Well Accessibility Considerations in Well Completion Designs for Long-Reach and Deviated Offshore Wells

Abstract AA is a new gas field located offshore Sarawak currently under field development planning phase. The elongated field structure consists of multi-stack reservoirs that are located up to 15,000 ft tvdss. Two options for developing the shallow Phase 1 wells (down to H800) have been assessed; completing at either one or two wellhead platforms. To decide between the two options, the team needed to be confident about the ability to safely intervene these wells in future, which triggered detailed accessibility analyses for all wells considering various intervention methods. Four main intervention methods assessed were slickline, braided line, electric line (E-line) and coiled tubing (CT). This paper provides the details of well accessibility analyses conducted during development planning stage. Sensitivities on the types of intervention activities, bottom-hole assemblies and friction factors were also studied. The findings from the study has significantly changed the well completion designs of the long reach deviated wells justifying use of smart wells. This systematic well accessibility approach was applied for the first time in PCSB to replace the traditional rule of thumb of simple 60 degree deviation used as a cut-off for well accessibility. Field Background AA Field is located offshore Sarawak within Baram Delta province. It is one of the deepest resources that are currently being developed in this area. The 6-km elongated field structure has multi-stack reservoirs, with the targeted reservoirs located some 10,000 - 15,000 ft tvdss (Figure 1). The large pressure differential and different water encroachment in each reservoir increase the level of complexity in developing these resources since zonal isolation is required. Well creaming exercise found that 5 development wells are sufficient to drain the reserves of Phase 1 shallow reservoirs down to H800 (Figure 2).