The Use of 4D Dynamic Synthesis in Brown Field Development: A CaseStudy of S-P3 Infill Well Maturation, Preparation and Drilling

摘要

Based on the Field Development Plan (FDP), AKPO Reservoir ST was developed with two crestal producers(ST-P2 and ST-P1) and two water injectors at the periphery (ST-W2 on the eastern flank and ST-W1 onthe western flank). However, the results of a time lapse seismic monitor (4D M-2) in addition to dynamicsimulation showed that the attic oil of S-Reservoir would be bypassed at the end of Field life. The timelapse seismic monitor (4D M-2) results also showed that the main producer in the S-Reservoir; ST-P2 wasrisking early water breakthrough from the ST-W2 water injector at the toe. Hence, the need for an infill wellto mitigate these identified risks. This paper presents the maturation & drilling strategy, well results and theproduction performance of the first infill well of the AKPO Field. The infill maturation strategy involved the update of the geological model with recent well/ 4D seismicinformation, evaluation of the present static uncertainties on in-place volumes, history matching of thedynamic model in line with current field behaviour and the evaluation of the incremental production andeconomic value of the infill well. S-P3 trajectory was designed as a sub-horizontal drain to target and produce the attic oil in the S-Reservoirup-dip of producer ST-P2. It was completed across two fault blocks to ensure drainage of the southern panelas fault behaviour remains one of the main uncertainty. The well trajectory was placed as far up-dip aspossible, with its toe set higher than the shallowest completion of ST-P2 in the S-reservoir. The final well result for S-P3, drilled in Q4 2016, was outstanding, thanks to excellent integration ofseismic, geological and dynamic data. The main results included: 1. Optimal well placement, as a result of real time adjustments of the well trajectory aided by reservoirnavigation tools 2. More attic oil found as a result of shallower top of S-Reservoir 3. Incremental production of 15 kboepd over 2 years and an incremental reserves of ~10 Mboe.