Study On Optimization Of Liquid Rate Increase Strategy For Offshore Heavy Oil Reservoirs With Strong Bottom Water

The vast majority of offshore oil and gas resources in China is heavy oil resources,which is difficult to develop.In the Bohai bay area,the heavy oil reserves account for76% of the total reserves of the area.In the development process,after the well starts to produce water,the water cut rises rapidly.Liquid rate increase is an important measure to stabilize production,with low investment and quick results,and is widely used in major oil fields.However,at present,in some oilfields,wells have experienced a sharp increase after liquid rate increase in water cut,and the liquid rate increase has become a "water rate increase ".Other wells have not seen effective results after liquid rate increase.Based on the researching of domestic and foreign literature,this article has conducted in-depth research on the liquid rate increase of offshore heavy oil reservoirs with strong bottom water.Taking LD32-2 oilfield as an example,a three-dimensional displacement model with edge and bottom water is made for physical experiment in order to study mechanisms of high-multiple water drive and EOR.Research on distribution of remaining oil after liquid rate increase in bottom water heavy oil reservoirs is carried out.The infill potential of the oilfield,as well as the optimal design of the liquid rate increase scheme are studied through numerical simulation methods.Finally,some strategies which can be used for liquid rate increase in high water cut periods of bottom water heavy oil reservoirs are proposed.The results of the study show that after the oil field reaches a high water-cut stage,multiple rounds of liquid rate increase can effectively increase production;the water saturation at the top of the reservoir is low,while the water saturation at the lower part of the reservoir is higher;under the high multiple water flooding condition,when the watercut exceeds 98%,the liquid rate increase capacity can be increased by 5-12 times;if the horizontal wells suitable for liquid extraction in the work area continue to be produced according to the design,the oil production can be increased by 1.03 million cubic meters within five years,with a recovery rate of 18.9 %,If the infill production is carried out in the area with infill potential and synchronized with the liquid rate increase measures,a better production increase can be achieved.