Welltec® Light Packer prevents sustained casing pressure in the US

Challenge
Well construction & integrity
Sub Standard Graphics 3D JUSCO213715 00000
  • Well type Unconventional oil producers
  • Depth ~7,000 ft (2134 m) TVD; ~16,000 ft (4877 m) MD inc

Background

An operator in the DJ Basin in Colorado was experiencing sustained casing pressure (SCP) on approximately 30% of wells. These wells are unconventional oil production wells that target a shale formation that requires hydraulic fracturing to create the necessary permeability to allow the flow of the oil. The SCP prevented the operator from completing (hydraulically fracturing) the wells due to local regulations, which require remediation of SCP prior to completion. Local regulations require SCP at the surface to be under 200 psi.

The average cost to remediate these wells is approximately $300,000 USD each. Additionally, some wells potentially could not be remediated, because the challenge was in the production annulus, the client would have to abandon the wells, losing the investment of between $2 and $3 million USD per well. The volume of wells experiencing unmitigated SCP was also preventing the operator from acquiring new drilling permits.
The client tried several solutions, including remedial options—cement squeezes, molten eutectic alloys, and casing expander solutions—and preventative options—standard cement slurries, premium cement slurries (with latex), and expanding cement slurries. Each of these solutions failed to reduce the SCP.
The client needed an innovative solution. After close collaboration with the client, Welltec® deployed the 812 Welltec® Light Packer XL (812WLP XL).

Operation

For this operation, the 812WLP XL was outfitted with the Protect: Smart valve, which would enable the WLP to be floated in with the casing, and the Protect: Prime valve, which would restore casing integrity after expansion of the WLP.
During a recent delivery in early 2022, twenty-four WLPs were externally mounted and welded onto the 5-1/2” production casing supplied by the client and delivered in batches of four with each batch being delivered within three weeks of receiving base pipe from the client. The WLPs were delivered directly from Welltec’s Houston Product Center to the wellsite, providing convenience to the operator.

For each of the 24 deployments, the WLP was floated in hole as part of the production casing string to TD, with the WLP placed at approximately 2,900 ft (884 m) MD in non-permeable, competent shale where the hole is approximately deviated by 14°. In some of the wells, rotation of the production casing at 20 rpm was necessary to reach TD, which posed no risk to the WLP’s robust construction.
The air was circulated out of the bore to float the production casing to TD, followed by cementing operations. Upon completing cementing of the production casing with top of cement just below the surface casing shoe, a wiper plug was pumped to TD to clean the inside of the 5-1/2” production casing. After the wiper plug reached TD, and while the cement in the annulus was still “green,” the WLP was expanded by applying up to 5,500 psi of pressure from surface against the wiper plug using the cement pumps. The pressure-up sequence to fully expand the WLP took approximately 20 minutes. At this point, the WLP was fully conformed to the borehole, and the operation was completed.
The WLP solution was introduced as part of the well construction with minimal impact on the existing well program, making it easy to deploy. The WLP solution was selected due to its proven track record in other markets in the world, as well as the fact that the WLP provides metal-to-rock contact for long term isolation of the production casing annulus. During the solution selection process, the WLP was presented to the local regulator and received positive feedback.

Achievements

After deploying the WLP in the 24 wells on the pad, none of the wells had SCP at surface. The client realized approximately $1.4 million USD in savings across the 24 wells with the success of this operation.

Preventing SCP via the WLP ensures the wells can be hydraulically fractured on schedule without delays. In turn, completing the wells on time leads to earlier production. The WLP provided a rapid solution that could be immediately expanded after deployment, especially when compared with some of the alternatives trialed where some solutions required a separate wireline run for activation, or others that required a wait period of days before being activated by downhole conditions. The operator has since ordered WLPs for all remaining planned wells for 2022, bringing predicatablity and efficiency to their operations.

Nick Rakic, Solutions Director

“The WLP is a robustly engineered solution, qualified using the most stringent qualification standard that has enabled my client to deliver wells faster and safer, while realizing significant savings. Going forward, I believe this should be the standard in well construction to ensure more efficient operations and cleaner world for future generations.”

Well schematics

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