The systematic approach adopted by a service company and a Brazilian National Oil Company (NOC) to achieve the goal of safely abandoning wells with different completion types using light workover vessels is discussed. Having determined the abandonment methodology, the service company personnel developed processes and procedures to reach the objective. These include advances in coiled tubing (CT) rigup procedures and using a real-time telemetry system. This approach facilitated the timely and cost effective abandonment of more than 15 wells since 2017 in a safe and environmentally acceptable manner.
This paper describes a subsea pigging and hydrotesting unit (SPHU) that provides technology for remote flooding and testing of pipelines in water depths up to 2000 m (6,562 ft). The benefits of having a submerged pump that uses seawater for tests are related not only to safety, but also to schedule and deck-space optimization.The SPHU has the capability to filter and chemically treat flooding water while continuously regulating and monitoring the flooding and pigging operations. The system includes a subsea data logger that allows remote monitoring and logging of pressure, temperature, flow rates, and volumes. Once in place, the SPHU uses power available from a remotely operated vehicle (ROV). The ROV is used to control the rate of pressure increase in the pipeline by varying the flow rate provided by the ROV-driven pressurizing pump.One of the most significant advantages provided by this equipment is that strength-test operations can be completed entirely on the seabed, moving the risks posed by high-pressure fluids to a location far from personnel. Various versions of the SPHU have been successfully deployed on over 90 pipeline operations to date, adding significant value to offshore projects by allowing more flexible and efficient usage of vessels. To better illustrate the use and benefits provided by this unit, case studies will be presented based on operations performed in Brazil in the last two years.
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