Research On Reservoir Characteristics And Control Factors Of P Formation In The North Slope Of Bongor Basin,Chad

Taking the theories of petroleum reservoir geology and sedimentary petrology as instructions,and on the basis of previous studies,combined with geological background,core and logging data,the petrological characteristics,physical properties and diagenetic characteristics of P Formation in the north slope of Bongor Basin are studied by means of thin section analysis,X-ray,scanning electron microscopy and conventional mercury injection analysis.Then,the dominating factors of reservoir are comprehensively analyzed,the reservoirs are classified and evaluated,and the favorable areas are predicted.The results show that the lithology of P Formation is mainly arkose,lithic arkose and little feldspathic litharenite with the characteristics of low compositional maturity and low textural maturity,reflecting the characteristics of rapid accumulation near source.The main diagenesis types include compaction,cementation and dissolution,and reservoir is in the A-B stage of middle diagenesis.The reservoir has good physical properties with medium porosity and medium-high permeability.The main types of reservoir space are intergranular dissolved pore and residual intergranular pore.The physical properties of reservoir are mainly influenced by sedimentation,diagenesis and tectonism.Based on the correlation analysis among characteristic parameters of pore structure and physical properties,the classification parameters of pore structure are picked out.Reservoir is divided into four types and their discriminant function is established by Q-cluster and Bayes discriminant analysis,in which type ? reservoirs are favorable targets for exploration and development.Four favorable reservoir areas are predicted based on various research results.