Detailed Description :

Platforms in the Leman field have been modified and refurbished under separate contracts, the most recent of these being 49/27F and G. In parallel with these latest contracts the refurbishments of 49/27E was undertaken in-house by Amoco Production Support Group. The in-house approach for E was apparently successful and showed savings in both schedule and expenditure in comparison with the Simplification Programme implemented on F and G. The objective of this review was to quantify and compare the projects and to account for the apparent differences in time and costs.

Platform 49/27 E is a double jacket installation, which was classified as “manned”. It was the intent to carry out major works to allow the platform to be classified as “not normally manned installation” (NNMI). All functions would then be controlled and monitored from the onshore terminal at Bacton. The target date for the reclassification was November1994. Within the scope of the project the process was to be de-bottlenecked by by-passing and then decommissioning the existing process equipment, untreated gas would then flow direct to the production header, exported to 49/27A for compression and then exported to Bacton.

Platform 49/27F consists of a drilling platform (FD) with wells producing gas feeding a processing facility on an adjacent platform (FP) through flowlines. After on board processing and fiscal standard flow measurement, the gas is exported to 49/27A, via 49/27BT, for re-compression and export to Bacton terminal. The intention of the work was to convert the platform to a NNMI.

Each of the offshore installations was different in detail, layouts and status, and in order to make valid comparisons of the projects it was necessary to first identify these variations and then to adjust the comparisons accordingly.

The approach adopted for the review was to produce tabulations comparing aspects of the projects with the aim of providing easily accessible results. These included the original design philosophies, representing the scope of work for each installation; the methods of execution of the work; the documentation produced; for equipment and materials supplied for each project; and the overall cost summaries. Sources of information were project documents, meetings and interviews with project personnel, and a visit offshore to the E, F and G installations.

The study report provided detail cost comparisons between the projects, identified areas of innovation / excellence and made recommendations for how future projects of a similar nature could be approached.