NORSOK STANDARD D-002 Edition 2 (2013)

Transcription

1 Date: NORSOK STANDARD D-002 Edition 2 (2013) Well intervention equipment Frequently asked questions - FAQ

2 NORSOK

3 INTRODUCTION NORSOK standard D-002 Revision 2 was released in June The purpose of this document is to ensure uniform interpretation and practicing of the standard by answering some of the frequently asked questions regarding the standard, the changes since revision 1 and how it can be implemented. 4.7 Fluid pumps Do the requirements of section 4.7 apply to pressure testing pumps? Answer: Section 4.7 applies to pressure testing pumps intended to verify well barriers below the tree. It does t apply to pressure testing pumps intended to test the well intervention stack above the tree. 4.7 Fluid pumps Do the requirements of section 4.7 apply to pressure testing pumps? Answer: Section 4.7 applies to pressure testing pumps intended to verify well barriers below the tree. It does t apply to pressure testing pumps intended to test the well intervention stack above the tree Working environment Does NORSOK D-002 require a control cabin to be designed as permanently manned even if it is manned less than 8 hours per day as defined in NORSOK Z-015 Revision 4? Answer: Yes. The standard requires any control cabin to be designed as permanently manned, regardless of the number of hours it is manned per day. NORSOK

4 5.3 Safety Head and SIL requirement Why does NORSOK D-002 define a minimum safety integrity level (SIL) for the safety head when the referred Norwegian Oil and Gas Association guidelines 070 states that background for setting a minimum SIL requirement [for well intervention] is t found to be available? Answer: Several organizations commented on the lack of a minimum integrity level of the increasingly complex pumps and skids when the standard was up for revision. The requirement of SIL2 was adapted from the drilling requirements already implemented rather than basing it on historical failure records (as NOROG attempted for their guideline 070 twelve years earlier). Does NORSOK D-002 define a minimum safety integrity level (SIL) for all rams / valves in the rig-up? Answer: No. The standard sets a minimum safety integrity level only for the ram or valve classified as the safety head for the operation. What type of physical objects can act as a safety head? Is a ram-type valve the only permissible type? Answer: Any ram or valve satisfying the requirements of section 5.2 and 5.3 can be classified as the safety head for the operation. A n-exhaustive list of potential candidates is given in section 5.3. The standard does t require ram-type valves for the safety head. 5.5 Independence of control unit Does the requirement of independence of barriers include a remote control panel located inside the control cabin? Or can the panel monitor and control multiple functionalities (for instance, line wiper, tool catcher, GIH, and BOP)? Answer: No failure of the associated systems related to one well barrier shall hinder or impede the functionality of the other well barrier. And the associated systems of the safety head shall t be combined with any other functionality. The only exception is the allowance of combining the systems of the safety head and the BOP. A remote control panel located inside the control cabin shall satisfy these requirements. Hence, monitoring and control of the pressure control head can be combined with support functions like line wiper and tool catcher but t with the safety head. NORSOK

5 8.2 Grease injection Why has the grease injection capacity been tripled from Revision 1 of NORSOK D-002? Answer: Deepwell demonstrated in 2010 the insufficiency of the old requirement (0.25 liter/min) to provide a robust seal around a moving wire. These tests were done as a result of two incidents at Srre and Statfjord. They were performed with various types of grease and at different temperatures. Further testing in 2011 showed that 0.75 liter/min is sufficient for robust sealing. Does the standard require the rated grease flow simultaneously from all installed grease pumps? Answer: No. The standard does t require the rated grease flow simultaneously for all pumps. It does require that each pump individually can supply more than 0.75 l/min at the maximum anticipated operating pressure and that the change-over from one grease pump to ather is possible without reducing the injection pressure. 8.9 Pressure test pump Why is a pressure of 1000 psi required for the high flow filling? Answer: The 1000 psi requirement for the highest pump rate is a misspelling. It should say 100 psi and will be updated in the next revision Wellhead pump Does NORSOK D-002 require a minimum safety integrity level required for a pump or a local ESD used to control the HMV and / or DHSV in intervention mode? Answer: No. The safety head is the only function requiring a minimum safety integrity level (SIL) for well intervention according to the standard. If the HMV is defined as the safety head it requires a local control panel satisfying SIL2. If the HMV is t defined as the safety head it is ordinarily t a well barrier element during well intervention (except during rig-up and rig-down) and requires therefore minimum safety integrity level. The same considerations are valid for the DHSV. NORSOK