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§ 51 Drilling fluid system

The drilling fluid system shall be designed such that it mixes, stores, circulates and cleans a sufficient volume of drilling fluid with necessary properties to safeguard the drilling fluid's drilling and barrier functions.
The high pressure section of the drilling fluid system with associated systems shall also have the capacity and working pressure to be able to control the well pressure at all times.
Section last changed: 01 January 2011

Drilling fluid systems mean complete systems with sufficient capacity to mix, store, pump, recondition and cover the need for a fluid-based well barrier. The drilling fluid system area should be designed to avoid harmful exposure for personnel and the environment. The system should be connected to monitoring systems to ascertain the condition of the fluid, system and well.
The system should be adapted to normal operations and emergency situations.
For general requirements related to design of chemical plants, see Section 15.
In order to fulfil the requirement relating to drilling fluid systems, the NORSOK D-001 standard Chapters 5 and 6 should be used in the area of health, working environment and safety, with the following additions:
  1. Return of the drilling fluid from the well should take place in a closed system to avoid evaporation,
  2. The system for monitoring drilling fluid volume should compensate for the facility's movements and should include indicators on the drill floor with audio and visual alarms. When drilling wells with high pressure and high temperature, the need for temperature and pressure sensors in critical locations such as before and after the choke manifold and in the blowout preventer, should be assessed. For general requirements related to drilling fluid parameter monitoring instruments, see Section 17,
  3. Gases from the reconditioning unit should be vented through separate pipes to a safe area.
For general requirements related to barriers, see the Section 5 of the Management Regulations and Section 8 of these regulations.
For mobile facilities that are registered in a national ship register, DNVGL-OS-E101 Chapter 2, Section 5, Paragraph 7 may be used as an alternative.