The Ampa-1 and 2 platform complexes, installed in the mid 60s in 75 ft. water depth, were the first major offshore developments in the S.W. Ampa Field, 8 miles offshore Brunei. In order to continue production and allow further development of the offshore South West Ampa oilfield reserves the original drilling and production platforms of the Ampa 1 and 2 Product ion complexes platforms of the Ampa 1 and 2 Product ion complexes required replacement or major repairs because of general deterioration. This paper describes the Ampa 1 and 2 Revamp project and the conclusions drawn from its successful project and the conclusions drawn from its successful completion with special emphasis on the technical achievements and safety precautions.
Two of the drilling platforms, AMDP-1 and AMDP-2 were on study found to be structurally unsound to the extent that a ban on use of a derrick equipment set was made. Replacement or repair was considered essential before the winter monsoon season of 1984 to avoid the risk of partial collapse. The project scope included: - the replacement of the entire AMDP-1 structure and topside facilities around the existing 19 well conductors. (To abandon the existing wells and replace the structure with a new platform and new wells would have been a markedly more expensive and less economic proposal). - the salvage of the structurally unsound production platforms at Ampa 1 and 2. - the strengthening of AMDP-2 structure by grouting of four of its legs. - general upgrading to modern engineering standards. - the installation of a new production platform AMPP-1 at Ampa-1 designed to stabilise the combined production from both complexes. For ease of reading, refer to the attached figures in Appendix 1 for overview.
Preparatory work Preparatory work - Conceptual Studies - Project Plan
The preparatory work commenced with the engagement of an experienced consultant to prepare a conceptual design leading to a detailed design recommendation for the salvage of the old AMDP-1 structure and installation of the new AMDP-1 (R) structure around the existing nineteen well conductors. This necessitated a detailed survey of the structure to establish both its structural condition and estimate the weights which would be encountered during the salvage operations. The scope for grouting of the AMDP-2 jackets was defined similarly. On completion of the conceptual design, models of both the existing and replacement structures at AMDP-1 were built to ensure that all parties had a clear appreciation of the scale of the project and the sequence of execution. These proved invaluable as the project progressed.
Project Plan Project Plan A detailed Project Plan was prepared in early 1983 to establish the scope, objectives, target milestones, budgeting aspects, economics, risks and uncertainties and quality assurance plans. This served as the principal reference document for the project against which changes could be monitored and project against which changes could be monitored and controlled. Comprehensive work package checklists were developed to establish the timing and control for key activities such as design, fabrication, decommissioning, salvage, installation procedure preparation and hook-up/ commissioning activities. Some of the activities such as decommissioning- /well securing/jacket salvage/disposal and jacket installation in close proximity to well conductors were identified as non-routine activities and therefore they were given special consideration during the project development. Sufficient resources and lead times were allocated to review these non-routine activities in order to eliminate potential problems. An example of the potential problems problems. An example of the potential problems during the jacket salvage work was the possibility of partial or total collapse of the structure during removal, and the risk of damaging the well conductors. It was appreciated at the conceptual design stage that early and significant involvement of Company Construction Engineers, crane barge Superintendents and diving specialists would be required for the identification and development of the salvage and installation procedures. Without such early involvement, design and fabrication of the temporary salvage and installation aids and resolution of the technique would not have been possible or at least would not have met with the same success in meeting the project schedule. The strategy was to prove the procedures by commencing with the simplest salvage procedures by commencing with the simplest salvage scope (AMPP-1 bridges/topsides and jackets) before proceeding with the progressively more critical proceeding with the progressively more critical salvage and installation lifts in close proximity to the well conductors. Precedence network planning was utilised to plan and control a network of 74 activities with supporting cost, time and resource data. This computer based tool was maintained online throughout the project and is considered essential for the successful execution of projects of this nature.
Ampa-1 Revamp Scope
Well plugging and securing
Ampa-1 Complex decommissioning
Pre-salvage underwater preparatory work
Tie-back of the well conductors
Hook-up and commissioning
Outline Sequence (See also Appendix 1 Figure 3)
Prior to the start of the revamp, the Ampa-1 complex comprised two drilling platforms, one production platform and one riser platform production platform and one riser platform interconnected by bridges. The production platform (AMPP-1) and the old drilling platform (ADMP-1) would be replaced completely at the end of the project. project. The offshore work began with pipelines relocation and some surface facilities modifications to enable the AMDP-20 production to be directed temporarily to Ampa-2 complex. This step ensured no loss of production from AMDP-20 during the AMDP-1 salvage production from AMDP-20 during the AMDP-1 salvage operation.