This paper discusses the challenges & lessons learned during the planning, execution, and evaluation of an implemented workflow to perform a water shut off (WSO) operation in an offshore well located in the Arabian Gulf. The objective of this project was to perform a mechanical WSO by closing two sleeves in inflow control devices (ICDs) that were contributing 46% of the overall water production, as identified by a pre-intervention production log.

The overall low success ratio in shifting ICD sleeves using conventional coiled tubing (CT) led the operator to implement a workflow that involved the usage of an intelligent CT. Fiber optic equipped (FOE) CT was selected because it would deliver the accurate depth correlation required to locate the ICD sleeve and engage the shifting keys with the sleeve. The FOE CT would provide the strict control of the operation, and the precise measurement of the downhole forces required for ICD manipulation. Finally, the FOE CT would enable the evaluation of ICD shifting in real time.

The well featured a horizontal section with 15 ICDs and a minimum restriction of 2.697-in. A 2 1/8- in. outside diameter shifting tool was used. The tool was designed to be hydraulically actuated because expansion of the keys is required to engage on the 4.500-in. sleeve, and the pushing force would come from the CT itself.

The challenging operation was successfully executed, and two ICDs were closed according to plan during the first trial attempt using the FOE CT. The job phase 2 was achieved in two runs. In the first CT run, the ICD sleeve cavity was conditioned by cleaning it using a high-pressure rotating nozzle and a mix of organic and inorganic dissolver fluid systems. In the second run, the sleeves were shifted to the closed position. distributed temperature sensing was performed before and after the ICD sleeve manipulation to facilitate a detailed evaluation of ICD shifting. As a result of this project, there was a substantial water cut decrease, from 30% to 17%, leading to improved reservoir management and completion sustainability. The operational success resulted in a notable increase in oil production, of approximately 15%.

This paper aims to share technical information about the workflow that was developed to perform a WSO operation in an offshore horizontal well that had an ICD completion. This project represents the first trial using FOE CT to perform ICD manipulation in the United Arab Emirates. The operation was performed from a barge in an efficient, safe, and cost-effective manner.