Method of predicting the on-set of formation solid production in high-rate perforated and open hole gas wells

摘要

A method for predicting the on-set of sand production or critical drawdown pressure (CDP) in high flow rate gas wells. The method describes the perforation and open-hole cavity stability incorporating both rock and fluid mechanics fundamentals. The pore pressure gradient is calculated using the non-Darcy gas flow equation and coupled with the stress-state for a perfectly Mohr-Coulomb material. Sand production is assumed to initiate when the drawdown pressure condition induces tensile stresses across the cavity face. Both spherical and cylindrical models are presented. The spherical model is suitable for cased and perforated applications while the cylindrical model is used for a horizontal open-hole completion.