We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Hydrocarbon Generation and Expulsion of the Upper Triassic Source Rocks in the Western Sichuan Depression: Assessment for Unconventional Natural Gas.
- Authors
GUO Yingchun; SONG Yan; PANG Xiongqi; WANG Youwei; YANG Keming; LI Boyuan
- Abstract
Tight-sand gas in the Jurassic and shale gas within the fifth member of Xujiahe Formation (T3×5) in the Western Sichuan Basin (WSD) are currentiy regarded as the most proiific emerging unconventional gas plays in China. This study conducted a conventional evaluation of T3×5 source rocks in the WSD, and investigated their hydrocarbon generation and e×pulsion characteristics, including intensity, efficiency and amount. The results show that, the T3×5 source rocks are thick (generally >200 m), and have a high total organic content (TOC), ranging from 2.5 to 4.5 wt%. It is thus indivative of a great hydrocarbon generation potential when they underwent high thermal evolution (Ro>1.2%) in the area. In addition, an improved method of hydrocarbon generation potentiai is applied, indicating that the source rocks reached a hydrocarbon e×pulsion threshold with vitrinite reflectance (Ro) reaching 1.06%, and that the comprehensive hydrocarbon e×pulsion efficiency is about 60%. The amount of hydrocarbon generation and e×pulsion from T3×5 source rocks is 3.14×10 t and 1.86×10 t, respectiveiy, with a residual amount of 1.28×10 t within them. Continuous-type tight-sand gas is predicted to have developed in the Jurassic in the Chengdu Sag of the WSD because of the good source-reservoir configuration; the Jurassic sandstone reservoirs are tight, and the gas e×pelied from the T3x5 source rocks migrates for very short distances verticaliy and horizontaily. The amount of gas accumulation in the Jurassic reservoirs derived from T3x5 source rocks is up to 9.3×10 t. Geological resources of shale gas are up to 1.05×10 t. Small differences between the amounts calculated by the volumetric method and those obtained by hydrocarbon generation potential method may be due to other gas accumulations present within interbedded sands associated with gas shales.
- Subjects
CHINA; HYDROCARBONS; ROCKS; NATURAL gas; GAS reservoirs; TRIASSIC Period
- Publication
Acta Geologica Sinica (English Edition), 2015, Vol 89, Issue 1, p175
- ISSN
1000-9515
- Publication type
Article
- DOI
10.1111/1755-6724.12403