Tractor-assisted EmPulse Jobs in Complex Horizontal Wells
No matter the type of well, either vertical or horizontal, or the type of completion and its complexity, maintaining well integrity is fundamental to sustain operations, protect the environment and meet regulatory requirements in any country.
The assessment of the condition of multiple casings is a critical step in controlling the well life cycle. High-resolution tools, such as TGT’s EmPulse* proprietary electromagnetic logging tool, are being developed to meet these challenges and facilitate our Customers’ decision-making processes.
Our Customer had a well drilled, cased and completed in 2000 as a horizontal water injector. A well intervention performed in 2010 required milling from the heel of the horizontal section over few hundred meters into it. Three years later, the well developed sustained annulus pressure in the B annulus. After bleed off, the pressure did not build up again. The Customer suspected that a shallow section could have a leak due to the presence of an aquifer, but they could not assess it because of the inability to pump fluid and create dynamic conditions. They were also intrigued by the effect of the 2010 milling operation and the condition of the 9 5/8″ and 13 3/8″ casings.
TGT’s well integrity experts reviewed the well history and suggested employing the EmPulse* multi-string electromagnetic metal loss evaluation tool to assess the integrity of the 7″, 9 5/8” and 13 3/8″ casings riglessly in one tool run. The Customer accepted the proposal but requested to use tractor services to speed up the intervention because of the unavailability of coiled tubing units and time constraints, as they wanted to take advantage of an open slot for a workover unit within their busy schedule to repair the well. TGT’s operations team aligned with the conveyance company to conduct a rigorous test on a tractor and TGT’s tools because this was the first time the EmPulse* would be employed in this way.
The EmPulse survey identified multiple spots of metal loss on the surface only at a depth of 50 m in the aquifer interval. It also found extensive metal loss in 9 5/8″ casing, which was severely weakened by this process. The 7″ casing was heavily damaged by a metal loss of more than 30%.
Based on TGT’s survey results and analysis that identified extensive damage and further operational needs, the Customer decided to perform a short workover and plug the well for further plugging and abandonment.