Page 351 - Offshore Electrical Engineering Manual

338 CHAPTER 3 Semisubmersibles and Mobile Offshore Drilling Units

ELECTRICAL DRILLING DIRECT CURRENT AND ALTERNATING
CURRENT SEMICONDUCTOR DRIVES

Refer PART 2 Chapter 11.

CEMENT KILL PUMPS AND CONTROLS
In addition to normal cementing facilities, emergency cement pumps are provided,
usually consisting of one or more diesel-driven pumps, independent of the other rig
systems, so that they can be used in emergencies to prevent well blowouts.

DRILLING MUD FACILITIES

It is also vital to provide a continuous supply of drilling mud of the correct weight
and density to lubricate and cool the drill, to bring the cuttings to the surface and to
control the well.

FIRE AND GAS SYSTEMS AND VENTILATION CONTROL ON
RIGS

Good reliable ventilation is essential for the shale shaker mud pump and mud tank
rooms to control the release of hazardous gases by the returning mud.
See also PART 2 Chapter 15.

THE UK OFFSHORE SAFETY CASE LEGISLATION
A semisubmersible operating ‘permanently’ as an oil and gas production unit will be
classed as a ‘fixed installation’ and be required to meet the UK Offshore Safety Case
Legislation (see PART 9 Chapter 1).
If the semisubmersible is working as a ‘mobile’ rig in the UK waters, the UK
Safety Case Legislation does not normally apply. Such a rig will be subject to clas-
sification and survey by a certifying authority and be required to meet their rules.
Other UK legislation may also apply, however.