Journal of Canadian Petroleum Technology, Vol.42, No.11, 40-44, 2003
Production optimization of liquid loading gas condensate wells: A case study
Liquid production can be a serious problem in gas condensate wells nearing the end of their production life. As the pressure in the drainage area is depleted, the gas velocity in the production tubing falls below the critical rate resulting in inadequate energy to lift all the condensate out of the wellbore. The condensate migrates down the tubing and collects at the bottom of the completion increasing the bottom hole flowing pressure and, in many cases, killing the well. A similar liquid loading problem can be also encountered in low productivity gas condensate wells. This paper investigates the behaviour of gas condensate wells in a deep basin fractured sandstone reservoir in Alberta. Regardless of the initial well productivity, sooner or later, declining reservoir pressures and/or poor productivity cause wells to liquid load. The first and the cheapest solution is to produce these wells intermittently. Although such wells continue to flow, the liquid fallback still tends to increase the average flowing bottom hole pressure, thus reducing the production rate. The paper discusses the process of selecting the best candidates among such wells for the next level of intervention, which is the installation of plunger lift systems. As a result, 19 wells were equipped with plunger lifts and a significant production increase has been observed. The project has been a technical and economic success so far and is now being extended to the rest of the field.