When drilling offshore wells, well-bore architecture will typically require casing strings larger than 13-5/8-in. to be "hung-off in the casing hanger located at the wellhead. To date, this has been the most widely used method, albeit a time consuming and usually costly approach. With solutions needed to alleviate these issues, a new expandable technology has been developed as an alternative to the conventional approach.

An expandable large-bore liner hanger that allows an operator to set a liner instead of a full string of casing has recently been designed. Plans for operations within the Gulf of Mexico region began after successful applications of the new large-bore expandable liner hanger were run in other parts of the globe. With internal diameter restrictions coming into play at the wellhead in the Gulf, the original product required some design modifications.

The contents of this paper will cover the development and successful installation of the first large-bore expandable liner hanger (LBELH) in deepwater Gulf of Mexico operations for ENI's Triton well. Advantages in this installation included casing placement flexibility, redundant seals at the top of casing, improved load support reliability, the capability of rotation and reciprocation during cementing, cost reduction, elimination of requiring the casing hanger to seal in the casing adapter, and complications with shallow deviation.

Due to the successful installation of the large-bore expandable liner hanger, the customer was able to save on costs of 2,300 feet of 16 in. casing, greatly improving economics for the project. With the slick-bore design of the system, equivalent circulating densities were greatly lowered. Coupling this feature with the capability to rotate and reciprocate during cementing greatly improved the cementing quality, as well as run-in speeds, with no mud loss. These two features are expected to increase well life and reduce future remedial work to the well.

By eliminating the requirement to properly and precisely space out liner jobs on floating rigs in deepwater regions, pressure integrity issues of conventional systems can be avoided.

You can access this article if you purchase or spend a download.