Laserfiche WebLink
~~ ~ - <br />' ,~'`6~~"'4U UNITED STATES ENVIRONMENTAL FROTEC71ON AGENCY <br />_,~_ g REG10N V111- , <br />~j 9E9 tEth STREET - SUfTE 500 <br />DENVER. CDLOAADD 80202.2466 <br />Nr..• <br />APR 1 ° 1994 <br />SUBJECT: GROUND WATFR SECTION GUIDANCE NO. 34 <br />Cement bend lcccing/~techni es and interpretation <br />FROM: Tom Pike, Chief ~' /Lz...~ <br />UIC Direct Implementatio S~ ection <br />T0: All--Section-Staff --- - - <br />Montana Operations Office ,- _ <br />These procedures are to be follcwed when running and <br />intez-YZeting cement bond loos far injecticn and production (area <br />of review) wells. <br />FART I - PREPARE THE WELL <br />Allow cement to cure fcz a sufficient time to develop full <br />ccmpre9sive strenetfl. A =_afe bet is to let the cement cure <br />for 72 hours. If you run the bond loa before the cement <br />achieves its maxirum ccmpressive strength, the log may show <br />poor bonding. Check cement 2:andbooks for curing times. <br />circulate the Lcle vitL a tlvid (eitLer vater or mud) of <br />uniform consistency. Travel times are influenced by the <br />type of fluid in the hole. If the fluid changes between two <br />points, the travel times may "drift," causing difficulty in <br />interpretation and gvality control. <br />Be prepared to run tLo cep eat Dond log under pressure to <br />reduce tLe effects o! micro-annulus. Micro-annulus may be <br />caused by several reasons, but the existence of a micro- <br />annulus does not necessarily destroy the cement's ability to <br />form a hydraulic seal. If the log shows poor bonding, rerun <br />the log with the slightly more pressure on the casing as was <br />present when the cement cured. This will cause the casing <br />to expand against the cement and clcse the micro-annulus. <br />FART II - PARAMETERS TO LOG <br />Amplitude (mv) - This curve shcws how much acoustic signal <br />reaches a receiver and is an important indicator of cement <br />bond. Record the amplitude on the 3 foot spaced receiver. <br />Travel Lims (pad - This curve shcws the amount of time it <br />takes an acoustic sienal to travel between the source and a <br />receiver. For free pipe of a given size and weight, the <br />travel time between points is very predictable, although <br />variable among different ccmpany's tools. Service companies <br />should be able to provide accurate estimates of travel times <br />for free pipe of a given size and weight. Travel time is <br />required as a quality ccntrol measurement. Record the <br />travel time on Lhe 3 faoL spaced receiver. <br />Rsnr.a on F~erd~/ MM <br />