Study on Development Well Pattern Density of Deep Oil-Bearing Strata in Loufangping Oil Area of Wuqi Oilfield

In order to develop the unused Chang 8 and Chang 9 reservoirs reasonably and efficiently, it is necessary to establish a set of reasonable well pattern system to accumulate experience and guide the efficient and reasonable development of other deep oil-bearing areas in Wuqi oilfield. The water flooding recovery factor of Reservoirs 8 and 9 is studied in the research area, along with the relevant parameters. Based on the relationship between different well spacing densities and recovery rates at various flow rates, well spacing densities of 6.8 wells per kilometer are determined for the study area. Based on the actual well pattern density of 9.2~18 Walls/km 2 in the developed Triassic oil fields in the west of Yanchang Oilfield, considering the connection of new and old well patterns, it is determined that the development well pattern density of Chang 8 and Chang 9 reservoirs should be 10~15/km 2 , and the well pattern density deployed at 300 m well spacing is basically suitable. On the basis of the analysis of the maximum principal stress and fracture orientation in the study area, the well pattern plan is deployed on the basis of the original 300 m~300 m square well pattern as far as possible to inherit the original pattern, using 300 × 300 square reverse nine-point well layout, and using the reverse nine-point injection method. The results of this study have a certain guiding value for the development of deep reservoir in this area and even the whole Wuqi oilfield.