Horizontal Well Parameter Optimization Of Qinhuangdao 32-6 Bottom-water Heavy Oil Reservoir With Interlayers

The development of heavy oil reservoir with bottom water is an important part of reservoir development in China.For such reservoirs,according to a large number of field data,the existence of interlayers could restrain bottom water coning.Besides,remaining oil distribution is directly influenced by interlayers.Therefore,the analysis of the influence of interlayer factors on heavy oil production is very important for the efficient development of bottom-water heavy oil reservoirs with horizontal well.Based on the parameters of Qinhuangdao 32-6 oilfield,a heavy oil reservoir numerical model is established with both bottom water and interlayers.Under the condition of single horizontal well,three factors(interlayer dimensionless size,interlayer dimensionless vertical position and interlayer permeability)are considered in this paper to investigate the influence of interlayer on bottom-water heavy oil recovery.On the basis of the results from single factor analysis,a multi-factor orthogonal experiment is designed to determine the degree of influence for each interlayer parameter.The ordering of influence degrees is interlayer dimensionless size,interlayer dimensionless vertical position and interlayer permeability.In addition,a multiple linear regression equation is obtained with three independent variables and one dependent variable(i.e.,reservoir recovery degree).In addition to single well condition,according to the actual development situation of Qinhuangdao 32-6 oilfield,different well patterns(i.e.,row well pattern,staggered well pattern and inverted nine spot flooding pattern)are considered in the interlayer factor analysis in this paper.The influences of interlayer dimensionless size,interlayer dimensionless vertical position and interlayer permeability on production under different well patterns are investigated.Besides,the differences of the influence of interlayer factors between single horizontal well and well patterns are analyzed.As a result,two principles for well arrangement for heavy oil reservoirs with bottom water are summarized in this paper: firstly,water injection wells are supposed to avoid interlayers and the optimal location for production well is on the top of the interlayers;secondly,the applicability of row well pattern,staggered well pattern and inverted nine spot flooding pattern is different according to different conditions,the best one is inverted nine spot flooding pattern.And inverted single horizontal well and nine spot flooding pattern are chosen as examples to optimize well spacing as well as the length and vertical location of horizontal well in this paper.The influences of interlayer parameters on horizontal well development are summarized in this paper.In addition,the optimal well spacing scheme and the parameter optimization for horizontal well in bottom-water heavy oil reservoir with interlayers are investigated in this paper.The development theory for bottom-water heavy oil reservoir with interlayers is further studied.