东营凹陷古近系沙四段页岩微观孔隙结构特征

Micropore structure characteristics of shale in the Paleogene Sha-4 Member,Dongying Sag

页岩储层微观孔隙结构特征是储层物性特征评价的重要内容之一。本研究使用氩离子抛光-场发射环境扫描电镜技术对渤海湾盆地东营凹陷沙四段页岩中的微孔结构进行了观测,并运用图像处理软件JMicroVision对各类型微孔进行了定性和定量分析。结果表明:孔径介于100~801nm的粒内孔以及100~981nm的粒间孔对页岩总孔隙度贡献最大;粒间孔和粒内孔的大量发育与矿物含量高有关,其中含量最高的黏土矿物的粒间孔和粒内孔与微裂隙伴生,并在页岩中呈条带状分布。氩离子抛光-场发射环境扫描电镜结合JMicroVision定量分析技术精度可达纳米级,能够为页岩微孔隙研究提供直观可靠的资料。

Micropore structure characteristic of shale reservoirs is one of the significant contents for shale reservoir physical properties appraisal. The micropore morphology of Paleogene Sha-4 Member shale was investigated using focused Ar-iron beam polishing （Ar- FIB） and field-emission environmental scanning electron microscope （ESEM） and micropore qualitative and quantitative analysis were processed with JMicroVision software. Results show that intragranular with 100 ？801 nm and intergranular pores with 100 ~981 nm take a largest proportion in total shale pores; abundant intergranular and intragranular pores in shale are associated with high mineral content, especially clay minerals; intergranular and intragranular pores in clay minerals always develop accompany with microfracture as band in shale reservoirs. The accuracy of Ar-FIB and FESEM technology combined with JMicroVision software can reach nanometer grade, and provided visualized and reliable data for shale reservoirs research.