Coiled tubing (CT) is an efficient means of intervening in a well, eliminating the need to call out a rig, run tubing, or kill the well. Over the last few years CT drilling, real-time telemetry, complex milling tools, through-tubing completions, and other new applications substantially increased CT efficiency by eliminating runs with longer BHAs. However, conventional deployment bar technology has prevented widespread implementation of these applications because of height requirements, economics, and safety risks.
Optimized equipment for executing long-BHA operations
The new pressure deployment CT system from Schlumberger eliminates those limitations, making it easier for operators to benefit from the efficiency benefits of CT services with long BHAs. The system minimizes stack height and location footprint, improving safety, economics, and efficiency when running long BHAs into a live well.
The technology is particularly valuable when stack height is limited, such as on mast units, deepwater (or otherwise high-cost) platforms, or land operations with expensive, oversized cranes. Moreover, although traditional pressure deployment systems have focused solely on long perforating strings, this system has the flexibility to deploy other long BHA types as well, including real-time telemetry CT applications.
Faster operations using less fluid
A major operator often perforates its wells on the North Slope of Alaska with 30-ft BHAs run on CT. The BHA length is limited by height restrictions of the CT mast units, which the operator prefers because of their general operational efficiency compared with conventional CT units. However, wells typically have 90 to 150 ft of pay to be perforated, with that interval increasing in some cases up to 400 ft. This consistently necessitates multiple CT runs, increasing the amount of time on location and fluids pumped to achieve the operator’s goals.
In March 2017, the operator first deployed the new pressure deployment CT system for one of its North Slope wells. The system was used to perforate well segments totaling 70 ft in just one run with 35 bbl of fluid, compared with three runs and 100 bbl of fluid for a conventional operation limited to 30-ft BHAs.
Since that first operation, hundreds of feet of pay have been perforated in single-run jobs, with repeatedly high efficiency. Since the technology’s introduction, it has reduced perforating runs by 80% in operations where it has been used and eliminated the need for costly crane setups.
Engineered CT system for safety and efficiency
The flexible system combines several new technologies:
- A compact powered sheave replaces the whole slickline unit required for the conventional deployment bar technique.
- A quick pressure test feature eliminates the need for time-consuming shell tests to be repeated each time a new tool section is added.
- A stabilized work window and lubricator connection eliminate the need to work under a suspended load.
- An innovative BOP maintains two well barriers during tool makeup and enables positive pressure tests on each well barrier in the direction of flow at each deployment stage. The BOP’s advanced mechanical tool locator also takes the guesswork out of deployment bar placement, improving efficiency, reliability, and well control.
The combination creates a system that is unique in the industry for risk reduction and process safety in tool deployment. For details, visit the pressure deployment CT system web page.