Study On Triassic Sedimentary Characteristics And Hydrocarbon Exploration Potential In Luoyang-Yichuan Area

Paper range for Luoyang-Yichuan area,which Tun 1 well of Upper Triassic chunshuyao formation fracturing test obtained industrial gas flow,showing the potential for oil and gas exploration and prospects,but failed to achieve the commercial production.With dew head,drilling,earthquake,measuring wells and analysis laboratory,established corresponding of deposition mode on the based of modern deposition theory.And through researched deposition features,deposition phase type,deposition phase features,each deposition phase plane distribution law and deposition development history of Upper Triassic in Luoyang-Yichuan area.While,researched the conditions of oil and gas,identified the features of hydrocarbon source rock,born and row hydrocarbon period times,exploration potential of oil and gas,features of storage rock,space type and favourable storage layers evaluation and the forecast of Upper Triassic in Luoyang-Yichuan area,by combination the analysis of drilling wells.And analyzed the effects of deposition on hydrocarbon source rock and storage rock,the features of oil and gas and main control factors,and preliminary summarized mechanism and law of oil and gas of Upper Triassic.Through integrated analysis,we cleared the exploration of direction and field on the based of combination of geological and geophysical,and optimized the favourable target district,which will bring the contribution of comprehensive evaluation of tight sandstone gas reservoir and exploration system,the new increased reserves and production based for China petrochemical contributing to the sustainable and stable development of the eastern oil fields.By study on evolution of tectonic characteristics and basin evolution,we found that Luoyang-Yichuan area and Ordos Basin are the same large sedimentary basin until Mesozoic Triassic,and the settlement center is located in the Luoyang-Yichuan area,sedimentary center is located in the Ordos Basin.Luoyang-Yichuan region experienced 9 basin tectonic evolution stage;which are intercratonic depression stage,late Hercynian weak compression stage,early Indosinian intracontinental depression basin stage,late Indosinian differences orogenic stage,early uplift Jurassic intermountain depression basin stage,early Yanshan thrust-folding stage,mid Yanshan fold and thrust faulted basin stage,late Yanshan differences uplift stage,Himalayan extensional rift depression basin stage.And it can be divided into 9 third-level tectonic units: Yima-Yiyang-Yichuan thrust belt,Yima sub-sag,Yiyang sub-sag,Luoyang sub-sag,Xin'an north slope,Songshan north slope,Yaling-Baisha nose structural belt,Yichuan north and South sub sags.Through the research on stratum,sedimentary,sequence of Upper Triassic in Luoyang-Yichuan area,the area mainly developed fluvial,Delta,lacustrine sedimentary system,various types of sedimentary facies;among them,delta front prodelta and semi deep lake facies are the main sedimentation of the Late Triassic.It has been clear about on the foundation of sedimentary facies and sedimentary system that were characteristics,scale,shape,spatial distribution and deposition of different spatial relationship and sedimentary phase of temporal and spatial evolution regularities.And established sedimentary model of fluvial and delta lacustrine,combined with the structural evolution results,which laid the foundation of petroleum geological conditions in Luoyang-Yichuan area.According to the research of hydrocarbon source rock,reservoir rock and other oil and gas accumulation conditions of Triassic in Luoyang-Yichuan area,the Triassic mudstone has the characteristics of large thickness,abundance and high maturity,oil and gas born generating,now buried shallower.Through the oil source correlation analysis,the Upper Triassic oil and gas are come from the Upper Triassic hydrocarbon source rocks;and early Middle Jurassic is the main reservoir forming period.The Triassic sandstone is development,thickness,various types,and delta front sand body is the main reservoir,which has low porosity and low permeability(tight sandstone reservoir);It included two kinds of reservoir space types: sandstone matrix pores and cracks;The main pore types are dissolution pore and micro cracks.By analysis of drilled wells of Triassic oil and gas reservoir characteristics,the Triassic oil and gas shows have characteristics of vertical display well long and thickness,plane with large range,continuous distribution.Oil source correlation analysis proved that oil and gas mainly from Upper Triassic source rocks,with characteristics of source and reservoir symbiosis,short-range transport and accumulation.Oil and gas reservoir has tight sandstone oil and gas reservoirs characteristics of low porosity,low permeability,low abundance,low pressure and low productivity,and the reservoir quality and hydrocarbon source rock are the key factors for hydrocarbon accumulation.Through comprehensive analysis,the tight sandstone oil and gas reservoirs is the main exploration areas and direction in Luoyang-Yichuan area;the upper Triassic is the key strata of tight sandstone oil and gas exploration;Yichuan north and South sub sags and Yima sub sag are the favorable zone;Yaling-Baisha nose structure is relatively favorable zone.Reservoir prediction is the direct method and the method in target selection;horizontal well drilling is the effective engineering of oil and gas exploration and development.