Latest advancements in well integrity and refrac operations using SwellPlug technology

LISA BLANKENBURG, TAQA 

INTRODUCTION 

Targeted wellbore isolation is a continual necessity for oil and gas operators. These operations are often performed to maintain well integrity—especially during recompletions, interventions, and well abandonment. Issues such as sustained casing pressure, casing deformation or damage, and excess water production also call for precise isolation efforts. If not properly addressed, these problems can lead to regulatory non-compliance or render the well economically unviable.  

A common challenge for operators is the need to isolate existing perforations or intervals to mitigate water production. This need can arise at any point in the well's life and, if not addressed, may lead to reduced production or additional complications, such as scale buildup and corrosion, in turn diminishing overall economics. 

Traditional approaches often involve setting a liner patch or using mechanical packer systems, followed by a cement squeeze or chemical treatment. These methods can be complex and costly. For example, liner patches reduce the wellbore’s inner diameter (ID), limiting future access and potentially changing production/injection rates. Moreover, many of these conventional solutions—especially cement squeezes and mechanical packers—may not provide long-term integrity and can fail or require multiple remediation attempts. 

In the case of recompletion or refrac operations, a cemented liner system is typically installed to isolate the current producing zone, allowing the previously unstimulated portions of the well to be fractured. This, too, causes significant ID restrictions and can pose multiple challenges, including landing the liner on depth and getting a comprehensive cement behind the liner, due to the very small annular space remaining. These challenges can result in underperformance of the stimulation treatment and overall reduced post-treatment production. 

Fig. 1. SwellPlug mixture of coarse and fine particles.

In response to operator demand for a more comprehensive solution, TAQA developed SwellPlug, a game-changing technology that has been field-proven across a full and varied range of scenarios. 

Operationally simple to deploy, it delivers effective, permanent isolation of existing target intervals to allow water shutoff, re-completion and even repair casing integrity.   

TRIED AND TESTED SWELLPLUG TECHNOLOGY 

SwellPlug is helping well intervention strategies by offering permanent, chemically resistant isolation across a broad range of well conditions, effectively sealing perforations, fractures, and micro-annuli without the need for activation fluids. 

A proprietary water-swellable material is combined with an activated fibre and engineered to provide comprehensive wellbore isolation fractures, annular spaces, perforations and even micro-annuli without the risk of dehydration or shrinkage over time. The particles come in three sizes fine, coarse and super coarse, ranging from 100µm to 8mm, which are mixed according to the requirements of every individual challenge, Fig. 1. 

The swellable elastomer particles are pumped from the surface into the target interval and are allowed to swell in-situ to provide an effective high-pressure seal up to 10,000 psi. Particles are batch-mixed at surface and pumped downhole, using standard cementing equipment. The design and volume of the particulate material are based on the length of the zone to be isolated. 

Fig. 2. SwellPlug Fine on the left and SwellPlug Coarse on the right.

These particles use a combination of super-absorbent polymers and osmotic swell mechanisms to optimize speed and strength of the swelling process and utilize a base material to maximum chemical resistance, Fig. 2. 

Benefits of this type of technology include maintaining full wellbore ID without the need for mill-outs or post-treatment intervention; simplicity of deployment; and suitability for all environments. It has multiple applications, including water shut-off, casing repair, P&A applications, and re-completion applications, by providing a permanent seal, and can withstand significant pressure cycling, maintaining integrity over the lift of the well. 

Some other key features include: 

• Withstands temperatures up to 482°F (250°C) and pressures exceeding 10,000 psi. It can be used for all sized isolation options (from micro annuli to large fractures) Compatible with various well fluids, including acids, drilling fluids, brines, H₂S, and CO₂. 
• Functions without activation fluids, simplifying deployment. It resists high-pressure cycling, ensuring durability in fracturing and recompletion applications  

SwellPlug also offers the following benefits over conventional cement squeezes, mechanical packers, and expandable liners: 

• No ID restrictions: Unlike liner patches, SwellPlug maintains full wellbore access for subsequent interventions, without the need for mill out operations. 
• Permanent, non-reversible swelling: Ensures long-term zonal isolation without the risk of dehydration. 

This technology has been deployed and has provided effective solutions for a range of scenarios across the sector.   

CASE STUDIES 

Case Study 1: Casing repair during fracturing in the Permian basin  

Challenge: A Permian operator faced casing damage at 18,130 ft MD, due to a mill-out operation breaching the casing wall, followed by proppant intrusion, leading to significant fluid losses. Traditional solutions were deemed inadequate, given the extent of the damage.  The Solution: A total of 500 lbs of SwellPlug swellable material was bullheaded into the wellbore at 6,250 psi. This comprised 400 lbs of super course material to  with a size range from 6 mm to 8 mm and 100 lbs of course material, ranging from 1 mm-3 mm in size. Water was heated to 180^oF to ensure more efficient swell time. To give adequate isolation time, the well was shut in overnight, to allow the treatment to settle, expand and seal effectively. 

The Result: The well was shut in overnight, achieving an 87-88% reduction in flowrates, restoring well integrity for refrac operations.    

Case Study 2: Severe loss control mitigation in Australia   

The Challenge: An operator in Australia began drilling into a depleted zone, resulting in over 900 bbl/hr losses of drilling fluid. After three years of attempting alternative LCM solutions in this area, and multiple sidetracked wells, they needed a more robust solution.   

The Solution: A 35-bbl pill of SwellPlug LCM was pumped through open-ended drill pipe into the loss zone. The pill was comprised of the coarse-sized particulate, as well as the activated fiber, with results being seen immediately after treatment.  

The Result: The fluid losses reduced from 900 bbl/hr to 200 bbl/hr within the first 2 hrs and ultimately reduced to 0 losses within 6 hrs. This resulted in a client-estimated savings of $1 million, compared with previous treatments.   

Case Study 3: Mitigated losses during plugging and abandonment  

The Challenge: An operator in the western United States was conducting a P&A operation, and after punching the casing in the upper section of the well, they encountered a significant loss zone of approximately 180 bbl/hr. These losses prevented them from setting the cement plug as part of the regulatory requirements for plugging and abandonment in the region. Historically, this would have been treated with multiple cement plug treatments, taking considerable time and product to resolve.   

The Solution: SwellPlug was deployed, and a 4-bbl pill, combined with warm produced  brine, was pumped into the loss zone. An immediate response was seen with returns to surface noted at 0.5 bbl/min, showing the effects of the product sealing. The well was shut in for approximately 4 hrs, after which full returns were established, and the cement plug was successfully set.   

The Result: The losses were stopped, allowing the plugging and abandonment to continue with the cement plug, without need for repeat treatments. 

LISA BLANKENBURG is North America Technical Sales Director at TAQA (Industrialization & Energy Services Company), based in Denver, Colo. She has held this position since May 2023. Previously, she served as business development manager at Greenfield Environmental Solutions, LLC, from June 2022 to May 2023. Before that, the bulk of her experience was at SLB in positions of increasing authority/responsibility from May 2005 to August 2020. Ms. Blankenburg earned a BASc degree in chemistry from University of Wyoming in May 2005.