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and maintenance cannot be overemphasized. All rig personnel
should be familiarized with BOP operation — their lives could
depend on it.
Thorough testing and maintenance of the BOPs must be
conducted on the surface to ensure a long and dependable
operational life subsea. For surface testing, a test stump carrying
the male profile of the wellhead provides a landing area for the
BOP stack. When the hydraulic connector at the bottom of the
stack is latched onto the stump, all seals may be checked for leaks.
The following should be observed when surface-testing the BOP:
Any special diagnostic procedures recommended by the
manufacturer for each component should be conducted.
The control system should be pressure tested before testing
the BOP.
All components should be tested at rated working pressure.
Pipe rams and annular preventers should be closed around
drill pipe to avoid damaging the seals.
All hydraulic connections and connectors must be
inspected carefully for leaks in pressure testing the BOP stack with
a drill pipe test tool installed in the test stump, it is advisable to
leave the bore of the test tool open to the atmosphere so leaks may
be detected quickly. The open bore also prevents the test tool from
becoming a projectile in the event of thread failure because the test
pressure acts across the effective area of the drill pipe cross section
and considerable upward force is generated.
At the conclusion of the functional and pressure testing, the
BOP stack is disconnected from the test stump and is ready to be
run on drill pipe running tools or on the marine riser (fig. 2.11).
Subsea testing, of course, cannot be as extensive as surface testing.
The frequency of subsea testing may vary with operators as well as
with local regulations governing the minimum frequency of subsea
testing. A test plug run on drill pipe seals off the casing while
testing. Flow from the pipe would indicate a leak in the test plug.
The blind shear rams may be function-tested periodically, but no
satisfactory method is available currently for pressure testing
without high risk of rupturing the casing.

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