石油科学通报2025，Vol.10Issue(4)：633-646,14.DOI:10.3969/j.issn.2096-1693.2025.01.020
陡陆坡背景下的海底扇内部储层质量差异
Reservoir quality differences within the submarine fan under a steep continental slope setting:A case study of the X gas field,Rovuma Basin,East Africa
摘要
Abstract
The submarine fan is an important reservoir for oil and gas in deep water areas.The differences in reservoir quality have a significant impact on the differential accumulation and exploitation of oil and gas.Previous studies have conducted extensive research on the differences in reservoir quality of submarine fans.However,the characteristics and distribution patterns of reservoir quality differences within submarine fans under a steep continental slope background are still unclear.This paper takes the Oligocene submarine fan reservoir in the X gas field of the Rovuma Basin in East Africa as the research object.By integrating core,well logging and seismic data,an in-depth study has been carried out on the control of reservoir quality differences and distribution patterns of submarine fan sedimentary microfacies and lithofacies under the steep continental slope background.The results show that the changes in reservoir quality within the submarine fan are mainly controlled by rock texture,lithofacies(association)and sedimentary microfacies under the circumstance of weak diagenesis.Grain sorting and clay content mainly control the porosity and permeability of the reservoir,respectively,but the relationship between grain size and reservoir properties is very complex.In sand-rich lithofacies,fine sandstones have the highest porosity due to their good sorting,and massive gravel-bearing coarse sandstones have the highest permeability due to their low clay content.Under the steep continental slope background,the submarine fan sedimentary microfacies are arranged in the order of muddy channel-sandy channel-lobe main body-lobe edge along the source direction,resulting in the source-directional differences in reservoir quality in the order of"poor,good,and poor".The proximal muddy channel consists of fine-grained and clay-rich lithofacies,with overall poor physical properties.In the middle position,the sandy channel and lobe main body change to massive gravel-bearing coarse sandstone lithofacies and medium-coarse sandstone lithofacies,with low clay content and improved to good physical properties.Among them,the reservoir quality of the sandy channel is better than that of the lobe main body.The internal high porosity and high permeability zones of the sandy channel are in the form of elongated lenses,while the relatively high porosity and high permeability areas of the lobe main body are in the shape of lobes.The distal lobe edge changes to fine-grained lithofacies(fine-medium sandstone,fine sandstone)with increased clay content and gradually deteriorated physical properties.关键词
陡陆坡/海底扇/鲁伍马盆地/储层质量差异/岩相Key words
steep continental slope/submarine fan/Ruvuma Basin/reservoir quality differences/lithofacies分类
天文与地球科学引用本文复制引用
熊绮聪,吴胜和,徐振华,陈梅,王敏,余季陶,王瑞峰..陡陆坡背景下的海底扇内部储层质量差异[J].石油科学通报,2025,10(4):633-646,14.基金项目
国家自然科学基金(42002112)、中国石油勘探开发研究院和中国石油大学(北京)合作项目(RIPED-2021-JS-552)联合资助 （42002112）
