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Evaluation of cement -American Soda #28-21 <br />CBL and CAST tools were tun in the above listed well to evaluate the placement and quality of the cement slurry. CBL/CAST logs were run in both casings, from the base <br />of each string to surface or to the fluid level in the casing string. A cement basket is positioned near the bottom of the shorter string and cement is placed in the annulus from <br />[he cement basket [o near surface. <br />The logs on this well indicate the following: <br />Depth Interval Description Isolation <br />Evaluation CAST <br />Impedance Value CAST <br />Impedance Character CBL Pipe Amplitude MSG pipe signal <br />TD to 1,677' Free Pipe (long string) No isolation I.8 Flat conststent 62, Free pipe value strong <br />1,677' Cement Basket N/A N/A N/A N/A N/A <br />1,677' [0 1,670' Benlonite Plug Good >2 Medium activity < free pipe value Faded Slightly <br />1,670' [0 1,500' Mixture of Spherlite and conventional cmt Good <1 - 5 Med. To high Activity Low, primarily < 10 Faded to none <br />1,500' [0 1,468' Partial cement and free Fluid Poor 2 Flat consistent in spots > good bonded sections Faded Slightly <br />1,468' to 1,066' Good conventional cement Good >3 Medium activity Low, < 10 Faded to none <br />1,066' l0 1,052' Panial cement and free Ouid Poor 2 - 3 Flat consistent in spots 40 - 50, near free value Faded Slightly <br />1,052' to 320' Good conventional cement Good 3 -4.5 Med. To high Activity Low, < 20 Faded to none <br />320' [o [op of log Spherlite cement Good <I - 3 Low activity, consistent < free pipe value Faded < free <br />Circumjerentia/ Acoustic Scanning Too/ (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 to <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 I.5 flat consistent curve response <br />Drilling Mud I.5 - 2.5 Flat consistent curve response <br />Lightweight Cements 4 - 4 high activity curve response <br />Conventional Cements 2 - 6 medium to high activity curve response depending consistency of slurry <br />Cement Bond Lag (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 not completely disappear in lightweight cement as in conventional cements. <br />Respectfully, <br />Tom Riebel <br />Halliburton Energy Services <br />