Method of Surface Interception To Access Annulus With Abnormal Gas Pressure

Topics: Well integrity/control
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One of the operator’s newly acquired ventures is in the North field offshore Qatar. Abnormal rise in Annuli C and D pressures during the last phase of drilling highlighted the need to investigate the condition of producing wells on other platforms. The chances of inner annuli becoming charged with shallow-gas pressure and possible communication to Annulus D was thought to be a well-integrity concern. Establishing safe access to the sealed and potentially gas-charged Annulus D thus posed a challenge.


The North field is offshore northeast of Qatar and is the world’s largest nonassociated-gas field. The wells are typically 7-in. monobore completed with a 26-in. conductor and three casing strings. Wells are completed with a liner-top isolation packer, tied back to the surface with 7-in. corrosion-resistant-alloy tubing.

The annuli between the well casings are labeled A (7×10¾ in.), B (10¾×13⅜ in.), C (13⅜×18⅝ in.), and D (18⅝×26 in.). Provisions were made for monitoring and bleeding off pressures in Annuli A, B, and C.

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper IPTC 18122, “A Safe and Efficient Method of Surface Interception To Access Outermost Sealed Annulus Charged With Abnormal Gas Pressure Relieves Well-Integrity Concerns,” by Prashun Kumar Das and Wael Moneer El-Mandrawy, Qatargas, prepared for the 2014 International Petroleum Technology Conference, Kuala Lumpur, 10–12 December. The paper has not been peer reviewed. Copyright 2014 International Petroleum Technology Conference. Reproduced by permission.
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Method of Surface Interception To Access Annulus With Abnormal Gas Pressure

01 January 2016

Volume: 68 | Issue: 1