OIS Completes Multi-Operator Well Abandonment Campaign in North Sea

Acteon company Offshore Installation Services (OIS) has successfully completed a suspended well abandonment campaign in the UK North Sea involving four individual operators. A total of six wells in Categories 1, 2.1 and 2.2 were abandoned, including three for Nexen and one each for Dana Petroleum, Premier Oil and a fourth operator. The operation to abandon the well for Premier Oil (Category 1) was slightly unusual in that in this case the tree was still in place following the well's earlier suspension.

OIS planned and organized all aspects of the six well abandonments on behalf of the group of operators. This encompassed the initial approvals process, the formulation of the contracting strategy, the development of detailed procedures, procurement, the appointment of specialist service providers and the overall logistics, right through to the recycling and disposal of the recovered wellheads. The entire exercise was supervised offshore and supported onshore by qualified and experienced teams from OIS.

The campaign was conducted from the DP2-class, light construction vessel MV Island Valiant. The vessel made two trips in the period between 20 July and 16 August. During the first trip, OIS's proprietary suspended well abandonment tool (SWAT) was deployed through the vessel's moonpool for the necessary light intervention work on the wells, essentially involving the setting of cement plugs across all the casing annuli in accordance with North Sea legislative requirements. During this exercise, four of the suspended wells were completely plugged and abandoned within a period of 10 days. A second trip was made to sever the wellheads beneath the seabed (and to remove the tree in the case of the Premier Oil well).

Vic Morrell, president of OIS, said, "Multi-operator abandonment campaigns provide significant cost savings for the individual operators who share the mobilization and project management costs – though serious attention needs to be paid to the various overlapping contracts with each of the operators, notably in terms of the reasonable division of cost and risk. The projects also carry appreciable operational responsibility and call for a combination on our part of technical and organizational skills plus strong, experienced leadership."

Feedback from the operators was overwhelmingly positive and generally focused on the professionalism surrounding the campaign. Chris Kelly, technology and performance team leader at Nexen, said, "The organization of the various different service companies, along with the cooperation and proactive input of the Island Valiant crew, ensured that the campaign was a total success. The whole operation was successfully completed without any HSE issues or impact on the environment." Jane Murray, geologist with Dana Petroleum, added, "A professionally organized and managed campaign….our well was successfully abandoned without incident and in a safe and timely fashion."

This is the latest in a line of multi-operator abandonment campaigns undertaken by OIS (either under its own banner or that of an earlier Acteon company). The company can lay claim to a subsea well abandonment record that includes in excess of 100 wells. SWAT has been a major contributing factor in establishing this record. With its proven design, its ability to be deployed from a relatively simple DP2-class vessel, high mechanical reliability and multiple safety features, the tool is unrivalled in this application.