Expandable HP/HT Liner Hanger Increases Pressure Integrity

Abstract

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 29494, “HP/HT Expandable Liner Hanger Technology With Superior Pressure Integrity,” by Edward S. Royer and Robert A. Turney, TIW, A Drill-Quip Company, prepared for the 2019 Offshore Technology Conference, Houston, 6–9 May. The paper has not been peer reviewed. Copyright 2019 Offshore Technology Conference. Reproduced by permission. This paper describes a high-pressure/high-temperature (HP/HT) expandable liner hanger product that offers metal-to-metal and elastomer sealing capabilities at the liner top in the host casing. The system delivers increased hanging capacity and seal integrity for installing casing strings of various lengths. The expansion process is achieved using a multipiston hydraulic running tool with pressure application to displace an expander inside the hanger body. Expandable Technology Expandable technology provides operators an alternative to conventional liner hanger and packer systems that typically use slips and cone components configured on the outer diameter of a hanger body that require translation of the slips onto the cone for installation of the liner hanger in the host casing. Conventional liner-top packer systems typically also require drillstring weight for the mechanical force required to energize a sealing element that produces the annular seal between the liner and host casing strings. Fig. 1 shows a comparison between a conventional liner hanger and packer system and the system described by the authors of the complete paper. Expandable liner hanger and packer technology has evolved from years of product development and has gained market share with the increase of successful field installations. These systems consist of an integral hanger body design that incorporates elastomeric sealing elements normally bonded on the outer diameter. Hanger body expansion into the host casing is accomplished with the application of hydraulic pressure through a setting tool to create enough force to displace an anvil through the hanger body inner diameter. Interference between the hanger body inner diameter and the anvil outer diameter creates the interaction necessary for the creation of radial growth required to facilitate interference with the host casing. The described system differs from other expandable systems in its propagation of expansion using a proprietary tool that is a tubular component with a distinctive outer diameter profile. This tool, known as the expander, is displaced with an interference fit inside the system’s integral hanger body to create the expansion needed to anchor and seal to the host casing. A multi piston hydraulic running tool, with pressure activation initiated by liner wiper-plug displacement during cementing or a setting ball dropped from the surface, applies force to displace the expander and carries the liner (which is of Q-125 material grade) downhole. The expanding tool is permanently installed inside the hanger body. The contact pressure generated during the expansion process is preserved, which ensures an installation with enhanced anchoring ability that provides the added benefit of high collapse resistance from annular pressure. Multiple segmented slips are installed and retained in machined pockets oriented on the circumference of the hanger body. Elastomeric sealing elements are installed on the hanger body’s outer diameter bordered by metal seal ribs. The combination of metal and elastomer sealing elements provides redundancy for ensuring pressure integrity at the liner top. The system allows a large inner diameter after setting.