1 Introduction
1.1 Introduction
As the subsea production system has proven its reliability in service and as its cost, in relative terms, has fallen, the oil industry has come to accept it as a technically viable and competitive field development option.
Figure 1.1 - A Variety Of Field Development Options Exist as Subsea Technology Moves Into Deeper Waters.
The focus of this document is deepwater developments. The term “deepwater” is subject to interpretation, but in general one can assume it to be beyond the reach of current saturation diving technology. Subsea developments within diver accessible depth are so routine as not to merit much comment these days. For this discussion we are assuming deepwater to begin at water depths well beyond the practical range of saturation diving, within the reach of current generation ADS equipment and extending to depths that require methods other than human intervention, such as remote control or ROV intervention. This covers a range of roughly 300 to 3000 meters. It should be noted that 3000 meters represents the approximate limit of current well completion experience, although exploration drilling activity continues to push into deeper waters.
There are five main subsea production system manufacturers in the world. These are Aker Solutions, OneSubsea, Dril-Quip, TECHNIPFMC and BHGE. All have capabilities in each of the main Subsea Production System equipment categories, with varying depth of product range, track record and capacity. Many other companies manufacture subsea valves, subsea connection systems, etc. but are not considered to be Subsea Production System suppliers because their ranges of products are limited.
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1.2 Scope
The scope of this study is to provide an overview of subsea production systems technology.
Section 2 describes the various field architecture types and the basis for selection of a particular field architecture.
Subsea SPS equipment can be divided into four categories, namely wellhead systems, xmas tree systems, manifold and connection systems, and production control systems. These are each described in Sections 3, 4, 5 and 6 respectively.
Sections 7 addresses topics which relate to design and operation of deepwater Subsea Production Systems, and which are common across the main equipment categories.
In Section 8, the various test programs used to qualify and prove the adequacy of SPS equipment design, and check the manufacturing are described. Items to consider when planning the commissioning and start-up of a subsea production system are identified.
Finally, Section 9 is dedicated to Risk Assessment and Management of Subsea Production Systems in the project phase.
Figure 1.2 - Subsea Production Systems Offer a Cost Competitive Option for Deepwater Field Developments (Girassol field, Angola, Total)
1.3 Codes, Standards, Specifications and Reference Documents
1.3.1 Codes & Standards
[1] | API_RP_14B | ||
[2] | API_RP_16Q_D | ||
[3] | API_RP_17A_D | ||
[4] | API_RP_17G | ||
[5] | API_RP_17N | ||
[6] | API_RP_17P | ||
[7] | API_RP_17Q | ||
[8] | API_SPEC_14A | ||
[9] | API_SPEC_16A | ||
[10] | API_SPEC_16F | ||
[11] | API_SPEC_17D | ||
[12] | API_SPEC_5CT | ||
[13] | API_SPEC_5DP | ||
[14] | API_SPEC_5L | ||
[15] | API_SPEC_6A | ||
[16] | API_SPEC_6D | ||
[17] | API_SPEC_8A | ||
[18] | API_STD_17F | ||
[19] | ASME_B1634 | ||
[20] | ASME_B313 | ||
[21] | ASME_B314 | ||
[22] | ASME_B318 | ||
[23] | ASME_B31G | ||
[24] | ASME_IX | ||
[25] | ASME_V | ||
[26] | ASME_VIII | ||
[27] | AWS_D1-1_D1-1M | ||
[28] | DIN_EN_10204 | ||
[29] | DNVGL_OS_C101 | ||
[30] | DNVGL_OS_C401 | ||
[31] | DNVGL_OS_D201 | ||
[32] | DNVGL_RP_0002 | ||
[33] | DNVGL_RP_0034 | ||
[34] | DNVGL_RP_A203 | ||
