| 摘要: |
| 羌塘盆地是青藏高原最大的含油气盆地,也是中国潜在的石油战略后备区之一。新的油气地质调查发现,盆地内发育优质古生代烃源岩,主要为石炭系、二叠系的暗色泥岩,具有机碳含量高的特征,机质类型主要为Ⅱ2-Ⅲ型,Ro值大多为1.50%~2.40%,处于高成熟-过成熟阶段。前那底岗日组的古风化壳是盆地内新发现的潜在的储集层,其覆盖于二叠系以及前人已确定的三叠系肖茶卡组地层之上。新发现的上侏罗统-下白垩世白龙冰河组泥灰岩夹膏盐、页岩是区域上较好的盖层。盆地内近年来在地表发现油气显示250余处,其中最重要的是发现了现代天然气泄漏的泥火山,并采集到了天然气样品。综合考虑沉积相、烃源岩、储集层、盖层、保存条件等因素,优选了6个有利区块,其中,托纳木和半岛湖区块作为潜力目标区进行了勘探。 |
| 关键词: 羌塘盆地 古生代烃源岩 古风化壳 泥火山 天然气 |
| DOI： |
| 附件 |
| 投稿时间：2014-07-20修订日期：2014-08-16 |
| 基金项目:国家自然科学基金(41172098)资助和全国油气资源战略选区调查与评价国家专项“青藏高原油气资源战略选区调查与评价”项目(XQ2009-01) |
|
| Recent progress in oil and gas geological exploration in the Qiangtang Basin, northern Xizang |
| FU Xiu-gen, WANG Jian, TAN Fu-wen, CHEN Ming, LI Zhong-xiong, CHEN Wen-bin, FENG Xing-lei |
(1. Chengdu Center, China Geological Survey, Chengdu 610081, Sichuan, China;
2. Key Laboratory for Sedimentary Basin and Oil and Gas Resources, Ministry of Land and Resources, Chengdu 610081, Sichuan, China) |
| Abstract: |
| The Qiangtang Basin lies as the largest petroleum basin on the Qinghai-Xizang Plateau and a potential strategic reserve area for petroleum exploration in China. Our results of recent petroleum geological survey in the Basin show that the excellent Palaeozoic source rocks mostly composed of the Carboniferous and Permian dark mudstones are characterized by higher contents of organic carbon, with the II2 to III types of kerogen in organic matter, and maturities Ro values ranging between 1.50% and 2.40%, indicating the stages of oil-window maturity to overmaturity. The palaeo-weathering crust within the formerly Nadigangri Formation is believed to be the newly-discovered potential reservoir rocks in the Basin, which are overlain upon the Permian and formerly Triassic Xiaochaka Formation strata. The newly-discovered Upper Jurassic-Lower Cretaceous Bailongbing River Formation marls intercalated gypsum and shales are considered to be good seal rocks in the Basin. More than 250 sites of oil and gas showings have been distinguished in the Mesozoic formations in the Basin in recent years. Best of all, a large number of modern active mud volcanoes generated by the natural gas seepage have also been recognized in the northern Qiangtang Basin where the gas samples were collected. In the light of sedimentary facies, source rocks, reservoir rocks, seal rocks and preservation of oil and gas resources, six hydrocarbon exploration prospects are delineated, and the Tuonamu and Bandao Lake areas are selected as the potential targets for future petroleum exploration in the Qiangtang Basin. |
| Key words: Palaeozoic source rock palaeo-weathering crust mud volcano natural gas Qiangtang Basin |
