Hydraulic fracturing has proved to be the most efficient and common completion method to increase well productivity in low-pressure tight sandstone formations in Western Siberia.

However, the efficiency of the overall completion process is influenced not only by the applied fracturing technology but also, to a large degree, by the postfracturing well cleanout operation. It is important to remove all the proppant left in the wellbore and to ensure the flowback of loose solids behind the casing. Using coiled tubing for this purpose improves well productivity, boosting fracture conductivity and ultimately decreasing the number of workover operations associated with downhole equipment failure caused by solids production. A workover rig circulating through jointed pipe may be used for the cleanout operation.

However, because of the inability to create an underbalanced state in the wellbore using this technique, it is not possible to ensure removal of all loose solids as well as all residual fracturing fluids from the fracture. Furthermore, applying overbalanced cleanout in these depleted formations normally results in high workover fluid losses which reduces the productivity of the well. A three-stage well cleanout method has been developed to produce optimal drawdown on the formation.

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