摘要
吉木萨尔芦草沟组页岩油层系岩性复杂,揭示不同类型储集层微观孔隙特征及非均质性控制因素,有利于指导该区页岩油甜点评价及优选。本文优选芦草沟组30块页岩油储集层样品,采用场发射扫描电镜、高压压汞、核磁共振等实验手段,刻画页岩油储集层微观孔隙结构,探讨混积型页岩油孔隙非均质性的控制因素。结果表明,芦草沟组发育7类孔隙和3类孔喉组合;随渗透率降低,粒间孔、粒间溶蚀孔等大孔减小,粒内溶蚀孔和晶间孔增加,"大孔-细喉"组合过渡为"短导管"和"树形网络"组合,孔径及可动饱和度均降低。页岩油孔喉非均质性主要受控于粒度和方解石、黏土胶结,前者决定较大孔(>1μm)能否发育,后者进一步缩小孔隙或孔喉,增加非均质性;在两者联合控制下,孔隙度与孔喉参数的相关性较差。
The lithology of shale-oil reservoir in the Lucaogou Formation is very complex.Understanding the heterogeneity of microscopic pores in the shale oil reservoir as well as its influencing factors will be useful for evaluating and optimizing the"sweet spots"of shale oil.The paper studied the heterogeneity of microscopic pores in shale oil reservoirs and its controlling factor by systematically characterizing 30 shale oil reservoir samples from the Lucaogou Formation using a variety of methods,e.g.field emission scanning electron microscope,high-pressure mercury injection,nuclear magnetic resonance.The results showed that a combination of 7 types of pore and 3 types of pore-throat was developed in the Lucaogou Formation,and with permeability decreased,the larger pores,such as intergranular dissolution pores and residual intergranular pores,decreased and the proportions of intragranular dissolution pores and intercrystalline pores increased,the pore-throat combination of"large pores connected by narrow throat"was gradually replaced by the combination of"short conduit-like shape"and"tree-like shape",and both the pore size and movable saturation decreased.Heterogeneity of pore structure was controlled by grain size and cementation,among which the grain size played a leading role in determining the development of larger pores(>1μm),while the cementation of clay and carbonate played a role in shrinking the size of pores and pore-throat and increasing the microscopic heterogeneity.These two aspects together lead to poor correlations between porosity and permeability of shale oil reservoirs.
作者
董岩
肖佃师
彭寿昌
李映艳
王锰
高阳
张方
DONG Yan;XIAO Dian-shi;PENG Shou-chang;LI Ying-yan;WANG Meng;GAO Yang;ZHANG Fang(Research Institute of Exploration and Development,Xinjiang Oilfield Company,PetroChina,Kelamayi 834000,China;Key Laboratory of Deep Oil and Gas,China University of Petroleum(East China),Qingdao Shandong 266580,China)
出处
《矿物岩石地球化学通报》
CAS
CSCD
北大核心
2021年第1期115-123,共9页
Bulletin of Mineralogy, Petrology and Geochemistry
基金
中国石油石化集团专项(2019E-26)
国家自然科学基金项目(41972139,41602141)
中央高校基本科研业务费专项资金(18CX02069A)。
关键词
微观孔隙结构
非均质性
影响因素
页岩油储集层
芦草沟组
microscopic pore structure
heterogeneity
influencing factors
shale-oil reservoirs
Lucaogou formation
