GINI coefficient: An effective way to evaluate inflow profile equilibrium of horizontal wells in Shengli Oil Field

A new Inflow Gini Coefficient (GN) is introduced to directly and quantitatively to evaluate the equilibrium of horizontal well inflow profile. GN reflects to the difference of inflow profiles between actual well and ideal well simulated by a 3D oil-water black oil model. GN ranges from 0 to 1, and profile becomes more unbalanced with larger GN. 70 sample wells in Shengli Oilfield have been statistically studied to relate GN to production performance parameters, and then, 0 < GN < 0.1 is classified as balanced grade, 0.1 < GN < 0.3 as unbalanced grade, while GN > 0.3 as extremely unbalanced grade. GN selected the best schemes of profile control for 20 application wells, and averagely increased daily oil production from 13.9 m(3)/d to 20.2 m(3)/d, decreased water cut from 82.5% to 75.6% when GN dropped from 0.246 to 0.127. Further, the variation of daily oil production and water cut after profile control is found to increase exponentially with linear decrease of GN. It can be concluded that, GN provides effective guidance for inflow control of horizontal well to ensure successful results, the performance of horizontal well with more unbalanced inflow profile, especially GN > 0.3, always has great potential to be improved.