鄂尔多斯盆地甘泉地区延长组长7段页岩气储层特征研究

发布时间：2018-08-05 13:53

【摘要】：北美地区海相页岩气的成功勘探和开发为中国页岩气的研究提供了重要启示,但由于中国湖相页岩气储层地质情况不同且脆性矿物成分含量较少,相关理论认识不能简单地直接套用,因而根据中国不同地区的实际情况开展页岩气储层特征研究成为非常规油气地质研究的新热点。鄂尔多斯盆地三叠系延长组发育两套半深湖-深湖相页岩,近期伊陕斜坡东南部多口页岩气井的成功钻探证实了该区具有适宜的页岩气形成条件和巨大的勘探潜力,准确厘定页岩气储层特征是该区页岩气选区评价的关键问题。本文以鄂尔多斯盆地甘泉地区延长组长7段页岩为研究对象,采用多种地质评价和实验分析技术,对页岩气储层的空间展布特征、矿物组成、地化特征、储层孔隙类型和物性特征进行研究。采用的实验方法和分析技术主要有XRD矿物组分分析测试、岩石热解实验、氩离子剖光后扫描电镜观测、高压压汞实验、气体吸附实验和脉冲衰减法气测孔隙度实验。主要取得了以下认识：(1)甘泉地区长7段页岩主要为黑色页岩夹薄层灰黑色粉砂质泥岩、灰黑色含化石泥岩以及泥质粉砂岩,该区页岩气储层的矿物成分主要为石英、长石与粘土,此外还含少量碳酸盐、菱铁矿和黄铁矿；(2)页岩气储层有机质类型以Ⅱ1型-Ⅱ2型为主,TOC峰值在2%～6%,Ro变化范围为0.51%～1.25%,三者综合作用共同决定储层含气量；(3)页岩气储层的孔隙类型可以分为粒间孔、粒内孔和有机质孔,粒间孔包括碎屑颗粒粒间孔和粘土矿物粒间孔,是页岩内最主要的孔隙,粒内孔包括溶蚀孔和晶间孔,显著增加了储层有效孔隙,有机质孔的发育程度与有机质的成熟度密切相关；(4)研究区页岩气储层主要发育孔径为2-100rnm的中-大孔,2rnm以下的微孔和100nnm以上的大孔的体积相对较小。储层中含粉砂质纹层页岩比纯页岩的孔隙发育。
[Abstract]:The successful exploration and development of marine shale gas in North America have provided important inspiration for the study of shale gas in China. However, the geological conditions of China's lacustrine shale gas reservoirs are different and the contents of brittle minerals are relatively low. The related theories can not be applied directly, so it is a new focus of unconventional oil and gas geology to study shale gas reservoir characteristics according to the actual conditions in different regions of China. Two sets of semi-deep lacustrine-deep lacustrine shale have been developed in the Triassic Yanchang formation of Ordos Basin. Recent successful drilling of several shale gas wells in the southeast of the Yishan slope has proved that this area has suitable conditions for shale gas formation and great exploration potential. Accurate determination of shale gas reservoir characteristics is a key issue in shale gas selection evaluation in this area. In this paper, the shale of member 7 of Yanchang formation in Ganquan area, Ordos Basin, is taken as the research object. By using various geological evaluation and experimental analysis techniques, the spatial distribution characteristics, mineral composition and geochemical characteristics of shale gas reservoir are studied. Pore types and physical properties of reservoirs are studied. The main experimental methods and analytical techniques used include XRD mineral composition analysis and measurement, rock pyrolysis, scanning electron microscope observation after argon ion profile, high pressure mercury injection experiment, gas adsorption experiment and pulse attenuation gas porosity test. The main results are as follows: (1) the shale of Chang 7 in Ganquan area is mainly composed of black shale with thin layer of gray and black silty mudstone, gray black fossil mudstone and shaly siltstone. The mineral composition of shale gas reservoir in this area is mainly quartz. Feldspar and clay, in addition to a small amount of carbonate, siderite and pyrite; (3) the pore types of shale gas reservoir can be divided into intergranular pore, intragranular pore and organic pore. Intergranular pore includes clastic intergranular pore and clay mineral intergranular pore. The development degree of organic matter pores is closely related to the maturity of organic matter. (4) the volume of micropores below 2rnm with the pore size of 2-100rnm and the macropores above 100nnm are relatively small in shale gas reservoirs in the study area. The porosity of shale with silty grain layer is higher than that of pure shale in reservoir.
【学位授予单位】：西北大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.13

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