Page 532 - The ROV Manual - A User Guide for Remotely Operated Vehicles 2nd edition

Part 9: Remotely operated tool (ROT) intervention systems
A concern for ROV operators is ISO 13628 Part 8 (13628-8) and API 17H (which are identical standards) for “ROV Interfaces on Subsea Production Systems.” The standard will not be detailed here but the important aspects, for later reference to the standard itself, will be highlighted.
The standard identifies several ROV intervention configurations (per 13628-8—see Figure 19.26):
1. Vehicle with manipulators for direct operation of the interface
2. Vehicle with manipulator-held tooling
3. Vehicle with tool deployment unit (TDU)
4. Dual downline method (ROTs or remotely operated tooling)
5. Vehicle with tooling skid or frame
These are discussed in more detail in the following sections.
19.7.1 Manipulator operation of the interface
This configuration is straightforward in that the typical two-manipulator operation has one grabber holding the vehicle in place while the second (more dexterous) manipulator operates the tooling interface. The interface to the subsea facility is via direct operation of the work item with the manipulator’s end effector.
19.7.2 Manipulator-held tooling
As opposed to the manipulator end effector performing the work, the manipulator-held tool inter- faces directly with the subsea structure. Detailed in Figure 19.11, the types of manipulator hand configurations are compatible with standard grips—the “T-bar” handle and the “fish tail” handle (see Chapter 20). The parallel hand configuration mates easily with the T-bar, and the fish tail works with the curved finger jaw.
Any number of tooling can be held with the common gripper/handle interface and be powered by the vehicle’s hydraulic or electrical power system. The various types of tooling available for manipulator holding/deployment are further detailed in the next chapter.
19.7.3 Tool deployment unit
As depicted in Figure 19.27, the TDU is a separate module from the ROV frame that is attached (typically) to the front or rear of the vehicle’s frame to accurately position the tool. A TDU is very similar to a skid, but typically the TDU is the interface module (i.e., the TDU docks with the inter- face as opposed to the vehicle docking to the interface with an underslung skid). The TDU is placed between the vehicle and the interface so that the tool can be specially designed for a job- specific task and then switched out once the task is completed. The TDU will typically have its own flotation (so as to minimally affect vehicle performance) and can be used in substitution of, or complimentary to, the vehicle’s manipulators.
Standardized subsea production equipment interfaces will have a docking point receptacle, whereby a docking port can be positively attached to the interface for secure tool mating. Figure 19.28 depicts single and twin point docking probes located on the TDU side that locks into
19.7 Subsea interface standards 529