World's First: Annular Barrier Installed in a Subsea, Deepwater Well without the Use of Cement

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.

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Case History - Metal Expandable Annular Barrier for Zonal Isolation in Challenging Cement Operation in West Africa

Bagal¹,

Dulic²,

Onadeko³

2016

All Days

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It is well recognized that a failed isolation can have detrimental consequences on HSE, well productivity, and life of the well. This paper presents the case history of a metal expandable annular barrier used to provide cement assurance via a hydraulic seal in a challenging side-tracked well in West Africa. The initial well was shut in shortly after being brought on production due to excessive precipitation of scale. Investigations identified a shallow formation separated from the production zone by a thin shale section, and prompted questions on the effectiveness of the cement across the production casing. The metal expandable barrier was then selected to assure sealing in the side-tracked well. Two barriers were mounted on the 9-5/8" casing and deployed through the milled window. Following the cement operation, hydraulic pressure was applied to expand rapidly the sleeve bodies in wet cement and set against the 12 ¼" borehole thereby creating an impenetrable seal. The sealing was ultimately confirmed by the absence of scale during production compared to the previous experience of shut-in after only 18 hours of production. The barriers are seal backed stainless steel sleeves. The expansion process increases the differential pressure capabilities of the packers due to work hardening of the metal sleeves. This also provides a high degree of anchoring. The barriers are full-bore, highly customizable, and are tested ISO14310. The application was for cement assurance but this technology is also applied as zonal isolation in cement-less completions. The metallurgy allows the packer to shape fit into either an open hole with irregular geometry or inside a casing to preclude annular pressure build up by giving a life-of-well reliable seal. Stopping migrating fluids behind pipe has become a critical HSE issue to the industry. The application of this technology allows preventing loss of life and resources.

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World's First: Annular Barrier Installed in a Subsea, Deepwater Well without the Use of Cement

Cited by 7 publications

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Petroleum exploration and production in Brazil: From onshore to ultra-deepwaters

Petroleum exploration and production in Brazil: From onshore to ultra-deepwaters

Evolution of a Well Annular Barrier for Mitigation of SCP

Case History - Metal Expandable Annular Barrier for Zonal Isolation in Challenging Cement Operation in West Africa

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