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Evolution of overmature marine shale porosity and implication to the free gas volume

Authors :
Feiyu WANG
Jing GUAN
Weiping FENG
Linyan BAO
Source :
Petroleum Exploration and Development, Vol 40, Iss 6, Pp 819-824 (2013)
Publication Year :
2013
Publisher :
KeAi Communications Co., Ltd., 2013.

Abstract

The porosities of the Lower Cambrian shale and Upper Ordovician-Lower Silurian marine shale from the Sichuan Basin were analyzed using He-Hg porosimetry and field-emission scanning electron microscopy, to discuss the relationship of porosity to the organic matter maturity, total organic carbon (TOC) and free gas volume. Overmature (Ro greater than 2%) shale samples with a TOC less than 5% display a positive correlation between TOC and porosity, but samples with a TOC greater than 5% display a limited increase in porosity with increasing TOC. The porosity of shale decreases generally with increasing maturity in the overmature stage. The free gas in porosity is the key factor for successful development of shale gas, and free gas volumes are controlled by porosity and gas saturation. Higher TOC shale has higher porosity and gas saturation. The Lower Silurian Longmaxi Formation shale has a higher TOC, Ro ranging from 2.0% to 2.3%, its porosity and gas saturation are significantly higher than the Lower Cambrian shale. The high free gas volume results in high production in the Lower Silurian Longmaxi Formation shale pay. Key words: marine shale, porosity, free gas, overmature, Sichuan Basin

Details

Language :
English, Chinese
ISSN :
18763804
Volume :
40
Issue :
6
Database :
Directory of Open Access Journals
Journal :
Petroleum Exploration and Development
Publication Type :
Academic Journal
Accession number :
edsdoj.8d6907d20834f698d5657b2e419c9fe
Document Type :
article
Full Text :
https://doi.org/10.1016/S1876-3804(13)60111-1