西藏措勤盆地中生界生储盖特征和含油气远景评价  

Characteristics of Mesozoic source-reservoir-cap rock association and hydrocarbon prospect evaluation in the Coqen basin,Tibet

作　　者：魏玉帅[1,2] 王成善[1,2] 李亚林[1,2] 朱利东[3] 王立成[1,2] 

机构地区：[1]中国地质大学地球科学与资源学院,北京100083 [2]中国地质大学青藏高原地质研究中心,北京100083 [3]成都理工大学沉积地质研究院,四川成都610059

出　　处：《地质通报》2011年第10期1575-1586,共12页Geological Bulletin of China

基　　金：国家自然科学基金项目<青藏高原措勤盆地白垩纪中期构造事件及其油气地质意义>(批准号:41172129);中国地质调查局全国油气资源战略选区调查项目<青藏高原羌塘外围重点海相盆地优选与综合评价>(编号:XQ2004-06)

摘　　要：措勤盆地是青藏高原仅次于羌塘盆地的海相含油气盆地。根据近年来新取得的资料,结合前人的研究成果,对中生代措勤盆地的生储盖层特征进行了综合研究。结果表明,措勤盆地中生界存在3套烃源岩,郎山组灰岩有机质丰度低,以Ⅰ—Ⅱ1型干酪根为主,处于成熟阶段;多尼组川巴段泥质岩有机质丰度较高,多为Ⅱ2—Ⅲ型干酪根,达到高成熟—过成熟阶段;而接奴群泥质岩有机质丰度低,为Ⅲ型干酪根,达到高—过成熟阶段。新发现的雪上勒、革吉和弄瓦3处白云岩是盆地内优良的储层;多尼组泥质岩和郎山组灰岩可作为区域优良的盖层。中生界存在着郎山组和多尼组2套自生自储自盖的组合,且多尼组组合更优。另外,盆地北部中生界目的层大片出露,保存条件较差,建议下一步勘探考虑深部上古生界目的层。Located in central Tibetan Plateau,the Coqen basin is the second largest marine hydrocarbon-bearing basin in Tibet Plateau,covering an area of 140000 km2.Data obtained in recent years were combined with previous studies to investigate the characteristics of source rock,reservoir,and cap rocks.The results show that total organic carbon（TOC） content in limestone of Langshan Formation is very low.The organic matters were composed of typeⅠ-Ⅱ1 kerogen and have reached the mature stage.The argillaceous rocks of Chuanba Mmember of Duoni Formation contain higher TOC and are composed mostly of type Ⅱ2-Ⅲ kerogen which has reached the high mature to over mature stage.The TOC content of argillaceous rocks in Jienu Group is lower.The organic matter is mainly type III kerogen at the high mature to over mature stage.The newly discovered dolomites located in Xueshangle,Geji and Nongwa show excellent reservoir capability characterized by low porosity and low permeability,with the development of some medium porosity and permeability reservoirs.Regionally,mudstone of Duoni Formation and limestone of Langshan Formation have good sealing properties as the cap rocks.Therefore,there exist two source-reservoir-cap rock assemblages characterized by self-source,self-reservoir and self-sealing.However,Mesozoic exploration targets are extensively exposed and poorly preserved.It is suggested that the Upper Paleozoic target strata should be considered as the next exploration objects.

关 键 词：烃源岩 储层 盖层 远景评价 中生界 措勤盆地 

分 类 号：P534.5[天文地球—古生物学与地层学] P618.13[天文地球—地质学]