Neutral-We Proppant Improves Post Treatment Cleanup and Enhances Productivity

Abstract

A well, with very low bottomhole pressure, required frequent workover operations due to pump failures from sand production. A gravel pack was designed to minimize the production sand issues. However, to sustain low pore pressure (less than 0.1 psi/ft) without affecting well productivity, lower drawdown was needed during an acceptable sand control completion. This presented a challenge due to massive completion brine losses and increased risk of formation damage. These challenges could create impairment in well productivity. Usually, a rig utilizing coiled tubing is used to handle the flowback and unload the well. To increase the amounts of flowback fluid, and minimize formation damage, the completion of this well used a neutral wet proppant. The proppant, which had surfaces that are neither oil nor water wet, was used in this gravel pack to improve the flowback fluids recovery. The expected benefits of this proppant were to (1) eliminate capillary pressure within the proppant pack and (2) alter the interaction between aqueous/organic (hydrocarbons) and the proppant surfaces. This would be accomplished by decreasing the intra-molecular interactions between the fluids and the proppant surfaces thus resulting in improved flow compared to native surfaces. Lightweight ceramic (LWC), neutral-wettability proppant was used to improve clean-up and enhance fluid flowback recovery. Extensive laboratory testing on the proppant was performed ahead of the job, including properties and compatibility with stimulation fluid. This proppant had both hydro- and oleophobic properties. The hydrophobic properties improve the flow of the aqueous fluids, while the oleophobic properties improve the flow of the hydrocarbon phase. The proppant was pumped similarly to any other conventional proppant and no changes in the procedures were needed. After completion of the job, the well was shut-in and the flowback un-loading was performed a week later. This completion relied on using ESP to perform the cleanup and producing the well concurrently to reduce the operation time and cost spent during well unloading. After completion, 100% of all pumped brine was recovered leading to an enhanced production rate with no impairment or coiled tubing lifting post treatment required. The cleanup was carried out after one week from the treatment date. The well cleanup, in comparison with wells that used conventional proppant, was much faster and saved $50,000. The calculated productivity index is 3.2 compared with 2.8 bpd/psi before the treatment representing 15 % gain. No sand production was observed during production performance nor seen in the wellbore during pump replacement after two years of continuous production period. The average run life prior to this treatment was 3 months, thus impacting not only the well productivity but also the run well life.