鄂尔多斯盆地南缘平凉组非常规储层特征  

Characteristics of Unconventional Reservoirs in Pingliang Formation,Southern Margin of Ordos Basin

作　　者：史鹏[1] 张建锋[1] 周伟[2] 刘刚[1] 孙建博[1] 王晖 SHI Peng;ZHANG Jian-feng;ZHOU Wei;LIU Gang;SUN Jian-bo;WANG Hui(Natural Gas Research Institute of Shaanxi Yanchang Petroleum(Group)Co.,Ltd.,Xi'an 710065,China;School of Earth Science and Resources,Chang an University,Xi'an 710054,China)

机构地区：[1]陕西延长石油(集团)有限责任公司天然气研究院分公司,西安710065 [2]长安大学地球科学与资源学院,西安710054

出　　处：《科学技术与工程》2024年第21期8861-8868,共8页Science Technology and Engineering

基　　金：国家科技重大专项(2017ZX05039001005);延长石油集团科研项目(ycsy2022jcts-B-42);国家自然科学基金(51804036);中国科学院西部之光基金(XAB2021YW03);陕西省自然科学基金面上项目(2023-JC-YB-368)。

摘　　要：鄂尔多斯盆地南缘奥陶系平凉组发育泥页岩和碳酸盐岩两种类型的烃源岩。为研究平凉组源储一体型非常规油气储层特征,通过野外地质剖面观测、岩心观察及样品分析测试,对平凉组源岩层系的烃源岩属性及储集层属性同时进行分析。研究表明,平凉组泥页岩类烃源岩主要发育在研究区西南部陇县-岐山地区,沉积环境为台地边缘斜坡,其岩性以硅质页岩、钙质页岩夹粉砂岩为主。碳酸盐岩类烃源岩主要发育在研究区中东部旬邑-铜川地区,沉积环境为台地边缘礁滩及开阔海台地,岩性以泥灰岩、泥晶灰岩为主。平凉组烃源岩干酪根类型以Ⅰ型为主,含少量Ⅱ1型;有机碳含量平均0.41%,属于中等烃源岩;等效镜质体反射率平均值为1.73%,岩石热解温度T_(max)平均值达489℃,属于高成熟阶段;平凉组烃源岩脆性指数较高,孔隙度平均为1.38%,渗透率平均为0.05 mD,泥页岩物性总体优于碳酸盐岩;甲烷吸附量分布在0.64~2.16 cm^(3)/g,平均为1.71 cm^(3)/g,其中泥页岩和泥灰岩甲烷吸附量明显高于泥晶灰岩。综合分析认为陇县-麟游地区平凉组泥页岩发育,硅质脆性矿物含量高,物性及含气性较好,可进一步开展海相页岩气勘探。中东部旬邑-铜川地区泥灰岩类烃源岩具有较好的生烃能力和甲烷吸附能力,具备形成自生自储型泥灰岩非常规天然气储层的基本条件;泥晶灰岩类烃源岩可有效生烃但储集性和甲烷吸附能力较差,建议与礁滩相储集体共同开展生储盖组合研究,进行碳酸盐岩天然气勘探。Ordovician Pingliang Formation in the southern margin of the Ordos Basin develops two types of hydrocarbon source rocks:mud shale and carbonate rocks.In order to study the characteristics of the source-storage integrated unconventional oil and gas reservoirs in Pingliang Formation,the properties of hydrocarbon source rocks and reservoirs were simultaneously analyzed through field geological profile observations,core observations,and sample analysis tests.The results indicate that mud shale source rocks are mainly developed in the Longxian-Qishan region(i.e.the southwest part of the study area).The sedimentary environment is a plateau margin slope,and the lithology is mainly marl and micrite limestone.Carbonate source rocks are mainly found in the Xunyi-Tongchuan region(i.e.the central-eastern part of the study area).The sedimentary environment consists of platform edge reef shoals and open sea platforms,and with the main lithologies being mudstone,mud-crystal limestone.The kerogen type of source rocks in Pingliang Formation is mainly type I,with a small amount of typeⅡ1.The average organic carbon content is 0.41%,implying that they are moderately productive source rocks.The average vitrinite reflectance is 1.73%,and the average value of rock pyrolysis T_(max) is 489℃,indicating a high mature stage.The Pingliang Formation source rocks exhibit high brittleness,with an average porosity of 1.38%,and an average permeability of 0.05 mD,and the physical properties of shale rocks are better than that of carbonate rocks.Methane adsorption capacity ranges from 0.64 cm^(3)/g to 2.16 cm^(3)/g,with an average of 1.71 cm^(3)/g,and mud shale and marlstone show significantly higher methane adsorption than micrite limestone.Comprehensive analysis suggests that Pingliang Formation in the Longxian-Linyou region has well-developed mud shale,high content of siliceous brittle minerals,favorable physical and gas-bearing properties,indicating significant potential for further exploration of marine shale gas.In the central-eastern Xu

关 键 词：鄂尔多斯盆地 平凉组 烃源岩 非常规储层 地球化学特征 页岩气 

分 类 号：P618.13[天文地球—矿床学]