PO: Doc. id: POS-AA04-IO31-R01 Title Subsea Processing Terminology Author(s) Client Jan Olav Hallset, Poseidon Group AS Åge Jevnaker, Poseidon Group AS Note: This document is the property of Poseidon Group AS and shall not be reproduced to a third party without prior written approval. 01 16.06.2007 joh - joh Issued for review Rev. Date Originator Check Approve Description POSEIDON GROUP AS Skogstøstraen 25 N-4029 Stavanger Phone: +47 51 20 16 40 Fax: +47 51 20 16 60 www.poseidongroup.no
Transcript
PO: Doc. id: POS-AA04-IO31-R01
Title
Subsea Processing Terminology Author(s)
Client
Jan Olav Hallset, Poseidon Group AS Åge Jevnaker, Poseidon Group AS
Note: This document is the property of Poseidon Group AS and shall not be reproduced to a third party without prior written approval.
01 16.06.2007 joh - joh Issued for review Rev. Date Originator Check Approve Description
POSEIDON GROUP AS Skogstøstraen 25 N-4029 Stavanger Phone: +47 51 20 16 40 Fax: +47 51 20 16 60 www.poseidongroup.no
2 THE INTEGRATED INFORMATION PLATFORM (IIP) PROJECT........................................4
3 SUBSEA PRODUCTION SYSTEMS................................................................................................5
4 SUBSEA PROCESSING.....................................................................................................................6 4.1 Subsea separation ..........................................................................................................................7 4.2 Subsea pumping ............................................................................................................................7 4.3 Subsea power supply .....................................................................................................................7 4.4 Subsea injection of water ..............................................................................................................8 4.5 Subsea compression ......................................................................................................................8 4.6 Subsea injection of gas ..................................................................................................................8
5 TERMINOLOGY................................................................................................................................9 5.1 Boosting system definitions ........................................................................................................10 5.2 Injection system definitions.........................................................................................................10 5.3 Separation system definitions......................................................................................................11 5.4 Electrical system definitions........................................................................................................11 5.5 Control system definitions...........................................................................................................12 5.6 Well system definitions ...............................................................................................................12 5.7 Template definitions....................................................................................................................12
1.1 Document scope This document is a deliverable from the Integrated Information Platform for reservoir and subsea production systems (IIP) project. It is an addition to DNV’s report /1/; providing information regarding Subsea Processing Equipment. The overall objective of the IIP project is to increase production from subsea systems by providing high quality data to decision support systems in operation centres off- and onshore. The objective of the project can be divided into two: • Support exchange of data between computer systems without loss or confusion of meaning of data. • To provide a platform for integration of life cycle data across multiple applications and disciplines. Data integration is combining information derived from several independent sources into one coherent data set. Because independent sources often have overlapping scopes, combining the data requires overlaps to be recognized, duplications to be removed, and possibly new data to be represented. To enable high quality data integration we must name and define ‘things’ in reservoirs, wells and subsea production facilities; resulting in a standardised terminology (name) for the ‘things’ (equipment): • Poseidon’s task in the IIP project has been to contribute to an equipment terminology for subsea
processing systems that can become part of a ISO standard (ISO 15926). Towards, this end this document reports the result of Poseidon’s work as follows: • A quick introduction to the IIP project • A quick introduction to subsea production systems • An introduction to subsea processing • A definition of high level terms for subsea processing equipment Further work has to be done to break the equipment terms down in more detail and then to define the so called product models (PM) for the developed terms. A PM defines the relation between equipment parts (how they are connected). This is left to future (IIP) projects.
1.2 References 1. Subsea Production Equipment Terminology, DNV doc. 2005-1522
2. Ormen Lange Subsea System Report, Hydro doc., 37-00-NH-X15-00071
3. Design and Operation of Subsea Production Systems, ISO-13628-1
4. Remotely Operated Vehicle (ROV) interfaces on subsea production systems, ISO-13628-9
2 The Integrated Information Platform (IIP) project The IIP project is a three year project which commenced in June 2004. It is funded by the Norwegian Research Council and the project participants. The main partners in the 4 year project (2005-2007) are: • DNV (Project leader) • Statoil, Hydro, Petromaks (sponsors) • FMC • National OilWell • NTNU • OLF The IIP project has the objective of identifying an optimal set of real time data from reservoirs, wells and subsea production facilities, partially improving and integrating this information to provide an open and standardised information platform using ISO 15926-2.
The project have been enabled by integrating the ontologies from several industrial data and technical standards and adding these ontologies to ISO 15926-4 (Reference Data Library). The number of information types and the broad scope of this integration in an open solution make this project unique. In addition, safety requirements according to the Norwegian Petroleum Directorate (NPD) will be met.
