四川威远地区九老洞组页岩微观非均质性

Micro heterogeneity of Jiulaodong Formation shale, Weiyuan Area, Sichuan

隋青林

SUI Qinglin

（中国石化胜利油田分公司勘探开发研究院，山东 东营 257015）

(Research Institute of Exploration and Development, Shengli Oilfield Company, SINOPEC, Dongying 257015, China)

目前，国内外对于页岩非均质性的研究刚刚起步，相关理论还不成熟。文中利用X射线衍射手段，结合观察九老洞组页岩样品的薄片和扫描电镜，在微米级—纳米级的尺度下，从矿物组分、微观孔隙和微裂缝3个方面来评价页岩的微观非均质性。从矿物组分的角度来看，主要矿物为石英，其次为斜长石和黏土矿物，样品矿物组分和含量上没有明显的差异性。在厘米以上尺度，页岩岩性和矿物组分纵向非均质性较弱；而在微观尺度下，矿物组分对孔隙发育和分布状态影响较大，非均质性明显，而且随着观测倍数增大，页岩微观非均质性将会越来越明显。从微观孔隙的角度来看，主要发育粒间孔、粒内孔、晶间孔和有机质孔等类型。在微观尺度下，页岩孔隙类型、分布和孔径大小差别较大，非均质性明显。从微裂缝的角度来看，在2 711~2 815 m的页岩岩心，下部裂缝较上部发育，表明在毫米级—厘米级的裂缝非均质较为明显。微米级—纳米级的微裂缝尺度变化较大，微裂缝可分为黏土转化缝、成岩收缩缝和异常高压缝，微裂缝形态多样，其发育特征和配置关系在微观尺度下具有强非均质性。

At present, the research on the heterogeneity of shale reservoirs has just started, and the related theories are not mature. Using x-ray diffraction, thin sections and scanning electron microscope(SEC) of shale samples in micron and nanometer scales, the micro heterogeneity of shale is evaluated from three aspects of mineral composition, micro pore and micro fracture. From the perspective of the mineral composition, the main minerals are quartz, followed by plagioclase and clay minerals. There is no significant difference in the mineral composition and content of the samples. The vertical heterogeneity of shale lithology and mineral composition is weaker in the centimeter scale. But in the micro scale, the mineral composition has a great influence on the pore development and distribution, and the heterogeneity is obvious. With the increase of the observation scale, the micro heterogeneity of shale will become more and more obvious. From the view of micro pore, it mainly developed intergranular pore, intragranular pore, intercrystalline pore and organic matter pore. In the micro scale, the pore type, pore distribution and pore size of the shale are different, and the heterogeneity is obvious. From the view of micro fracture, in the 2711￣2815 m shale core, the lower part of the fractures is better developed than the upper part, which shows that the fracture heterogeneity is more obvious in the millimeter level and centimeter level. Micro fracture scale of micron and nanometer level changes large, and micro fracture can be divided into clay transformation fracture, shrinkage fracture and abnormal high pressure fracture. The morphology of micro fracture is diverse, and the development characteristics and configuration relationships have strong heterogeneity in the micro scale.

10.6056/dkyqt201701004