Oil & Gas Geology ›› 2014, Vol. 35 ›› Issue (3): 295-302.doi: 10.11743/ogg20140301

Previous Articles     Next Articles

Gas accumulation and exploration direction of the Permian and Triassic reservois of reef-bank facies in Sichuan Basin

Guo Xusheng, Huang Renchun, Fu Xiaoyue, Duan Jinbao   

  1. Exploration Southern Company, SINOPEC, Chengdu, Sichuan 610041, China
  • Received:2014-06-17 Revised:2014-05-15 Online:2014-06-08 Published:2014-07-11

Abstract:

Through systematic analysis of gas component,carbon isotope,thin section and inclusions,we found that the Permian and Triassic reef-bank reservoirs are dominated by natural gas from secondary cracking of crude oil.The Longtan Formation(Wujiaping Formation)is the major source rocks.The gas reservoirs experienced three stages,namely earlier oil accumulation in ancient lithologic reservoirs,ancient crude oil cracking and gas adjusting and re-accumulation.The hydrocarbon accumulation pattern is characterized by multiple hydrocarbon supply,accumulation near the source,lithology reservoirs,oil-gas conversion and later adjustment.And the present day gas reservoirs are mainly controlled by three factors.Firstly,the hydrocarbon kitchen of the Permian source rock controls the adequacy of oil-gas source.Secondly,the distribution and scale of reservoirs of reef-bank facies control the scale and location of hydrocarbon accumulation.Thirdly,later preservation conditions determine the finally accumulation of gas.By systematically summarizing the sedimentary characteristics and hydrocarbon accumulation conditions of the discovered reef-bank gas reservoirs(outcrops),we believe that reservoirs of platform margin reef-bank facies,intra-platform shoal facies and the Lower Permian shoal facies are the favorable targets for further gas exploration.

Key words: carbonate rock, reef-bank gas reservoir, Permian,Triassic, Sichuan Basin

CLC Number: