In recent years, drilling operations are facing increasing challenges. Deepwater and ultra-deepwater environments, HPHT applications, anomalous pressure regimes and reduced margins between pore and fracture gradients are setting new critical thresholds to the ability of reaching new hydrocarbon reserves and are raising new operation safety issues for business sustainability. In this framework, best practices and a series of dedicated tools have been developed throughout the years. Nowadays, the best oil industry practice to cope with these problems is represented by Managed Pressure Drilling Systems (MPDS), consisting of surface tools and equipment that enhance drilling capabilities and grant a safe drilling process. To complement MPDS, the possibility to introduce new safety barriers directly into the well has also been considered. Among these barriers a new casing valve,with surface control lines, rated for HPHT and sour environments has been developed. As known, casing valves are integrated into casing string and isolate the open hole when no drill string is present below the last casing point. Casing valves are thus directly reducing the risk associated with tripping in and out of the hole and, in specific cases, can lead to considerable cost savings avoiding the necessity of mud cap barriers to restore trip margin whenever necessary. In addition, associated to MPDS, casing valves represent a testable barrier for isolating the open hole when a double independent barrier is required to safely continue operations such as in BHA tripping, liner running etc. This paper describes the first worldwide application in deep well sour environment of a 10 ¾ casing valve that was set in operations in 2011. In the paper both qualification process and installation experiences are described and reported.


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