March 2023
SPECIAL FOCUS: Sustainability

Expanding the limits of enhanced oil recovery

During a recent project in the Middle East, an operator required isolation of non-producing perforations to reduce water production and deliver more efficient hydrocarbon recovery. Coretrax deployed its ReLineWL rigless expandable straddle which eliminated the requirement for a rig, delivering an efficient solution to production optimization.
Scott Benzie / Coretrax

The last five years have, undoubtedly, been one of the most transformational periods in the history of the oil and gas industry. The combination of a global pandemic and rising climate change tensions has resulted in the oil and gas sector reviewing current portfolios, to identify opportunities to reduce its carbon footprint and deliver more sustainable operations.    

While the energy transition continues to evolve, and the rising demand for renewable energy reduces reliance on fossil fuels, there is still a clear need for oil and gas in the near future, with a recent industry report highlighting that oil and gas is set to comprise 49% of the energy mix in 2050.1 

In response to global environmental targets, a radical shift has taken place within the energy industry, in regard to environmental, social and governance (ESG) strategies, and companies are under growing pressure to recover hydrocarbons utilizing more responsible methods. For operators, this move has resulted in an increased focus on unlocking greater commercial value from existing wells, to deliver continued energy security with reduced carbon intensity. Technology is playing a key role in this activity, with new and advanced solutions supporting field life extension, by tackling the most complex and mature well challenges. 


In the Middle East, there have been clear steps taken to support more sustainable operations in recent years. The region is one of the largest producers of oil in the world, with large reserves in Saudi Arabia, Iraq, the United Arab Emirates and Kuwait. In line with international climate objectives, national oil producers in the area have taken clear steps to identify where environmental savings can be gained, while continuing to meet global energy demands. 

Saudi Aramco, Saudi Arabia’s national oil company (NOC), released its first-ever sustainability report last year, which highlighted the operator’s ambition to achieve net-zero Scope 1 and Scope 2 greenhouse gas emissions across its wholly owned and operated assets by 2050. The company is already the world’s lowest carbon emitter when compared to leading producers, demonstrating that decarbonization methods and efforts are working2. The report also noted how the business will continue to increase its share of investment in research and development to leverage new technology and address sustainability challenges. 

With the Middle East being such a high-activity region, it offers significant opportunities for operators to apply new technology, which will deliver maximum recovery in existing wells. 

Effective well intervention for maximum recovery. Well intervention is crucial to increasing operational efficiency and garnering greater hydrocarbon recovery. Extending the life of existing wells can also actively reduce the requirement to drill new wells, by optimizing production from current reservoirs. With the global well intervention market projected to reach $9.3 billion by 2026, up from an estimated $7.6 billion in 2021, it is evident that operators are eager to enhance efficiency and improve existing production.3 

Water production is a common issue in producing wells and can often exacerbate as the field matures, resulting in costly and time-consuming remediation. The produced water can contain toxic and hazardous substances, high levels of salts and other impurities that make it difficult to handle and pose a risk to the environment. Large volumes of water can also create storage and transportation challenges, in addition to the high cost of treatment and disposal. Straddles have been a traditional method used to effectively isolate sections of open hole or perforated casing, which are experiencing significant water production, to reduce the by-product and boost production.

However, many conventional straddles are generally deployed via WireLine methods, creating considerable operational expenditure and can often restrict the inner diameter (ID) of the well, meaning any future well intervention operations will be significantly more complicated. Particularly in the Middle East, rigless operations for the deployment of expandable technology is still a relatively new concept.

While the oil and gas industry has embraced a range of technically advanced straddles over the last decade, the tools were generally designed to be a temporary, retrievable solution, so they often have a limited lifespan. Conventional straddles can also pose the risk of choking production, leading to further work required, and many result in significant reduction of ID, which can negatively impact production rates as well as increase project costs. 

During a recent onshore campaign in Saudi Arabia, a major operator required isolation of non-producing perforations but was seeking a more efficient method, when compared to traditional straddles. The operator required a system that could be deployed via a rig-less method to support these objectives. Coretrax, a global leader in oil and gas well integrity and production optimization, deployed its ReLineWL expandable straddle to achieve the project’s aims, Fig. 1. 

The tool eliminates the requirement for a rig, delivering sustainability benefits. Image: Coretrax
Fig. 1. The tool eliminates the requirement for a rig, delivering sustainability benefits. Image: Coretrax

Advanced technology to drive production. Coretrax was approached by the operator when it required isolation of non-producing perforations (Fig. 2) over two upper formations in an unconventional tight gas formation, while leaving the lower perf live for production. Of the four perforated zones in the tight gas wellbore, only one was producing. The remainder were creating significant volumes of water.  

Fig. 2. The one-trip ReLineWL effectively isolates non-producing perforations. Image: Coretrax
Fig. 2. The one-trip ReLineWL effectively isolates non-producing perforations. Image: Coretrax

A detailed, multi-finger imaging tool (MIT) assessment was first conducted, to provide accurate and detailed data of the current geometry and condition of the wellbore ID. To further reduce the carbon intensity of the project, analysis of the information collected was conducted remotely, to reduce personnel onsite. Following full evaluation by Coretrax’s field technicians and the operator, the ReLineWL expandable straddle was selected as the most suitable solution, as it would adequately support wellbore loads. 

The permanent system can be run on a wireline, eliminating the need for expensive rig deployment, and its slim outer diameter (OD) means it is capable of passing through ID restrictions, such as sub-surface safety valves, Fig. 3. In this particular project, the well had an internal diameter of 4 in. but presented a further challenge with a 3.688-in. nipple restriction. The tool was specifically designed to pass this restriction, and the expandable technology allowed it to bypass the nipple before it was set below. 

