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Field A consists of multi stacked reservoirs in high geological complexity and heterogeneity setting, with waterflooding has been the secondary drive mechanism for the past two decades. However, in recent years, the field experiencing significant production decline that warrant immediate mitigation plan and action. Therefore, this paper highlights challenges and best practices in rejuvenating water injected reservoir to improve field production by integrating geological re-interpretation, data acquisition and analytical evaluation. The reservoir is defined in deltaic environment with complex fluvial reservoir architecture. Despite no indication of structural trap or compartmentalization, there is significant variation in reservoir performance across the field indicates lateral heterogeneity that is affecting the areal sweep efficiency. Poor production-injection allocation data due to commingled production, aggravated by tubing leaks have hindered for an optimum formulation of waterflood strategy in the past. As part of the mitigation plan, depo-facies definition and stratigraphy boundaries were further refined, guided by well and reservoir pressure performance. Besides, inter-well tracer injection implementation proved to be the game changer - unfolded hydrodynamic connectivity and flow path of injected water understanding, established actual producer and injector pairing, and identified poor or unswept areas. It was supported by comprehensive analytical water injection performance analysis including Hall's Plot, Chan's Plot, Jordan's Plot as part of the routine surveillance activities to trigger any non-conformance. More aggressive well intervention also helped to identify and rectify well issues. As the outcomes, there is opportunity to increase water injection rate by 30% field wide by reactivating idle wells, converting producers to injector, and maximizing the existing injection within the safe fracture limit. The subsurface risks on fracture gradient uncertainty and sweep inefficiency due to water cycling to be mitigated via injectivity test with gradual injection, close monitoring of liquid rate handling at surface, and pattern balancing between injectors and producers. The liquid rate is expected to be restored and sustained nearing the historical peak, hence improve field production and temper the decline. This paper presents the best practices to address the challenges in a matured waterflood reservoirs, considering the complex geology setting. Understanding of the flood pattern from tracer analysis, supplemented by producer-injection performance assessment and well integrity status validation enabled water injection to be ramped up at the right area in strategically and safely manner.

A 500m open hole horizontal well with 2 segmented sections was completed with Single Trip Completion with RFID technology in July 2021. This is the first application in Petronas asset which resulted into 21% of cost saving in well completion element against conventional two trips completion. Despite successful of well completion, well unloading phase is distressing to meet the expected production target. This paper elaborates on single-trip completion operation with RFID application and challenges faced during well unloading job to deliver one of the highest oil producers in Malaysia Petronas Carigali asset. Radio-frequency identification (RFID) technology offers interventionless in both activation and contingency in well completion activity. The technology utilized the optimal completion activation solution in minimizing the well cost and reducing operational risk, thus, resulted into significant rig time saving. The RFID has facilitated well completion deployment in high angle well in one trip. As conventional new infill well completion phase, well unloading is the vital stage to demonstrate the well completion is upright placed at desired depth and the well completion accessories are fully operated. KX reservoir in PR field was discovered via exploration well and essential downhole tests were deployed namely DST, PBU, Downhole and Surface sampling to obtain as much as reservoir & crude oil data due to its green field reservoir. The FDP team forecasted the production rate as per proven acquired data. Unfortunately, one of the reservoir parameters was predicted undervalued which constrained 3 kbopd additional oil production to be commercially produced. RFID tool of completion accessories has the actuation mechanism which enables for single trip completion, and it eliminates well intervention job, negates the needs of tractor service, and reduces the risk of stuck of tools. The RFID suite of tools offers three activation mechanism which provide utmost flexibility in both downhole equipment activation and contingency methods to optimize the cost further particularly in marginal PR field development. Though getting the achievement of first application of single trip completion with RFID, this project has suffered irresolute GOR during well unloading phase. Higher actual GOR against tested data during DST and PVT sampling caused high flowing pressure at surface which exceeded the PSV (Pressure Safety Valve) setting pressure, thus, hindered the actual technical potential of the promised oil producer in Petronas Carigali asset. RFID is technology enabler for single-trip completion project in PR field which indirectly improves economics of marginal field development. Decent downhole and surface data acquisition during exploration doesn't assure guaranteed reservoir & crude property data to be used during field development plan.