Research On Residual Oil Distribution And Adjustment Solution For Karamay Formation Of 4-1 Oilfield

As for the reservoirs in 4-1 oil deposit which have only 70% of the cut with the recovery degree of 15.6%,the corresponding injection relationship can not be formed,because the well point in the injection-production pattern on the horizon is seriously damaged,and only few wells are exploited.Therefore,this area was classified as an abandoned oil reservoir in 1993 for special management.The oil reservoirs have high heterogeneity with more vertical layers,little exploitation of oil reservoir and large remaining reserves.The main reservoir in this area is rarely exploited,and the entire flooding condition is relatively weak.In addition,the water content of the whole reservoir before abandoning is relatively low.Thus,the reservoirs have a large secondary development and adjustment potential.By studying and understanding the structural characteristics,reservoir characteristics,oil sands distribution rule and the existing problems arising from the development of the reservoirs in this area,the distribution rule of residual oil on the horizon and profile is clarified and identified.The area where remaining oil is enriched is identified.At the same time,the potential of each single layer is determined by quantitative analysis of the remaining oil in each single layer.Research results about residual oil are used to determine the adjustment thinkings and develop the principle of adjustment.By using a variety of reservoir engineering methods,the form of well pattern,well spacing and pressure retention degree and other mining technology policy indicators which are suitable for this area are developed,and the overall potential tapping scheme is put forward.After single well production capacity is determined based on the initial oil test data and the numerical simulation,the capacity of the block is determined,and the reservoir development index is forecasted to optimize the reasonable scheme.In order to reduce the overall risk of entire potential tapping and adjustment,well groups in a representative area is selected for pilot test.Then,the corresponding data are collected,and the overall development and adjustment is implemented on the basis of the test group exploitation effect.Through the overall development and adjustment,the final recovery rate of the oil reservoirs can be increased by more than 15 percentage points,which can provide reference for the development of similar reservoirs.