| Popis: |
Agbami Well-BB was completed as a dual zone frac pack intelligent completion. Barely a month after the well was put on production, while carrying out optimization on the well to increase production, flow from the upper zone decreased and further testing indicated that the zone’s production had dropped significantly. From the analysis of the well, it was observed that productivity decrease was as a result of plugging upstream of the interval control valve (ICV). Analysis further showed that the plugging in the well was speculated to be caused by lost circulation material (LCM) pumped during the completion of the well, when significant fluid losses were observed through the frac pack after a fishing operation unsettled the sand control packer. To clean out the well and free the completion of the restriction caused by the LCM, the multi-disciplinary team set up recommended the use of the established method used for acid stimulation in Agbami. This involves the use of a subsea support vessel equipped with dynamic positioning and remote operating vehicle (ROV). Utilizing the subsea support vessel, customized dual conduit system utilizing two coil tubing strings connecting to the gas lift valve on the subsea tree were used to bullhead acid into the well. The well clean out operation increased production from the zone by about 8000 bopd and restored the zone to its initial productivity. Lessons learned include:Understanding the cause of the plugging was important in determining the acid recipeAll initial produced fluid from the flowback was routed to a single tank for isolation to prevent entry of possible contaminated fluid into the FPSO process system. This technical paper describes the troubleshooting on the well, acid selection process, well clean out and acidization procedure/operation, the results, best practices and lessons learned. |
