Abstract:

Based on core observation, testing and logging data of Chang 6 reservoir at H area in Ansai Oilfield, the heterogeneities of Chang 6 ^{1- 2}, Chang 6 ^2-1 and Chang 6 ^{2- 2} sublayers are studied, and the effect and control action of the heterogeneities on oil-bearing property are analyzed. The result shows that there are strong interlayer heterogeneity and strong in-layer heterogeneity, but weak planar heterogeneity of Chang 6 reservoir in the study area. The rhythmicity of grain size in vertical direction and the stratification features are important factors for the hydrocarbon distribution. The in-layer permeability heterogeneity and the difference of stratification coefficient between each sublayer play a weak role in controlling the hydrocarbon distribution. The difference of sand density also controls the hydrocarbon distribution, but not the main controlling factor. The oil-bearing properties are mainly controlled by the sand body distribution and reservoir properties, and the microscopic heterogeneity in pore structure controls the full degree of hydrocarbon entering into the reservoirs.

Key words: Liuhua organic reef, sedimentary facies characteristics, reservoir characteristics, controlling factors, Miocene Zhujiang Formation, Pearl River Mouth Basin