - start-page with recent projects will appear when starting the GUI. A sub-setting is "show the project list on the start-page". Use cached static data: This is set by default during installation. The GUI will then store certain data the first time the simulator is started. This speeds up file loading and is recommended to obtain the best performance from the program. The General tab can also be used to specify if the program shall execute auto-save at specified intervals. In the OLGA version tab one can specify which version to use by marking one of the displayed versions. External programs that should be available from the Tools menu can be specified under the External Tools tab. Some programs are set by default during installation and the user can specify additional programs like Excel, a text-editor etc. The Graphics tab is used to specify the pipeline layout view: Turn the background grid on and off and specify the colours of the gridlines. Set the canvas colour. Choose the interpolation method for the flowpath lines. Set flowpath colour.

Simulation with bundlesThis description covers Fluid Bundles, Solid Bundles and Annuluses. In OLGA 6 these bundle types are network components. In this chapter the simulation of bundles is illustrated by a SOLIDBUNDLE example. To add a SOLIDBUNDLE right click the case level tab and choose Add > ThermalComponent > SOLIDBUNDLE (see figure below).

When the Solid Bundle is added, go to the property window and specify the required fields: DELTAT and DTPLOT. These parameters govern the frequency of updates of output from the FEMTherm computation (i.e. the computation of temperatures in the solid). The LABEL and MESHFINENESS fields may also be updated. A bundle in OLGA 6 consists of several components. The components of the bundle are flowpaths, shapes and possibly internal bundles. Note that all the components that constitute the bundle must be defined (added) elsewhere. Flowpaths and Lines must be defined as FlowComponents, Shapes must be defined under Library and bundles must be defined as ThermalComponents. Position labels to use for the specification of TO and FROM must be defined for each flowpath under "Piping".

To add a component to a bundle (i.e. to specify that it is a part of the current bundle) choose Add > BundleComponents > COMPONENT in the Model View as shown in the figure below.

In the property window for the new component, specify the required fields: The type of the component (specify either a FLOWPATH, a LINE, a FLUIDBUNDLE, an ANNULUS or a SHAPE) The start and stop position of the Bundle (TO and FROM) The geometric center of the component (XOFFSET and YOFFSET) The OUTERHVALUE of the component (optional) Note that the position of the origin of any cross-sectional coordinates is irrelevant as long as all coordinates within one and the same bundle refers to the same coordinate system. It is only the relative cross-sectional position that matters.

About SHAPES A SHAPE in OLGA 6 defines the circumference of an area where a cross-sectional temperature profile may be computed by the FEMTherm module. Within this area heat is assumed to be transported by conduction in the radial direction. To add a SHAPE to a case right click the Library in the Model View and choose Add > SHAPE. In the property window for the new shape, fill out the type of the shape (CIRCLE, ELLIPSE, RECTANGLE, POLYGON) and the material. For any type of SHAPE the layout of the cross-section must also be defined. As illustrated by the property window to the right, a Circle requires the specification of a radius, an ellipse requires a width and a height, a rectangle requires the specification of coordinates of the lower left and upper right corners, and a polygon must be defined by a series of coordinates.

About LINES A LINE in OLGA 6 is a flowpath for which a simplified one-phase computation is performed. LINEs can be connected in networks, just as regular flowpaths can, but in a LINE network all the network components must have the parameter LINE set to YES. A complete case may contain several LINE-networks and several multiphase networks, but the two types of networks can not be coupled to each other. To add a line to a case in the GUI, right click the FlowComponent in the Model View and choose Add > FLOWPATH. In the property window for the new flowpath select LINE=YES. Then select FLUIDTYPE (gas, oil or water). Connect the LINE to a node in the same manner as other flowpaths are connected. Note, however, that the connected nodes must also have the parameter LINE set to YES.

About CROSSOVER nodes A CROSSOVER node in Olga 6 is a special type of single phase node which can be used in LINE networks only. The CROSSOVER node is a pressure boundary node with the following additional features: It must be connected to two LINES, and it imposes a given pressure difference (called MAXPRESSUREBOOST) between these two lines (at the connection point). A crossover node is added to a case in the same manner as any node is added: right click the FlowComponent in the Model View and choose Add > NODE. In the property window for the new node select TYPE=PRESSURE and LINE=CROSSOVER, then enter the rest of the required fields.

Simulation with ControllersIn OLGA 6 the controllers are signal components. Signal components are a special kind of network components, able to transfer signals between each other. Coupling in the signal network is possible between the following components (notice that a controller is always involved): Pipeline section variable (via a transmitter) to controller Inline component (ex. valve, pump, compressor etc.) to controller Sources (source and well) to controller Node variable to controller Separator variable to controller Controller to controller Controller to inline component Controller to separator Controller to source This chapter describes how to connect signal components in the GUI. Signal network terminology The following explanations of the terminology used for signal networks can make it easier to understand how controllers are connected to other components. A signal component is a component that can send and/or receive a signal. A signal component (e.g. a controller) is connected to other signal components (e.g. a flowpath) via terminals. Terminals are best explained with an example; A PID Controller has 3 terminals, 2 for receiving signals (the setpoint signal terminal and the measured signal terminal) and one for sending signals (the output signal terminal). Another signal component like a separator can send its holdup value as a signal to the PID Controller. The holdup will be sent via the measured signal terminal of the controller. The PID Controller will calculate an output signal based on the measured value and send it via the output signal terminal to e.g. a valve. A signal is just a value. There isnt much difference between a signal in a signal network and a flow in a flow network. The flow represents a physical flow of oil, gas or water while the signal can represent anything. The meaning of the signal to the signal component depends on which terminal that is used to send the signal. In the example above the signal represented a measured value since it was sent via the measured signal terminal. A flowpath may send measured values as signals. To do this one must add a transmitter to the flowpath. The transmitter acts as an output signal terminal for the flowpath. Most inline process equipment added to the flowpath can act as a signal terminal for the flowpath in the same way as a transmitter (you may for example connect a controller directly to a valve). Graphical configurations of controller connections Coupling of signal components is possible with two different techniques in the graphical user interface; i) Coupling with drag and drop - or ii) Coupling through the connection view Drag and drop coupling The drag and drop coupling between two signal components is done in the same manner as between two multiphase network components: 1. Click a component and drag towards another component in the signal network (see list of legal couplings above) 2. Release on the second component. A context menu is shown with available terminals to connect from and to

3.

Choose one of the available terminals to connect from (only OUTSIG_1 is available in the figure above) and a terminal to connect to (MEASRD and SETPOINT is available in the figure above). A connection between the two components is created.

4.

Select variable to transmit. If the coupling is between a transmitter and a controller, a variable to be transmitted has to be given. Setting this variable must be done in the connection view

Coupling using the connection view The drag and drop technique for coupling components in the signal network is less practical when the case is large with many components. Dragging from one component to another may involve zooming to view both components, and thereby making the coupling difficult. It is possible to connect signal components using the connection view without seeing the other components. In the figure below the connections for a PID-controller is shown. All terminals (in-/out-signals) for controller CNTRL-1 are listed in column one (Terminal). Column two (Connected NC) and three (Connected terminal) lists which network components and terminals the controller is connected to. If a user-chosen variable is supposed to be transmitted column four (Variable) is us

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