_ Advanced well completions have proven to be an effective method of moderating gas breakthrough while producing a thin oil rim when placed in a heterogenous, carbonate reservoir. In addition, several studies have proven that the application of autonomous inflow control devices (AICDs) acts as a type of insurance policy against geological and dynamic reservoir uncertainties to reduce the risk and variation in the expected oil production profiles. During 2019 and 2020, Sarawak Shell Berhad conducted development campaigns in the central Luconia province in a thin oil rim carbonate reservoir offshore Sarawak, Malaysia. The horizontal, approximately 6,000-ft development wells were expected to intersect with different geological layers with varying rock properties, resulting in an uneven reservoir influx toward the wellbore. Oil production from these wells was expected to suffer severely from early gas and water breakthrough. To produce the oil rim without the risk of early gas production, global production optimization specialist, Tendeka, incorporated FloSure AICDs in the lower completion design at the reservoir interface along the horizontal section of the wells. As an active flow control device, the technology delivers a variable flow restriction in response to the properties of the fluid entering the wellbore and the rate of flow passing through it to help manage gas coning/cusping risks. The fluid is then lifted to surface with natural in-situ gas lift built into the upper completion. A three-phase development was planned for the field, and to date, two phases have been completed. New-Generation ICD The first AICD completion was installed in Norway in 2008 and widely implemented in the Troll field in 2013 with very encouraging results (SPE 159634). However, its use is relatively new to both the Asia Pacific region and this type of application. Similar to a standard ICD which balances the influx of reservoir fluids, the FloSure AICD will delay the production of unwanted effluents prior to their breakthrough (proactive solution). However, once a breakthrough occurs, the device restricts the production of unwanted effluents with lower viscosity, such as gas (in light oil applications) and both gas and water in viscous oil production (reactive solution) (OTC 30403, OTC 30363, SPE 193718). The device delivers a variable flow restriction in response to the properties of the fluid and the rate of flow passing through it. Flow enters the device through the nozzle in the top plate of the body. This impacts the disk and spreads radially through the gap between the disk and the top plate, then turns around the top plate and is discharged through several outlet ports in the body (Fig. 1). The overall geometry of the device is critical to its ability to balance these forces effectively and create the desired fluid-dependent pressure drop. Field A employed 7.5-mm AICD valves to match the performance of the devices to the potential well flow rate. The oil, water, and gas viscosities are 0.40 cP, 0.27 cP, and 0.018 cP, respectively, at downhole flow conditions.

This paper presents a state-of-the-art, automated gas lifted smart completion design, installed safely using Side Mounted Guns (SMG) to reduce well control risks for a carbonate field in Sarawak with a dominant threat of karst losses. It demonstrates how an SMG system was used to decrease installation time and minimize formation damage. The new 3D finite element software technique represents a step change in the ability to predict shock loading from complicated perforating systems and the subsequent effect on downhole completion components. Several challenges were addressed at the planning phase of the project, including the use of a new 3D finite element software to evaluate dynamic perforating shock loading and determine the optimal distance to safely place the key completion components in the well. A variety of system integration tests (SITs) were also introduced to verify compatibility of the SMG system in highly deviated well conditions and deploying through casing with inner diameter changes. Three wells have been successfully perforated with a long tubing-conveyed SMG system along with the smart well completion components, such as an inflow control valve (ICV), downhole pressure gauges, and seal assembly, which were then tested as fully functional after the gun detonation. During the well cleanup operation, the perforated gas cap was successfully used to lift the oil from the reservoir underneath the gas cap as an in-situ gas lift.

During 2019 and 2020 the field operator conducted development campaigns in a thin oil rim carbonate reservoir offshore Malaysia. The horizontal development wells were expected to intersect heterogeneous formations with varying properties resulting in an uneven reservoir influx toward the wellbore. Oil production from these wells was expected to suffer severely from an early gas breakthrough. These challenges were recognized to be mitigated by deploying Autonomous Inflow Control Devices (AICDs), installed at reservoir interface along the horizontal section of the wells. The AICDs can manage the reservoir fluid influx entering the wellbore and therefore optimise the well performance. To improve oil production and ultimate recovery, AICDs were incorporated in the lower completion design for the development wells. The Rate Controlled Production (RCP) AICD was chosen for this application. It is an active flow control device, delivering a variable flow restriction in response to the properties of the fluid and the rate of flow passing through it. This paper summarizes the integrated technical learnings from this project. An integrated workflow was followed to design and deliver the AICD applications successfully for the operator in an offshore light oil reservoir with huge uncertainties in remaining oil thickness and reservoir properties. The wells with a horizontal length of ~6000 ft were drilled in a relatively thin oil formation. The well intersected different geological layers with different rock properties. The lower well completions comprised of RCP AICD valves, shrouded with debris filter screens with an in-situ gas lift system in the upper completions helping to lift the fluids to the surface. The wells were segmented into compartments with blank joints and swell packers and tailored AICD placements based on individual well's real-time log data to properly restrict the production of unwanted fluids. Through teamwork between the companies, the wells were successfully completed with AICDs. The final modelling was performed just in the time span between reaching target depth and running the completion. Over two years of production, the wells completed with AICD not only have not seen any problem in terms of solid production, but they have also successfully exhibited limited GOR development which enabled oil production optimization. A PLT was also run recently in one of the wells to analyze further the zonal contribution of each section of the well and how AICD has effectively choked back the gas in selective zones. The results show that the AICD completion ensured a balanced contribution from the entire 6000 ft long horizontal section in the well despite the heterogeneity of the carbonate reservoir and has potentially reduced the gas production significantly to enable more optimized oil production within gas offtake limits in the reservoir management plan.