Accumulation conditions and model of Permian deep lithologic oil reservoirs in Fukang Sag,Junggar Basin
Using experiments such as organic carbon,rock pyrolysis,mass spectrum and chromatography,rock thin sections,cast thin sections,and scanning electron microscope,and taking the Permian Upper Wuerhe Formation reservoir in Fukang Sag of Junggar Basin as the research object,this paper studies the oil reservoir types and various reservoir-controlling conditions and further reveals the accumulation model of the Upper Wuerhe Formation in Fukang Sag.The results indicate that:(1)The type Ⅰhydrocarbon source rocks deposited in the saline water reducing environment of Lucaogou Formation have sufficient supply of aquatic organisms,high organic matter abundance,high maturity and good oil generation potential,providing rich material sources for later oil and gas accumulation.(2)The Upper Wuerhe Formation is a fan-delta and lake sedimentary system with large burial depth and strong compaction.Dissolution pores and fractures are the main types of deep ultra-low porosity and ultra-low permeability reservoirs and the main channels for oil migration.(3)The mudstone cap rock of Wu 3 Member creates good conditions for oil and gas preservation,and the source faults and associated fracture networks provide the most convenient channels for oil and gas migration.Under the action of overpressure system,oil and gas continuously accumulate and form reservoirs.(4)Various accumulation conditions are mutually configured to form an accumulation model of"source-reservoir integration,fault transport and overpressure accumulation".Oil and gas continue to accumulate,forming the current deep and large lithologic oil reservoir of the Permian Upper Wuerhe Formation.The research results can provide reference basis for the exploration of deep oil reservoirs in the Upper Wuerhe Formation of Fukang Sag and other lithological oil reservoirs in China.
lithologic oil reservoirsreservoir-controlling conditionsaccumulation modelUpper Wuerhe FormationFukang Sag
万方数据
维普
