柴达木盆地三湖坳陷第四系泥岩气藏成藏模式  

Accumulation mode of Quaternary mudstone gas reservoir in Sanhu Depression,Qaidam Basin

作　　者：宋德康 刘晓雪 邵泽宇 姜振学[2] 侯栗丽 王昱超 贺世杰 刘冀蓬 SONG Dekang;LIU Xiaoxue;SHAO Zeyu;JIANG Zhenxue;HOU Lili;WANG Yuchao;HE Shijie;LIU Jipeng(Research Institute of Exploration and Development,Qinghai Oilfield Company,PetroChina,Jiuquan,Gansu 736202,China;China University of Petroleum(Beijing),Beijing 102249,China)

机构地区：[1]中国石油青海油田分公司勘探开发研究院,甘肃酒泉736202 [2]中国石油大学(北京),北京102249

出　　处：《油气藏评价与开发》2023年第4期495-504,共10页Petroleum Reservoir Evaluation and Development

基　　金：国家自然科学基金面上项目“陆相页岩储层岩石组构和孔隙机构特征及其对含气性的控制机理”(41872135)。

摘　　要：研究三湖坳陷生物成因泥岩气藏形成的条件和成藏模式,有利于完善生物气成藏机理与富集规律,对指导第四系泥岩气藏勘探开发具有重要理论和现实意义。以三湖坳陷第四系泥岩为研究对象,通过可溶解有机碳分析、孔隙度测定、色谱质谱分析等实验,明确了三湖坳陷第四系泥岩气藏成藏条件,建立了第四系泥岩气藏的成藏模式。研究结果表明,三湖坳陷第四系泥岩可溶解有机碳含量高,有机质类型为草本腐殖型,气温极低、气候干旱,有利于生物成因气的生成;三湖坳陷第四系具有高孔低渗的特征,发育大量微纳米孔隙,为生物成因气的赋存提供了大量孔隙空间;气体运移方式以菲克扩散和滑脱流动为主,由于泥岩自封闭作用,生成的生物成因气在原位聚集成藏。在晚喜马拉雅构造运动影响下,泥岩自封闭性被破坏,受浮力作用,生物成因气向上运移,在相邻的构造高部位泥岩中重新聚集成藏,在纵向上与常规砂岩生物气藏相互叠置。The study of formation conditions and accumulation mode of biogenetic mudstone gas reservoir in Sanhu Depression is essential for understanding the accumulation mechanisms and enrichment rules of such gas reservoirs.It holds significant theoretical and practical implications for guiding the exploration and development of Quaternary mudstone gas reservoirs.This research focuses on the Quaternary mudstone in the Sanhu Depression as the main subject.To determine the reservoir formation conditions and establish the accumulation mode,various experiments were conducted,including soluble organic carbon analysis,porosity determination,and chromatography-mass spectrometry analysis.The results reveal that the presence of high levels of soluble organic carbon and herbaceous humic organic matter,along with cold and dry conditions,create favorable conditions for the generation of biogenetic mudstone gas.The Quaternary formation in Sanhu Depression has the characteristics of high porosity and low permeability with numerous micro-nano pores that provide ample space for the occurrence of biogenetic gas.Gas flow primarily occurs through Fick diffusion and slip flow.The self-sealing effect of mudstone leads to the in-situ accumulation of biogenetic gas.However,during the late Himalayan tectonic movement,the gas containment of mudstone is disrupted.As a result of buoyancy,the gas migrates upward and accumulates in high parts of the mudstone,which are adjacent to the gas-generating center,and are superimposed longitudinally with sandstone biogenetic gas reservoirs.

关 键 词：生物成因泥岩气藏 形成条件 成藏模式 三湖坳陷 第四系 

分 类 号：TE122[石油与天然气工程—油气勘探]