Study On Hydrocarbon Accumulation Characteristics Of Changxing-feixianguan Formation In Micang Mountain Leading Edge

The frontal concealed structural zone of the Micang Mountain,northeastern Sichuan Basin,is a prospective area for oil and gas exploration,but the exploration degree there is still low due to the intensity of tectonic deformation and the complexity of hydrocarbon accumulation process.In order to clear the northeastern Sichuan basin in Micangshan before the zone in Changxin-Feixianguan reservoir conditions for the purpose,based on the research on the forming conditions of natural gas,the main controlling factors of reservoir forming natural gas,summary of natural gas reservoir formation conditions and enrichment regularity,prediction of natural gas favorable exploration area.This paper summarizes the previous research results of hydrocarbon source rocks in Micangshan area mainly developed before two Permian Wujiaping formation and formation of hydrocarbon source rocks,hydrocarbon generation intensity,with the formation of large and medium gas source conditions.Through the thin section observation,meters before Micangshan zone of Changxin reservoir rock types are mainly bioclastic limestone,bioclastic dolomite and dolomite in particles,pore is not developed,experienced compaction,pressure solution and cementation;Feixianguan reservoir rock types are mainly oolite dolomite powder and fine dolomite,reservoir space types in intergranular pores,intragranular dissolved pores,intergranular dissolved pore,which belongs to low porosity and low permeability reservoir,through cementation,dissolution,compaction,pressure solution and weak diagenesis dolostone of complex,compaction and cementation is the main factor leading to the densification of the reservoir,dissolution is the key factor for the formation of high quality reservoir.Nanjiang Tongnanba area Wujiaping formation and hydrocarbon source rocks in the Dalong formation early Jurassic late Jurassic in the threshold of hydrocarbon generation,entered the peak,the late Jurassic to early Cretaceous to wet gas stage;Silurian hydrocarbon source rocks in the threshold of hydrocarbon generation in early three to Early Triassic,Middle Jurassic to late Jurassic reached the peak of oil and moisture stage.At the end of the early Cretaceous,the strata began to uplift and hydrocarbon generation gradually ended.The filling time of the Feixianguan Formation(mainly the first member of the Feixianguan Formation)occurred in the late Jurassic from 158 to 153 Ma,and the charging time of the natural gas occurred about 148 to 145 Ma in the late jurassic.The paleo reservoir is not developed in the study area.Only in Jinxi 2 wells,1 wells,1 New Kowloon Blackpool wells fly dolomite reservoir for a period of the development of paleo oil reservoir is small,fly three undeveloped ancient reservoir.The hydrocarbon generation intensity,reservoir distribution and development,ancient oil reservoir development degree based on natural gas preservation conditions and comprehensive discrimination that Changxin and Northeast Sichuan Feixianguan Formation of favorable zones in study area only 2 more favorable gas accumulation and preservation zone:(1)through Hebachang and '1 Tongnanba anticline well area is conducive to the formation of pore fractured gas reservoir;(2)Kowloon 1 wells and 1 wells in the new Blackpool Tongnanba anticline area,buried fault fold belt for natural gas accumulation and preservation area more favorable.