First Commercial Single-Diameter 8 x 9-5/8 in. Solid Expandable Openhole Clad Eliminates Tapering and Isolates Problem Section

Abstract

The solid expandable tubular system brought about a significant step change in downhole architecture by instituting a technology that reduces wellbore tapering and conserves precious hole size. The single-diameter solid expandable system takes that technology to another level by eliminating the tapering effect and preserving hole size. Although the idea of the single-diameter approach has been in development for years, the concept became a reality with the installation of an openhole cladding system in the Middle East.

An operator used an 8 x 9-5/8 in. single-diameter openhole clad to isolate a troublesome shale section between ~1,500 and 1,650 ft (~456 and 503m) in a large field in the north of Oman. Previous attempts to mitigate this area with cement-reinforced slotted expandables proved unreliable. Setting regular casing in this section would compromise hole size, hinder well economics, and reduce production. The single-diameter solid expandable system provided a post-expansion inside diameter (ID) of 8.60 in. This pass-through retained an ID large enough to run the same 8-1/2 in. BHA as previously used for subsequent drilling. After placement and expansion of the single-diameter openhole clad, an 8-1/2 in. BHA was deployed to further well construction operations with adequate hole size.

This paper will describe the first installation, including evaluation and operational considerations as well as the results affirming the technology’s ability to isolate problem areas without sacrificing hole size. In addition, the paper will discuss the development of the technology and explain the potential to mitigate a variety of problems and conditions.