Fine Description Of Reservoirs And Corresponding Evaluation Of Injection-production Horizons In Youquanzi Oilfield

This paper belongs to the description of oil and gas reservoirs and the sub-direction of oil and gas field development geology under the direction of oil and gas field development engineering.The reservoirs in Youquanzi Oilfield have poor physical properties,thin layers and poor connectivity.At present,there are some problems,such as difficult water injection,high injection pump pressure,poor formation water absorption capacity,no injection,ineffective oil wells,complex oil-water relationship and so on.Aiming at the problems faced by Youquanzi oilfield itself and water injection,a comprehensive evaluation method of injection-production horizon correspondence in Youquanzi oilfield is put forward based on static analysis and production characteristics analysis of injection-production wells.Based on fine stratigraphic division and correlation,corresponding evaluation of injection-production horizon is carried out based on structural location,distribution of sedimentary microfacies,reservoir and reservoir characteristics and production characteristics of injection-production wells.By synthesizing the evaluation results of various factors,the comprehensive evaluation of injection-production horizon correspondence is further completed,and the measures and suggestions are put forward.The main achievements are as follows:(1)A comprehensive evaluation method of injection-production horizon correspondence in Youquanzi Oilfield is proposed.Considering that the oil-water flow in reservoir is controlled and influenced by many factors such as structural location,sedimentary microfacies distribution,reservoir,reservoir characteristics and production characteristics of injection-production wells,the relationship between the structural location,sedimentary microfacies distribution,reservoir and reservoir characteristics,production characteristics of injection-production wells and the corresponding injection-production horizons is analyzed in turn.A comprehensive analysis of the corresponding injection-production Horizons in Youquanzi Oilfield is put forward.Method.(2)Stratigraphic division and fine correlation were carried out.Using the data of bio-fossil,core and well logging,the stratigraphic division scheme is determined firstly,the key well profile and stratified backbone profile are constructed,then the stratification of 229 wells is sorted out,and the stratigraphic division of 45 new wells is completed,which lays the foundation for the evaluation of injection-production horizon correspondence.(3)Research on structural characteristics and evaluation of injection-production horizon correspondence based on structural location were carried out.According to the influence of gravity on fluid flow,the evaluation principle of corresponding structural location of injection-production horizon is formulated.The structural location of oil and water wells in well groups is analyzed statistically.The results show that the structural location of a few well groups in the area will affect the effect of water injection.(4)The characteristics of sedimentary microfacies and the corresponding evaluation of injection-production horizons based on the distribution of sedimentary micro facies were carried out.Based on core description and logging data,the distribution characteristics of sedimentary microfacies are studied.It is found that the vertical and lateral phase transitions are frequent in Youquanzi oilfield.According to the contact type of sedimentary sand body,the principle of evaluating the connectivity of sedimentary sand body is determined.Statistical analysis of the connectivity of a single well in the main horizon(microfacies type)shows that the microfacies of the main oil formation in most well groups are beach bar and overflow sheet sand.(5)Reservoir characteristics?reservoir characteristics and injection-production horizon correspondence evaluation based on reservoir and reservoir characteristics were carried out.Core and logging data show that the oilfield belongs to low porosity and permeability reservoir,and there is no uniform oil-water interface.The evaluation principle of reservoir and reservoir correspondence between injection and production wells is determined.The corresponding situation of reservoir and reservoir is analyzed by using logging interpretation and stratigraphic division results.The results show that most of the reservoirs and reservoirs in this area correspond well.(6)Production characteristics analysis of injection-production wells and comprehensive evaluation of corresponding injection-production horizons are carried out.Analyzing the production data of injection-production wells,it is found that the production has improved since water injection in 2011,but nearly half of the wells in the area have no effect or obvious effect on water injection,and the overall effect of water injection is poor.Finally,based on the evaluation results of interwell sedimentary sand body connectivity and reservoir and reservoir correspondence,combined with the analysis of production characteristics of injection-production wells and the evaluation results of structural location,the comprehensive evaluation principle of injection-production horizon correspondence is determined,and the comprehensive evaluation of injection-production horizon correspondence in Youquanzi Oilfield is completed,and the corresponding measures and suggestions are put forward.