Lacustrine Basin Fills in an Early Cretaceous Half-Graben, Jiuquan Basin, NW China: Controlling Factors and Implications for Source Rock Depositional Processes and Heterogeneity  

作　　者：Chengcheng Zhang Hua Wang Si Chen Junjie Yu Yuantao Liao Zongsheng Lu Jun Wei 

机构地区：[1]Nanjing Center,China Geological Survey [2]Key Laboratory of Tectonics and Petroleum Resources, Ministry of Education, China University of Geosciences [3]School of Earth Sciences, China University of Geosciences [4]PetroChina Yumen Oilfield Company

出　　处：《Journal of Earth Science》2019年第1期158-175,共18页地球科学学刊（英文版）

基　　金：supported by the National Natural Science Foundation of China (NSFC) Program (No. 41472084);the Major National Petroleum Program in the ‘Thirteenth Five-Year’ Plan (No. 2016ZX05006-006-002);the Comprehensive Geological Survey Project of Ningde Coastal Zone (No. DD20189505);the Open Fund of Evaluation and Detection Technology Laboratory of Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology (No. KC201701);the Natural Science Foundation of Shandong Province (No. ZR2016DB29)

摘　　要：Studies on basin fills have provided significant insights into reservoir distribution and prediction in petroliferous basins, however, the effect of basin fills on source rock properties has been underexplored. This paper documents basin filling characteristics and their implications for depositional processes and heterogeneity of source rock in the Qingnan subsag of the Jiuquan Basin, by using subsurface geological data from recent hydrocarbon exploration efforts in this area. Drill core data reveals that the basin fill of the Qingnan subsag was dominated by fan delta-lacustrine systems, in which deposition of the fan deltas along the basin margin was mainly through gravity flows. The temporal and spatial evolution of the depositional systems indicates that the basin fill was characterized by a continuously retrogradational process, with decreasing extent of fan deltas in vertical succession. Weakening of tectonic activities and climate change from humid to semi-arid are interpreted to be the main control factors that were responsible for the retrogradational basin fill. The different depositional environments in the early stage and late stage of the retrogradational basin filling history resulted in the different depositional processes and properties of source rocks. This study suggests that source rock heterogeneity associated with basin fills in lacustrine basins should be considered in hydrocarbon exploration.Studies on basin fills have provided significant insights into reservoir distribution and prediction in petroliferous basins, however, the effect of basin fills on source rock properties has been underexplored. This paper documents basin filling characteristics and their implications for depositional processes and heterogeneity of source rock in the Qingnan subsag of the Jiuquan Basin, by using subsurface geological data from recent hydrocarbon exploration efforts in this area. Drill core data reveals that the basin fill of the Qingnan subsag was dominated by fan delta-lacustrine systems, in which deposition of the fan deltas along the basin margin was mainly through gravity flows. The temporal and spatial evolution of the depositional systems indicates that the basin fill was characterized by a continuously retrogradational process, with decreasing extent of fan deltas in vertical succession. Weakening of tectonic activities and climate change from humid to semi-arid are interpreted to be the main control factors that were responsible for the retrogradational basin fill. The different depositional environments in the early stage and late stage of the retrogradational basin filling history resulted in the different depositional processes and properties of source rocks. This study suggests that source rock heterogeneity associated with basin fills in lacustrine basins should be considered in hydrocarbon exploration.

关 键 词：BASIN FILLS source rock DEPOSITIONAL process RIFT BASIN Jiuquan BASIN 

分 类 号：P[天文地球]