Abstract

The well construction strategy for the Deepwater Malikai project, Malaysia, included 36-in. structural pipe jetting and 13 5/8-in. surface casing riserless cementing for top-hole sections with the objective for further development of lower sections with tension leg platform (TLP). Cementing of the 17 ½-in. surface hole mainly dominated by shale formation and penetrating multiple shallow faults required isolating shallow gas sands by bringing top of cement to the seabed, thus meeting the well integrity requirement stipulated by the Malaysian Petroleum Management (MPM).

The cement slurry design for the 13 5/8-in. casing with riserless mud recovery system includes selection of lightweight trimodal particle-size distribution cement blend optimized with a gas migration control agent and low-temperature dispersant. This mitigates dynamic losses in unconsolidated formations and faults having narrow margins between pore and fracture pressures. Cement slurry achieves faster compressive strength and static gel strength development at lower seabed temperature, preventing casing subsidence and providing good shoe strength. The cement job design respects density and friction pressure hierarchies, providing flat fluid interfaces between successive fluids pumped, combined with optimal casing standoff and displacement efficiency ensuring effective mud removal in highly deviated large-annulus top-holes.

This paper will discuss the extensive laboratory testing employed to qualify the engineered trimodal lightweight cement slurry design and effective mud removal strategy fit for the applications on the seven batch-set top-hole sections, achieving zonal isolation requirement.

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