Ed Galloway And Walter Scott, Oceaneering International, Inc.
The vast offshore infrastructure – of platforms, pipelines, and subsea wells – depends on remotely operated vehicles (ROVs) to perform tasks during installation, repair and removal operations at water depths below the range of divers. To support deepwater operations, innovative attachments – ROV tooling – have been developed to carry out a wide range of routine and specialized work during every phase of offshore activity.
An Oceaneering ROV dredging under a pipeline.
Tethered to the surface and controlled by operators on service vessels, ROVs are self-propelled submarine devices. ROVs carry lights and video cameras so operators can see the subsea work environment and have hydro-electric power units and telemetry that drive and manipulate tools to perform specific tasks. The ROV is analogous to a tractor, and ROV tools are its functional implements. Instead of mowing, digging, and plowing, ROV tools manipulate wellheads, tighten bolts, connect flow lines, perform inspections, and cut and grind pipe, among many other tasks. ROV tools, and the components they interface with, require innovative designs to perform tasks without the dexterity of human divers.
The first ROV tools were developed to directly mimic tools used by divers. Handheld brushes used to clean wellheads were attached to rotating shafts on the ROV. These simple attachments have since evolved into extremely efficient cleaning heads, sized to match specific wellhead designs and project needs.
Suites of tooling have been developed to suit industry needs, inclusive of tooling required to complete pipeline repair. ROV operable devices including dredges, lift frames, coating and insulation removal tools, and cutting attachments have been added to the catalog available to operators.
Additional advancements in technology are also evident in the three standard ROV tooling categories: drilling support, completion, and production enhancement tooling.
Drilling Support Tooling
The extensive ROV toolkit used to support drilling operations includes torque tools, impact wrenches, hub cleaning tools, hard and soft line cutters, grinders, ROV dredgers, cleaning tools, pH meters, current meters, BOP skids, annulus valves, metrology systems, tree connectors, hot stabs, and lock down measuring sleeves—all of which have undergone design modifications to ensure their operability in the harshest conditions and in deepwater applications. Innovative systems like flying lead orientation tools (FLOTs) enable quick and efficient connection of flying leads to wellheads and manifolds, and seal test kits enable efficient testing of seals on connections once they are made.
Completion tools, often deployed in conjunction with Installation, Workover, and Control Systems (IWOCS), are essential to the assembly and activation of the subsea infrastructure and are the most widely used category of ROV tooling.
Rotary torque tools used to support completion operations have the capability to deliver up to 25,000 ft-lb of torque. ROVs can deploy specifically designed, high-pressure duplex pumps for injecting methanol, glycol, seawater, and control fluid into wellheads and subsea equipment. FLOTs provide efficient interconnection of subsea components during the completion phase.
A full range of linear valve actuator tools, operated hydraulically or mechanically, provides the interface with ROV-operable valves, hot-stab manifolds, and torque tool buckets. Instrumentation including inclinometers, current meters, torque meters, and flow meters, along with data telemetry systems, help ensure reliable operation.
ROV-mounted skids can convey injection pumps, and modular skids have been designed to provide auxiliary hydraulic power in the subsea environment during completion operations in deep water fields. A specialized hydrotest skid enables testing of flow lines up to 20 miles long at up to 20,000 psi.
ROV tooling used for production enhancement performs flowline remediation or well stimulation on subsea flow lines that are blocked by hydrates, paraffin, or asphaltenes. Oceaneering’s ROV deployed Flowline Remediation System includes a liquid/gas separator and a subsea hydraulic power unit and is controlled on board the service vessel. It was designed to provide the most effective and least invasive method for clearing hydrates from flow lines. Alternatively, a hydrate remediation ROV skid can be used to remediate smaller lines at water depths up to 10,000 ft.
Class I-IV Torque Tool.
Oceaneering also offers an innovative and cost-saving rigless and riser-less well stimulation system that can be used to enhance production from subsea wells with vertical or horizontal trees. The system can be configured to inject stimulation chemicals at rate of up to 15 bbl per minute at up to 15,000 psi using a single or dual vessel configuration.
Planning for ROV Operations
According to ROV tooling experts, oil company operators should consider several factors when planning tool requirements for subsea operations. As operators regularly contract for ROV services from local or global companies, it is important to understand the capabilities of the ROV systems available on location. Work-class ROVs have varied electrohydraulic power ratings, and the tooling used must be able to function within the ROV’s capabilities and must be compatible with control and telemetry lines within the ROV. Oceaneering has developed its ROV tooling to be compatible with all commercial ROV systems, eliminating the need to onboard additional tooling to meet the requirements of various ROV types.
Operators must also provide the tool supplier with information about the ROV-vessel interface and define how the ROV will be deployed. ROV launch and recovery systems (LARS) are a common method of deployment and are often built into the service vessel. It is, therefore, important to ensure proposed tool skids have adequate clearance when attached to the ROV.
To control costs, some operators scrimp on contingency ROV tools and spare parts. However, given the high cost of logistics and downtime, it is sensible and a sound economic approach to order adequate spare parts, backup tools, and contingency ROV tooling to address common problems.
Technical support is another consideration. A qualified ROV tool technician on board the service vessel can resolve issues as they occur and keep equipment in good operating condition. When selecting an ROV tool supplier, operators should pay particular attention to the supplier’s service infrastructure and its ability to respond in a timely manner with engineering support and equipment.
Multipurpose Cleaning Tool.
Custom Tooling Packages
ROV operations supporting subsea activities require a wide variety of tooling (cutting, cleaning, measuring, torque tools, etc.). Sourced individually, these tools are likely to arrive at the shore base and service vessel in multiple crates that occupy an inordinate amount of deck space and are difficult to manage. Custom tooling packages offer a solution to improve efficiency, reduce logistics, and minimize the tooling footprint. Delivered in a single Connex box, tooling kits can be tailored to provide standard and contingency tools, as well as spare parts, for specific applications.
Continuous Technology Development
As subsea activity increases globally and deepwater technology advances, continuous development of new ROV tooling is required. Oceaneering has a dedicated design team focused on development of ROV tooling. Long-term projects include innovative systems commissioned by deepwater operators to create tooling to interface with subsea equipment at greater water depths and at higher pressure ratings. In the next decade, it is anticipated that more than 1,000 of the world’s 9,000 offshore platforms will be decommissioned. This further highlights the changing and challenging environments that ROV tooling must evolve to meet. Oceaneering is at the forefront of developing these solutions and builds prototypes at its Houston facilities. The tooling is tested underwater at NASA’s Neutral Buoyancy Laboratory located on site.
As requirements for ROV tooling for use in deepwater applications increases, so must the innovation and effort dedicated to meeting the industry’s needs. Adequate planning and bundled tooling packages for drilling support, completions, and production enhancement offer operators a costeffective, tailored solution to meet project needs in deepwater applications. Technological advancements and new designs will further bolster the tooling catalogs available to operators and ensure the safety and integrity of ROV operations.