西藏中部尼玛盆地页岩气地质特征及资源潜力

Geological characteristics and resource potential of shale gas in Nima Basins,central Tibet

位于西藏中部的尼玛盆地,面积约3000km2,是一个第三系陆相沉积盆地。通过野外地质调查,发现了两处暗色页岩,暗色页岩沉积厚度累计可达20m;有机地球化学数据暗示页岩具有生成页岩气的巨大潜力;利用类比法,估算出尼玛盆地页岩气资源量约为100～200×108 m3,具有较大的潜力。西藏中部班公湖-怒江缝合带发育一系列第三系陆相盆地,包括尼玛、伦坡拉、洞错和阿翁错盆地,这些盆地具有相似的地质背景与演化历史,具有页岩层发育的广阔空间,具有"小而肥"的特点,是西藏值得进一步深入研究的地区。

The Tertiary Nima Basin in central Tibet covers an area of some 3000km2 and is closely similar to the nearby Lunpola Basin from which commercial volumes of oil have been produced. By field geological survey, shale with thickness of 20m were discovered in Nima Basin; Organic geochemistry date indicate that the shale have excellent shale gas potential. The Nima Basin shale gas reserves reach 100- 200×10^8m3 by analogy method. A number of Tertiary continental basins are located on the approximately east west surface trace of the Bangong suture in central Tibet, including the Lunpola Basin, the Nima Basin, the Dongco Basin and the Avengco Basin, which have similar geological setting and evolutionary history. These basins may have great shale gas potential and should be given much more attention.