Fishing More Than 3,000 Meters of 1-3/4-in Coiled Tubing A Case Study

Abstract

We describe the situation and challenges, the implemented process and strategies, and the downhole tools used during the remedial work to successfully recover 3041 m of 1 3/4-in coiled tubing (CT) pipe lost-in-hole during an acidizing job. During an acidizing job through the CT string as a part of a workover job in a well of a mature field in offshore Mexico, after filling the pipe with acid, the CT operator was ready to spot it across the perforated interval. When the up-hole movement started, the CT weight reached approximately 36,000 lbf (normal pulling weight at that depth in the previous runs) and then the CT weight went to 0 lbf. After retrieving the pipe to surface, it was noticed that only 199 m of CT were recovered from the well, leaving +/- 3041 m of CT pipe inside the hole. After a total of 43 runs and over 20 days, the entire CT string including the Bottomhole assembly (BHA) was recovered, and the well was put back on production. The key was to conform the top of the fish with a downhole motor equipped with a milling shoe, and then exploit the versatility and fast rig up/down capabilities of slikcline to position the fishing tool on the top of the fish. After the fish was latched, a GS profile was left in hole, thus allowing the CT to latch and retrieve the entire fish. Fishing operations are considered more an art than a science because of all the variables involved, for example, type and top of the fish, restrictions along the wellbore, available fishing equipment, pulling capacities, and so on. However, following industry best practices, fishing can switch from a nightmare to a useful learning and successful experience. The authors will summarize the milestones in the operation, which serves as an example of collaborative work between the operator and service company that led to a successful outcome.