Work in certain critical areas represents a safety hazard on offshore installations. Typically, these will include areas where work is performed at different elevations, (congested) areas with moving loads, areas near pressure containers/piping, areas with risk of toxic substances, leakage of explosive/flammable gases and/or fluids etc.
On an offshore drilling rig two areas in particular, which are usually manned, are identified as critical in this respect, namely the drill floor area and the moonpool area.These areas are identified as key areas to focus on to prevent injuries (or in a worst-case scenario fatalities) to personnel, and damage to equipment and facilities.
In this blog article we will discuss how to reduce the risk of unintended incidents in these areas on an offshore drilling rig.
The drill floor area and the moonpool area
These two areas are arguably the busier areas of an offshore drilling rig. It is the areas where the drilling operations are executed; tubulars and riser joints are moved from the pipe deck to the drill floor inside the derrick and connected to a drill string by use of various tools/equipment. The drill string is then handled, lowered into the sea and wellbore, to drill the well.
In the moonpool area, BOPs, Christmas trees (XMTs) and other equipment are moved in and out of the open moonpool under the drill floor, connected to the drill string, riser string or other similar equipment to be lowered into/retrieved from the sea.
The moonpool area is a very congested area with a variety of equipment:
- Winches
- Cranes
- Special equipment
- Piping
- Hoses
- Wires
This and more are installed to support a variety of drilling operations. One principal difference between the drill floor area and the moonpool area, is the degree of repetitive operations. The drill floor area is characterized by a relative high degree of repetitive operations, while the moonpool area is not.
Suggested reading: Read more about How to reduce risk of dropped objects on an offshore rig here
The drill floor area – automation and mechanization
Mechanization/automation are means not only to improve efficiency and consistency, but also to move people out of areas especially exposed to hazards. On a modern (floating) drilling rig, the pipe-deck/drill floor area is highly mechanized and/or automated.
The main driver for this development has mainly been removing people out of hazardous areas to reduce risk of injuries and fatalities. Increased efficiency has also been a key driver. Over the last 10-20 years, the development on a modern floating drilling rig has been remarkable; from manually operated individual tools/and machines, to automated computer-controlled systems supported by a variety of sensors and cameras, operated from a drillers cabin in a safe position on/near drill floor.
With current technology, drill floor operations can partly or completely, be controlled from a remote location and in theory with no personnel on drill floor. No operators have gone to this extreme per date, as it is considered critical to have personnel on-site to supervise operations and be able to intervene, as and if required. On an automated drill floor, personnel have been released from demanding physical and risk exposed activities, and are instead performing more supervisory work, planning of operations and maintenance.
The implementation of automation has reduced unintended operational disruptions and risk to personnel. The number of injuries and/or accidents are also significantly reduced. Another benefit of computer-controlled operations is a more consistent operation of the equipment, which means less wear and tear and increased longevity of the equipment.
In total, introduction of automated operations on the drill floor has removed people out of harm’s way and increased overall operational safety, efficiency and consistency. The benefit from the automation process is so positive that basically all modern floating rigs are built to very high mechanization/automation standards on the pipe deck/drill floor.
The moonpool area – automation
The mechanization level, let alone the automation level, is far less developed for the moonpool area.
This may sound counterintuitive given the successful development of automation for the pipe deck/drill floor area. However, while the drill floor area is an obvious candidate for automation given its high degree of repetitive operations, the moonpool area with its variety of operations in a congested area is not.
It does not make things easier to automate when various trolleys, skids, equipment, hoses, wires, or sheaves are in operation at irregular intervals and with varying setups. When not in use, equipment and its accessories are typically stored/parked in available (parking)areas (which typically are limited and often inadequate).
Consequently, when not in operation, such parked items or equipment will often obstruct other ongoing operations. Given the nature of the operations to be performed in the moonpool area and the available space, this area is not, as it stands today, a technically and commercially viable candidate to automate.
Suggested reading: How Updated Handling Systems Can Give Your Rig a Competitive Advantage
The moonpool area – mechanization
Even modern floating drilling rigs have often surprisingly low mechanization levels in the moonpool area, rendering activities in this area more dependent on manual work, involving manriding operations (also over open sea). Most rigs also have significant potential to optimize safety and efficiency by better organizing storage/parking of equipment, wires and hoses when not in use.
Personnel seen working in critical areas – equipment is available to remove this personnel.
However, technology is available to mitigate many of these hazards and inefficiencies.
Below is a non-exhaustive list of some of these technologies:
- MPD ClickStab® automated handling systems:
- Handsfree, wireless controlled connection of mud return, hydraulic and electric control lines.
- Reduces spent connection time of 12-48 hours down to a few minutes and manning requirement utilizing up to 10-12 persons down to 1-2 persons.
- No work over open sea or other manual operations. No moving parts on Slip Joint.
- Dedicated parking space for equipment and hoses draped away to avoid disruption of other operations.
- Kill & Choke (ClickStab®) automated handling systems:
- Handsfree, wireless controlled connection of K&C, booster and conduit lines.
- Reduces connection-time from 12 hours to minutes and manning requirement from up to 10-12 persons to 1-2 persons.
- No work over open sea or other manual operations.
- No moving parts on Slip Joint.
- Dedicated parking space for equipment and hoses draped away to avoid disruption of other operations.
- XMT/BOP handling systems including lateral guiding:
- Remotely operated, always secured and handled from storage position to sea and back.
- N-Line / DAT Riser tension handling and parking systems:
- Remotely operated handsfree handling and safe parking of riser tension cylinders.
- Mechanized connection to riser.
- No manriding operations required.
N-Line / DAT Riser tension handling Arms in operation – removes personnel from critical areas.
- Moonpool Multi-purpose cranes:
- Remotely operated.
- Running along rails in the moonpool.
- Rotation, tilting and telescoping, removes manual work and improves efficiency.
- Covering large areas of the moonpool.
Multi Purpose crane covers a large area of the moonpool and removes personnel from critical areas.
- Specially designed moonpool access-baskets:
- Running on rails in the moonpool.
- Extended reach and placement to optimize operations and avoid interference with other operations when not in use.
- Motorized MUX/POD, umbilical saddles and Reels:
- Hydraulically powered Umbilical Power Saddles and Reels for automatic handling and correct positioning of MUX/POD and umbilical cables.
- A remotely controlled system which improves operational efficiency and safety when making up storm loops related to landing of BOPs.
- Other specially designed equipment improving safety and efficiency:
- BOP bonnet exchange system
- BOP Test pipe handler Systems
- BOP and XMT access systems
- Versatile and mobile cherrypickers (access baskets)
- Quick Connector hang-off tool
Conclusion
Focus on increased safety and removing personnel from critical and hazardous areas have been a priority in the offshore industry for decades. New technologies, including mechanization and automation, have contributed significantly to these efforts and have yielded good results.
The drill floor/pipedeck areas are highly mechanized/automated on modern floating rigs. Another area exposed to unintended incidents, the moonpool area, is lagging due to the nature of the operations performed in this area.
However, a number of selectable technologies are available to alleviate these challenges which will provide a
higher degree of safety and at the same time improve the overall operational efficiency of the moonpool area, and drilling operations in general.
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