Study On Optimization Of Hydrodynamic Development Mode At High Water-cut Stage In Fault Block Reservoirs

The fault block reservoirs have entered the high water-cut development period.After longterm injection development,a fixed water flow channel is formed in the formation.Under low oil prices,how to change the underground pressure field,change the direction of water flooding,and strengthen the weak wave zone through the adjustment of injection and production are the difficulties in reducing the cost and increasing efficiency of fault block reservoirs.The hydrodynamic development method is a main means of improving the quality and efficiency of water flooding reservoirs under low oil prices.The hydrodynamic development method means that when the well pattern is relatively fixed,the investment and cost are not increased,and the most economical water flooding development method is utilized.By changing the injection and production parameters and changing the internal water pressure driving mode of the reservoir,the technology to change the underground flow field,precipitation and oil increase,and reduce cost and increase efficiency are achieved.According to the type and development status of fault block reservoirs,a typical reservoir model and residual oil enrichment model were established.The reservoir numerical simulation technique was used to study the range and extent of different types of remaining oil.On the basis of the specification and classification of hydrodynamic development methods,the mechanism of enhancing oil recovery by different hydrodynamic development methods was clarified.Through the research on the influencing factors of hydrodynamic development methods(including oil well distance from fault,dip angle,water body multiple),a set of hydrodynamic development models suitable for the characteristics of fault block reservoirs was formed.The parameters quantitative policy limits and optimization methods of different hydrodynamic development methods were determined to improve the technical support for the development of fault block reservoirs at high water-cut period under low oil price.The research results show that the remaining oil enrichment types of the Xianhe fault block reservoir include:fault angle control type,high part fault control type,physical property control type,well pattern control type.Water injection,periodic oil recovery and injection-production coupling can increase the utilization range and degree of remaining oil.The mechanism of hydrodynamic development to adjust the flow field is to change the oil field by changing three fields: one is to change the pressure field of the reservoir by changing the pressure of the injection well point;the second is to change the water flooding flow field by changing the pressure field of the reservoir;the third is to change the reservoir saturation field by changing the pressure field and the streamline field.The farther the oil well is from the fault,the higher the degree of hydrodynamic development.Borderless and bottomless water reservoir is more suitable for the development of injection-production coupling mode.The injection-production coupling method has good adaptability to inclined reservoirs.It quantitatively determines the cycle limit of periodic injection and periodic oil recovery development,and the cycle water injection system with short injection and long shutdown and the cycle oil recovery system with long production and short shutdown are more suitable for oil field development.