An offshore operator in Brunei faced the challenge of increasing the injectivity in water-flooded fields to improve hydrocarbon production. The solution chosen was to use a stimulation vessel with coiled tubing (CT), nitrogen, and pumping capability to perform well interventions to achieve the injection targets. The operation faced challenging offshore weather conditions, limited platform access, lack of crane facilities, aging offshore facilities, and had to provide an emergency disconnect system, while improving the operational efficiency from existing methods.
The stimulation vessel was used in conjunction with some new concepts to the CT offshore operation. These novel concepts included using a full catenary system for CT operations, a dynamic positioning vessel, a knuckle boom crane, and a heave compensated gangway. The full catenary system was selected for the CT operation to minimize lifting hazards, improve equipment installation lead times, and improve the stimulation vessel operating efficiency. The dynamic positioning vessel eliminated anchoring requirements and provided enhanced efficiency for evacuation and approach to offshore facilities. The knuckle boom crane provided the capability to lift in different angles for equipment placement in difficult positions, even underneath a platform helideck. The heave compensated gangway provided extremely safe transfer of personnel between the stimulation vessel and the offshore facilities. It also provided a safe emergency response and evacuation facility in the event of sudden severe weather, platform emergency, or worsening sea conditions.
The advantages and benefits of using these concepts for offshore operation have resulted in a significant improvement in terms of operational efficiency and safety for the stimulation vessel.