Bekapai field is a mature oil and gas field located in offshore of Mahakam Delta, East Kalimantan, Indonesia. This field plays an important role in increasing hydrocarbon production in Mahakam Delta. The accumulated hydrocarbon existed from shallow until deep interval in complex multilayered fluvial-deltaic reservoirs. Hydrocarbon bearing-reservoirs in this field varied from unconsolidated sands at shallower interval to consolidated sands at deeper interval. To maintain field production, the hydrocarbon potential at transition zone (between unconsolidated to consolidated sands) need to be reviewed whether it can be performed by direct perforation or using sand control intervention job for production.
Information of boundary between consolidated and unconsolidated reservoirs is very crucial for well completion optimization and sand production prevention. No sand control is needed to complete the consolidated reservoirs. By having reliable sand consolidation boundary, then well completion program could be optimized and maximizing production rate with less sand production issue.
This integrated sand consolidation evaluation is performed by evaluating all available data, such as conventional core analysis, cementation of petrography and SEM analysis, core physical check, sonic log response (DTshear, VpVs-DT plot), density-sonic cut-offs, downhole and laboratory rock scratch tests, critical depletion analysis, and production data. This integrated evaluation provides the estimated depth boundary between unconsolidated and consolidated sands in Bekapai field for supporting well completion program and reservoir perforation strategy. A trial of direct perforation job combined with continuous surface sand monitoring in this transition zone has been performed on several wells, and it is providing positive results in terms of good production gain and manageable sand-risk production. Following these positive outcomes, other candidates within the transition zone will be progressed as direct perforation job instead of sand control completion job which will significantly reduce the operating cost. To further extent, these results also support the optimization of completion strategy of future wells in Bekapai field.
This paper will explain the methodology, analysis of each data and its application, result and planning in Bekapai field that located in Mahakam Delta. This sand consolidation evaluation methodology might be applied as well in other oil and gas field areas, especially for the fields located in median axis of Mahakam Delta area.