The IIP project focus is to support integration of applications related to subsea oil&gas exploration and production. In order to support this, the project is developing PMs for reservoir and subsea production systems by using information from the following areas: - Geometry and topology - Seismic - Drilling (WITSML) - Reservoir characterization - Production - Safety and automation system - Subsea equipment - Reliability and maintenance (ISO 14224) - Reservoir uncertainty. The intention is to cover data required for any application, but at this stage only alpha-numeric data is covered. 3D geometry may be added at later stage. The terminology included in this document is a part of the model – or Reference Data Library - developed in the project. The library is the IPR of the POSC Caesar Association and is intended for future standardization at ISO. The standardization process in ISO has not yet been completed; hence some changes might occur due to comments from other ISO members. These changes will be handled and documented by the IIP project. The Tyrihans field, where Statoil is the operator is used as a case in the project. The specifications from Tyrihans have been used for selecting an initial set of terms for subsea equipment. This set has been further generalized; mainly by including additional terms defined in ISO 13628 “Petroleum and natural gas industries – Design and operation of subsea production systems”.
3 Subsea production systems A subsea oil and gas production system (SPS) includes most of the main elements found in a conventional platform production system, but is unique when it comes to remoteness in installation, service and operation. The figure below illustrates the Ormen Lange system /2/; where the subsea infrastructure is connected to a shore facility in Nyhamna near Molde in Norway.
Figure 3-1 Ormen Lange layout
Subsea production systems represent a cost effective solution where the expected production rate doesn’t justify a costly platform. This is often the case for marginal fields and small oil/gas pockets, which are out of range of existing platforms. Subsea production units offer also the advantage of being less sensitive to the sea surface conditions and to the water depths, which have made them very “popular” when deep-water field are designed. Subsea production systems are used as applications in: • Marginal fields, are typically small reservoirs with complex geology and limited production
potential, which makes conventional platforms economic unfeasible. • Tie-ins to existing infrastructure. The geometry and depth of a reservoir may be such that some
parts cannot be reached from a platform using conventional drilling techniques or horizontal wells. • Deep water and artic developments. Subsea production units offer the advantage of being less
sensitive to the water depths and harsh surface conditions. More details on requirements for subsea production systems can be found in the operator companies’ technical standards, as well as in relevant international standards, for example /3,4,5/.
4 Subsea Processing Subsea processing is not an established technology, and not a lot of subsea processing equipment has been installed yet. Thus, a terminology has to be based on the current developments as described below. /6/ reports that the present status regarding technology for subsea processing on the NCS is represented by the developments of Tordis and Tyrihans for oil fields, and Snøhvit and Ormen Lange for gas-condensate fields. Even though these developments are technological state-of-the-art projects, subsea technology building-blocks such as subsea compression and power- and signal transmission over even longer distances are still unrealized. For multiphase transport the gaps are essentially related to the production and transport of complex fluids when the transport distance exceeds what is feasible for pipeline insulation and heating. For the lighter gas-condensate systems, there are also gaps to be closed regarding flow modelling for very long transport lines. In addition, recovery rates from subsea completed wells will have to increase and reach almost the same level as platform completed wells.
Figure 4-1 The Tordis SSBI module with a subsea sepearator followed by a multiphase booster pump and a water injection pump.
More cost-efficient solutions will be required to enable smaller discoveries to be developed. This will require improved understanding and tools to predict the relevant transportation phenomena. This also includes new areas such as subsea separation, subsea compression, and lightweight intervention. Current subsea processing implementation is limited to multiphase pumping and bulk water separation. In the future, an increase in capability and functionality is foreseen. This includes necessary equipment to facilitate multiphase transport over long distances such as small and large scale gas compression and high capacity multiphase pumps with corresponding high voltage power supply, efficient three-phase separation, and subsea injection of gas and water. More sophisticated equipment and application will impose stricter requirements on instrumentation and control and further development is foreseen in particular for monitoring system performance.
4.1 Subsea separation In 2001 subsea water separation and injection were demonstrated on Troll Pilot for the first time. Subsea separation technology will next be used on the Tordis field that comes on stream in 2007. Future needs will include lightweight and compact separation equipment for deepwater use. The next generation of subsea separation equipment is expected to apply other principles of separation than the traditional gravity separation vessel used on topside installations. Centrifugal-force based compact equipment and other sophisticated separation methods are expected to be applied. Although a solution for sand removal has been developed for Tordis, further development is likely to be required with respect to performance, reliability and robustness. The Tordis solution is based on injection of sand with the separated water. This will not be acceptable for all applications. Oil in water measurement from subsea separators is an area with significant technology gaps as none of the instruments used topside can be easily adapted. This technology is a key to subsea separation.
