By: John Fraser, chief operating officer, Coretrax
Stuck pipe is one of the most significant challenges facing the drilling sector and can cost operators millions of dollars to remediate.
When attempts to release stuck pipe by jarring, acid, or other methods fail, severing the drill string and preparing side-track operations or abandonment of the hole is often required to resolve the issue.
Traditional recovery methods generally require wireline services and high energy sources such as explosives, which involve specialist tools and often dedicated personnel. This creates significant additional project costs and non-productive time (NPT) with equipment often taking weeks to deploy.
Coretrax, a global leader in oil and gas well integrity and production optimization, has developed the HyPR Holesaver as an effective solution to recover stuck pipe. The tool is the world’s first hydraulic pipe recovery system. It is the quickest and safest, low-cost means of recovering stuck pipe while maximizing hole recovery.
The HyPR Holesaver was recently used in conjunction with Coretrax’s DAV-MX™ circulation sub for a UAE operator. The tools were successfully deployed to severe the stuck pipe in a record time of one hour, compared to several weeks with conventional methods.
Addressing stuck pipe challenges
There are two main types of stuck pipe which result in the operator unable to rotate or pull the drillstring out of the hole:
- Differential pipe sticking occurs when the drillstring becomes embedded in the mud cake that forms on the wall of a permeable formation
- Mechanical pipe sticking is caused by the accumulation of drilling cuttings in the annulus, often because of inadequate hole cleaning or other borehole instabilities.
Conventional methods to relieve stuck pipe carry several hazards and can increase NPT with mobilization, often taking weeks. The use of explosives and chemical cutters are both high-risk operations that require experienced personnel and specific permits. Operations on the asset must also be suspended during use, resulting in increased downtime and the associated cost.
Developed as an alternative solution to addresses costly stuck pipe issues, the HyPR Holesaver system is a pre-placed/replaced sub or subs within the bottom hole assembly (BHA). These lie dormant in the string to provide a contingency during drilling operations. With no moving parts, the full strength HyPR sub can be turned into severance points by simply deploying the HyPR Smart Dart.
It is typically run in conjunction with a circulation tool located below it to provide an alternative circulation path in the event of a pack-off. This also ensures mud is in good condition before commencing cutting. When a stuck pipe event occurs, a ‘smart dart’ is pumped from the surface into the circulation sub. Upon land out in the circulation sub seat, it will regain full circulation, thereby putting the operator back in control of the well and enabling mud conditioning to take place.
Once satisfied with the condition of the mud and hydraulics, a second ‘smart dart’ is deployed and pumped from the surface into the hydraulic cutting sub. Here, when it lands on the seat of the sub, at appropriate flow rates, the cutting can begin. The dart is pumped to redirect the flow of mud, creating a high-velocity stream of fluid, using the existing mud system to effectively erode and sever the string.
Typically, within two to three hours of pumping, the sub will sever into two parts, and the cutting time can be accelerated by applying appropriate torque. This results in a very smooth and clean cut, enabling operators to commence fishing, plugging, or side-track operations almost immediately.
Record-breaking pipe severance
During a drilling campaign, a UAE-based operator encountered stuck pipe at 12,785ft due to heavy losses. Conventional solutions would have taken weeks to remediate the issue and incurred high operational costs. However, as the HyPR Holesaver was already pre-placed in the BHA as a contingency, the operator could begin work to sever the drillstring almost immediately.
Before activating, the operator first positioned a Coretrax DAV-MX CircSub beneath the HyPR HoleSaver to optimize circulation flow for the HyPR dart. The multi-cycle circulation bypass tool delivers greater results than ball-activated systems and can be used across a range of applications, including loss curing, hole-cleaning, and displacement or lost circulation material (LCM) spotting. The simple to use device is suitable for deepwater, high angle, and high pressure/high temperature (HP/HT) wells and required no reconfiguration or service hand.
Once deployed, the HyPR dart was delivered at 200gpm, with the operator increasing the flow rate to 520gsm (3,980psi) to begin cutting. After 45 minutes of cutting, pressure reached 3,990psi, and the operator’s pre-planned calculations indicated that applying 25kft lbs of torque would twist off the pipe. In traditional pipe severance operations, a 90 per cent inner diameter erosion target is generally selected, which can take two to three hours to achieve. By applying the torque at 60 per cent, the operator achieved an effective severance within one hour – a new record for stuck pipe recovery. This allowed the company to successfully plug and abandon and pull out of hole.
Complex and costly issues such as stuck pipe require the latest technology to tackle and overcome the problem quickly and effectively to restore operations. By combining multiple technologies to create a bespoke solution, even more significant results can be delivered to allow operators to reduce NPT and increase efficiencies. As reduced operational costs continue to be at the forefront of the industry, it is essential that new technology is developed to address these challenges head-on.