期刊
ENERGY EXPLORATION & EXPLOITATION
卷 33, 期 3, 页码 317-337出版社
SAGE PUBLICATIONS INC
DOI: 10.1260/0144-5987.33.3.317
关键词
Shale gas of the Yanchang Formation; Carbon isotope; Gas origin; Gas source analysis
资金
- Chinese National Natural Science Foundation [41102078]
- Chinese National Major Fundamental Research Developing Project [2011ZX05008-004]
- Shaanxi Province Innovation Project of Science and Technology Overall Planning [2012KTZB03-03-01]
The continental lacustrine-fluvial facies are the main sedimentary environment of the late Triassic Yanchang Formation in the Ordos Basin of China. The 7th Member and 9th Member of the Yanchang Formation (Chang 7 and Chang 9 for short) are shale members that contain an abundance of rich organic matter, in which, natural gas has been found. Ascertaining the genetic types and sources of the shale gas is of considerable significance to the evaluation of the exploratory potential and to reduce the exploratory risk in the Yangchang Formation. The analysis of the geochemistry characteristics of the shale gas, shale desorbed gas and dissolved gas of crude oil in the Yanchang Formation, of the study area, has have been performed. The result shows that the three types of gases are dominated by methane and that the dryness is less than 0.92 and ranges from 0.64 to 0.8. The three types of gases in the Triassic Yanchang Formation have similar gas components but are completely different from the gas components in Palaeozoic coal-derived type gas. The delta C-13(1) values of the shale gas, shale desorbed gas and crude oil dissolved gas vary between -41.6% and -51.6%, and the average value is -47.8%. The delta C-13(2) varies between -40.1% and -33.6%, and the delta C-13(3) is between -38.6% and -30.8%. The shale gas, shale desorbed gas and crude oil dissolved gas are all oil-type pyrolysis gases, which originate from the shale of Chang 7 and Chang 9. The results indicate that all of the gases have components of lighter methane carbon isotopes, which is obviously inconsistent with the low thermal maturity (0.7%<= Ro <= 1.3%) of the shale in the study area. The experiments demonstrate that the isotope fractionation during the process of gas adsorption and desorption is the primary cause of the inconsistence.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据