Study On Development Limit And Water Injection Scheme Based On Fault Lateral Sealing

China's petroleum energy is highly dependent on foreign countries,and the production of domestic conventional reservoirs shows a decreasing trend.In order to secure the energy rice bowl and meet the steady growth demand of domestic petroleum energy,the safe and efficient development of complex fault block reservoirs has become an important part of production replacement.Therefore,this paper studies the optimization of water injection scheme for complex fault block M oilfield,determines the development limit by using reservoir engineering and numerical simulation,and improves the degree of reserve production and recovery.Based on the strike and distribution of faults,the fault types are divided into zone controlling,circle controlling and injection production controlling faults;Considering the distribution of faults on the plane,the fault combination relationship is divided into triangle,parallel and right angle;According to the reservoir and fluid characteristics,the main sand bodies are determined to be small layers L50,L82,L100 and L102,which are vertically divided into three development layer series:Layer Series 1 is composed of L10?L50 oil formation,layer series 2 is composed of L60?L100 oil formation,and layer series 3 refers to the L100 oil formation with horizontal wells deployed.Single index evaluation and comprehensive evaluation shall be conducted for recovery factor,decline rate,water cut rise rate,water storage rate,production degree of water drive reserves,control degree of water drive reserves,water drive index and formation pressure maintenance level.According to the industrial classification standard,the development effect of the whole area belongs to class II level.Layer 1 belongs to class I level,layer 2 belongs to class I level,and layer 3 belongs to class II level.The whole area and each layer still have the potential to further enhance oil recovery.In geological modeling,petrel is used to calculate the fault conductivity factor to quantitatively characterize the lateral sealing of the fault,and then the fault conductivity factor and the static and dynamic data of the oil field are imported into eclipse numerical simulation software for historical fitting of M oil field.Taking the cumulative liquid production as the accuracy index,the fitting accuracy is 96.6%,and the fitting accuracy is good.Based on seepage mechanics theory and fault lateral sealing theory,a fault lateral sealing judgment model is established to determine the differential pressure limit of fault lateral sealing.According to the reservoir engineering theory,taking the maximum oil production as the target,determine the reasonable formation pressure.From the production end of the oil well,use the inflow performance equation to determine the reasonable bottom hole flow pressure and the reasonable liquid production.Taking the safe water injection as the goal,the material balance method is used to calculate the reasonable injection production ratio corresponding to the pressure recovery rate,and the reasonable water injection volume is converted from the relationship between the reasonable injection production ratio and the reasonable liquid production.After the preliminary distribution of the splitting coefficient,the water injection volume is optimized based on the two safe water injection indexes of fault lateral sealing pressure difference limit and formation fracture pressure.The reasonable formation pressure limits of layer series 1,2 and 3 is 11.39MPa,11.84MPa and 13.91MPa respectively.The reasonable bottom hole flowing pressure limit range of production well is4.08?6.46MPa,and the average value of stratum series are 4.58MPa,5.43MPa and 6.34MPa respectively.The limits of reasonable liquid production of strata are 9.26×10~4m~3/mon,4.68×10~4m~3/mon,0.27×10~4m~3/mon as follows.Finally,adhering to the principle of"maintaining reasonable formation pressure and reasonable liquid production on the basis of ensuring water injection safety",through scheme prediction and optimization,it is determined that 3%of the pressure recovery rate of well pattern adjustment is the best scheme.The pressure recovery speed limits of layer 1,layer 2and layer 3 are-0.0384mpa/mon,0.0213mpa/mon and-0.0789mpa/mon.The limits of reasonable injection production ratio of strata are 0.8614,1.2203 and 0.7106.The reasonable water injection limit of the formation are 7.98×10~4m~3/mon,5.71×10~4m~3/mon,0.19×10~4m~3/mon as follows.The average value of reasonable bottom hole flow pressure limit of formation water injection wells is 15.34MPa,16.44MPa and 20.47MPa.The cumulative oil production of the whole region in the best scheme is 859.12×10~4m~3,compared with the basic scheme,the cumulative oil production increment is 241.12×10~4m~3,oil increase of single well is 5.97×10~4m~3?...