A rig crew runs the recess shoe for the linEXX expandable liner system (Photo courtesy of Baker Oil Tools).
A commercial well in southeastern Oklahoma in the United States received the world’s first monobore expandable liner extension system.

BP, in collaboration with Baker Oil Tools, developed the linEXX solid expandable system that was used in the well.

The installation included an RC9-R recess shoe run on 95¼8-in. parent casing string, FORMlock expandable hanger/packer, 36 joints of 8-in. expandable liner with a .345-in. wall and an RNX guide shoe. The companies used the catEXX expansion tool system to expand the liner.

Advantages of the new system include one-trip, top-down expansion to extend the already existing 95¼8-in. casing string. At the same time, the installation team was able to maintain the full inside diameter of the parent casing at 81¼2-in. The system also gives the companies the flexibility is isolate problems downhole which, in turn, encourages deeper wells by maintaining the size of the liner.

During the installation, the team first installed a contingency recess shoe on the 95¼8-in. parent casing at 2,588 ft (789 m). The group then ran 1,514 ft (461 m) of 8-in. expandable liner and located the recess shoe. At that point team members expanded the hanger and liner through the full length and retrieved the guide shoe in a single downhole trip. The operation expanded the liner by 18% to an 8.625-in. inside diameter and an 81¼2-in. drift inside diameter.

Once installed, they pressure-tested the system, opened the circulating sleeve in the recess shoe and cemented the expanded liner in place with a K-1 cement retainer. Returns came back through ports in the recess shoe.

The team then drilled out the retainer and cement and continued drilling below the show at 4,020 ft (1,225 m) with standard rotary steerable directional tools. The final step involves isolating the linEXX system with production casing before completing the well.

Operators and service companies have worked for years to prove the economic and operational feasibility of monobore expandable liner extensions to replace conventional casing designs under the assumption that the monobore extension would allow the operator to drill deeper exploratory and producing wells while maintaining larger well bores in the target formation. That option is now available.

Another advantage of the system occurs when an operator must isolate the well bore from reactive shales, subsalt environments, formations with low fracture gradients and other situations encountered in drilling.

The monobore extension allows the operator to deal with those situations without reducing casing and without the consequent need to reduce the size of the hole size in the target formation.

For more information, visit www.bakerhughes.com.

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