Natural Gas Pool Formation Analysis Of The Mid-deep Strata In Banqiao Sag

Banqiao sag is one of the most important oil-rich sag in Huanghua depression, which isrich in oil and gas resources. After40years of exploration and development, now it is in themid-late development. The third resources evaluation results show that the deep natural gasresource has great potential, but the exploration rate is low, which is an important field of theincrease areas in banqiao sag. Due to the low degree of deep proved, the deep natural gasaccumulation mechanism and the exploration direction are not clear. So it is need to workdeep in the gas accumulation, which can make the utmost use of the gas exploration.In this paper, on the basis of drilling, well logging and logging data, combined with a largenumber of analysis and assay material, the major hydrocarbon source rocks (gas source rocks)space exhibition, the geochemical characteristics and hydrocarbon generation and evolutioncharacteristics were studied in banqiao sag. Established deep natural gas into hydrocarbonevolution mode,and carried out the deep natural gas quantity of resources; At the same timefor the natural gas found is done the anatomy of the system, determining the deep natural gasgenetic types and source, analysis of the natural gas accumulation key control factors, andwith natural gas accumulation simulation technology, studying the matching relation ofaccumulation effect process of efficient gas accumulation and key factors of role. Establishedthe deep natural gas accumulation model. Clearing the advantage of the deep natural gasexploration target.The result proves that multiple sets of hydrocarbon-generating sequence are developed inbanqiao sag. Major gas-generating strata consist of Es3, Es1zand Es1x. The source rock of Es3is widely distributed with large thickness, high abundance of organic matter and high degreeof thermal evolution, which is the main gas source rock formation, natural gas resource is richin deep strata. Due to deep abnormal pressure development，the hydrocarbon source rocks ofthermal evolution effect obviously lag, compared with evolutionary pattern in normalenvironment, the gas generation threshold of hydrocarbon source rocks in banqiao sagobviously slant deep, the main gas generation strata located in deep. The gas source analysisresults confirmed, deep natural gas mainly comes from Es3in high evolutionary stagescracking of the generation of natural gas, reflecting deep natural gas has advanced “selfgeneration and self preservation” reservoir formation characteristic in late-stage. The maincontrol factors of deep natural gas reservoir forming include tectonics, hydrocarbon sourcerocks, reservoir, cap rock, P-T environment and configuration relationships. The type of traps determine genetic types and distribution of deep natural gas, and the source rock distributionand evolutional characteristics control natural gas accumulation of time and verticaldistribution, reservoirs physical property determine the degree of gas enrichment, the cover ofcap rock ability is the important guarantee of natural gas accumulation, and the P-Tenvironment determines external environment factors of natural gas accumulation.Natural gas dynamics of petroleum accumulation simulation. The results indicate thatduring the Nmxsedimentary period, the sourcerocks, reservoir, cap rock and energy fieldconfiguration relationships are the most favourable in banqiao sag，which is the key period ofdeep natural gas accumulation. Through the natural gas accumulation of the geologicalfactors and action process analysis, high efficiency of gas accumulation conditions is the highefficient matching of superior quality source kitchen development, hydrocarbon generationhistory, hydrocarbon expulsion history and trap development. Consequently，through thecomposite accumulation of time and space of key elements configuration curve can determinethe deep natural gas for favorable exploration area. The natural gas of Es3deep for favorableexploration area concentrate distributs in Shanggulin area.The the natural gas accumulation analysis technology in this paper is suitable for the deepnatural gas in low degree of prospecting stage target optimization, for drilling deploymentprovides scientific basis for decision-making.