USIT-CBL – Identify microannulus See this real example where:
USIT-CBL was run in 7 in casing, common cement G type.
Fresh water as borehole fluid (8.4 ppg)
Two passes were performed (0 and 1000 psi)
Extra pass represented 1.5 hr more operating time
Interval from 10250 to 10300 ft shows a microannulus USIT-CBL COMBINATION DOES NOT NEED PRESSURE IN CASING!
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USIT-CBL – Identify microannulus USIT-CBL real example. Two passes (0 and 1000 psi) CBL 0 psi (see bond index curve) CBL high reading + USIT good bond = microannulus CBL 1000 psi (bond index reduced) Microannulus checked
USIT Remains th e SAME
S c h l u m b e r g e r P r i v a t e
USIT-CBL – Identify microannulus An extra pressure pass means
Pressure test to wireline equipment and rig equipment
Unnecessary pressure exerted to casing (this can be avoided)
Extra pass – extra time (going down, log up, etc) AN EXTRA PASS MEANS MONEY $$$
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USIT-CBL – Identify microannulus
USIT-CBL (0 psi)
Black curve on track one is CBL amplitude coming from sonic tool.
Black curve on cement (USIT) map is the bond index curve coming from sonic tool as well.
IF CBL SHOWS BAD CEMENT AND USIT SHOWS GOOD BOND THIS MEANS MICROANNULUS!
