When a well and its infrastructure must be dismantled, it is critical to ensure they pose no safety or environmental threats. Poorly abandoned wells can lead to non-compliant status with regulatory agencies, so the technological innovations that tackle this challenge are increasingly in demand.

Weatherford International is one of the companies working to address this industry need. Its Well Intervention Unit, used for plugging and abandonment (P&A), is a case in point. It is a compact rigless hydraulic pulling-and-jacking unit that delivers powerful capability with lightweight, modular operating systems in minimal footprints.

Traditional P&A equipment often is problematic in price-sensitive and safety-conscious abandonment operations. Jackup rig installations can be not only very expensive but can increase exposure to safety issues, and snubbing units require a lot of assembly time and are difficult to move from well to well.

Weatherford’s rigless well intervention unit won the remediation category in E&P magazine’s Meritorious Awards for Engineering Innovation. Judged by an independent team of experts, these awards recognize new products and technologies that offer innovation in concept, design, and application. (Image courtesy of Weatherford International)

P&A in the GoM

A six-pile platform in the Gulf of Mexico was damaged by Hurricane Katrina, leaving it leaning at approximately 15°. Before the storm it was fully operational, with 10 producing wells and one partially drilled conductor, so the platform drill deck was loaded with production equipment. Inspections and surveys determined the structure was acceptably stable, although one corner leg had penetrated the support shale. All of the well conductors were bent at or below the mud line.

Because the platform was leaning, snubbing units and jackup rigs had been eliminated as viable P&A options.

The operator secured the platform, installing a second four-pile platform at the leaning corner of the structure. Laser surveying was conducted to establish exact relations of the wellheads to the new structure.

Due to the damage, exact weights were critical to ensure the total equipment load on the structure fell within the weight parameters allowing for an overpull of approximately 100,000 lb. The operator needed a solution that would meet its specific weight requirements, skid easily from well to well, and have a minimal footprint because deck space was limited.

Weatherford’s pulling-and-jacking unit averaged less than one hour moving from one well to another. Its load capacity and compact design enabled efficient retrieval and tubular laydown. And by cutting well casings approximately 15 ft (5 m) below the mud line by effectively tripping 3½-in. OD drillpipe with cutting assemblies into the wells, sensitive work was accomplished without incident.

All of the work was completed two months ahead of schedule, resulting in significant cost savings. The unit spent 299 days on location, with 2,276 job safety and environmental impact analyses conducted and no recordable injuries or incidents.

Offshore