Parameter Optimization Of Slotted-liner Completion Of Horizontal Wells In Low Permeable Gas Reservoir

In traditional liner completion of horizontal wells, the parameters(including slot shape, slot length, slot width, slot style) of slotted-liner are usually uniform along the wellbore. To do so may be convenient, however, the characteristic of the unbalanced inflow profile was often ignored. Generally the inflow rate at the heel of the horizontal well is greater than that at the toe of the well. Using the constant parameters of liner completing horizontal well in gas reservoir with bottom water may cause water coning, which reduces premature water flooding. This phenomenon would be more obvious for low permeability reservoir because anisotropy prevails in this kind of formation. In this paper, we consider all those bad factors and analyze the effect of parameters of slotted-liner on productivity and inflow profile, presenting a method to optimize liner completion. Firstly we derive the pressure response in gas reservoir under slotted-liner completion and discretize the formulae. Based on the pressure response in oil reservoir, we obtain the solution by replacing the old pressure with pseudo pressure function. Secondly we study the influence of drawdown along horizontal wellbore on inflow distribution, followed by coupling reservoir flow with wellbore hydraulics. Three types of flow rigimes: pseudo-radial flow, steady-state flow and pseudo-steady-state flow are considered. Actually we present the numerical solution of coupling model, compile MATlab programme and conduct the example calculation. At last, we discuss the the effect of blank/liner ratio, slot length, slot width, slot style, slot angle and drilling damage on well productivity and product profile with the coupling model. We also propose a method to optimize parameters of slotted-liner. The method controls the inflow distribution by adding or cutting mechanical skin factor caused by slotted-liner. Combined with economical assessment principle, the method would balance inflow profile, delay breakthrough time and eventually improve reservoir recovery.