Method of determining by numerical simulation the restoration conditions, by the fluids of a reservoir, of a complex well damaged by drilling operations

摘要

Method of determining by numerical simulation the optimum conditions to be applied in a horizontal (or complex) well drilled through an underground reservoir so as to progressively eliminate (restore), by the fluids from the reservoir, deposits or cakes formed in at least a peripheral zone of the well as a result of drilling and completion operations. ;The method essentially comprises acquiring initial data obtained by laboratory measurements of the values, according to the initial permeability (ki) of the formations surrounding the well, of the thickness of the cakes and of the damaged permeability (kd) and restored permeability (kf) values of this zone, as a function of the distance (r) to the wall of the well, discretizing the damaged zone by means of a 3D cylindrical grid pattern forming blocks of small radial thickness in relation to the diameter of the well, and solving in this grid pattern the diffusivity equation modelling the flow of the fluids through the cakes by taking account of the measured initial data and by modelling the evolution of the permeability as a function of the flow rates (Q) of fluids flowing through the cakes, so as to deduce therefrom the optimum conditions to be applied for producing the well. ;Application: production of hydrocarbon reservoirs for example under deep offshore conditions in weakly consolidated formations (Gulf of Mexico, Angola, etc.).