--> Combination of Deep Reading and Near Well Bore Scale Measurement in Accessing Thin Facies Carbonate Reservoir

AAPG Asia Pacific Technical Symposium

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Combination of Deep Reading and Near Well Bore Scale Measurement in Accessing Thin Facies Carbonate Reservoir

Abstract

The reservoir Paciran (Mundu) Carbonate Formation at Sirasun Field of Kangean Block has been deposited in deep slope-shelf carbonate environment which has facies property variation. There is enough lithologic variation from very fine-grained marl and wackestone to permeable packstone and grainstone. The primary constituent of these packstone and grainstone is globigerinid foraminifera with a small matrix content of lime mud. Three horizontal development wells have been drilled in Sirasun Field targeting this grainstone facies which has good porosity and permeability with thinnest target around 5ft TVD. The main challenge of this well is to land and steer the well inside relatively thin facies reservoir thickness of grainstone. It also has lateral property distribution and vertical depth uncertainty due to limited offset well as this was the first development campaign without any prior knowledge of drilling horizontally in the Sirasun Field. The feasibility performed suggests the electromagnetic base Reservoir Mapping while Drilling which was able to map all of the critical marker boundary before penetrating the target zone and use all of those markers to accommodate any change during drilling related to formation uncertainty. The result by combining all of the Reservoir Mapping While Drilling inversion as well as near bit measurement has led to successful geosteering navigation process to place the well inside reservoir with high definition configuration of selected technology. Its capability of mapping reservoir along the wellbore give deep understanding of facies distribution. As an addition, near well bore scale image complement the Reservoir Mapping while Drilling Result to give details reservoir property and geometry. The successful of Reservoir Mapping while Drilling application on this project contribute increasing well deliverability by optimized drilling in production section and saving potential cost of eliminating pilot hole or side track.