Hydrocarbon generation and organic matter enrichment of limestone in a lacustrine mixed sedimentary environment: A case study of the Jurassic Da'anzhai member in the central Sichuan Basin, SW China  

作　　者：Qi-Lu Xu Bo Liu Xin-Min Song Qing-Ping Wang Xu-Dong Chen Yang Li Yu Zhang 

机构地区：[1]Shandong Provincial Key Laboratory of Deep Oil and Gas,China University of Petroleum(East China),Qingdao,Shandong,266580,China [2]Institute of Oil and Gas,Peking University,Beijing,100871,China [3]PetroChina Research Institute of Petroleum Exploration and Development,Beijing,100083,China [4]Petroleum Exploration and Production Research Institute,SINOPEC,Beijing,100083,China

出　　处：《Petroleum Science》2023年第2期670-688,共19页石油科学（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grants 41902131 and 41821002 and 4169130014).

摘　　要：The hydrocarbon generation effectiveness of lacustrine limestone has been gradually proven. The Da'anzhai Member limestone is the most important Jurassic oil-producing layer in the central Sichuan Basin, and the characteristics of limestone organic matter are often overlooked. 175 typical samples of different lithologies from 19 wells were systematically analyzed to determine hydrocarbon generation, controlling factors and formation models by analyses of organic matter, minerals, elements, isotopes and petrography. (1) Lacustrine paleoenvironments can be beneficial for the enrichment of organic matter in limestone. A favorable environment would be a quiet, low-energy zone in a warm and humid climate with an appropriate supply of terrestrial inputs. (2) Lacustrine limestone has a higher organic matter conversion rate, and a lower hydrocarbon generation threshold than argillaceous source rocks, and can be effective source rock. (3) The mud-bearing shell limestone from the forebeach to the lake slope is thick, with a relatively high abundance of organic matter, and its hydrocarbon generation is effective. This study can clarify the effectiveness and enrichment of the limestone organic matters in the study area, and contribute to an understanding of hydrocarbon generation for full-rock system in a lacustrine mixed sedimentary environment.

关 键 词：Lacustrine limestone Full-rock system Organic matter evaluation PALEOENVIRONMENTS Lake evolution Terrestrial inputs 

分 类 号：P618.13[天文地球—矿床学]