Main Controlling Factor Of Xujiahe Formation Reservoir-developing, The Northeast Area Of Central Sichuan Basin

The objects of the research are the second member and the forth member and the Sixthmember of xujiahe Formation in the northeast of central Sichuan basin,researching insedimentary facies,lithology feature,diagenism,crack developing, Analyzing and generalizingthe forming mechanism of high grade reservoir and predicting the beneficial districts ofrelevant reservoir formations.Xujiahe Formation belongs to delta deposit system, mainly consist by delta plain and deltafront subfacies, including the microfacies of channel on water, channel under water and rivermouth dam.obviously by developing channel on water and channel under water.There are five reservoir rock types including debris quartz sandstone, lithic sandstone andlithic arkose. accumulate sandstones have extremely rich of debris but have middle to lowfeldspar about the framework and grain feature, feldspar content supplies the main substancecomponent for denudation. Primary intergranular bore is one of the main accumulation holeform, the conservation of primary intergranular bore is correlated about the developing ofcircle along chlorite, when the primary intergranular bore and feldspar secondary corrodedhollow overlay, they constitute t developing preferable reservoir of the native distic.The developing of accumulation sandstones hole is affected by deltaic environmental ofriver mouth dam, far grit dam,sand sheet and raise among bay,more importance go throughdiagenism compaction,quartz oversize,calcite,dolomite adglutinate packing action,compactionpressolution,metasomasis and autogeny quartz fill、ferro calcite alternation ect.All of themdestruct the reservoir.Base on the research of core fissure data, refer to log response and test data,knowing the loganswer feature of fissure development.The research demonstrate:in longgang area,the fissuremainly develop in the Sixth member of xujiahe Formation, the second member and the forthmember of xujiahe Formation are not well developed;in yingshan area, the fissure mainlycentralize in the second member of xujiahe Formation,but the degree of developing can not compare with longgang areaTotally, the northeast area of central Sichuan basin belongs to low pore-low permeation,also in some areas developing preferable high grade reservoir.Base on the research ofsedimentary facies, diagenism and how to influence Reservoir-developing,analysis theforming conditions and influencing factors of high grade reservoir of xujiahe Formation.Through the research knowing forming of high grade reservoir based on deposition,lithology,diagenism and crack.