Three Phase Treatment Enhances Performance of Aging Well with Mechanical and Chemical Issues

Abstract Operators face many challenges as a well approaches end of life. Decisions must be made in regard to the economic feasibility of performing a stimulation treatment to prolong well production verses P & A. This is the situation that a Gulf of America (GOA) operator was facing for a well in their field that was plagued with multiple issues including organic deposition, barium sulfate scale deposition in the screen/near wellbore area, fines migration and water management. The restimulation design consisted of a multiphase approach that included: Phase I -a screen/near wellbore soak to remove organic deposition and barium sulfate scale. Phase II- a diverted mud acid treatment that included specialty stimulation chemistry to address, organic deposition, acid soluble scale, and fines issues. Phase III- a diverted scale squeeze to help to delay the onset of scale deposition. Phase IV- water management was discussed but since water handling is not currently an issue on this platform this treatment was dropped from the program. The challenge for this well treatment was the inclusion of the high pH barium sulfate removal treatment and the pH sensitive scale squeeze in conjunction with the low pH acid job. The low pH acid has potential compatibility issues with both treatments. Special design considerations were taken to prevent the compatibility issues and place an effective treatment that minimized the amount of vessel mobilizations to the field making the treatment economical. The operator performed multiple treatments on a well that would not have been able to pass the economic hurdle had standalone treatments been recommended. The effectiveness of the treatment was evaluated via formation responses and production rates. This paper will provide information related to the design, execution, and outcome of this unique multi-phase treatment.