Buoyance-driven hydrocarbon accumulation depth and its implication for unconventional resource prediction  

作　　者：Xiongqi Pang Chengzao Jia Wenyang Wang Zhangxin Chen Maowen Li Fujie Jiang Tao Hu Ke Wang Yingxun Wang 

机构地区：[1]State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum(Beijing),Beijing 102249,China [2]College of Geosciences,China University of Petroleum(Beijing),Beijing 102249,China [3]Exploration&Development Research Institute,China National Petroleum Corporation,Beijing 100724,China [4]State Key Laboratory of Lithospheric Evolution,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China [5]Chemical and Petroleum Engineering,Schulich School of Engineering,University of Calgary,Calgary T2N 1N4,Canada [6]State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development,Beijing 100083,China

出　　处：《Geoscience Frontiers》2021年第4期93-109,共17页地学前缘（英文版）

基　　金：by the National Natural Science Foundation of China(No.U19B6003-02);the National Basic Research Program(973)of China(No.2011CB201100).

摘　　要：The discovery of unconventional hydrocarbon resources since the late 20th century changed geologists’understanding of hydrocarbon migration and accumulations and provides a solution to energy shortage.In 2016,unconventional oil production in the USA accounted for 41%of the total oil production;and unconventional natural gas production in China accounted for 35%of total gas production,showing strong growth momentum of unconventional hydrocarbons explorations.Unconventional hydrocarbons generally coexist with conventional petroleum resources;they sometimes distribute in a separate system,not coexisting with a conventional system.Identification and prediction of unconventional resources and their potentials are prominent challenges for geologists.This study analyzed the results of 12,237 drilling wells in six representative petroliferous basins in China and studied the correlations and differences between conventional and unconventional hydrocarbons by comparing their geological features.Migration and accumulation of conventional hydrocarbon are caused dominantly by buoyance.Wepropose a concept of buoyance-driven hydrocarbon accumulation depth to describe the deepest hydrocarbon accumulation depth driven dominantly by buoyance;beyond this depth the buoyance becomes unimportant for hydrocarbon accumulation.We found that the buoyance-driven hydrocarbon accumulation depth in petroliferous basins controls the different oil/gas reservoirs distribution and resource potentials.Hydrocarbon migration and accumulations above this depth is dominated by buoyancy,forming conventional reservoirs in traps with high porosity and permeability,while hydrocarbon migration and accumulation below this depth is dominated by non-buoyancy forces(mainly refers to capillary force,hydrocarbon volumeexpansion force,etc.),forming unconventional reservoirs in tight layers.The buoyance-driven hydrocarbon accumulation depths in six basins in China range from 1200mto 4200 m,which become shallowerwith increasing geothermal gradient,decreasing part

关 键 词：Nature energy Fossil energy Oil and gas resources Conventional hydrocarbon reservoirs Unconventional hydrocarbon reservoirs Buoyance-driven hydrocarbon accumulation DEPTH 

分 类 号：P618.13[天文地球—矿床学]