Petroleum Science >2010,??Issue 3:??347-354 DOI: https://doi.org/10.1007/s12182-010-0076-y
Genetic types and distribution of shallow-buried natural gases Open?Access
文章信息
作者：Gao Yang,Jin Qiang and Zhu Guangyou
作者單位：
College of Geo-resources and Information, China University of Petroleum, Dongying, Shandong 257061, China;College of Geo-resources and Information, China University of Petroleum, Dongying, Shandong 257061, China;Petroleum Exploration and Development Institute, PetroChina, Beijing 100083, China
投稿時間：2009-01-07
引用方式：Gao, Y., Jin, Q. & Zhu, G. Pet. Sci. (2010) 7: 347. https://doi.org/10.1007/s12182-010-0076-y
文章摘要
Great volumes of shallow-buried (<2,000 m) natural gases which are mainly composed of biogases and low-mature gases have been found in the Mesozoic-Cenozoic sedimentary basins in China. Many shallow gas reservoirs in China are characterized by coexistence of biogas and low-mature gas, so identifying the genetic types of shallow gases is important for exploration and development in sedimentary basins. In this paper, we study the gas geochemistry characteristics and distribution in different basins, and classify the shallow gas into two genetic types, biogas and low-mature gas. The biogases are subdivided further into two subtypes by their sources, the source rock-derived biogas and hydrocarbon-derived biogas. Based on the burial history of the source rocks, the source rock-derived biogases are divided into primary and secondary biogas. The former is generated from the source rocks in the primary burial stage, and the latter is from uplifted source rocks or those in a secondary burial stage. In addition, the identifying parameters of each type of shallow gas are given. Based on the analysis above, the distributions of each type of shallow gas are studied. The primary biogases generated from source rocks are mostly distributed in Quaternary basins or modern deltas. Most of them migrate in watersoluble or diffused mode, and their migration distance is short. Reservoir and caprock assemblages play an important role in primary biogas accumulation. The secondary biogases are distributed in a basin with secondary burial history. The oil-degraded biogases are distributed near heavy oil pools. The low-mature gases are widely distributed in shallow-buried reservoirs in the Meso-Cenozoic basins.