Enabling Riserless Subsea Wireline Interventions: A Step Change

Abstract All wells will likely require some form of well intervention during their lifecycle to optimize and maintain their production output. To be able to perform an intervention, well access itself is a critical element to the planning and safe execution of operations. Perhaps sometimes regarded as mundane, this can quickly be complicated by being in a remote location, lack of access to appropriate equipment to be able to rig up over the well, the length and diameter of the intervention string itself, the well state and more. Nowhere has this become more apparent than when intervening on subsea wells, whereby the wellhead is submerged on the surface of the seabed, which brings significant additional cost and risk to operators. This paper will cover the global growth of subsea well stock and discuss the importance this has in today's energy mix. The complexity of subsea well access will be discussed and a brief history of enabling technologies with be provided. The papers will then specifically explain the issues with wireline open water subsea interventions and how they bring specific challenges to this environment. A new greaseless wireline subsea intervention system will be described and how it can overcome such issues. The system compromises of already existing polymer locked wireline cable technology and its integration in a new subsea intervention pack off that can then be incorporated into subsea intervention lubricators. A successful field test of the system will be presented and the results of the campaign provided. The paper will conclude why such systems should become the default methodology for performing such operations, bringing new levels of operational confidence and certainty for all stakeholders.