A New Concept to Predict Sand Production from Extended Reach and Horizontal Wells

Abstract

Abstract The technology of extended reach and horizontal wells has recently progressed significantly. These wells have very few cost effective choices like slotted liners and openhole completion methods. Hole instability and sand production are the main problems of these completion techniques. To predict sand production an elastic plastic spherical cavity or cylindrical symmetry is assumed. Also, Mohr-Coulomb criterion is proposed for bore hole failure solution.These methods have limited applications and need actual cores to measure shear failure properties of rocks. This paper introduces developed equations to predict sand production from extended reach and horizontal wells. A combination of Mohr Coulomb criterion and Von Mises criterion for cylindrical symmetry is developed and proposed to determine the hole instability and sand production. These equations allow calculating the sand free production rate for extended reach and horizontal wells depending on the uniaxial compressive strength of the rock. They also allow evaluating the effect of inclination angle, azimuth angle, well length and values and directions of in-situ stresses. Also, the equations can be applied easily in any area. Introduction The benefits that come from drilling horizontal and extended reach wells such as achieving high flow rates and reducing gas and water coning in thin reservoirs have been well documented. Horizontal and extended reach wells have been applied through the oil and gas industry to enhance project economics and develop reservoirs that would otherwise not be commercial. These wells have also been applied in high productivity reservoirs for the purpose of reducing gas and/or water coning, thereby improving drainage efficiency and ultimate recovery [1]. The completion technology for horizontal and extended reach wells presents numerous design possibilities. The simplest and least expensive method is completing the well as open hole or using slotted liner. The majority of the wells are being completed using these design methods. However these techniques are usually facing sand production when excessive drawdown is applied [1].