The Principle of Target Influx Selection and the Optimization Process of Variable-ICD Completion Design for Heterogeneous Reservoirs

Abstract

ICD completion has been rapidly developed due to its effective mitigation of unwanted water breakthrough in horizontal wells. It prolongs the no-water production time by introducing an extra pressure drop in high inflow rate zones. With respect to the horizontal well, equally distributed influx is generally regarded as the ideal influx to achieve the longest no-water production period. Howeverin some cases, like producing with fixed bottom-hole pressure (BHP), this may not always correct. When designing the ICD completion, the target inflow profile should be carefully selected. The horizontal well needs to be selectively completed with variable ICDs to minimize the reduction of well productivity.In this paper, a reservoir-wellbore coupling model will be given for influx computation, in which the ICD pressure drop is considered. Then we will propose the selection principle of the target inflow profile for ICD optimization on the constraints of BHP limits, required daily production and no-water production periods. The cumulative production at the time of water breakthrough is selected as the evaluation criteria. The flowchart of the ICD optimization process for the heterogeneous reservoir will be illustrated; and a synthetic case study will be carried out with a comparison of open-hole completion, constant ICD completion and optimal ICD completion. Results indicate that the effect of the water control of ICD completion can be maximized with a reasonable selection of the target inflow profile.