Accumulations of Primary Microbial Gas: Commonalities and Main controlling factors

Abstract

Several large and giant accumulations of primary microbial gas have been discovered in recent years, including Tamar field offshore Israel, Zohr field offshore Egypt and Zawtika and other fields offshore Myanmar. Although the origin of these primary microbial gases can be readily established from their molecular and isotopic composition, factors that control the size of accumulations are less constrained. Various researchers identified the following factors that may control the volumes of generated and accumulated primary microbial gas: inter-bedding shales and sandstones, certain optimal combination of burial rate and geothermal gradient, volume of source rocks with certain content of total organic carbon, size of fetch area, methane solubility etc. In this presentation, I use geological and geochemical data from 34 sedimentary basins in 20 countries where fields of primary microbial gas occur and suggest geological environments and basin histories that favor accumulations of large pools of primary microbial gas.

AAPG Datapages/Search and Discovery Article #90336 ©2018 AAPG Asia Pacific Region, The 4th AAPG/EAGE/MGS Myanmar Oil and Gas Conference, Myanmar: A Global Oil and Gas Hotspot: Unleashing the Petroleum Systems Potential, Yangon, Myanmar, November 13-15, 2018