Chemical-Based Recovery of Downhole Tools Obstructed by Soluble Deposits Using a Slickline Activated Fluid Carrier

Abstract A new fluid carrier was developed and evaluated for downhole transport and localized release of chemical agents to recover stuck tools. The carrier enables controlled application of acids or solvents to dissolve mineral scale. It was field-tested in 11 wells, successfully restoring production in less time than conventional solutions. Slickline interventions confirmed the obstruction's depth, type, and condition. The job design specifies the type and volume of chemicals required based on well conditions. The procedure begins with well control, followed by tool assembly, loading the chemical agent, and positioning the tool at the wellhead. The fluid carrier can transport up to 4 gallons of liquid. Upon reaching the target depth, a bypass mechanism is activated via slickline operation, allowing for controlled chemical release. Field trials were conducted in 11 wells with different stuck tools: standing valves (seven wells), jet pump (three wells), and blanking plug (one well). In each case, a tailored chemical treatment was prepared, loaded into the fluid carrier, and conveyed via slickline to the obstruction depth. The fluid was released through a mechanically activated bypass system at depth, followed by a four-hour reaction time to maximize the chemical removal of calcite scale. Subsequent verification and fishing runs were carried out using conventional slickline tools. In all wells, full recovery of the stuck equipment was achieved. The use of the fluid carrier significantly reduced operational time, enabling intervention windows of less than 24 hours per well, compared to the typical three-day duration required by coiled tubing units in the region. Additionally, an 80% reduction in direct operating costs was estimated, improving the economic and operational efficiency of the interventions. The tool proved to be a reliable alternative for operations in wells affected by chemical scale and similar obstructions. This work presents an innovative solution for recovering stuck tools caused by chemically soluble obstructions. It enables the precise and controlled placement of chemical agents at the bottom of the well. Its deployment is simple and requires only slickline, significantly reducing intervention time and operational costs compared to conventional methods by facilitating tool release and the rapid restoration of production.