May 2017, Vol. 244, No. 5
Features
Canadian Natural Offers Internal Pipeline Cutter Tool for Abandonments
Canadian Natural Resources Limited (Canadian Natural) is an oil and natural gas production company with operations in Western Canada, the U.K. portion of the North Sea and offshore Africa. Technology plays an important part of ensuring safe, effective and efficient operations at Canadian Natural, which led to the creation of a new design for the Three Wheel Internal Pipeline Cutter (IPC) tool. This tool is primarily used for cutting pipeline risers on well sites and pipeline rights-of-way with minimal ground disturbance.
Improving Practices
There has been an ongoing effort to improve pipe-cutter capabilities for more than 100 years. For instance, a three-wheel cutter patented by William Tucker in 1895 resembles Canadian Natural internal design in some respects, but it can only be mounted externally around the pipe (U.S. 532845). More recently, an IPC tool patented in 2009 uses a rotating system to cut pipe internally with one wheel, but it cannot be operated manually because a rotational power source is required to forcefully drive a saw blade (U.S. 7574807).
Canadian Natural’s IPC tool has a planetary consisting of multiple gears and a scroll that extrudes the shoe guide holding the cutter wheels, allowing for operation manually or with the use of a power source. Additionally, its three-wheel cutter enables the tool to cover more internal surface area than a one-wheel design for a continuous cutting groove without threading, as well as being self-centralized inside the pipeline.
A need to manufacture a new IPC tool resulted in the development of alternative solutions in 2011 that could remove pipeline risers more efficiently and at a lower cost (Figure 1).
Figure 1: Exploded-view drawing of IPC tool.
A basic prototype was created in an effort to that sought to improve upon existing IPCs with a low-cost design that is easy to use, lightweight and capable of operating in remote locations without the use of a power source. A key component to proceeding with the development of this tool was the ability to cut and remove pipeline risers safely on well sites while eliminating ground disturbance and any other potential safety risks associated with heavy equipment.
Instrumental in the design and manufacture of the product was a senior pipeline field consultant, the Team Lead of Pipeline Abandonments at Canadian Natural and MachinePro. Together, the design, drawings, manufacture and building of the IPC tool resulted in a cutting-edge technology for pipeline abandonments.
How It Works
The developed IPC tool (Figure 2) and its subsequent use in the field is described in this article. After cleaning/purging the pipeline, then plugging the pipeline by mechanical means as per regulations, the pipeline riser is externally cut to a level surface.
Figure 2: Depiction of assembled IPC tool with handle.
The IPC cutter head with its adaptable handle can extend downward to a depth of 16 feet by attaching multiple handle lengths. The IPC tool is then lowered down the vertical section of the pipeline to the horizontal part of the pipeline. The tool handle is designed with a centering cap to center on various sizes of pipelines (i.e. 3- to 6-inch pipe), as the centering portion of the handle is internally ringed for stability and centralization on the prepared level surface (Figure 2).
Afterward, the pipeline is cut internally with the use of an outer rotation handle and an inner torque handle. The inner torque handle is used to extrude the three specially machined and hardened cutter wheels from the housing assembly. The outer handle is then used to turn the entire assembly internally in the pipeline.
The cutter head assembly consists of a planetary system, which includes a scroll and a gear assembly to reduce the gear ratio on the cutter wheels (Figure 3). The handle has an indicator that shows how far the wheels have extended to prevent the operator from overextending and damaging the cutter wheels.
Figure 3: Planetary system depicting the gears and scroll assembly for IPC tool.
Performance Assessment
This new IPC cutting tool was developed and has been field-proven in March 2017 in Red Deer, Alberta. The tool was found to be efficient, easy to assemble and easy to use. Tests confirmed the IPC tool’s ability to successfully cut both steel, schedule 40 and schedule 80 pipes. Future developments would consider the use of different wheel types to cut a variety of other pipeline materials.
The tool operator was able to cut the pipeline riser successfully in less than 20 minutes. Once the pipeline riser was cut, the removed pipe segment was disposed of and the void was filled.
Benefits
Cost savings are realized by eliminating any excavation when compared to conventional removal methods. The principle benefits are the transportability to remote locations that are accessible by ATV, snowmobile or pickup truck. There are substantial cost savings for remote locations, since the cost of mobilizing heavy equipment is eliminated.
Additionally, an IPC tool can be operated by one person, if required. Pipeline risers can be removed from active leases, reducing space requirements for surface facilities. Since the footprint is nonexistent, the lease sites can be reclaimed faster, returning these sites back to their original state.
The IPC handle can be easily compacted to transportable lengths while the cutter handle is designed to attach to all sizes of the IPC cutter head assembly. Though this cutter can be manual, it can be adapted for use with a handheld battery-powered device. Torque specifications and procedures have been written for the use of this tool to avoid damaging the cutter wheels by over-torqueing the assembly system.
Conclusion
Previous internal pipe cutting tools are commercially available, but the usability and inherent benefit of a three wheel IPC tool was realized in Canadian Natural’s design – a robust and safe solution that can be used at a variety of site locations for efficient removals. Going forward, Canadian Natural will implement the use of the IPC tool companywide. Continuing advancement and improvements of this internal cutting tool technology will be conducted to minimize maintenance requirements and ensure longevity.
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