Comprehensive Evaluation And Prediction Of Favorable Reservoirs Of The Permian Upper Urho Formation In The Shawan Depression Of Junggar Basin

A large set of thick sandy conglomerate reservoirs are developed in the Permian upper Urho formation in the Shawan depression,Junggar basin.The sedimentary environment of the glutenite reservoir in the target layer of the sag is complex,especially the formation environment and genetic mechanism of zeolite and other mineral components are complex and diverse,with strong reservoir heterogeneity.Previous studies have shown that the Permian upper Urho formation in the Shawan depression developed a fan delta lake sedimentary environment,and the rapid accumulation of sediments is one of its major characteristics.At present,the research on the plane distribution law of glutenite reservoirs and the main controlling factors of reservoirs is not deep enough and clear enough.In this paper,starting from the slope area rich in oil and gas in the upper Urho formation,the petrological characteristics,diagenetic evolution characteristics,pore throat structure and physical properties of the glutenite reservoir developed in the study area are analyzed and studied by means of core observation,microscope experiment,scanning electron microscope,energy spectrum analysis and other experimental means.The sedimentary environment of the upper Urho formation in Shawan depression is defined,and the reservoir characteristics and the main controlling factors of reservoir formation are clarified,On this basis,the favorable reservoir plane distribution prediction is carried out.The study can get the following views:(1)the target layer in the study area is fan delta sedimentation,the main rock types are sandy conglomerate,sandstone and mudstone,and the glutenite is the main rock facies;The main filling components of interstitial materials are argillaceous and laumontite minerals,and there is an obvious regional zoning between the two components.(2)The formation time of zeolite cement in Glutenite is later than that of Iraqi Mongolian mixed layer minerals,earlier than dissolution and large-scale oil and gas filling.The diagenetic evolution is characterized by acid-base interaction.The diagenetic evolution stage of the target layer is mainly in the middle diagenetic stage,and some are in the late diagenetic stage a.(3)The pore types in the study area are mainly intergranular dissolved pores,residual intergranular pores,some intergranular pores and a small amount of microcracks.(4)The development of pyroclastic materials in the study area provides a good material basis for the formation of laumontite.The alternating action of acid-base environment creates congenital conditions for the precipitation and later dissolution of laumontite,makes it develop multiple secondary pore zones,and improves the reservoir performance of the target formation.(5)Based on the analysis of the main controlling factors of the upper Urho formation reservoir in Shawan depression,the favorable exploration areas of First member of upper Urho formation and Second member of upper Urho formation are predicted.