Fig. 3. The ReLineWL is capable of passing through ID restrictions such as sub-surface safety valves. Image: Coretrax
Fig. 3. The ReLineWL is capable of passing through ID restrictions such as sub-surface safety valves. Image: Coretrax

The system can effectively isolate leaking or compromised completions components, including sliding side doors, inflow control valves, inflow control devices, gas-lift valves and chemical injection valves, amongst others. Its shoeless design also means there is no requirement for a drill-out to be completed, so the tool saves valuable rig time with a one-trip solution and does not introduce any unwanted debris into the wellbore. 

To ensure the operation remained economical during the intervention, it was essential the well remained live to negate the need for any downtime, so the tool had to be capable of withholding high pressures while setting the expandable straddles. Without this capability, the gas would have to be vented from the well to reduce the load. This procedure often requires specialist equipment and can take up to 20 days, resulting in significant downtime. The ReLineWL system was designed to operate in live well conditions (Fig, 5), with external pressure ratings capable of sustaining formation pressure loads.  

Fig. 5. The tool is designed to be deployed in live well conditions. Image: Coretrax
Fig. 5. The tool is designed to be deployed in live well conditions. Image: Coretrax

Delivering extended reach with expandable technology. The trouble zone extended over a 30-ft section, and the ReLineWL’s ability to stack allowed it to support the non-producing area. The expandable seals were designed and manufactured to deliver a gas-tight seal indefinitely at any expansion ratio within the wellbore and for the life of the well. Many conventional straddles are not suited to large problem zones, as big-bore patches do not stack neatly, meaning the isolation of several perforation intervals often limits the ID of the well, negatively impacting overall production rates. 

Three 3⅝-in. straddles were deployed on wireline, removing the requirement for a rig, at depths of up to 13,531 ft, and they successfully expanded to isolate the non-producing sections within the liner. The patches were confirmed through a MIT log post. Once in place, the tool’s 75% expansion ratio ensured a maximum production conduit to surface, delivering a 700% greater flow area when compared to traditional straddles, Fig. 4. By creating a large ID, the ReLineWL effectively optimized access to the wellbore while negating integrity issues. To enhance production even further, the system can also be configured to smart completion products, such as autonomous inflow devices (AICDs), to selectively eliminate gas and water production and provide a comprehensive workover solution. 

Fig. 4. The system delivers a 700% greater flow area when compared to traditional straddles. Image: Coretrax
Fig. 4. The system delivers a 700% greater flow area when compared to traditional straddles. Image: Coretrax

The application of the technology successfully eliminated the requirement for a land rig, delivering significant cost savings and reducing the project’s carbon footprint. By enabling continuous access to the reservoir below, the operator could also efficiently carry out future diagnostics or data gathering. If the ReLineWL had not been deployed, the operator would have been forced to plug and abandon the well. 

Rig-less well intervention to reduce carbon intensity. Coretrax’s expandable technology garnered similar results during a recent project in Saudi Arabia, when a major national operator experienced significant water ingress across a 4½-in. liner, which was negatively impacting production levels. The remediation had to provide an optimal length of less than 30 ft, with an ID of less than 3 in., while delivering a life of well solution. Following well data analysis, a 3.7-in. OD ReLineWL was selected as the optimal system. 

In separate deployments, two patches, each 28 ft in length, were deployed on an e-line electric cable, effectively passing a 0.77-in. ID restriction at 6,465 ft. They were set within the liner, with the depth correlated using a casing collar locator (CCL) and Gamma ray technology, before being successfully expanded across the water producing zones. The post expansion solution delivered an ID of 3.145 in., providing a maximum conduit to surface. 

The ReLineWL eliminated the requirement for an expensive workover rig, and the well was effectively brought back online, with a reduction of around 31% in water production and an estimated 1,400-bpd increase in oil production. This system also delivered environmental benefits, by significantly reducing the requirements for surface water management. 

Bespoke solutions to meet demand. As expansion technologies continue to advance, they can now be customized for integrity, recompletion and open-hole applications, providing casing patch and refracing solutions to an industry that is increasingly being driven by cost efficiency, safety and sustainability responsibilities. The chassis of the ReLineWL was originally designed to accommodate the most common casing sizes, but it is not limited to these requirements. This bespoke approach will be vital, as the industry continues to tackle more complex and challenging wells in the pursuit of lowering carbon emissions.  

Supporting the energy transition. The ReLineWL directly addresses challenges that corroded or compromized tubing carries, including loss of well integrity, a rising level of produced water and mud management costs. However, the tool distinctively goes beyond its ability to support wellbore integrity with its primary functions, to support carbon neutrality efforts as well. This technology is a strong example of the gains that can be achieved for the evolving global energy sector, by delivering emission reductions through intelligent, non-heavy intervention. This approach ultimately removes the requirement for large-scale workovers—or in severe cases, plugging and abandonment of the well—at a time when economical and sustainable recovery is imperative. 

While the energy transition continues at pace, decarbonizing oil and gas operations to meet ESG responsibilities is vital, as we accelerate toward a net-zero future. Adopting technology which can extend the life of existing fields, while actively addressing global climate objectives, can help enable operators to realize greater environmental and financial rewards.  


About the Authors
Scott Benzie
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. Scott has held several design engineer roles at major energy services companies throughout his career. Innovating ground-breaking tubular expansion technologies for drilling, completion and production operations, Scott has extensive R&D experience.
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