Research On Water Flooding Adjustment Of BW Bottom Water Heavy Oil Reservoir

The BW block formation can be divided into four layer groups,and the layer groups are not connected to each other.Its reservoir is characterized by high permeability of mesopores,strong heterogeneity,and development of argillaceous interlayers within the layers.The BW block belongs to the bottom-water heavy oil reservoir,and the viscosity of the formation crude oil is 68-790 mPa s.The BW block has been put into operation since 2001,and the initial production of each well is relatively high.As of October 2017,most of the wells have entered a high water cut period,but the falling range of formation pressure is small.The recovery of the block is low and there is still a large amount of residual oil existed in the formation.It is the central task of the block to find out the law of water intrusion and the distribution of remaining oil.This paper establishes a block numerical simulation model.On the basis of matching and production history matching,the water invasion law and remaining oil distribution law were studied by combining geological and production dynamic characteristics.Finally,the corresponding potential tapping schemes are proposed for different types of remaining oil distribution,which provides technical support for the remaining oil tapping potential.Through reservoir engineering methods and numerical simulation,the following understandings are made:the water intrusion mode of the reservoir is mainly bottom water intrusion,and Bentiu 1A is edge water intrusion.The residual reserves are mainly distributed in Bentiu 1B,Bentiu 2B and Bentiu 3,and its distribution factors are structure,septum/interlayer,fault,independent small sand body and development well network,etc.Through the numerical simulation study of single well steam stimulation,reasonable injection and production parameters were established.The idea of tapping potential for residual oil is:(1)drilling new or side-tracking wells to solve the problem of poor control of the well pattern;(2)adjusting the perforation horizon in the longitudinal direction to solve the problem of high water content in the vertical well;(3)Technically,the use of steam stimulation for thermal oil recovery solves the problem of the single problem of development technology.On this basis.Three types of adjustment programs including horizon adjustment,infill well and steam stimulation were designed.Through the numerical simulation optimization scheme,the final preferred adjustment scheme is 9 wells of the horizon adjustment well,and the recovery can be increased by 0.48 percentage points than the basic scheme;15 wells are indented on the basis of the horizon adjustment,and the recovery can be increased by 1.94 percentage points than the basic scheme;on the basis of the infill well,5 steam stimulation wells are implemented,and the recovery can be increased by 2.21 percentage points than the basic scheme.