柴达木盆地北缘侏罗系有效烃源岩特征及油气聚集规律  

Characteristics of effective source rocks in the Jurassic and hydrocarbon accumulation patterns in the areas near the northern margin of the Qaidam Basin

作　　者：翟志伟[1] 张永庶[1] 杨红梅[1] 沙威[1] 年秀清[1] 郝小梅[1] 仁仟[1] 张建杰[1] 

机构地区：[1]中国石油青海油田公司勘探开发研究院

出　　处：《天然气工业》2013年第9期36-42,共7页Natural Gas Industry

基　　金：国家科技重大专项"大型油气田及煤层气开发"子课题(编号:2011ZX05003-006)

摘　　要：柴达木盆地北缘地区具有典型的前陆盆地特征,已发现的油气田多集中在冷湖—南八仙构造带。为了拓展勘探局面,对该盆地北缘地区有效烃源岩特征以及油气运聚规律进行了研究。通过分析野外露头及钻井取心样品的地球化学特征,明确了侏罗系烃源岩的有利分布区;在对冷湖—伊北、德令哈两大主力生烃凹陷烃源岩生烃潜力分析的基础上,预测该区侏罗系天然气的资源量为4 903.4×108 m3。对油气运聚规律的研究结果表明:①该区自下而上发育有基岩古潜山、侏罗系、古近系、新近系等4套储盖组合,有自生自储、下生上储、下生侧上储、源外等4种源储组合;②在经历晚燕山期和喜马拉雅期的多次构造运动后,形成了以中下侏罗统为烃源岩,以基岩、侏罗系、古近—新近系为储集层的下生上储、自生自储和源外成藏等多种模式的油气藏;③断层、渗透性砂体及不整合面是该区油气运移的重要通道,而断裂活动、岩石破裂以及构造运动是油气运聚的主要动力。The area near the northern margin of the Qaidam Basin has the typical characteristics of a foreland basin, and the oil/gas discoveries are mainly made in the Lenghu-Nanbaxian tectonic zone. In order to find large hydrocarbon fields there, this paper studies the characteristics of effective source rocks and hydrocarbon accumulation patterns in this study area. The effective source rocks were mapped by analyzing the geochemical behaviors of outcrops and core samples. Based on the analysis of the hydrocarbon generation potentials of major source rocks in the Lenhu-Yibei and Delinha kitchens, the Jurassic natural gas resource volume was estimated to be 490.34 billion m3. The following findings were made from the study of hydrocarbon pooling mechanisms in this study area. a. There are four reservoir- seal combinations, namely basement buried hills, the Jurassic, Paleogene, and Neogene Fms, and four source rock - reservoir combinations including source rock - reservoir being the same layer, lower source rock - upper reservoir, lower source rock - lateral upper reservoir, and source rock - reservoir outside kitchen, b. After experiencing multiple tectonic movements in Late Yanshanian and Himalayan Periods, the above source rock-reservoir combinations were formed with the Low and Middle Jurassic Fms as source rocks, and the basement rock, Jurassic, Paleogene and Neogene Fms as reservoirs, c. Faults, permeable sandbodies and unconformities acted as the major pathways for hydrocarbon migration; faulting, rock fracturing and tectonic movement provided the major driving forces for hydrocarbon migration and accumulation.

关 键 词：柴达木盆地北缘 前陆盆地 有效烃源岩 生烃潜力 资源量 断裂系统 不整合面 油气运聚 

分 类 号：P618.13[天文地球—矿床学]