In brownfield developments, prolonging the production life of the wells beyond the 30-year original well design life has been one of the challenges in managing well integrity. This challenge is often compromised by multiple tubing leaks or, in the worst case, by parted tubing caused by metal fatigue, erosion, and corrosion. The issue is often observed in many wells in the S field and usually occurs at a shallow depth between the tubing hanger and subsurface safety valve. The conventional through-tubing repair technique becomes increasingly difficult and ultimately tends to be unsuccessful. Moreover, with the challenge of low oil prices, a simple single-trip system, necessary to reduce costs and increase the success rate, is preferred. Several cost effective approaches to repair production tubing leaks have been available in the market for quite some time. These conventional methods (e.g., stackable slickline straddle, multi-run coiled tubing (CT) conveyed straddle, and tubing patches) come with basic tools, but require difficult manipulation to set and retrieve some of the assemblies, which are permanently installed, that may complicate future well abandonment. For wells with multiple leaks or where the completion tubing has been parted, complete replacement of completion tubing will be the only solution because of the severity of damage. This typically requires a workover rig or snubbing unit at both economically and operationally significant expense. It also typically results in a significant amount time required for well preparation, mobilization, and demobilization of the rig. In addition, the retrieval of this degree of corroded completion is not straightforward because it can come apart piece by piece, which will consume additional time. This paper describes the first customized, through-tubing hanger system installed at the lower master valve (LMV) of its kind. This unique repair method uses a coiled tubing-conveyed swellable packer, a hanging mechanism at the LMV, and through-tubing swellable packer elastomers at both top and bottom of the assembly. A description of the single-trip technology is presented, with a brief description of its engineering development and the installation procedure. The candidate selection process and installation procedure are discussed; information about the economics is provided to demonstrate that this type of repair was economically superior to a rig workover. This paper presents the successful field application of a new well intervention technique to repair multiple shallow leaks in production tubing in S field, an offshore field located in Malaysia. Effective teamwork among various parties through all phases, including engineering design, LMV fabrication, through-tubing hanger customization, swellability laboratory testing, and the execution phase, were key elements to the success of this pioneer project. By demonstrating the operational possibility and a low-cost alternative to an expensive rig workover, this unique technique has created more new opportunities to restore the integrity of shallow leaks and can be run in wells with parted tubing in similar brownfield wells.

The Seligi field, located 240 kilometers offshore peninsular Malaysia in the Malay basin was discovered in May 1971 and is one of the largest oil fields in Malaysia. Sand production in the Seligi field has been observed, especially from the J reservoirs group. Within the Seligi field, Well G was identified as one of the wells with sand production to surface that could lead to sand accumulation at surface facilities and erosion of equipment. Historically, there had been no in-situ sand control measures in the well. The default practice for sand control was to choke back the well, to prevent triggering of the surface sand probe (production with maximum sand-free rate). This approach however is a compromise, while it limits sand production, it also limits the production potential of the well (well technical potential). As part of the production enhancement assessment program, remedial sand-control methods were considered to increase the oil production while minimising sand production. Among the options considered was ceramic downhole sand screen installation. Ceramics have been used in many extreme erosion and corrosion applications, with ceramic sintered silicon carbide being 50 times harder than steel. Ceramic sand screens made with sintered silicon carbide offer much higher erosional resistance at speeds of 300ft/s sand impingement velocity. Due to the aggressive nature of the sands and high velocities of greater than 50ft/s in Well G, a through-tubing ceramic sand screen was selected. The ceramic sand screen served as a fit for purpose solution that allowed the well potential to be fully maximised, enabling a continuous production with minimal sand production at surface. This paper reviews the first successful pilot installation of through-tubing ceramic sand screen in Well G in the Seligi Oil Field, Offshore Peninsular Malaysia. Discussed are careful analysis and planning, i.e. velocity calculations, tool deployment simulations, tool inspections and detailed job procedure leading to a successful installation. With the ceramic sand screen installed, the well was able to produce at 100% production choke opening with lower tubing head pressure and has not produced sand at surface despite multiple shutdowns and well bean ups. The installation has also removed the need to have sand handling facilities at topside and has generated an implicated cost saving from expensive intervention programs. Given the success of this pilot installation, a baseline in sand control has been set for this field, with new well candidates being considered for future replication.