Page 148 - Well Control for Completions and Interventions

140 Well Control for Completions and Interventions

from 5000 psi components. Similarly, the working pressure of surface
BOP equipment will sometimes be higher than the wellhead to which it
is attached. Working pressure limits must be defined by the rating of the
weakest component in the system.
In addition to the pressure classifications, the API list component
codes that are used when describing a BOP stack configuration. These
are:
A 5 annular preventer.
G 5 rotating head.
R 5 single ram type BOP with one set of rams, blind or pipe depend-
ing on operator preference.
R d 5 double ram type preventer with two sets of rams, blind or pipe
depending on operator preference.
R t 5 triple ram type preventer with three sets of rams, blind or pipe
depending on operator preference.
CH 5 high remotely operated connector attaching wellhead or
preventers.
CL 5 low pressure remotely operated connector attaching; the marine
riser to the BOP.
S 5 spool with side outlet for choke and kill lines.
M 5 1000 psi.
These codes can be used to describe how a BOP is, or needs to be,
configured. By convention the code should be listed from the bottom of
5
the stack upwards. For example, 15 M 13/8 in. RSRRA refers to a stack
5
that has a 15,000 psi working pressure with a through bore of 13/8 in.
(13.625). It is equipped (bottom to top) with a ram preventer, drilling
spool, ram preventer, ram preventer, and annular preventer. The abbrevi-
ated description does not provide any information about the type of ram
preventers used.
Figs. 4.1 4.3 show example API configurations for each pressure clas-
sification. It should be noted that these configurations represent the mini-
mum requirement for each working pressure classification. Different
operators and drilling contractors often have more stringent requirements.
Similarly, more stringent requirements are called for by some regulatory
authorities. For example, the NORSOK minimum requirement for
2
BOPs is one annular preventer, one shear/seal ram, and two pipe rams.
1. Up to 2000 psi (13,800 kPa) working pressure
For pressure below 2000 psi the minimum requirements are:
• Annular preventer and a ram preventer or two-ram preventers.