A problem arises if the tubular element has to be retrieved from the well to an offshore platform (such as a floating platform), for example because the tubular element has suffered damage. Since a column of wellbore fluid extending from the platform into the well is needed during retrieval of the tubular element an offshore conduit, also referred to as offshore riser, is to be installed between the platform and the wellhead. Retrieval of the tubular element together with the hanger through the conduit requires the conduit to be of relatively large diameter. Consequently the conduit is heavy, and the platform has to be suited to the heavy conduit.
USPTO Backgrounds
USPTO Backgrounds