[35] | DNVGL_RP_B401 | ||
[36] | DNVGL_RP_E101 | ||
[37] | DNVGL_RP_F112 | ||
[38] | DNVGL_RP_F302 | ||
[39] | DNVGL_RP_N101 | ||
[40] | DNVGL_RP_O501 | ||
[41] | DNVGL_SE_0045 | ||
[42] | DNVGL_SE_0478 | ||
[43] | DNVGL_ST_E271 | ||
[44] | DNVGL_ST_F101 | ||
[45] | DNVGL_ST_F301 | ||
[46] | EN_13509 | ||
[47] | IOGP_JIP_33_S_561 | ||
[48] | ISO_10423 | ||
[49] | ISO_10432_1 | ||
[50] | ISO_10433 | ||
[51] | ISO_13533 | ||
[52] | ISO_13628_1 | ||
[53] | ISO_13628_15 | ||
[54] | ISO_13628_2 | ||
[55] | ISO_13628_3 | ||
[56] | ISO_13628_4 | ||
[57] | ISO_13628_5 | ||
[58] | ISO_13628_6 | ||
[59] | ISO_13628_7 | ||
[60] | ISO_13628_8 | ||
[61] | ISO_13628_9 | ||
[62] | ISO_14313 | ||
[63] | ISO_14723 | ||
[64] | ISO_17776 | ||
[65] | ISO_19900 | ||
[66] | ISO_3511 | ||
[67] | ISO_898 | ||
[68] | ISO_9001 | ||
[69] | NACE_MR0175 | ||
[70] | NORSOK_D_001 | ||
[71] | NORSOK_D_002 | ||
[72] | NORSOK_D_007 | ||
[73] | NORSOK_D_010 | ||
[74] | NORSOK_M_001 | ||
[75] | NORSOK_M_101 | ||
[76] | NORSOK_M_120 | ||
[77] | NORSOK_M_501 | ||
[78] | NORSOK_M_503 | ||
[79] | NORSOK_M_601 | ||
[80] | NORSOK_M_630 | ||
[81] | NORSOK_M_650 | ||
[82] | NORSOK_N_001 | ||
[83] | NORSOK_N_004 | ||
[84] | NORSOK_U_001 | ||
[85] | NORSOK_U_009 | ||
[86] | NORSOK_U_102 | ||
[87] | NORSOK_Z_001 | ||
[88] | NORSOK_Z_007 | ||
[89] | NORSOK_Z_008 | ||
[90] | OSPAR | ||
[91] | SAE_AS4059 | ||
[92] | SAE_J343 | ||
[93] | SAE_J517 | ||
[94] | SI_1019 | ||
[95] | SI_913 |
1.3.2 TOTAL Standards
[96] | GS_EP_SPS_001 | ||
[97] | GS_EP_SPS_002 | ||
[98] | GS_EP_SPS_004 | ||
[99] | GS_EP_SPS_006 | ||
[100] | GS_EP_SPS_007 | ||
[101] | GS_EP_SPS_008 | ||
[102] | GS_EP_SPS_009 | ||
[103] | GS_EP_SPS_010 | ||
[104] | GS_EP_SPS_012 | ||
[105] | GS_EP_SPS_016 | ||
[106] | GS_EP_SPS_018 | ||
[107] | GS_EP_SPS_019 | ||
[108] | GS_EP_SPS_021 | ||
[109] | GS_EP_SPS_023 | ||
[110] | GS_EP_SPS_024 | ||
[111] | GS_EP_SPS_025 | ||
[112] | GS_EP_SPS_027 | ||
[113] | GS_EP_SPS_028 | ||
[114] | GS_EP_SPS_029 | ||
[115] | GS_EP_SPS_030 | ||
[116] | GS_EP_SPS_031 | ||
[117] | GS_EP_SPS_032 | ||
[118] | GS_EP_SPS_033 | ||
[119] | GS_EP_SPS_034 | ||
[120] | GS_EP_SPS_035 | ||
[121] | GS_EP_SPS_036 | ||
[122] | GS_EP_SPS_037 | ||
[123] | GS_EP_SPS_038 | ||
[124] | GS_EP_SPS_047 | ||
[125] | GS_EP_SPS_048 | ||
[126] | GS_EP_SPS_141 |
1.3.3 Deepwater Reference Books
[127] | T084-EN001 | ||
[128] | T084-EN002 | ||
[129] | T084-EN003 | ||
[130] | T084-EN004 | ||
[131] | T084-EN005 | ||
[132] | T084-EN006 | ||
[133] | T084-EN007 | ||
[134] | T084-EN008 | ||
[135] | T084-EN009 | ||
[136] | T084-EN010 | ||
[137] | T084-EN011 |
1.4 References
This study is based on the following sources
Industry available documentation such as OTC papers
Vendors / Manufacturer published technical data.
In house technical data from the subsea contractors.
In house past experience in subsea SPS works
For more details on field architecture, subsea tie-ins or subsea control system refer to the following Offshore Reference Books [136], [133] and [131].
1.5 Acknowledgements
We wish to thank the manufacturers and subsea contractors for the provision with courtesy of technical information and photographs of their products.
1.6 Definitions & Abbreviations
1.6.1 Definitions
- Annulus
The annular space between the production casing and the production tubing.
- Casing
Tubular steel conductors of progressively smaller sizes through which a well is drilled.
- Casing Program
The sequence of casing installed in a well. A common casing program is 30” (conductor), 20” (surface casing), 13-3/8” (intermediate casing) and 9-5/8” (production casing).
- Dual Bore Tree
A subsea christmas tree with production and annulus bores passing vertically through the tree body. Also known as a “Conventional” or “Vertical” tree.
- Horizontal Tree
A subsea christmas tree with production and annulus bores branching out horizontally through the side of the tree and the tubing hanger in the upper part of the tree.
- Lower Riser Package
A device similar to a small BOP attached to the tree mandrel used for emergency well control and riser disconnect when running, retrieving or working over a dual bore tree.
- Low Pressure Housing
The machined forged steel housing welded to the top of the conductor (usually 30” or 36”) into which the wellhead is installed.
- Marine Riser
A system used with floating offshore drilling rigs for guiding the drill string and circulating drilling fluids between the drilling rig and the subsea BOP.
- Mono-Bore Tree
A subsea tree with the production bore passing vertically through the tree body and the annulus bore exiting through the side of the tree.
- Mudline Suspension System
A system for hanging casing at or below the mudline in offshore wells drilled using a surface BOP.
- Pack-Off
The system of seals installed in the casing hanger for sealing the annular space between successive strings of casing.
- Production Flowline
The piping through which the production fluids are delivered from a production tree or manifold..
- Production Platform
For purposes of this Chapter, the term Production Platform means the host surface production facility that receives and processes the production fluids from the subsea wells. It could be a fixed platform, a jackup production platform, or a floating structure such as a spar, semi-submersible, TLP or FPSO.
- Production Tubing
The tubing through which the production fluids are delivered from the reservoir to the production tree, also known as the completion.
- Subsea Production Manifold
An assembly of valves, piping and instrumentation mounted in a fabricated steel structure installed on the sea floor for gathering production from several production trees. May also distributes, controls and injects chemical to the production trees.
- Subsea Tree
A christmas tree designed for installation on a subsea wellhead.
- Subsea Wellhead
A machined, forged steel housing welded to the surface casing of a subsea well to which a BOP or a subsea tree may be connected for controlling the well and containing well pressures during drilling and production operations.
- Seabed Conductor
The first casing installed for guiding the drill bit when a well is first started (usually 30” or 36”). It may be driven, jetted or drilled into place.
- Through-Bore-Tree
A subsea tree with the production bore passing vertically through the tree body and the tubing hanger in the tree body.
- Tree Connector
The mechanism at the base of the tree that connects the tree to the wellhead by means of a hydraulic or mechanical actuator.
- Tree Mandrel
A machined hub at the top of a dual bore subsea tree for connection of the tree running tool or the LRP and gaining access to the tree bore.
- Tree Running Tool
A specially designed tool used for lowering the subsea tree onto the wellhead and actuating the tree connector or, inversely, for removing the tree from the wellhead.
- Tubing Hanger
Installed in the wellhead system (for dual-bore trees) or in the production tree (horizontal trees) for supporting the production tubing in the well.
- Tubing Head
A term sometimes used for a wellhead with a tubing hanger but no casing hangers. See Mudline Wellhead.
- Tubing Spool Adapter
A wellhead adapter for 1) converting from a wellhead of one profile type to another or 2) providing a new wellhead seal surface if the original one is damaged.
- Wellhead Connector
A mechanism for connecting other equipment to a wellhead by engaging and locking onto the wellhead profile. See Tree Connector.
- Wellhead Profile
The external machined profile at the top of the wellhead that provides a load bearing shoulder and seal surface for the BOP connector or the tree connector.
1.6.2 Abbreviations
- ASA
Annulus Seal Assemblies
- BOP
Blow Out Preventer
- DCS
Distributed Control System
- EDU
Electrical Distribution Unit
- ESD
Emergency Shut Down
- ESP
Electrical Submersible Pump
- FAT
Factory Acceptance Test
- HCR
High Collapse Resistance
- HDM
Hydraulic Distribution Module
- HP
High Pressure
- HPU
Hydraulic Power Unit
- IWOC
Installation Workover Controls
- LP
Low Pressure
- LRP
Lower Riser Package
- MCS
Master Control Station
- MMI
Man-Machine Interface
- PSL
Product Specification Level
- PVXT
Production Vertical Xmas Tree
- ROV
Remotely Operated Vehicle
- SCM
Subsea Control Module
- SCMMB
Subsea Control Module Mounting Base
- SCSSV
Surface Control Sub-surface Safety Valve
- SFL
Steel Flying Lead
- SIT
System Integration Test
- TCU
Tool Control Unit
- THS
Tubing Head Spool
- TIV
Tee Injection Valve
- TUTA
Topside Umbilical Termination Assembly
- TUTB
Topside Umbilical Termination Box
- UJB
Umbilical Junction Box
- UPS
Uninterruptable Power Supply
- UTA
Umbilical Termination Assembly
- UTH
Umbilical Termination Head
- VSE
Valve Signature Emulator
