Study On Development Effect Evaluation And Adjustment Scheme Design Of Low Permeability Reservoir In Da373 Block

Da373 block is a low permeability block.The research of remaining oil distribution and development technology and policy in the later stage of development has become the main content of oilfield development research.In view of the problems of unclear understanding of Geology and unclear technical policy in the early stage of development in Da373 block,such as the increase of water cut in oil wells,excessive water injection pressure and the discontinuation of water injection due to the failure of water injection in the well,the development technical policy of Da373 block was studied.It is of great significance to study the injection characteristics of reservoirs under different injection and production parameters,the change characteristics of fluid,oil and water cut,and the change characteristics of pressure in order to obtain a reasonable development model and technical boundaries under certain geological conditions.In this paper,through fine stratigraphic correlation,fine structural and fault interpretation,reservoir characterization and other work,the geological characteristics of Da373 block are implemented,and the basic stratigraphic framework of Da373 block is established.Aiming at the characteristics of inactivity of edge and bottom water,insufficient natural energy and fast decline of dynamic liquid level in block Da373,Petrel is used to establish three-dimensional geological model.The grid of geological model adopts corner grid to divide the grid scale reasonably and establish vertical subdivision grid suitable for beach-bar sand reservoir.Through Eclipse,a dynamic numerical simulation model is established,which combines the historical information of oil production,water production,perforation,fracturing,acidification,sealing and other measures,and carries out historical fitting.The next step lays the foundation for the scheme design.The results show that:combining with reservoir engineering method and numerical simulation method,infilling and adjusting the well pattern of Da373 to the inverse nine-point well pattern,formulating the technical policy limit of water injection development,determining the reasonable injection-production well spacing of 225 m,the limit well spacing of 165m under the condition of oil-water well fracturing transformation,the lower limit of formation pressure of 25.6 MPa under the condition of production pressure difference of 10.0MPa and pump depth of 2200 m,and the corresponding formation pressure drop of 9.8 MPa,determining the production pressure.The difference is 10.0 MPa.It is estimated that the average production capacity in the first three years after implementation will be 1.42×10~4t,compared with the average new production capacity of 0.46×10~4t in the first three years before adjustment,the final recovery degree will increase by 3.7%,the production capacity will increase by 6.31×10~4t and the recovery rate will increase by 22%.