The Research Of The Remaining Oil In The Middle East Part Of The Nanwu Block And The Reasonable Well Spacing Density

The middle East part of the Nanwu block has entered into high water cut period now,the moisture content is 92.8%,and the recovery degree is 48.66%.Some problems are existed such as the distribution of residual oil is scattered and the contradiction between layers is prominent.In order to further improve the development effect and adjust the well pattern,we must divide the type of the remaining oil and calculate quantitatively.This paper formulate a method to divide the remaining oil type,based on the method,we compile a software to judge the types of remaining oil precisely.This method is based on the pressure data of the grid,take the range of maximum and minimum pressure around the well as the control area of the production well and injection well.The remaining oil which out of the range belongs to the out of well pattern control type,which in the control of either production well or injection well belongs to the injection-production faultiness type,which the longitudinal permeability variation coefficient is greater than 0.8 and 1 belongs to intermittent residual oil;the residual water absorption is less than the average water absorption of each layer of water well is divided into absorbent poor residual oil;the remaining remaining oil is divided into flat heterogeneous residual oil.It is concluded that up to June 2016,the remaining oil of out of well pattern control type is 1.50 million tons,accounting for 20.07%,the injection-production faultiness type is 1.92 million tons,accounting for 25.76%,the poor water absorption type is 0.61 million tons,accounting for 8.24%,the interlayer interference type is 0.92 million tons,accounting for 12.29%,the interlayer and plane interference type is 2.51 million tons,accounting for 33.64%.In view of the problems such as low desity and control degree of well spacing,imperfect relationship of injection and production wells,and the serious interlayer contradiction,four well pattern and five well spacing density have been designed.Using the numerical simulation and the economic evaluation,we obtain the optimum well pattern of the block is five-spot areal pattern,the optimal well spacing density of good and bad reservoir in S,P and G reservoir group is 34.05 per km~2 and 64.86 per km~2.