There are many oil layers in the vertical direction of complex fault block reservoirs. The development area of oil sand bodies on the plane is small

and the plane heterogeneity is strong. It is difficult to construct a regular well pattern for uniform displacement. At the same time

due to the influence of various closed boundaries of reservoirs

bypassed oil area is easy to form in the process of water flooding. In order to calculate the control degree of water drive reserves more accurately

evaluate the rationality and integrity of reservoir well pattern better

and find the way to adjust the well pattern

a more suitable new method

namely grid reserve method

is proposed for the shortcomings of traditional methods. By improving the division accuracy of the reserve control area in the well pattern on the plane

combining the geological conditions and the heterogeneity difference of the reservoir

and taking the injection-production well group as the basic unit

the geological reserves are controlled by the well pattern gridded layer by layer. The grid geological reserves are classified and counted

and those bypassed oil areas are found out

and then the control degree of the injection-production well pattern and the control degree of the water drive reserves are calculated. Finally

the potential of well pattern adjustment and encryption is obtained. This method is applied to the adaptability evaluation of the well pattern in Nanpu-101 fault block

and the uncontrolled and unused area of well pattern caused by complex boundary is found. After well pattern infilling

better potential tapping effect is show in this area. It is proved that this method has good adaptability in the evaluation of water drive reserves control degree in complex fault block reservoirs

and can be extended to other complex fault block reservoirs.