Organic Geochemical and Petrographic Characteristics of the Coal Measure Source Rocks of Pinghu Formation in the Xihu Sag of the East China Sea Shelf Basin: Implications for Coal Measure Gas Potential  

作　　者：WANG Yang QIN Yong YANG Liu LIU Shimin Derek ELSWORTH ZHANG Rui 

机构地区：[1]Key Laboratory of Coalbed Methane Resources and Reservoir Formation Process,Ministry of Education,China University of Mining and Technology,Xuzhou.Jiangsu 221008,China [2]School of Resources and Earth Science.China University of Mining and Technology,Xuzhou,Jiangsu 221116,China [3]Department of Energy and Mineral Engineering,G^3 Center and Energy Institute,The Pennsylvania State University,University Park.PA 16802.USA [4]Jiangsu Design Institute of Geology for Mineral Resources,Xuzhou,Jiangsu 221006,China [5]Neutron Scattering Division.Oak Ridge National Laboratory,Oak Ridge,TN 37830,USA

出　　处：《Acta Geologica Sinica(English Edition)》2020年第2期364-375,共12页地质学报（英文版）

基　　金：National Science and Technology Major Project(2017ZX05035004-002);the National Natural Science Foundation of China(41802183);the National Postdoctoral Program for Innovative Talents(BX201700282);the China Postdoctoral Science Foundation(2017M621870),the project of investigation and evaluation of special coal resources(DD20I60187-1).

摘　　要：Coal measure source rocks, located in the Xihu Sag of the East China Sea Shelf Basin, were analyzed to define the hydrocarbon generation potential, organic geochemistry/petrology characteristics, and coal preservation conditions. The Pinghu source rocks in the Xihu Sag are mainly gas-prone accompany with condensate oil generation. The coals and shales of the Pinghu Formation are classified from "fair" to "excellent" source rocks with total organic carbon(TOC) contents ranging from 25.2% to 77.2% and 1.29% to 20.9%, respectively. The coals are richer in TOC and S1+S2 than the shales, indicating that the coals have more generation potential per unit mass. Moreover, the kerogen type of the organic matter consists of types Ⅱ-Ⅲ and Ⅲ, which the maturity Ro ranges from 0.59% to 0.83%. Petrographically, the coals and shales are dominated by vitrinite macerals(69.1%–96.8%) with minor proportions of liptinite(2.5%–17.55%) and inertinite(0.2%–6.2%). The correlation between maceral composition and S1+S2 indicates that the main contributor to the generation potential is vitrinite. Therefore, the coals and shales of the Pinghu Formation has good hydrocarbon generation potential, which provided a good foundation for coal measure gas accumulation. Furthermore, coal facies models indicates that the Pinghu coal was deposited in limno-telmatic environment under high water levels, with low tree density(mainly herbaceous) and with low-moderate nutrient supply. Fluctuating water levels and intermittent flooding during the deposition of peat resulted in the inter-layering of coal, shale and sandstone, which potentially providing favorable preservation conditions for coal measure gas.

关 键 词：hydrocarbon generation POTENTIAL COAL FACIES COAL MEASURE GAS Pinghu Formation Xihu Sag 

分 类 号：P618.13[天文地球—矿床学]