Laserfiche WebLink
Evaluation of cement -American Soda #29-29 <br />CBL and CAST tools were run in [he above listed well to evaluate the placement and quality of the cement slurry. CBL/CAST logs were mn in both casings, from the base <br />of each string to surface or to the fluid level in the casing string. A centen[ basket is positioned near the bonom of the shorter string and cement is placed in [he annulus from <br />the cement basket [o near surface. <br />The logs on [his well indicate the following: <br />Depth Interval Description Isolation <br />Evaluation CAST <br />Impedance Value CAST <br />Impedance Character CBL Pipe Amplitude MSC pipe signal <br />TD l0 1,890' Free Pipe (long string) No isolation I.5 Fla[ consistent 62, Free pipe value strong <br />1,890' Cement Basket N/A N/A N/A N/A N/A <br />1,890' [0 1,884' 8entonite Plug Good 2 Medium acnvtty < free pipe value Faded Slightly <br />1,884' [0 1,736' Mixture o(Spherlite and conventional cmt Good <l -4.5 Med. To high Activity Low, primarily < 10 Faded to none <br />1,736' 10 1,716' Spherlite cement Good < I Low to medium activity < Gee pipe value Faded < free <br />1,716' to 1,634' Mixture o(Spherlite and conventional cmt Good <I - 4 Med. To high Activity Low, primarily < I S Faded <br />1,634' to 1,540' Conventional cement Good 3 - 5 Medium activity Low, < 10 Faded to none <br />1,540' [0 1,524' Partial cement and free fluid Poor 1.8 - 2 Flat consistent in spots Up to30 < Gee pipe value Strong <br />1,524' [0 550' Conventional cement Good 3 -4.5 Medium activity Low, primarily < 20 Faded to none <br />550' [0 235' Mixture of Spherlite and conventional cmt Goad <I - 3 Med. To high Activity < Gee pipe value Faded Slightly <br />X35' [o lop of log Spherlite cement Fair <I - 2 Low activity < Gee pipe value Strong <br />Circamjerenrial Acoustic Scanning Tool (CAST) impedance values for fluids are very consistent and manifests itself as a fairly straight line on the log. Cement slurries, <br />are more variable and show up as curves with much more activity or variability. By analyzing the value and the character of the impedance curves, it is possible [o <br />successfully evaluate the cement quality of conventional and lightweight cements. Typical impedance values for common materials or fluids are: <br />Gas or air <.5 high activity curve response <br />Water 1.5 flat consistent curve response <br />Drilling Mud LS - 2.5 flat consistent curve response <br />Lightweight Cements <1 - 4 high activity curve response <br />Conventional Cements 2 - 6 medium to high activity curve response depending consistency of slurry <br />Cement Bond Log (CBL) tools evaluate cement bonding to pipe and formation by measuring the changes in sound waves traveling through casing, cement, <br />and formation. Log presentations include a pipe amplitude curve and aMicro-Seismogram ®display in the form of light to dark shades. The amplitude <br />curve in lightweight cements will not read as low as published values for conventional cements. Comparisons to lowest value and to free pipe value are <br />necessary to fully evaluate. Pipe signal will no[ completely disappear in lightweight cement as in conventional cements. <br />Respectfully, <br />Tom Riebel, Halliburton Energy Services <br />