Fumiaki Matsuda¹, Y. Yoshida², R. Iwahashi¹, O. Tsukui², H. Ooki², H. Sato²

(1) Japan National Oil Corporation, Chiba-shi, Chiba, Japan
(2) Japan National Oil Corporation

ABSTRACT: Computer Simulation of Carbonate Facies Distribution and Shallow Diagenetic Process of Miocene Carbonate Reservoirs, Southeast Asia

The geological model of F6 field, offshore Sarawak, Malaysia was reconstructed based on detailed cores descriptions and samples analyses approximately at every ten feet including thin-section petrographic, faunal, biostratigraphic, XRD mineral compositional, and carbon and oxygen stable isotope analyses. The reservoir section in the upper part of the carbonate buildup was subdivided into the lower, middle and upper units. The lower unit mainly consists of a restricted back reef facies. The middle unit comprises an alternation of a shallow fore reef and deep fore reef facies. Backstepping of the reef occurred in deep fore reef environments with siliciclastic inputs. The upper unit is mainly composed of a relatively open marine reef facies. The reef was drowned during a major subsequent transgression.

The above-mentioned model was reconstructed using the Facies-3D carbonate model, which is a computer simulator for reconstruction of carbonate sedimentary processes, developed by the Technology Research Center of Japan National Oil Corporation. The model describes three-dimensional carbonate facies distribution based on water depth and current velocity in conjunction with paleo-topography, and modification of porosities in meteoric diagenetic environment. Simulation input parameters were extracted from interpreted geological and geophysical data in the field and through iterative simulations. The results of the simulations show that the Facies-3D carbonate model approximated to a high degree, facies distribution and porosity modification in meteoric diagenetic process. The Facies-3D carbonate model can be applied as a tool for reservoir characterization in a field scale.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado