Integrated Reservoir Characterization of a Miocene Carbonate Buildup Without the Benefit of Core Data-A Case Study from Central Luconia Province,Sarawak

摘要

Central Luconia Province is one of the world’s largest carbonate complexes,with over 200 known Miocene build-ups,created by coral reef structures growing on horst blocks.Most build-ups are gas reservoirs,but also include some oil fields.Traps are stratigraphic,as porous carbonates are encased in sealing shales.The main method used to model properties in Miocene carbonate patch reefs is a direct porosity modeling using Acoustic Impedance as a secondary variable.The lack of long cored sections in this block is the main reason for the absence of facies integration in the static model.Another challenge is the limited number of wells per patch reef,which makes the understanding of lateral facies variation very limited. The main challenge to model these reservoirs is to characterize the distribution of the multi-scale heterogeneities,where hydraulic properties are not necessarily directly related to porosity.Accurate rock typing and porosity determination are key components for establishing porosity–permeability relation- ships based on rock type.The study area is located in Central Luconia Province,offshore Sarawak.The discovery well proved several hundred meters of gas column down to the gas-water contact within a Cycle IV carbonate patch reef.A complete set of logs was acquired,although no cores were available for facies identification and calibration.This case study presents a methodology to populate facies and porosity in 3D through a holistic approach to data integration and using conceptual models from field analogues.