A semi-analytical framework for predicting the onset of sand production in a horizontal well is presented.The approach couples the flow in perforation tunnels with flow in the wellbore itself,to obtain a more accurate estimate of maximum sand free production rate in a well.The elastic equations of equilibrium are combined with the Mohr–Coulomb failure criterion to calculate the critical radius.A numerical,iterative solution method is used to compute the location of the elastic-plastic zone during well production.Instead of computing the pressure change in a cavity,which is difficult to characterize and implement in practice,the proposed model integrates the cavity stability criteria into the perforated wellbore inflow model to determine maximum sand-free wellbore flow rate.In addition to the typical perforation tunnel parameters such as cohesive strength,friction angle and perforation radius considered in past efforts,pressure loss effects in a wellbore(wall friction,acceleration,and fluid mixing)are incorporated into the proposed model.A numerical shooting method is then used to iteratively arrive at the maximum sand free rate for a perforated horizontal wellbore in a reservoir of known properties.Results show that without incorporation of the inflow model,the predicted maximum sand-free rates from prevailing approaches can be over-optimistic.The proposed method can be used to optimize perforation parameters to prevent sanding when designing well completions.
展开▼
