Evolution of a Well Annular Barrier for Mitigation of SCP

Abstract

A novel, Well Annular Barrier (WAB) was introduced back in 2011 as an open-hole, zonal isolation packer. Its strength, ruggedness and pressure capacity over the past four years has proven it a valuable solution. Especially for ensuring the successful cementing of casing strings which were required to be run through challenging environments such as overburden, depleted zones, water bearing sands or unconsolidated zones. Work is in progress to develop a verification system for WAB expansion and integrity, further growing its capabilities and the operating envelope in which it can be deployed. This will in turn increase the WABs potential applications, and use as a stand-alone, open-hole barrier. The newly developed system consists of pressure and temperature sensors either mounted independently from, or integrated with, the WAB. Annular sealing integrity will be confirmed by direct pressure measurement down-hole. For SCP applications, this will replace indirect confirmation of integrity via cement bond logs, which is the current practice. A verification table in line with requirements outlined in Norsok D-010 has been prepared to comply with industry standards for barrier verification. The current climate in the oil & gas industry calls for novel solutions to known challenges. Well integrity in the overburden is one such challenge the industry has a high focus on, and solutions must meet a challenging set of requirements. New solutions need to be equal to or better than existing ones, hence qualification requirements and documentation are paramount in delivering innovative solutions. Some operators do not accept sustained annulus pressure in producing wells, especially in HPHT applications. The WAB combined with this new Well Data Monitor (WDM) for verification of pressure seal is an evolutionary step that could eliminate this challenge. It offers a new ‘tool in the box,’ expanding the operating envelope and enabling advanced well construction with no compromises. This evolution of the WAB can aid to further prevent surface casing pressure (SCP), a huge concern throughout the industry. With the introduction of the WAB with sealing verification, operators can more easily construct robust and safe wells while at the same time, reducing construction time and cost.