Delivering Best-In-Class Shallow Water Tender-Assisted Drilling Wellhead Platform, a New Chapter

Abstract

This paper demonstrates another success story on delivering a new Best-In-Class Tendered Assisted Drilling (TAD) Wellhead Platform. A clear target/goal to achieve project value driver, ie. reduce CAPEX and accelerate project maturation speed. With demonstration of good front-end development work and project delivery strategies set from the beginning of the project, a series of strategic approach to deliver competitive scoping and requirement with the intent of achieving cost saving and minimize fabrication duration by meeting targeted weight reduction for both Topside and Substructures. The ultimate purpose of all these strategic approaches is to develop a set of standard template design and efficient project execution strategy for new TAD Wellhead platform that is replicable in Shell. Civil, Structural and Offshore Engineering discipline in Shell has leveraging past project good practices, lesson learnt and benchmarking against internal and external project to develop a fit-for-purpose design. Initial findings from the benchmarking study indicated at water depth of 143m in Sarawak water, jackets are launch-installed, typically. The continuous improvement exercises aimed to reduce both Topsides and Substructure weight, which eventually creates opportunity for jacket to convert from launch-installed in the initially concept to lift-installed jacket. Some of key successes from this improvement journey includes topside deck level/footprint optimization, optimized topside structural framing and deck leg spacing to have a small work-points from top, elimination of jacket dummy leg thus reduce overall jacket footprint/weight, lean foundation design, e.g. 1 skirt pile per leg etc. However, the key challenge to the lift-installed jacket concept at the water region of 140m remains at jacket lift weight that is limited by the typical heavy lift vessel crane capacity and it requires a stringent weather window limit. Hence, weight management, i.e. set NTE weight on the jacket lift weight is paramount and it needs to be managed from engineering phase all the way to offshore installation. The outcome of the continuous improvement journey showed tremendous satisfying result to save project cost and schedule. With massive reduction of jacket weight (>50%) thus it reduces fabrication schedule, and unlocks provision of yard flexibility that invites more competitive bidding from EPC contractors (especially small fabricator) thus potentially reduce overall EPC cost. The significant improvement in steel quantity reducing overall jacket steel material procurement cost and fabrication cost. Elimination of jacket loadout via skidding facility (for launch type jacket) that further reduces fabrication cost. This is the first lift-installed jacket in Shell Malaysia at this water region. Leveraging on project knowledge and learning, specific technical specifications for L2 TAD Wellhead Platform design and installation aids have been developed in shell, with the intent to standardize and simplify technical requirements.