Expandable casing patch and liner hanger

The systems operate using a hydraulic multipiston setting tool that presses an expander mandrel into the upper portion of the hanger body expanding it out to the wall of the outer casing. The length of expansion ranges from 12 in. to 24 in. depending on size and application. Once expanded, the hanger body forms an HP/HT metal-to-metal seal. The expander mandrel remains in place after the setting tool is released and incorporates a tieback receptacle for extending the casing patch or liner up hole as required. One of the down sides of expanded tube has been the collapse de-rating due to the increased D/T (diameter over thickness) ratios. As tube is expanded to plastic deformation, the wall gets thinner, and the resistance to collapse pressure goes down. With the expander mandrel left in place, the expanded hanger body is fully supported and therefore is able to meet the full collapse rating of the casing being run.

Casing patch

Figure 2. The liner hanger is an expandable system with an enlarged through bore, comparable to the internal diameter of the largest oilfield tubular string, capable of being installed within an existing tubing or casing string.

As a casing patch, the system is deployed as a multitrip, straddle-pack type application. An expandable packer is set below damaged casing or old perforations, and a metal-to-metal seal nipple is inserted into the tieback receptacle. The patch is extended up hole with conventional tubular, where an upper expandable packer is set, isolating the repair area between the two packers.

In late 2007, CNR International (UK) Ltd. began searching for alternative technologies for use in an upcoming workover on the Ninian Platform, located 108 miles (175 km) offshore the Shetland Islands, Scotland. CNR’s objective was to find a system that would provide an effective way to isolate two sets of perforations and convert the well from an oil producer to a water injector. In addition, CNR wanted to ensure it would have the option of re-perforating one of the straddled zones at a later date if required.

CNR selected the expandable casing patch system, and in January 2008, the system was installed. To meet objectives, the patch system was installed in a three-step, straddle configuration to individually isolate each set of perforations. The system was set up to run 41⁄2-in., 12.6# casing or 4-in. casing. The initial leg of the straddle was deployed with an expandable packer set at 14,254 ft (4,347 m) measured depth. Four and a half-inch, 12.6# casing was run to extend the initial leg up to 13,959 ft (4,257 m) where the middle expandable packer was set. The deployment of 41⁄2-in. casing inside 51⁄2-in., 20# was expected to be tight, and several tight spots were encountered from 12,612 ft to 12,672 ft that took some work to get by. CNR elected to go with the 4-in. casing for the upper leg of the straddle. The upper leg was deployed and tied into the middle packer with the upper expandable packer set at 12,627 ft (3,846 m).

The patch was set from 14,260 to 12,627 ft (4349 to 3,851 m) at an 80° well angle. The system exceeded customer expectations in both performance and ease of deployment.
Liner hanger system

Initial development of the expandable liner hanger concentrated on 51⁄2-in. x 75⁄8-in. and 75⁄8-in. x 95⁄8-in. sizes, with the primary driver being the HP/HT metal-to-metal annular seal. However, interest quickly grew with offshore and deepwater operators needing large-outside diameter (OD), tight-tolerance liner systems and with operators interested in drilling with liner systems.

Successful testing has been completed on sizes ranging from 95⁄8-in. x 113⁄4-in. up to 18-in. by 22-in. In the past year, six large-OD expandable liner systems have been deployed in sizes 95⁄8-in. x 113⁄4-in., 113⁄4-in. x 135⁄8-in., and 133⁄8-in. x 16-in.
Shell Oil Co. selected the expandable hanger system to deploy a 133⁄8-in., 72# x 16-in., 97# liner on the deepwater Alaminos Canyon 847 well, in the Gulf of Mexico. The liner length was 2,049 ft (625 m) with the top of the liner at 10,000 ft (3,050 m). The liner was cemented and the hanger expanded with 4,000 psi setting pressure, which equates to 1.1 million lb of expansion force at the hanger.

In another Shell deepwater well, the Augur A-10, a 95⁄8-in., 36# x 113⁄4-in., 65# expandable hanger was requested to run 2,834 ft (864 m) of liner to a total depth (TD) of 24,190 ft (7,377 m). It was expected that the liner might require rotation to get down. In fact, the liner was reamed thru the last 1,005 ft (306.5 m) of open hole. Initially it took 35,000 ft/lb to get rotation started. Then the torque broke back to 24,000 ft/lb. Once at TD, the liner was cemented, the hanger expanded, and the liner top tested to 2,500 psi.
Drilling with liner.

In mid-2004, Shell agreed to begin testing the expandable, drill-down liner system in its south Texas wells. The first well, the McAllen 128, required a 51⁄2-in., 17# liner to drill 1,000 ft (305 m) of new 61⁄2-in. hole. The 7 5/8-in. casing was set at 8,612 ft (2,626 m) and 61⁄2-in. hole was drilled conventionally to 10,625 ft (3,240 m), just above a depleted zone. Then 3,275 ft (998 m) of liner was picked up, and the last 945 ft (288 m) of 61⁄2-in. hole was drilled with the expandable liner system. The total drilling time with the liner was 65 hrs, with an average rate of penetration of 14.6 ft/hr. The maximum torque recorded was 5,000 ft/lb. The liner was cemented and the liner top tested to 2,000 psi.

In the next well, the MFWU 101, a 75⁄8-in. expandable liner was planned, but was not planned as a drill-in liner. However, just before reaching the 75⁄8-in. liner point, the well lost returns, and the decision was made to set a cement plug across the open hole and use the liner to drill out the cement. Then, 1,370 ft (417 m) of cement was drilled, and again returns were lost. The liner was cemented, the hanger expanded and the liner top tested to 3,400 psi.