Drawdown Management:A Technical and Economic Alternative for Sand Control in Wells:A Colombian Field Application

摘要

One of the most common problems during the hydrocarbon production is sand production.Efficient control of the sand production without causing formation damage will depend on the knowledge that we have of the reservoir and also of the designs and estimates that we make during the drilling,completion and production.Sand production causes many problems ranging from collapses in casing,failures of subsurface equipment and surface facilities and accumulation in downhole generating continuous inter-ventions,up to the point of making unproductive wells,thus putting in risk the future interventions of the wells and the capacity thereof in the long term. In the oil industry there is a diverse range of technologies to control and/or exclusion of sand in open hole and/or case hole that can be mechanicals or chemicals,but the selection must be done carefully, taking into account granulometric and mineralogical criteria for proper selection,because although that we choose the best alternative technique and do a good sand control,the solution may not be optimal from the economic standpoint. A good decision making process considers other alternatives for sand control,such as handling the drawdown pressure,which in some cases proves to be a technical and economic alternative,especially when the critical drawdown pressure(CDP)presents values over 40%of the reservoir pressure. A geomechanics evaluation establishes the predictive model of sand production,which allows us to determine the critical drawdown Pressure.From density logs,Vsh,sonic logs,etc.and correlations,the compressive strength(UCS),cohesion,angle of internal friction and mechanical properties of the rock (Young modulus,Poisson’s ratio,etc.)are determined.With a geomechanical model(previously selected and evaluated with field and laboratory data),the pressure gradient and the mechanical properties of the rock,the predictive model of sand production is established. This study was conducted in the fields:Lisama,Galán,Llanito,Yarigui,Cantagallo and Bonanza in Colombia.This article presents the case study in the well Lisama 166,where the drawdown management became a technical and economic alternative for sand control.