Study of optimization method for variable-density completion of horizontal well

Based on Landman variable density perforation model, a horizontal well variable-density completion coupling model is derived under non-homogeneous formation conditions. And an actual well is taken for example to calculate the production fluid profile of horizontal well under different perforation densities. The results show that the production fluid profile of the high and low permeability section tends to be even with the decrease of the perforation density of the high-permeability section. Based on the coupling model, optimization methods for the variable-density completion of horizontal well under uneven stratum conditions are put forward. The production fluid profiles of optimized perforation model, actual perforation model, and even perforation model are compared. According to the results, the horizontal well corresponding to the optimized perforation model is with the most balanced inflow profile. The frictional resistance of horizontal well bore and non-homogeneousness of stratum brings uneven distribution of pressure on production interval of well, resulting in uneven production fluid profile in the horizontal section and numerous production problems, such as uneven water crest and earlier breakthrough of bottom water [1, 2]. The variable density completion of horizontal well can effectively balance the frictional flow of horizontal well. Foreign scholar Landman [3], Sigmund Sognesad [4], etc. have receptively established horizontal well monophasic fluid flowing models by taking perforation into consideration. Liu Xiaoping, etc. have established horizontal well coupling models to analyze the production fluid profile of horizontal wells [5]. In order to balance the flow in horizontal wells, the optimization methods for horizontal well variable density perforation have been researched and the perforation parameters have been optimized. All the research results show that the adjustment to horizontal well perforation density can improve the inflow profile of horizontal wells and effectively relieve the inflow speed of bottom water crest [6-7]. However, most studies are focused on homogeneous formation. Started from variable density well completion coupling model of non-homogeneous reservoir, the function of variable density well completion in non-homogeneous stratum is analyzed; and based on such foundation, the optimization methods for horizontal well variable density perforation are proposed. ? (2014) Trans Tech Publications, Switzerland.