浅层海相页岩含气性特征及其主控因素——以昭通太阳区块下志留统龙马溪组为例

浅层页岩气（埋深小于1 500 m）的勘探开发具有成本低、建产快等特点，受到广泛关注。昭通国家级页岩气示范区太阳区块下志留统龙马溪组页岩气具有埋深浅、高含气量的特点，显示出良好的勘探潜力，但前人对该区浅层页岩气的含气性分布及主控因素研究较少。为了丰富这方面的研究，利用太阳区块龙马溪组一段页岩样品的分析测试资料，对其含气性特征及主控因素进行分析。研究区龙一₁¹小层总含气量最高，自下而上含气量逐渐降低，平面上龙一₁亚段页岩含气量高值区位于研究区北部和南部；有机质含量、矿物组分、储层物性及外部保存条件等对研究区龙一₁亚段浅层页岩含气性具有一定的控制作用。有机质是生成页岩气的原始物质，同时其生烃裂解形成的有机质孔为页岩气提供大量的储存空间，有机质含量是总含气量的最主要控制因素；硅质矿物含量高，有利于后期压裂开发。研究区龙一₁亚段顶底板地层岩性致密，封闭性良好，具有微超压—超压特征，有效阻止了页岩气逸散，勘探前景广阔。

Gas-bearing characteristics and major controlling factors of shallow marine shale: a case study of the Lower Silurian Longmaxi Formation in Taiyang block of Zhaotong area

The exploration and development of shallow shale gas has the advantages of low cost and fast production reduction, so it has attracted wide attention. The shale gas in the Lower Silurian Longmaxi Formation (S1l) in Taiyang block of Zhaotong National Shale Gas Demonstration Zone has the characteristics of shallow burial depth and high gas content, showing good exploration potential. However, the gas-bearing distribution and major controlling factors of shallow shale gas in this research area are rarely studied previously. In order to enrich the research in this field, this paper analyzes the gas-bearing characteristics and the major controlling factors of the shale samples of Long-1 subsection (S1l1) in the Taiyang block. The results show that the total gas content of S1l11-1 is the highest in the study area, the gas content gradually decreases from bottom to top, and areas with high shale gas content in S1l1 appear in the north and south of the study area on the plane. Organic matter content, mineral components, reservoir properties and external preservation conditions have a certain role in controlling the gas properties of shallow shale in S1l11 subsection of the study area. Organic matter is the primitivesubstance that generates shale gas, at the same time, the organic matter hole formed by hydrocarbon cracking sprovides a lot of storage pace for shale gas, while the content of organic matter is the major controlling factor of the total gas content. The high content of silicoide is conducive to later fracturing development. The adjacent rock strata of S1l11 subsection in the study area are compact in lithology, with good sealing property, showing the characteristics of slight overpressure and overpressure, which effectively prevents the escape of shale gas, and has broad exploration prospects.