地质学报（英文版）2008，Vol.82Issue(3)：629-635,7.
A Study of the Migration and Accumulation Efficiency and the Genesis of Hydrocarbon Natural Gas in the Xujiaweizi Fault Depression
A Study of the Migration and Accumulation Efficiency and the Genesis of Hydrocarbon Natural Gas in the Xujiaweizi Fault Depression
摘要
Abstract
In order to investigate the migration and accumulation efficiency of hydrocarbon natural gas in the Xujiaweizi fault depression, and to provide new evidence for the classification of its genesis, a source rock pyrolysis experiment in a closed system was designed and carried out. Based on this, kinetic models for describing gas generation from organic matter and carbon isotope fractionation during this process were established, calibrated and then extrapolated to geologic conditions by combining the thermal history data of the Xushen-1 Well. The results indicate that the coal measures in the Xujiaweizi fault depression are typical "high-efficiency gas sources", the natural gas generated from them has a high migration and accumulation efficiency, and consequently a large-scale natural gas accumulation occurred in the area. The highly/over matured coal measures in the Xujiaweizi fault depression generate coaliferons gas with a high δ13C1 value (＞ -20‰) at the late stage, making the carbon isotope composition of organic alkane gases abnormally heavy. In addition, the mixing and dissipation through the caprock of natural gas can result in the negative carbon isotope sequence (δ13C1 >δ13C2 >δ13C3 >δ13C4) of organic alkane gases, and the dissipation can also lead to the abnormally heavy carbon isotope composition of organic alkane gases. As for the discovery of inorganic nonhydrocarbon gas reservoirs, it can only serve as an accessorial evidence rather than a direct evidence that the hydrocarbon gas is inorganic. As a result, it needs stronger evidence to classify the hydrocarbon natural gas in the Xujiaweizi fault depression as inorganic gas.关键词
Xujiaweizi fault depression, hydrocarbon natural gas, migration and accumulation efficiency, genesis, carbon isotope fractionation, kineticsKey words
Xujiaweizi fault depression, hydrocarbon natural gas, migration and accumulation efficiency, genesis, carbon isotope fractionation, kinetics分类
天文与地球科学引用本文复制引用
LI Jijun ,LU Shuangfang,XUE Haitao,HUO Qiuli,XU Qingxia..A Study of the Migration and Accumulation Efficiency and the Genesis of Hydrocarbon Natural Gas in the Xujiaweizi Fault Depression[J].地质学报（英文版）,2008,82(3):629-635,7.基金项目
This paper is financially aided by the National Natural Science Foundation of China (No. 40572079), the Program for New Century Excellent Talents in University (No.NCET-04-0345), and the Venture Capital Foundation of PetroChina (No. 2005-01-02). （No. 40572079）
