This article, written by Special Publications Editor Adam Wilson, contains highlights of paper OTC 26750, “In-Service Hull Inspections for Avoiding Dry Docking Safely,” by D. Constantinis and P. Davies, EM&I Group, prepared for the 2016 Offshore Technology Conference Asia, Kuala Lumpur, 22–25 March. The paper has not been peer reviewed. Copyright 2016 Offshore Technology Conference. Reproduced by permission.
Current methods for external inspection of floating assets on station use divers or remotely operated vehicles (ROVs), but these methods incur high safety, people-on-board (POB), and cost penalties. The data produced by these methods are restricted by marine growth and limited access to isolation valves. The Hull Inspection Techniques and Strategy (HITS) joint-industry project (JIP) called for new methods to be developed that minimize or eliminate diving. This has been achieved by carrying out many of the inspections from inside the hull.
The exploration and production of deep-water hydrocarbon reserves requires evermore-complex and high-capital-value floating assets. There are a number of key drivers required to optimize profitable operations, including managing the integrity of the topside and hull while reducing cost and POB and complying with client, corporate, and regulatory requirements.
Floating production units can be designed for 25 years or more on station, and the new-generation ultradeepwater (UDW) drilling units also need to plan their integrity-management strategies without dry docking for extended periods (Fig. 1).
These requirements have driven the development of innovative methods for inspecting, testing, and maintaining pressure systems as well as hull structures, the latter sometimes not getting the integrity attention it deserves.
The HITS JIP was formed to address these issues, with membership from regulators, oil majors, class societies, lease operators, service companies, and educational bodies representing all sectors of the industry.
The HITS JIP drew opinion from the industry and concluded that there are principally four challenges that should be addressed:
Minimizing diving operations for hull in-water inspections
Minimizing man entry for inspection of confined spaces
Developing a capability to inspect cargo oil tanks with minimal cleaning requirements
Developing competency standards for hull inspectors
The HITS JIP does not carry out any developments itself but encourages industry to develop or adapt technology to improve hull-inspection techniques and evaluates the results.
An industrywide survey concluded that the first priority should be given to minimizing diving operations for hull inspection, and, accordingly, three of the HITS member organizations cooperated in the development of an alternative method.
This paper describes the new methodology; details how it has been applied to floating production, storage, and offloading vessels (FPSOs) and UDW drillships; and presents the lessons learned through site implementation.