New features on ROVs and control systems add flexibility and cut costs

Subsea maintenance with remotely operated vehicles (ROVs) has a substantial role in defining diverless subsea operations. System complexity, and hence also cost and reliability, are affected by the types of maintenance interfaces available. This concluding part of a three-part series covers Amoco's development of ROV tooling that incorporates variable buoyancy, a vertical running tool, and an electrohydraulic power package that includes a horizontal torque tool. In the development of a diverless subsea production system (DSPS), Amoco also has concentrated on designing new control systems and ROVs that can remain subsea for extended periods of time. The paper describes ROVs in general; maintenance ROVs; resident ROVs for monitoring and operation of remote seafloor installations; control systems; umbilical terminations; instrument packages; hydraulic control; local shutdown; and on-going development efforts.