The objectives and concepts behind BP Exploration's DISPS Project have been given elsewhere1,2,3,4 DISPS is the acronym for Diverless Subsea Production Systems and is currently BP Exploration's largest research and development project Its objective is to develop diverless subsea production technology by 1995 such that BP could commit to exploitation of a hydrocarbon accumulation in deep water after that date.
Two phases were foreseen when the Project commenced in 1986:
Phase 1: Development of concepts, principles, designs, techniques and equipment in water depths between 350 m and 750 m, culminating in a comprehensive programme of system testing
Phase 2: Prototype application of the developed technology in diver-accessible depths to gain operating experience and demonstrate BP's capability.
Phase 1 is due for completion in 1989, and within BP a possible location for Phase 2 is being pursued.
This contribution will first recap briefly on the principal studies undertaken and concept designs developed. Then it will summarize the component and system testing carried out to date together with the significant results Finally, the testing envisaged in 1989 will be outlined.
When the DISPS Project Team was formed in early 1986 its first task was to crystallize the previous studies and reviews into an agreed technological package for the statement of requirements (SOR). This document set out BP Exploration's requirement as sponsor of the programme, and to ensure that it adequately addressed BP's business needs the SOR was approved by a steering committee of senior managers from several departments within BP Exploration and BP Engineering.
In preparing the SOR the project consciously narrowed the scope of work to fit available resources and timeframes guided by a perceived priority list of technology gaps It also acknowledged that the SOR would be a snapshot of BP's perception as of mid 1986, and included elements to help with future reviews of the work programme.
The SOR, the project's reference book, summarized the background and detailed the objectives. It set out the design premises and philosophies, described the concept used as a basis for implementing the programme, and it formed the technical basis for our first few engineering study contracts The concept of DISPS being an enabling technology was promulgated
In order to focus the programme closely, the technology development was limited to subsea facilities and surface equipment to handle them, flowlines and umbilicals and their subsea terminations The ‘simplified’ design premise was that the seabed facilities would be controlled up to 10 km away from a surface facility, which would carry out the hydrocarbon processing for export.
The SOR gave rise to four major technology areas, in which conceptual designs have been prepared:
The objective of these studies was to identify the necessary development and testing requirements.
BP's DISPS concept which consists of a multiwell (2-18 wells) modular template, installed and maintained by diverless techniques, is centred on designs for 400 m water depths, but with a conceptual understanding of designs to 750m A perspective view of the DISPS Template configured for 8 slots is given in Fig 1, and a cross-sectional view is shown in Fig 2.