Global Meso-Neoproterozoic Petroleum Resources
State Key Laboratory of Petroleum Resources & Prospecting, China University of Petroleum, Beijing, China
The significant research progresses of Earth’s early life and biodiversity during the Proterozoic Era have established a material foundation for the Meso-Neoproterozoic sedimentary organic matter and related petroleum resources.
Since 1960s indigenous Neoproterozoic-Early Cambrian (Infracambrian) oil and gas have been reported and at least a dozen hydrocarbon plays or fields discovered in many parts of the world. So far there have been four regions that are known to produce Precambrian oil and/or gas. The Lena-Tunguska province in East Siberian Craton, Russia is potential the most important oil & gas producing area with a recoverable oil and gas reserve of 22.36×108toe, which was sourced from and reservoired in the Meso-Neoproterozoic Riphean and Vendian Strata. Most of the oils in Oman have been proven to be associated with the Neoproterozoic Huqif Supergroup source bed, especially for the south Oman salt basin, where some 3.5×108m3 of oil reserve was discovered only in the Harweel Cluster region. The reported oil reserve for the Baghewade oil field is 0.86×108t in the Blkaner-Nagaur Basin, Indian, and the Indian oil shows geological and geochemical similarities with Oman oil. Neoproterozoic Sinian to Early Cambrian sourced and Sinian produced gas occur in the the Leshan- longnvsi paleouplift of Sichuan basin, SW China, principally at the Weiyuan, Gaoshiti and Moxi three carbonate gas fields, the proven geological reserve is up to 408.61×108m3 of gas in the Weiyuan, with a total production of 143.88×108m3 within 17 years development, and recently more than 100×104m3 gas production was individually obtained from 3 exploration wells in the Gaoshiti and Moxi gas fields.
In addition, proven and potential Meso-Neoproterozoic-Lower Cambrian oil or gas flows, oil shows, bituminous veins and high quality source rocks have been reported in more than ten regions/countries. e. g., 223 indigenous Meso- proterozoic oil-seepages and bituminous sandstone were found in the Yanshan region, North China Craton, which had been sourced by Meso-proterozoic Hongshuizhuang Fm black shale and Gaoyuzhuang Fm black dolomite, while more than 100 Lower Cambrian bituminous veins in the Longmenshan region, Yangtze Craton, south China, sourced by Meso- proterozoic Sinian Doushantuo Fm black shale.
In a global view, Meso-Neoproterozoic is a notable potential oil and gas exploration realm, its primary petroleum resources could not be negotiable. In China, high organic abundance black shale and carbonate rocks are well developed as potential source beds, oil and bitumen shows widespread in some regions, but their thermoevolution level would be commonly referred to high-mature to overmature phases. However, it is still suitable for oil exploration in some specific region where the earth crust or lithosphere became thickening and geothermal gradient reduced (like the Yanshan region), as well as in the region where the overlying sedimentary caprocks are thinning so that Meso-Neoproterozoic strata have never been deep-buried (like the Longmenshan region). Both cases would be favorable to liquid hydrocarbon preservation. Otherwise, gas field can still be preserved in organic high- to overmature region (such as the Weiyuan-Gaoshiti-Moxi gas fields).
AAPG Search and Discovery Article #90175©2013 AAPG Hedberg Conference, Beijing, China, April 21-24, 2013