鄂尔多斯盆地红河油田长8油层组致密砂岩储层“甜点”成因机制  

Forming mechanisms of reservoir “sweet spots”in tight sandstones of Chang8 Formation,Honghe oil field,Ordos Basin

作　　者：王付斌[1] 尹伟[2] 陈纯芳[2] 

机构地区：[1]中国石化华北油气分公司勘探管理部,郑州450006 [2]中国石化石油勘探开发研究院,北京100083

出　　处：《石油实验地质》2017年第4期484-490,共7页Petroleum Geology & Experiment

基　　金：国家科技重大专项"中西部重点碎屑岩层系油气富集规律与勘探方向"(2016ZX05002-006)资助

摘　　要：鄂尔多斯盆地红河油田长8油层组储层物性普遍具有低渗—致密特征,但局部发育储层"甜点"(即相对优质储层),并控制着油气富集高产,因此,开展储层"甜点"成因机制研究对致密砂岩储层预测意义重大。通过大量岩石薄片、铸体薄片、阴极发光、扫描电镜、荧光薄片等的系统观察与统计,结合储层矿物组成、胶结物含量、物性测试分析,从沉积建造到成岩改造开展了储层物性影响因素的全过程分析,剖析沉积、成岩、破裂及油气侵位作用对致密砂岩储层储集性能的影响。结果表明,沉积作用是控制致密砂岩储层物性的第一位因素,奠定了致密砂岩储层发育的物质基础,并控制了其原始物性;成岩作用控制了致密砂岩储层的孔隙演化,其中建设性成岩作用控制了储层"甜点"的发育,并最终控制了孔隙型致密砂岩储层"甜点"分布;裂缝大大提高了致密砂岩储层渗流能力,并最终控制了裂缝—孔隙型致密砂岩储层"甜点"分布;油气侵位抑制了胶结作用的进行,是致密砂岩储层"甜点"重要的保持机制。Reservoir “sweet spots” （that is ,relatively high quality reservoirs） exist locally in the low- permeability, tight sandstone reservoirs of Chang8 Formation in the Honghe oil field,controlling hydrocarbon enrichment and production. This reservoir provides evidence and direction for prediction of tight sandstones to study their forming mechanisms. The impacts of sedimentation, diagenesis,fracturing and oil emplacement on reservoir quality of the tight sandstones during the whole reservoir evolution process from sedimentary construction to diagenetic reforma-tion were systematically analyzed using rock sections, casting thin sections, cathode- luminescence, scanning electron microscopy, micro fluorescence observations and statistics, combined with the analyses of mineral composition,volume of cementation minerals and reservoir physical tests. The results indicate that sedimentation is the most important factor controlling tight sandstone reservoir properties by providing a material basis and controlling the original properties of tight sandstones. Diagenesis is another factor which controls the porosity evolution of tight sandstones,and construction diagenesis controls the formation of reservoir “ sweet spots” in tight sandstones and the distribution of “sweet spots” in pore-type tight sandstone reservoirs. The superimposed reformation of structural fractures improves the reservoir properties of tight sandstones,especially the permeability, resulting in the distribution of “sweet spots” in fractured tight sandstone reservoirs. Oil emplacement inhibits cementation as one of the important mechanisms of “ sweet spot” preservation in the tight sandstone reservoirs.

关 键 词：储层“甜点” 沉积作用 成岩作用 油气侵位 长8油层组 红河油田 鄂尔多斯盆地 

分 类 号：TE122.24[石油与天然气工程—油气勘探]