A Novel Chemical Treatment and Well Completion Strategy to Prevent Scale and Production Losses in Shushufindi Aguarico Field

Abstract

In this case study, EP Petroecuador and Consorcio Shushufindi evaluate a chemical treatment and completion strategies to reduce the extensive impact of bottomhole scale deposits on oil production, electrical submersible pumps (ESP) run life, and operating costs of wells completed in the high-scaling tendencies reservoir. The positive impact on oil production optimization resulting from these strategies will also be discussed and the advantages, lessons learned, and constraints of this work. Conventionally, corrosion and scale chemical inhibitors are deployed through capillary lines; this method is effective up to the pump depth but does not prevent deposits at the perforations or at the lower completion and near wellbore. Rapid production decline or complete loss of production is observed, requiring costly well interventions. Laboratory analysis and evidences from the interventions show that lower T-sand fluids present a high-scale tendency at the bottomhole; therefore, a process to identify candidates and deploy chemical treatment in the rathole to prevent scale deposits was defined and proved. The technology selected was encapsulated scale inhibitors (microcaps). Based on the process, two wells were selected from a portfolio of 12 wells that match the criteria to apply the method to deploy the technology. The following observations were drawn: -Calcium carbonate (CaCO3) is the most common scale-ESP parameters and production surveillance are essential for early detection of problems associated with scale deposits at bottomhole-The action of microcaps and the installation of a pipe tail below the ESP base sensor allowed to deepen the continuous dosage of scale inhibitor and has already doubled the run life of the ESP equipment, with direct savings on operations costs (approximately USD 240,000) in the short time and continue and can continue to yield more.-According to post workover (WO) production tests of the two candidates and the performance of ESP parameters, the application of this strategy made possible to restore the productivity indexes and sustain them over time. This leads to reduction in production losses of 310 BOPD or 60% of the actual production in the similar period before the treatment.-The microcaps can be applied and refilled through rig-less annulus-It is a low-cost solution for scale problems at bottomhole. This document presents an analysis to reduce operating costs in wells that produce fluids with a high-scaling tendency at bottom hole, through an unconventional and low-cost strategy of chemical treatment from the sand face to the wellhead. This novel process and microcaps application can be used in wells in remote and difficult areas to service on a regular basis.