松辽盆地梨树断陷十屋油田区营城组、沙河子组储层成岩作用分析

Diagenesis of Yingcheng and Shahezi reservoirs in Shiwu Oil Field,Lishu Fault Depression,Songliao Basin

通过大量钻井岩心铸体薄片、扫描电镜、压汞、阴极发光、X-衍射、包裹体等分析,对松辽盆地梨树断陷十屋油田区沙河子组、营城组储层的成岩作用、成岩序列及孔隙演化进行了深入研究。该区主要成岩作用有压实作用、胶结作用、溶蚀作用及构造破裂作用,其中对储层物性具建设性的作用主要有溶蚀作用和构造破裂作用,而具破坏性作用的主要有压实作用和胶结作用。砂岩储层孔隙类型主要为原生粒间孔、粒间溶蚀扩大孔及少量裂缝的组合,以溶蚀孔隙为主。建立了砂岩储层的成岩序列,即机械压实→石英、长石次生加大→构造破裂→长石等铝硅酸盐溶蚀→粒状方解石胶结→早期进油→破裂→第二期溶蚀→连晶方解石胶结→晚期油气充注。研究认为,影响本区储层储集性能的主控因素为储层的沉积环境、成岩作用、构造作用及油气充注等因素。

Analyses such as casting thin slice,SEM,mercury penetration,cathodeluminescence,X-ray diffraction and inclusion were made with core samples from the Shahezi and Yingcheng reservoirs in the Shiwu Oil Field,the Lishu Fault Depression,the Songliao Basin,by means of which the diagenesis,diagenetic sequence and pore evolution of the two reservoirs were studied.The diagenetic effects in the study area were mainly compaction,cementation,denudation and structural fragmentation,among which denudation and structural fragmentation were contributive for reservoir physical property while compaction and cementation were destructive.The major pore style of sandstone reservoir was the combination of primary intergranular pore,intergranular erosion expand pore（accounting for the largest part） and a few fractures.The diagenetic sequence of sandstone reservoir was established as followed：mechanical compression→overgrowth of quartz and feldspar→structural fragmentation→erosion of aluminosilicate such as feldspar→cementation of grainy calcite→oil injection in the early stage→fragmentation→the second period of erosion→cementation of intergrowth calcite→late hydrocarbon injection.In the study area,the main controlling factors for reservoir property were sedimentary environment,diagenetic effect,structural effect and petroleum charging.