Presentation:1.PIPESIM Basics:

1. PIPESIM File Naming and structure2.Single Branch Model Basics (Iteration

Options).3.Building a Model.4.Description of PIPESIM Model

Components.5.Single Branch Operations.

PIPESIM Single Branch Model:

1. PIPESIM File naming.

File naming GUI input files

xxx.bps PIPESIM input file (single branch) xxx.bpn PIPESIM input file (network) xxx.pgw input file xxx.pvt Fluid Property PIPESIM-GOAL input

file xxx.fpt FPT input file

Output file xxx.out Output file xxx.sum Summary file xxx.plt Job plot (1 data point for each case) xxx.plc Case plot (1 data point for each

node)

2. PIPESIM Single Branch Model Basics:

Iteration Options: PIPESIM is a steady state multiphase flow

simulator.

PIPESIM performs simultaneous pressure and temperature calculations. It has three fundamental iteration options (with inlet temperature always defined):• Non-Iterative

Pin and Qin known, calculate Pout

• Iterate on PressureQin and Pout known, calculate Pin

• Iterate on FlowratePin and Pout known, calculate Qin

Solution algorithm Solution computed in flow direction Each pipeline is divided into a number of

segments determined automatically Pressure and energy balances in each

segment Fluid physical properties are calculated at

averaged conditions across each segment

Flow regime determined from gas and liquid superficial velocities

3.Building a Model:

Building a model

Define objects in the model, i.e. well completion, tubing, etc using the toolbox

Enter physical data, i.e. tubing ID, etc. Enter fluid data: black oil/compositional Set boundary conditions Select an operation

Single branch toolbox

POINTER

CONNECTOR

MULTIPLIER/ ADDER

NODEHORIZONTAL COMPLETION

TUBING

VERTICAL COMPLETION

REPORT TOOL

NA POINT

COMPRESSOR

EXPANDER

PUMP

SEPARATOR

HEATER/ COOLER

CHOKE

RISER

FLOWLINESOURCE

KEYWORD INSERTER

INJECTED GAS

ANNOTATION

BOUNDARY NODE

MULTIPHASE BOOSTER

4.Description of PIPESIM model components:

Well completion models

Well PI (Oil & Gas) Vogel Equation (Oil) Jones (Oil & Gas) Fetkovich Equation (Oil) Back Pressure Equation (Gas) Pseudo Steady State (Oil & Gas) Forcheimer’s Equation (Gas & Condensate) Hydraulic Fracture (Oil & Gas) Transient (Oil & Gas)

Inflow performance relationships Oil Reservoirs:

Well Productivity Index Vogel Equation Fetkovich Equation Jones Equation Pseudo-Steady-State

Equation Hydraulic Fracture Transient

Gas and Gas Condensate Reservoirs:

Well Productivity Index Back Pressure Equation Jones Equation Pseudo-Steady-State

Equation Hydraulic Fracture Forcheimer Transient

Well productivity index (PI)

For LiquidQ = PI x (Pws - Pwf)

For gas compressible reservoirs Q = PI x (Pws

2 - Pwf2)

where, Pws = static reservoir pressurePwf = flowing bottom-hole pressureQ = flowrate

Vogel’s equation

Empirical relationship for fluid below bubble point pressure:

q/qmax = 1 - (1 - C)(Pwf/Pws) - C(Pwf/Pws)2

where, C = PI Coefficient, normal value is 0.8

qmax = Absolute Open Hole PotentialPws = Static Reservoir PressurePwf = Bottom Hole Flowing Pressure

Fetkovich’s equation

Alternative to Vogel’s equation Empirical correlation

q / qmax = [ 1 - ( Pwf / Pr )2 ] n

The lower the value of n, the greater the degree of turbulence

Jones equation

Gas and saturated oil reservoirs Equations:

Gas: (P2) = AQ + BQ2

Oil: (P) = AQ + BQ2

whereA : Laminar flow coefficient (Darcy)B : Turbulent flow coefficient (Non Darcy)

Also known as “Forcheimer equation”

Back pressure equation

For gas wellsQ = C (Pws

2 - Pwf2)n

Schellhardt & Rawlins empirical equation Normally, 0.5 < n < 1.0

Pseudo - steady - state equation

Oil and gas reservoirs Darcy equation Parameters used in equation :

Permeability Thickness Radius (reservoir external drainage) / Area / Shape Skin (dimensionless skin factor) Wellbore diameter

Gas well: laminar and turbulent flow Oil well: laminar flow

Well completion options

ONLY valid when used with the pseudo-steady-state equation inflow performance model.

To calculate skin factor and turbulence coefficient (for gas wells).

Completion options: None (i.e. no skin resistance to inflow) Open Hole (well is not cemented or cased) Perforated (McLeod model) Gravel Packed (Jones model)

Horizontal completion models Distributed PI (finite conductivity):

Distributive PI: PI per unit length Steady State PI (Joshi) Pseudo Steady State PI (Babu & Odeh)

Single Point PI (infinite conductivity): Steady State PI (Joshi) Pseudo Steady State PI (Babu & Odeh)

Tubing data

Well Tubing Details Depth (TVD / MD) Detailed Profile Data Tubing ID’s - can be changed at any point

along the tubing Artificial Lift: Gas Lift, ESP etc. Tubing/annular/combined flow Ambient temperature profile

Flowline details

Flowline geometry: Length, ID Undulation profile Simple or Complex Heat Transfer

Flowline, Tubing Heat transfer Energy balance for each segment Heat enters

with flowing fluid through pipe wall

Two options: User specified overall U-value User supplied pipe coating information

Reference: A.C. Baker, M. Price. “modelling the Performance of High-Pressure High-Temperature Wells”, SPE 20903, (1990).

