The Research Of Accumulation Process Of The Natural Gas From Moxi-gaoshiti Area In The Central Of Sichuan Basin

Taking Longwangmiao formation gas reservoir in Anyue gas field,Sichuan Basin as the research object,the paper aim to clear the accumulation process by recovering the reservoir forming history and the study of the bitumen and paleo-reservoir.Comprehensive use of natural gas geology,geochemistry,basin modeling methods and means was executed.It is significant to deepen the understanding of the reservoir-forming regularity of gas reservoirs in Lower Paleozoic Central Sichuan palaeohigh and to promote the more discovery of natural gas reserves.The bitumen of study area is widely distributed and variety,most is thermal evolution and have high maturity,bitumen have a certain proportional relationship with crude oil cracking gas production,bitumen come from the lower Cambrian Qiongzhusi Formation.The paleo-reservoir have a certain scale and high maturity,much as normal-light oil.The paleo-reservoir are stratiform distributed,have a good corresponding relation with gas reservoir nowadays.According to the mineral inclusions occurrenced and the contact relationship with bitumen,combining with homogenization temperature of the fluid inclusions,we divide the Longwangmiao reservoir stratum into four periods:The first three phase formed in the continuous buried stage,in this stage three temperature rating represents the third phase of capture,the fourth stage formed in the tectonic uplift stage.According to the above study of the paleo-reservoir scale,Combined with inclusions homogenization temperature interval data and hydrocarbon source rock thermal evolution history of typical wells,we have been clear about the four stages of gas reservoir formation:palaeohigh forming stage;the paleo-reservoir large area of layered forming stage;the paleo-reservoir cracking stage;the late tectonic uplift gaseous hydrocarbon charging stage.