On a platform, facility modifications to cope with unexpected operating conditions or unanticipated problems may be made relatively easily at moderate cost. In contrast, subsea systems are placed on the seabed often beyond diver depth and are difficult if not impossible to retrieve or modify. Consequently the design must be optimized up front and have sufficient inherent flexibility to cope withthe unexpected. It is therefore critical to develop an operational strategy in conjunction with suppliers, designers and operational staff, concurrently with the design. Input from Operations personnel is necessary from project conception throughout detailed design, fabrication, system integration testing, installation and commissioning.
This paper discusses BP Exploration's work on the Pompano subsea project in the Gulf of Mexico and addresses many of the practical aspects in which Operations staff need to become involved with throughout a subsea project to ensure a problem free start-up and operation. It will provide a useful guide for Operations groups involved in the planning and operation of a subsea development.
The Pompano Field is located 24 miles southeast of the Mississippi River Delta and comprises 5 Gulf of Mexico Outer Continental Shelf lease blocks. See Fig. 1. It is being developed by BP Exploration Inc. and its partner Kerr McGee Corporation with a conventional 40 slot platform and a 10 slot subsea production template/manifold. The platform was installed during 1994, in the southeast corner of Wows Knelt Block 989, in a water depth of 1290'. The subsea production template/manifold was installed during 1995 in Mississippi Canyon Block 28, about 4.5 miles southeast of the platform, in a water depth of 1865'.
The Pompano production platform is the host platform for the subsea development. It is fitted out with the necessary equipment to receive production (maximum 24 mbpd) from the subsea wells and condition the process fluids for commingling with the platform production. Surface facilities are provided fm well control, TFL (Through the FlowLine) well servicing and chemical injection. The surface facilities are connected to the production template by a flowline/service line system with two 8" production flowlines, two 3" id service/ flowlines, hydraulic/ chemical and electrical umbilicals.
If reservoir pressure support is required, a six slot water injection template/manifold will be installed in Mississippi Canyon Block 28, approximately 500 feet southwest of the production template, and will he tied back to the Pompano platform with a 6" water injection flowline. The overall project concept is shown in Fig. 2.
First oil was achieved on schedule from the platform in the forth quarter 1994 and from the subsea template in the first quarter 1996.
The principle objective of this paper is to set out the factors that determine how a deepwater prospect may be successfully developed using subsea technology.
The key drivers for success in a subsea project are listed below and are discussed in detail in the body of the paper.
Define a strategy for reservoir management and resource conservation.
Determine well intervention requirements and a cost effective means of supply.
Ensure project robustness.