First Successful Application of a New Tailored Spacer System to Cure Losses through Coiled Tubing and Plug a Challenging Well in the Largest Offshore UAE Field

摘要

Drilling and cementing operations commonly experience lost circulation(LC),which can result in nonproductive time(NPT)and excessive costs.Losses were encountered while performing an offshore workover well operation in the UAE that challenged isolation objectives involving spotting a cement plug through coiled tubing.Selection of lost circulation treatments that may be deployed through coiled tubing is limited,increasing the difficulty in addressing losses.Previous attempts to cure losses and spot the cement plug were unsuccessful.This paper describes the application of a new tailored spacer system(TSS),engineered to reduce formation permeability and prevent lost circulation.Placement occurred through coiled tubing to successfully control losses in the thief zone,enable tagging of cement plugs,and achieve isolation for the zone of interest.The new TSS has been used on multiple cementing operations to mitigate losses,improve circulation,achieve top of cement(TOC)objectives,and eliminate remedial work;however,this case is the first global application of the TSS through coiled tubing in a plugging operation to stop lost circulation.Correctly evaluating and interpreting the well conditions,risk identification,analysis,and communication amongst operations personnel,and execution of good cementing operational practices led to utilization of the new TSS for this specific scenario of placement through the coiled tubing ahead of the cement slurry.Losses were prevented leading to a successful plug operation and enabling cementing goals to be achieved.