4.2 Subsea pumping Subsea multiphase pumping is a relatively well proven technology but further improvements will be needed with increased transport distances and water depths. This involves increased pressure boosting and capacity as well as the ability to handle more complex fluids (viscous crude). Restrictions in the gas tolerance and suction pressure of centrifugal liquid pumps may reduce the benefits of a subsea two-phase separation system. Further improvements in current pump technology are required.
Figure 4-2 Aker Kværner Subsea injection pump for Tyrihans
4.3 Subsea power supply The subsea electrical equipment seen so far is mainly control systems, but some pumps with voltages up to 6.6 kV are in operation. Upcoming field developments will demand steadily higher power at longer distance from existing infrastructure or shore. This will lead to a demand for reliable subsea high voltage equipment and frequency converters.
4.4 Subsea injection of water The Troll Pilot and the Tordis subsea process solutions represent the state of the art in subsea injection of water. Both applications utilize a single phase pump to inject the produced water in disposal wells. On Tordis the produced sand will also be injected together with the water. Future applications will include subsea injection of water for pressure support. Tyrihans will apply subsea injection of raw seawater in 2009.
Figure 4-3 The Troll pilot station, for subsea bulk separation, boosting, and water injection
4.5 Subsea compression There are an increasing number of gas fields where unprocessed wellstream will be transported over long distances to a suitable infrastructure (onshore, shallow water existing platforms etc.). These fields will benefit from a late life pressure boost. For many of them, subsea compression is believed to be a cost-efficient solution. No subsea gas compression technology has been qualified for field application. Several field development projects are aiming at utilizing this technology, and several Norwegian vendors have demonstrated their prototypes. Ormen Lange is in the process of qualifying technology in full scale.
4.6 Subsea injection of gas Subsea injection of gas is a future possibility that can be used both for pressure support and for gas lift. Pressure support is much more demanding than gas lift due to higher flow rates. Compared to subsea gas compression in wellstream transport the injection compressors are more challenging due to the high pressure demand. It is therefore foreseen that gas compression for transport will be implemented first.
5 Terminology The breakdown of subsea processing is based on the Tordis subsea SSBI (Subsea Separation Boosting and Injection) module, but has been generalised as shown in the figure below.
Subsea Processing
Well System Boosting Systems Separation Systems Injection Systems Electrical Systems Template Systems Control System - Production Well, Gas/oil
- El. Submersible Pump (ESP)
- Gravity-Based Separation
- Injection of Produced Water
- Transformer Unit - Subsea manifold - Subsea Control Module - Electric Power
Distribution
- Injection Well, Gas, Water/Sand
- Helicoaxial - Centrifugal Separation
- Injection of Seawater
- Subsea Power and Communication UnitMultiphase Pump
- Twin Screw Pump - Cyclone Separation - Injection of Gas - Multiphase Flow Meter
- Injection of Produced Sand
- Gas Compressor - Riser Gas Lift
Figure 5-1 Equipment for a general subsea processing system
The figure above shows that there are seven main equipment groups in a subsea processing module:
1. Boosting system, mainly consisting of various pumps fitted for the fluid to be transported.
2. Separation system, mainly consisting of a bulk separator tailored for subsea use.
3. Injection system, mainly being a high pressure pump adapted for the fluid to be injected.
4. Electrical system, is a high voltage system being able to supply the needed power to the subsea pumps and other equipment. Processing systems have a far higher power demand than traditional subsea systems.
5. Template system, which are the structure that the processing system is built on.
6. Well system, which is the well completion as in existing subsea systems
7. Control system, which will provide more sophisticated control and instrumentation functions that than today. This follows from the higher complexity of processing systems.
The three last groups should have terms defined in /1/, and are not elaborated here. However, it might turn out in a future detailed breakdown of the groups that the terms in /1/ has to be extended with new ones that are particular to subsea processing.
In the following you will find more detailed definitions of the terms for the seven groups, please also refer to the enclosed Excel spreadsheet: IIP-Subsea processing terms.xls.
6 Abbreviations DNV Det Norske Veritas FMC Food Machinery Corporation IIP Integrated Information Platform IPR Intelectual Property Right ISO International Standardisation Organisation MEG Mono Ethylene Glycol NCS Norwegian Continental Shelf NPD Norwegian Petroleum Directorate NTNU Norges Tekniske Naturvitenskalige Universitet OG21 Oil and Gas 21 (see www.og21.org ) OL Ormen Lange OLF Oljeindustriens Landsforening PLET PipeLine End Termination PM Product Model POSC Petrotechnical Open Standards Consortium RDL Reference Data Liberary ROT Remotely Operated Tool ROV Remotely Operated Vehicle SPS Subsea Production System SSBI Subsea Separation Boosting and Injection WITSML Wellsite Information Transfer Standard Markup Language
