Liu, Yan (Natural Gas Industry)Geological characteristics of gas-bearing shales in the Yanchang Formation and its resource assessment in the Ordos Basin
日期:2013年09月27日 10:51:20
标题:Geological characteristics of gas-bearing shales in the Yanchang Formation and its resource assessment in the Ordos Basin

作者:Liu, Yan ; Zhou, Wen; Deng, Hucheng1

期刊: Natural Gas Industry, v 33, n 3, p 19-23, March  2013;

Accession number:  20132116359796

摘要: This paper aims to make clear the shale gas exploration potential of the Yanchang Formation in the Ordos Basin. Based on outcrop investigation, core sample analysis, and old well data reexamination and in combination with organic geochemistry and rock analysis, gas content measurement, and isothermal adsorption curves, etc. , a systematic evaluation was conducted of formation distribution, petrological characteristics, geochemical characteristics, reservoir characteristics and other geological features like gas bearing in this study area. The following results were achieved. (1) The major target pay zones in this area are the members of Chang 4+5, Chang 7, Chang 9 in the Mesozoic Yanchang Formation, among which Chang 7 has the best quality in shales. (2) There is a wide distribution area of the lacustrine shales with great thickness, the sapropelic as the kerogen type, high TOC content, big distributional difference, strong adsorption ability, and the gas content of lacustrine shales is equivalent to that of marine shales. (3) By use of the volumetric method, the gas-in-place in the member of Chang 9 is calculated to be 0.4145 trillion m3, that of Chang 7 is 1.1506 trillion m3, that of Chang 4+5 is 0.2551 trillion m3; the resource reserves in the Chang 7 accounts for 63% of the total in the Yanchang Formation so that it can be selected as the first target zone in the shale gas exploration and development in this basin. In conclusion, it is considered that the shale gas resources are rich in the Yanchang Formation, Ordos Basin, which will be a new area for natural gas exploration and development in the future.(13 refs)