柴达木盆地油气勘探新进展

柴达木盆地位于青藏高原北部,受喜马拉雅晚期新构造运动影响,地质条件复杂,油气勘探难度大,自20世纪80年代尕斯库勒油田发现以后,勘探长期陷入沉寂。"十一五"(2006—2010年)以来,深化基础地质研究,在盆地演化、烃源岩分布、沉积储层、输导体系等方面取得了新的认识,明确了油气成藏主控因素,新建了走滑冲断-源外油气富集模式、坳内断褶-源上油气富集模式、凹陷斜坡-源内近源油气富集模式,高原咸化湖盆油气成藏理论得以丰富。在该理论指导下,梳理出盆地3大勘探新领域:盆缘古隆起、盆内凹陷—斜坡带、盆内晚期构造带,落实了21个有利区带,在昆北、英东、东坪、扎哈泉4个地区获得重大勘探发现,新增探明油气地质储量4.03×108t,为盆地前50年探明总储量的65%。

New advance of petroleum and gas exploration in Qaidam Basin

Located in the northern part of the Qinghai-Tibet Plateau, Qaidam Basin presents complex geological conditions as influenced by the Late Himalayan Neotectonics, leading to a great difficulty in oil and gas exploration. The exploration has no breakthrough for a long time since the discovery of Gaskule oilfield in 1980s. Since the "Eleventh Five-Year" (2006-2010) Period, the basic geological research has been deepened to obtain new understandings in aspects of basin evolution, source rock distribution, sedimentary reservoir and transport system, etc. Meanwhile, the main controlling factor of hydrocarbon accumulation has been identified. The hydrocarbon accumulation models have been newly created for outside-source gas in strike slip thrust, above-source gas in depression internal faulted fold as well as inner-source and near-source gases on depression slope, so as to enrich the hydrocarbon accumulation theories of plateau saline lacustrine basin. Under the guidance of theoretical knowledge, three new exploration fields in this basin were determined, i.e., basin-edge paleo-uplift, inner-basin depression-slope zone and inner-basin late tectonic belt, and a total of 21 favorable zones have been confirmed. Furthermore, major discoveries have been made during the exploration of four regions, i.e., the northern Kunlun, Yingdong area, Dongping area and Zhahaquan area; the newly added proven oil and gas geologic reserves is 403 million tons, accounting for 65% of the total basin reserves in previous half a century.