地质找矿论丛2025，Vol.40Issue(2)：206-216,11.DOI:10.6053/j.issn.1001-1412.2025.02.008
榆林-神木地区流体压力场演化及页岩气成藏过程动态分析
Dynamic analysis of fluid pressure field evolution and shale gas accumulation process in Yulin-Shenmu area
摘要
Abstract
In the northeastern Ordos Basin,a set of marine-continent transitional shale in coal system of Upper Paleozoic group is well developed.Scholars consider that the shale has potential for gas exploration and development.Dynamic evolution of Upper Paleozoic fluid and the mechanism of gas accumulation and storage have been extensively discussed,but the coupling relationship of formation of the abnormal pres-sure with shale gas reservoir has been rarely reported.Based on analysis of the shale gas accumulation and storage in periphery of the study area,combined with organic geochemical,petrological data,and gas con-tent measurement,this paper follows the major line of the pressure change characteristics to stress discus-sion of generation of hydrocarbon,formation of reservoir,and dissipation in the shale of Permian Shanxi Formation,and stratum pressure-control of reservoir.The results show that thick muddy shale is widely Distributed in the whole Yulin-Shenmu area and contains higher organic carbon and generally remains at amedium-high mature stage,thus is favorable for shale gas generation and accumulation.At present,the muddy shale is under weak super-pressure and normal pressure condition.Based on tectonic thermal evo-lution simulation and fluid pressure evolution history,gas accumulation in the shale is divided into three stages:hydrocarbon generation-pressure increase,unloading-pressure decrease and adjustment-final-ization.Paleo-super-pressure formation coincided with late Jurassic-early Cretaceous peak of hydrocarbon generation,and the early Cretaceous uplift of strata led to erosion and loss of the gas from the shale and destruction of the reservoir.Support of the paleo-super-pressure constrains burial compaction of the stra-ta,and keep higher porosity of the reservoir,resulting in formation of micro-fissures.Stratum with super-pressure and high energy contains large volume of free gas and the gas-bearing behavior of reservoir is bet-ter.Pressure of the stratum changes from super to normal or low leading to decrease of gas content of the stratum and transformation of reservoir type.According to the mentioned above,study on coordination of Upper Paleozoic pressure field evolution in the northeast basin with the shale gas enrichment and storage should be deepened,which can clarify distribution law of abnormal gas and is theoretically and practically significant to determine future prospecting direction.关键词
有机质/压力演化/页岩气/山西组/鄂尔多斯盆地Key words
organic matter/pressure evolution/shale gas/Shanxi Formation/Ordos Basin分类
天文与地球科学引用本文复制引用
梁正中,张晓磊,宫焕然,郝志磊,庞锦莲..榆林-神木地区流体压力场演化及页岩气成藏过程动态分析[J].地质找矿论丛,2025,40(2):206-216,11.基金项目
国家自然科学基金项目(编号:42062011)、陕西省科学技术厅重点研发计划(编号:2024GX-YBXM-511)、榆林市科技局项目(编号:22RCYPJB0103)和陕西高校青年创新团队(编号:2022-37)资助. （编号:42062011）
