The volcanic oil and gas reservoirs in eastern basins of China
|Location||International Geological Congress,oslo 2008|
|Author||Jin, Chunshuang۱; Dan, Weining۲; Qiao, Dewu۱; Zhang, Dawei۱|
|Holding Date||07 October 2008|
With more and more volcanic oil and gas fields are being discovered and developed, the volcanic rocks reveal great petroleum potential in eastern basins of China. The andesite in Upper Jurassic is the main volcanic reservoir in Erlian basin, and oil pools were discovered in Anan area. In Bohai bay basin, a great amount of oil and gas pools were discovered in Jiyang, Liaohe and Huanghua depressions in Paleogene.
The basalt and basaltic tuff are the main reservoirs in Jiyang depression, the basalt and trachyte of Liaohe depression, and the basalt and andesitic basalt of Huanghua depression. The basalt in Paleogene is the main volcanic reservoir in Subei basin.
In Songliao basin, there are approximately 140 billion cubic meters of measured gas initially in place found in deeper formations, and about 60-70% of total gas preserved in these volcanics and volcaniclastic rocks. In many deep fault depressions, there are indications or industrial flow of gas from volcanic rocks in the wells drilling into volcanic rocks. The rhyolite, basalt and rhyolitic tuff in Yingcheng formation of Lower Cretaceous, and the andesite in Huoshiling formation of Upper Jurassic, are the main volcanic reservoirs. The rhyolite and rhyolitic tuff in Yingcheng formation are the more productive volcanic reservoirs. The porosity and permeability of volcanic reservoirs vary unobviously with depth, which makes it is favorable to search effective reservoirs in deeper area. The upper subfacies of effusive facies, the loose deposits between subfacies of explosive facies and the inner subfacies of extrusive facies have been proved as perfect volcanic reservoirs. The underlying Shahezi formation and Huoshiling formation are the main source rocks for volcanic reservoirs, and the gas pools are dominated by lithologic and structural lithologic reservoirs.