--> Annular Barrier as an Alternative to Squeezes in Challenging Wells: Technology Review and Case Histories
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AAPG/SPE Africa Energy and Technology Conference

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Annular Previous HitBarrierNext Hit as an Alternative to Squeezes in Challenging Wells: Technology Review and Case Histories

Abstract

The drilling industry has always relied on cement as a primary Previous HitbarrierNext Hit. Although the cement represents about 5% of the well cost, when squeezes are required, cementing averages 17% of the well cost. Only 50% of the squeezes achieve the objective of establishing a Previous HitbarrierNext Hit for well integrity. A little bit more than half of the failures can be attributed to operational challenges (pump failure, cement contamination), or design oversights (cement recipe, centralizers). However there are still cement failures with perfect design and field execution. These failures typically exhibit some of the following characteristics: high deviation, high pressure, washouts, natural fractures, long casing section, heterogeneous sands. For these specific conditions, it is beneficial to add an assurance that would maintain the integrity of the well even in case of bad cement. Some of the assurances used include port collars, external casing packers (ECP) and swell packers. Port collars allow a squeeze above the first stage cement, while ECP serves as a base for a second stage cement, and swell packers provides a baffle for sustained casing pressure. A more recent technology is the well annular Previous HitbarrierNext Hit that can form a combined Previous HitbarrierNext Hit with cement, and can also be used as a stand-alone primary Previous HitbarrierNext Hit. The well annular Previous HitbarrierNext Hit is a metal-expandable Previous HitbarrierNext Hit that is expanded with hydraulic pressure. It is full bore, highly customizable, and qualified to ISO 14310. 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. The well annular Previous HitbarrierNext Hit has been deployed in a variety of wells to achieve well integrity with and without cement, protect the B-annulus from sustained casing pressure, or serve as a Previous HitbarrierNext Hit between reservoirs that cannot be commingled. This paper performs a review of the technologies used for cement assurance, their advantages and disadvantages. Case histories of well annular Previous HitbarrierNext Hit deployments are presented, including a case where the well annular Previous HitbarrierNext Hit was used as a stand-alone well Previous HitbarrierNext Hit element without the need for dispensation. This paper also discusses how the well annular Previous HitbarrierTop fits into the regulatory requirements for well construction providing to the drilling industry an alternative to cement for the purpose of well integrity.