Study On Development Effect Evaluation And Adjustment Strategy Of S Well Area In Jianghan Basin

The S well area is located in Qianjiang City,Hubei Province.Its regional structure belongs to the Qianjiang Sag of the Jianghan Basin,and its main producing layer is the upper strata of the fourth member of Qianjiang Formation of Paleogene.It is a medium-porosity and medium-permeability reservoir with strong reservoir heterogeneity.As of May 2019,the production in the study area has been continuously decreasing,the energy level has been kept low,the water content has been rising rapidly,and the development effect has been deteriorating.In order to improve the unfavorable development status of the study area,the reservoir engineering method was used to evaluate the development effect of seven indicators,including formation energy retention level,production decline and recovery efficiency.The research shows that the formation pressure in the study area is maintained at about 5MPa,which is about1/4 of the original formation pressure.The control degree of waterflood reserves is 35.6%,the utilization degree of waterflood reserves is 72.7%,the comprehensive water cut is 38.8%,the water cut rising rate is 2.9%,and the water storage rate is 25%.The production decline type belongs to hyperbolic decline,and the monthly decline rate is 11.12%.The current formation energy retention level,waterflood reserve control degree,waterflood reserve utilization degree,water storage rate,etc.are relatively low in the study area,and the production decline is rapid,the water cut is higher and the water cut rises quickly,which should be combined with the residual oil distribution of further perfecting injection-production well pattern,strengthen water injection,so as to improve the development effect,improve the ultimate recovery efficiency in the study area.Combined with the geological data of the study area,the Petrel geological modeling software was used to establish a three-dimensional geological model of the reservoir in the study area.Based on the three-dimensional geological model,the reservoir numerical model in the study area was established by using CMG numerical simulation software.On the basis of good historical fitting,the distribution characteristics of remaining oil in the study area were defined.The results show that under the influence of faults,structures,injection-production well patterns and reservoir heterogeneity,the remaining oil on the plane of the study area is mainly concentrated in the fault area,the area near the edge and corner of the reservoir,the high part of the structure and the area with imperfect injection-production well patterns.Longitudinal remaining oil in the study area is mainly concentrated in the strata of Qian4₃¹,Qian4₁⁰,Qian4^0zhong,Qian4^0xia,Qian4₁² and Qian4^2xia.Taking the T70X-3 water injection well group in the study area as an example,the remaining oil production mechanism is studied from the aspects of plugging high water-cut oil production wells,oil production well transfer injection,and injection wells reperforating.Taking the T70X-3 water injection well group in the study area as an example,the remaining oil production mechanism was studied from the aspects of plugging high water cut production wells,oil wells transfer injection wells and hole filling of water injection wells.Combined with the remaining oil distribution characteristics,adjustment measures such as deployment of new Wells,plugging of high-water-cut production wells,oil wells transfer injection wells,hole filling of water injection wells,fracturing and so on were formulated.Through the numerical simulation prediction index of development effect fifteen years later,the results showed that the cumulative oil production of the adjustment scheme more than the existing schemes 241,200 tons,recovery degree increased by 5.3%,improve development effect obviously.