A Statistical Comparison Of Cementing Techniques By Use Of Cement Bond Logs

Abstract

This paper is to be presented at the Four Corners Regional Meeting in Farmington, New Mexico, September 9–10, 1966, Amarillo Regional Meeting in Amarillo, Texas, October 27–28, 1966and at the California Regional Meeting in Santa Barbara, California, November 16–19, 1966, and is considered the property of the Society of Petroleum Engineers. Permission to publish is hereby restricted to an abstract of not more than 300 words, with no illustrations, unless the paper is specifically released to the press by the Editor of the Journal of Petroleum Technology or the Executive Secretary. Such abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the Journal of Petroleum Technology or Society of Petroleum Engineers Journal is granted on request, providing proper credit is given that publication and the original presentation of the paper. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines. Abstract The determination of optimum cementing technique is possibly the most valuable use for Cement Bond Logging. This con be accomplished through the use of a large number of bond logs made on wells where various cementing procedures were employed. Cement Bond Logs representing almost one-half million feet of cemented casing are herein used to compare the efficiencies of various cementing techniques. The study includes 352 bond logs from seven states. Results show that, in the average well, 71 percent of the cemented interval shows good bonding. Little variation is found to occur between overage percentage of bonding and geographic area, setting time, well temperature below 300 degrees F and depth. Rather wide variations are shown between percentage of bonding and the various oil companies, cement types, cement additives, mud types and casing size. The data presented appear to justify increased use of bond logs for selection of optimum cement type, cement additives, casing size, slurry weight and in consideration of other cementing variables. Only primary, single stage, cement jobs are studied so as to avoid using data influenced by squeeze cementing and fill-up problems. All logs studied employ the some type of equipment and calibration techniques. "Good bonding" and "cemented interval" are defined. Each log studied is assigned a numerical value of percentage of good bonding within the cemented interval. CBL (Cement Bond Logging) calibration methods and tool response are discussed to show that the quality of cement bonding in one well may be logically compared to that of other wells. An overage percentage of bonding from all wells studied is calculated and tabulations are made for each of the following variables: Geographic Location Cement Type Cement Volume Cement Additives Depth Range Slurry Weight Setting Time Caring Size Oil Company Maximum Temperature Measured Mud Type