The Growth of Coiled Tubing and the Benefits of Thinking Small Again

Terry, Adrian; Pate, Brad Andrews; Stanley, Rick

doi:10.2118/166496-ms

Cited by 2 publications

(3 citation statements)

References 11 publications

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“…Many older or depleted fields have logistical challenges such as onshore road access or offshore crane lifting/deck loading limitations that restrict the size of CT units Terry et al, 2013; Sundramurthy et al, 2014). These challenges translate in difficulties to economically justify deploying larger CT units.…”

Section: Small Ct Unitsmentioning

confidence: 99%

“…It was reported recently that small CT units have been utilized in Southeast Asia Terry et al, 2013;Sundramurthy et al, 2014). These units are capable of deploying a wide range of small CT sizes, from 3/8-, 5/8-, 3/4-, to 1-in.…”

Section: Small Ct Unitsmentioning

confidence: 99%

“…There are several well documented case histories in literature that show how smaller CT sizes, such as 1-in., have been successfully utilized for scale removal, solids cleanouts, milling, perforating, and gas lifting operations (Terry et al, 2013). Some of the factors enumerated above favoring larger CT have already been addressed by the industry for using smaller pipes.…”

Section: Introductionmentioning

confidence: 99%

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Smaller Coiled Tubing Diameter Achievable by the Use of Lubricants

2014

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The requirement for well intervention operations in laterals longer than 10,000 ft continues to grow. The current industry trend for servicing long laterals is to increase the coiled tubing (CT) diameter and use fluid hammer or tractor tools. While increasing the CT diameter remains a theoretical option to improve reach, practically, it creates logistical challenges with onshore road transport and offshore crane lifting/ deck loading limitations. Other options such as using fluid hammer and tractor tools may have reasonable operational range, but they have significant limitations by increasing circulating pressures and operational complexity and reducing CT speeds before lock-up. Using lubricants is the simplest, most predictable, and, sometimes, most cost-effective method. However, most current field results show only a 15 to 20% reduction in the coefficient of friction (CoF), from a generic value of 0.24 to 0.20. This CT friction reduction is not sufficient to run CT smaller than 2-in. in long laterals.In this paper, the current status of lubricant usage in well intervention operations is reviewed. Several results of an extensive laboratory program using the first in industry linear friction instrument especially targeting CT operations are also reported. More than 6,600 measurements have been performed to date with many combinations of CT and casing samples and lubricants currently used in field operations. Based on these laboratory results, a new lubricant was developed that results in significantly lower CoFs than previously seen under downhole conditions. The field CoFs with the new lubricant are in the 0.09 to 0.13 range (i.e., field CoF reduction of approximately 46 to 63% from the default value of 0.24) and validate the laboratory results. Numerical simulation results show that CT friction reduction of this magnitude facilitates the CT diameter size decrease in long laterals and brings great benefits to the industry by lowering the operational costs and carbon footprint. Decreasing the CT size is particularly beneficial in Southeast Asia where offshore smaller platforms and smaller CT sizes are vital for intervention operations in small diameter wells.

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Section: Small Ct Unitsmentioning

confidence: 99%

Section: Small Ct Unitsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Smaller Coiled Tubing Diameter Achievable by the Use of Lubricants

2014

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Cloud-Based Planning and Real-Time Algorithms Improve Coiled Tubing Cleanout Efficiency

Bardsen,

Nilsen,

Froyland

et al. 2024

Day 2 Wed, March 20, 2024

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Depleted wells require underbalanced coiled tubing cleanouts (CTCO) in which natural production from the reservoir assists solids transport. Conventional cleanout methods relying on fluid circulation pose a risk of fluid loss, reducing annular velocity and increasing the risk of formation damage or stuck CT pipe incidents. The use of nitrified fluids addresses some of those risks, but also introduces a new set of challenges. In addition to technical challenges, cleanout operations face logistics and operational constraints, which directly impact the feasibility and viability of the intervention. Digital tools provide a path toward increased efficiency and success rate of CTCO, but the suite of legacy software often used in CT operations relies on monolithic implementations, which limit the possible optimization of the planning and the connection between design and execution data. More generally, reliance on manual operations (whether during the design or execution phases) often leads to missing on potential optimization opportunities. The transformation of CTCO leveraging a new cloud-based CT hydraulics (CTH) simulator, real-time execution advisors, and autonomous conveyance brings a new level of flexibility and interconnectivity to the design and execution phases. CTH features state-of-the-art flow and transport models, which improve CTCO design capabilities, providing the required insights during execution time to optimize the cleanout operation. During the design phase of underbalanced CTCO, the designer needs to work with uncertainty on several parameters, such as reservoir pressure or PI distribution of the horizontal section. The architecture of the CTH allows sensitizing over every parameter, which generates a combinatorial number of scenarios, driving a larger-than-usual processing demand. The cloud-based service's processing capacity meets these demands during the job design phase to generate a large database of sensitized scenarios and delineate a safe and effective operational envelope. Two case studies show how CTH can be used during the design phase to ensure more efficient job execution in two horizontal oil wells in the Valhall brownfield. In the first one, the simulator was used to guarantee that the cleanout execution would be possible even if contingency plans due to gas lift valve failure had to be triggered. In the second, sensitivity analysis was conducted over the pumping rate and formation pressure, identifying a safe operating envelope that, once coupled with an adequate execution approach, led to 20% oil base savings. Efficiency of CTCO operations is further improved by implementing autonomous conveyance execution during the operations. This includes automatic control of depth and speed, achieving more than 10% more efficient speeds during run-in-hole and pull-out-of-hole activities. Pull tests need to be performed at set intervals during conveyance to ensure that the pipe is not getting stuck, which accelerates fatigue of the CT pipe. The autonomous system also includes a pull test optimizer that accounts for the pipe's fatigue profile, weld locations, and completion data to strategically adjust the pull test schedule. This reduces the effect of these tests on pipe fatigue by up to 28% over its lifetime and lowers the risks linked with running across downhole restrictions. Besides, autonomous conveyance and pull test execution liberates the CT operator to concentrate on other crucial aspects of the operation. These include managing and monitoring the CT unit, fluid pumps, remote-operated choke, and downhole tools, controlling real-time parameters, updating the job log, and managing the crew. This study demonstrates that by combining extensive cloud computing, advanced flow models, surface and downhole measurements with real-time interpretation and inference algorithms, and autonomous operations, CTCO operations can be conducted safer and more efficiently, in a repeatable manner, therefore reducing the operating time, fluid pumped, pipe fatigue, and greenhouse emissions, and allowing to raise the success rate of those operations to a new industry benchmark level.

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The Growth of Coiled Tubing and the Benefits of Thinking Small Again

Cited by 2 publications

References 11 publications

Smaller Coiled Tubing Diameter Achievable by the Use of Lubricants

Smaller Coiled Tubing Diameter Achievable by the Use of Lubricants

Cloud-Based Planning and Real-Time Algorithms Improve Coiled Tubing Cleanout Efficiency

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