Heat transfer (cont.)

U-values - Overall heat transfer coefficient relative to the pipe outside diameter (OD)

Defaults Insulated pipe 0.2 BTU/hr/ft2/F Coated 2.0 BTU/hr/ft2/F Bare (in Air) 20 BTU/hr/ft2/F Bare (in Water) 200 BTU/hr/ft2/F

Heat transfer (cont.)

Overall heat transfer coefficient can be calculated from the user supplied data

User can supply up to 4 coatings on the pipe w/ Thickness Thermal Conductivity

Also specify Pipe thermal conductivity Burial depth Ground thermal conductivity Ambient air/water velocity

Equipment

• Pump• Compressor• Choke• Flow Multiplier/Divider• Flow Adder/Substractor• Injection Point

Multiphase Booster Generic Multiphase

Pump Separator Expander Heater Exchanger Generic Equipment

(dP / dT)

5.Single Branch Operations:

Single branch operations

System Analysis Pressure/Temperature Profile Flow Correlation Matching Nodal Analysis Optimum Horizontal Well Length Reservoir Tables Gas Lift Rate v Casing Head Pressure Artificial Lift Performance

Flow correlation matching

To determine the most suitable flow correlation

Select the required flow correlations Enter measured pressure and temperature

survey data (FGS), through “MEASURED DATA”.

Enter known boundary conditions Results show each correlation and the

entered data

Pressure/temperature profile

Compute the pressure and temperature profile for a system and also vary some other parameters within system

Enter sensitivity variable Enter boundary conditions Resulting PSPLOT shows pressure or

temperature against depth (well) or elevation (flowline).

Can plot measured data also.

System analysis

Set up multiple sensitivity operation. Set up System Analysis Plot :

Specify calculated variable. Select X axis variable. Select any number of sensitivity variables (Z axis

variables).

In addition, also specify sensitivity relation. One variable Several variables that change together Several variables permuted against one another

Nodal analysis

Classical nodal analysis at any point (insert NA point in the model).

Break the system into two and compute the inflow and outflow around that point.

Resulting PSPLOT shows the classical inflow/outflow curves.

Nodal analysis

Pres

Pse

p

Inflow/outflow curvesPr

essu

re

ID = 3"

ID = 3 1/2"ID = 4"

Reservoir Performance

Flow Rate

WHP

= 3

00

Flow

ing

Bott

omho

lePr

essu

re

Flow Rate

Reservoir Performance

WHP

= 1

00

WHP

= 2

00

Reservoir tables Produce a table of bottom-hole pressures that

can be utilised by reservoir simulators. (VFP tables).

Interface to common reservoir simulators such as: ECLIPSE VIP PORES COMP4 MoRes

Artificial lift performance

Allows artificial lift performance curves (gas or ESP lift) to be generated and also varies some other parameters within system.

To produce input performance curves for GOAL.

Resulting plot is gas lift quantity (or ESP power) versus oil production rate.

Artificial lift systems

Gas lift Two Model Options :

Fixed injection depth & rate. Multiple injection points (Gas Lift Valves).

ESP (Electrical Submersible Pump)

Gas Lift Design

• New mandrel spacing.• Design for existing mandrels (current spacing). Casing & tubing pressure sensitive valves (IPO / PPO

valves). Valve spacing, test rack pressure calculations and valve

sizing. Unloading gas and liquid rate calculations – sizing of

unloading valves. Bracketing valve calculations.• Multiple static gradient options.• Database of valve parameters (editable).

Gas Lift Design

Additional Design Tools / Operations :

Deepest injection point calculation. Bracketing range calculations. Lift Gas Response Curves – how production rate and

injection depth respond to various sensitivities.

Analysis can be performed assuming “Optimum Depth of Injection” or “Injection at Specified Mandrel Depths only”.

Gas Lift Dagnostics

Simulate an existing well design (for current production & injection conditions).

Calculate valve status (open, closed, throttling). Determine valve throughput (based on bellows

load rate). Troubleshoot existing gas lift installation for

multi-porting, shallow injection etc.).

Gas lift design : Pressure – Depth Plot.

Electrical submersible pump

Database with a list of ESP manufacturers and models (i.e. Reda, Centrilift etc) is made available.

Base data: casing diameter, minimum & maximum flowrates and base speed.

Design data: pump speed, number of stages, head factor.

ESP performance curve

ESP variable speed curves

ESP Design

Selects & Designs a pump to meet design conditions of production rate and production pressure.

Select appropriate pump for casing size and production rate.

Select required number of stages. Identify requirements for separation. Identify power requirements. Analyse variable speed performance of the pump / well

system. Simple motor and cable screening requirements.

6. Multiphase Flow Modelling in PIPESIM:

Pressure change calculation method Determine the phase(s) present Determine the inclination angle Determine the flow pattern Calculate the elevational, frictional and

accelerational pressure losses or gains

Phases present

If the liquid volume fraction < 0.00001 then single phase gas exists

If the liquid volume fraction > 0.99 then single phase liquid exists

otherwise multiphase flow exists

Single phase flow correlations

Available Moody (default) AGA - Dry Gas Equation Panhandle A Panhandle B Hazen-Williams Weymouth

Inclination angle

If the inclination angle > 45° or < -45° then vertical flow patterns and pressure change correlations apply

otherwise horizontal flow patterns and pressure change correlations apply

Multiphase flow correlations

Published industry standard correlations: Duns & Ros Orkiszewski Hagedorn & Brown Beggs & Brill (original & revised) Mukherjee & Brill Govier, Aziz & Fogarasi AGA & Flanigan Oliemans Gray Noslip