Shale technology: Using expandable casing patches to reinforce well integrity

SCOTT BENZIE, Coretrax, an Expro company 

The rise of renewable technologies has undoubtedly placed new pressures on the oil and gas industry. Increasing sustainability concerns have impacted profitability, making operators second-guess investment choices and review business-as-usual practices in favor of “greener” choices. 

However, we must be realistic in our approach to the energy transition and acknowledge that it likely will be a drawn-out process. We’ve already observed ambitious net zero targets being set across the world and have subsequently seen these targets being missed¹, with the ambitions of the industry not yet reflecting its capabilities.  

While we can strive towards decarbonization of energy production, we also must concern ourselves with energy security. It will come as no surprise that the well-established oil and gas industry, alongside coal, will still comprise 40% of the world's primary energy demand in 2050². Clearly, it is not possible to simply abandon fossil fuels, and, instead, we must tackle a changing landscape to keep this critical industry going.

MAXIMIZING PRODUCTION WHILE MINIMIZING ENVIRONMENTAL IMPACT

Casing patch systems offer significant downtime reductions to operators in the face of unique well integrity problems, such as casing leaks or corrosion. 

While the oil and gas sector grapples with a myriad of challenges, operators remain focused on maximizing efficiency and optimizing production to ensure that global energy demands are met, but with a reduced carbon footprint. Environmental concerns are just one area that the industry now must contend with. The depletion of natural resources also means deeper wells and more complex reservoirs. This, in turn, represents additional cost, another prominent pain point for the industry.  

Ten years ago, when oil prices peaked and environmental impact was a lower priority, an operator would simply shut up shop, when faced with a poorly producing well, and begin drilling in a new field. But times are changing, and this can no longer be the case. Instead, the question we now must contend with is how we can feasibly minimize environmental impact while effectively navigating an ageing industry.  

Production issues can emerge at any stage in a well life cycle, adding complexity to operations. Unpredictable or damaged formations can cause drilling issues, where operational challenges like equipment failures can also cause disruptions. Notably, mature wells are more likely to encounter challenges and require intervention that can significantly impact productivity and the economic viability of the well. 

LOOKING FOR SOLUTIONS

Traditional solutions, including conventional liners or casing strings, have been the industry’s answer to remediating such issues and isolating problematic zones within a well. However, these tools come with their own drawbacks, significantly reducing the inner diameter (ID) of the wellbore and therefore negatively impacting production rates. As operators look to extend the life of existing wells in the interest of sustainability, it’s essential that zones can be isolated without compromising operators’ targets.  

While there may be no silver bullet to solve the problems currently being faced across the sector, technological advancements thus far have uncovered ways in which to extend the lifecycle of existing wells without negatively impacting drilling capabilities. Expandable tubular technologies, in particular, can be used to combat critical downhole challenges and maintain well integrity, while offering notable sustainability benefits. 

Unlike conventional liners or casing strings, expandable systems minimize the loss of the internal diameter (ID) of the wellbore, meaning that problematic zones can be remediated without negatively impacting production. This is particularly important in the case of mature wells that encounter unique challenges, such as casing leaks or corrosion. The application of the technology ultimately means operators can continue to produce from a reserve which may have been otherwise considered unviable, due to cost concerns. 

By increasing recovery in existing wells, the requirement for carbon-intensive new drilling activities drastically reduces, and therefore the recovery of efficient oil becomes far more sustainable. Ultimately, by improving the recovery percentage of a reservoir across its lifetime, through expandable intervention, the need for new wells is reduced. Some of the latest expandables available on the market today are also deployed via wireline, eliminating the need for a rig and further reducing the carbon emissions and associated costs.   

Using matching performance materials and seals, modern applications of expandable casing liners can handle high treating pressures and induced thermal loads encountered in the fracing environment and deep-set wells. Additionally, expandable casing patches prove advantageous, because they allow for targeted single-trip well reinforcement, without the need for extensive wellbore intervention, delivering both cost and time efficiencies. 

Modern applications of these technologies can be found across the world, but recent examples in Texas demonstrate key benefits of expandable tubulars to the oil and gas industry. The Southern state serves as the heartland of fossil fuel production in the United States, producing more than 43% of the nation’s oil³ on a yearly basis. Shale formations in the Permian basin and Eagle Ford shale make Texas a hotspot for both conventional and unconventional oil and gas extraction. However, the top U.S. producer is also home to ageing wells which increasingly require intervention and remediation. 

INNOVATIVE APPLICATIONS: CASING PATCH DEPLOYMENT IN THE EAGLE FORD

During a recent project in the Eagle Ford, Coretrax, an Expro company and a global leader in oil and gas integrity and well optimization, utilized a proprietary casing patch to address a well integrity concern. A major operator in the area required support in combatting a casing leak during real-time frac operations inside a 5 ½-in., 23# production liner.  

Following initial inspection by Coretrax engineers, the ReLine MNS (Fig.1), a proprietary casing patch, was selected as the most suitable solution, offering a large post-expansion ID and targeted intervention.

Fig.1. ReLine MNS technology is a key innovation that provides a single-trip solution, with no shoe milling to clad and seal various wellbore integrity concerns with minimal loss of inner diameter.

