Abstract

The shales in the 2^nd Member of Shanxi Formation in the east margin of the Ordos Basin were deposited in a marine-nonmarine transitional environment during the Permian. Based on the recent breakthroughs in the shale gas exploration and theoretical understandings on the shale gas of the study area, with a comparison to marine shale gas in the Sichuan Basin and marine-nonmarine transitional shale gas in the U.S., this study presents the geological characteristics and development potential of marine-nonmarine transitional gas in the study area. Four geological features are identified in the 2^nd Member of the Shanxi Formation in the study area has: (1) stable sedimentary environment is conductive to deposition of widely distributed organic shale; (2) well-developed micro- and nano- scale pore and fracture systems, providing good storage capacity; (3) high content of brittle minerals such as quartz, leading to effectively reservoir fracturing; and (4) moderate reservoir pressure and relatively high gas content, allowing efficient development of shale gas. The 2^nd Member of Shanxi Formation in the east margin of Ordos Basin is rich in shale gas resource. Three favorable zones, Yulin-Linxian, Shiloubei-Daning-Jixian, and Hancheng-Huangling are developed, with a total area of 1.28×10⁴ km² and resources between 1.8×10¹² and 2.9×10¹² m³, indicating a huge exploration potential. Tests of the 2^nd Member of Shanxi Formation in vertical wells show that the favorable intervals have stable gas production and high reserves controlled by single well, good recoverability and fracability. This shale interval has sufficient energy, stable production capacity, and good development prospects, as evidenced by systematic well testing. The east margin of the Ordos Basin has several shale intervals in the Shanxi and Taiyuan formations, and several coal seams interbedded, so collaborative production of different types of natural gas in different intervals can be considered. The study results can provide reference for shale gas exploration and development and promote the rapid exploitation of shale gas in China.

中文翻译：

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西北鄂尔多斯盆地东缘页岩过渡带地质特征及开发潜力

摘要

在2页岩^届山西的会员组鄂尔多斯盆地东缘沉积在二叠纪海洋-陆相过渡环境。基于页岩气勘探的最新突破和对研究区页岩气的理论认识，并与四川盆地的海相页岩气和美国的海相-非海洋过渡页岩气进行了比较，该研究提出了地质特征研究区海洋-非海洋过渡性气体的开发潜力和发展潜力。^第二阶段确定了四个地质特征研究区山西组成员具有：（1）稳定的沉积环境有利于有机质页岩的广泛分布；（2）发达的微米和纳米级孔隙和裂缝系统，具有良好的储存能力；（3）石英等脆性矿物含量高，导致有效的储层压裂；（4）适度的储层压力和较高的瓦斯含量，可有效开发页岩气。2^次山西的人员构成在鄂尔多斯盆地东缘中含有丰富的页岩气资源。开发了榆林-x县，石楼北-大宁-蓟县，韩城-黄陵三个优势区，总面积为1.28×10 ⁴ km ²，资源在1.8×10 ^12之间。2.9×10 ¹² m ³，勘探潜力巨大。^第二次测试垂直井山西组成员表明，该有利区间具有稳定的天然气产量和单井控制的高储量，良好的可采性和压裂性。系统的试井证明，该页岩层段具有足够的能量，稳定的生产能力和良好的开发前景。鄂尔多斯盆地东缘在山西和太原地层中有几个页岩层段，并夹有多个煤层，因此可以考虑在不同的层段内联合生产不同类型的天然气。研究结果可为页岩气的勘探开发提供参考，促进我国页岩气的快速开发。