ReLine MNS technology is a key innovation that provides a single-trip solution with no shoe milling to clad and seal various wellbore integrity concerns with minimal loss of inner diameter (ID), while providing high burst and collapse ratings. The cased hole system is designed for deployment on jointed pipe and can cover long or short intervals from 30 ft to 10,000 ft. It can be configured to expand and seal across various ID restrictions, allowing mature wellbores to be re-completed.   

Unlike other expandable systems, the running tool configuration allows the liner to be expanded in multiple load conditions. Importantly, it can be left at a neutral position before anchoring the top seal and exiting the liners with the inner string. This neutral load condition is critical for reliability in severe fracturing downhole environments. 

In this case, the liner was run into the wellbore and positioned over the damaged area. Using hydraulic cylinders, the casing was expanded, against the existing casing and forming a secure seal. Not only did this provide an effective isolation, but it also presents significant well integrity benefits, preventing future problems across the affected area. 

Metal-to-metal anchoring, using unique frac seals, allowed for the high-pressure application, proving successful when subsequently pressure tested at 12,000 psi. The solution provided a single-trip installation design across the liner to isolate the leak without any second trip to mill the shoe post-expansion. The operator ran extended range frac plugs, post-deployment, to stimulate the reservoir. Coretrax provided diagnostics on well performance, ensuring production returned to pre-intervention levels.  

Early intervention ensured avoidance of an underperforming well, building trust with the operator, who has since undertaken several additional projects with Coretrax. From submission of the initial client request, the operation was completed in less than 24 hrs, allowing the operator to restart frac operations. This demonstrates the significant efficiency benefits of expandable technologies, while providing an effective isolation solution to a well which would otherwise have been abandoned. 

CORROSION-BASED APPLICATIONS ALLOWING FOR ESP TO PASS

Expandable casing patches are suitable for diverse applications to support the remediation of various well integrity and downhole issues. The proprietary technology can be used to combat corrosion of aging wells. In a similar case to the above, Coretrax was mobilized to support an operator based in the Permian basin within western Texas. The client required isolation of more than 2,300 ft of 5 ½-in., 17# corroded well casing.  

In this region, in particular, corrosion serves as a key obstacle for aging wells, due to the high levels of carbon dioxide (CO₂) and hydrogen sulfide (H₂S), located in the San Andres formation. The client recognized a permanent solution to mitigate the corroded section was preferential to attempting multiple squeezes with minimal lifespan. Due to its shoeless design, Coretrax’s proprietary ReLine MNS casing patch (Fig. 2) was once again identified as a key solution to remediate the well without a requirement to drill out after expansion.  

Fig. 2. Expandable tubular technologies are proving to be a game-changer in the oil and gas sector, offering operators a versatile solution to some of the industry's toughest downhole challenges.

After detailed pre-planning, Coretrax engineers worked closely with the operator to ensure that the ReLine MNS system would be deployed effectively. The liner was successfully expanded across the corroded section of the well. Engineers expanded the liner across the affected area, setting seals in competent pipe selected above and below the corroded casing.  Once installed, it provided high burst and collapse ratings with minimal loss of inner diameter.   

Following installation, the system underwent pressure testing, which confirmed the integrity of the repaired section, ensuring that the well could resume operations. The large post-expanded inner diameter (ID) was particularly beneficial, as it allowed an electrical submersible pump (ESP) to be drifted through the expanded liner, ensuring that production could restart without complications. Through deployment of the ReLine MNS system, the operator experienced minimal downtime, and the well was quickly brought back online, maximizing production efficiency. The permanent nature of the solution also eliminated the need for future remediation, which would have resulted in costly operational delays.  

CONTINUING BUSINESS AS USUAL?

Expandable tubular technologies are proving to be a game-changer in the oil and gas sector, offering operators a versatile solution to some of the industry's toughest downhole challenges. As the global energy sector moves toward greener solutions, these advanced systems allow operators to extend the lives of existing wells, optimizing production and in turn minimizing environmental impacts of a traditionally large carbon footprint industry. By reducing the need for new drilling and lowering carbon emissions, expandable tubular technologies bridge the gap between maintaining energy security and meeting sustainability targets. 

As evidenced by recent applications, Coretrax’s proprietary casing patch systems offer significant downtime reductions to operators in the face of unique well integrity problems, such as casing leaks or corrosion. Two case studies outlined show time-efficient deployment and unique project factors in high-pressure environments and within problematic formations. These technologies not only enhance the economic viability of oil and gas projects but also contribute to safer and more sustainable extraction practices, positioning the industry for a more resilient future.  

REFERENCES

1. https://www.theccc.org.uk/2024/03/20/scotlands-2030-climate-goals-are-no-longer-credible/
2. https://totalenergies.com/news/energy-outlook-2023-our-insights-energy-transition-2050#:~:text=Global%20cooperation%20puts%20the%20Global,primary%20energy%20demand%20in%202050.  
3. https://www.eia.gov/state/print.php?sid=TX

SCOTT BENZIE joined Coretrax as chief technology officer in 2019, following its integration with Mohawk Energy, which he founded in 2004. He holds a Bachelor of Engineering degree in mechanical engineering from Heriot-Watt University, is a chartered engineer, and holds EUR ING status. Mr. Benzie has held several design engineer roles at major energy services companies and operators throughout his career. Innovating ground-breaking tubular expansion technologies for drilling, completion and production operations, he has extensive R&D experience.