The Use of Attenuation Standards for CT Scanning
Coles, M.E., Muegge, E.L., Auzerais, F.M., Frulla, P. and Kantzas, A.
SCA Paper No 9513, presented at the 1995 International Symposium of the Society of Core Analysts, San Fransisco, California, Sep. 12-14, 1995.
Use of CT scanning and related technologies to view and characterize reservoir core in conjunction with routine or special core analysis is widespread and increasing. Currently, CT scanning of core materials is accomplished at many different laboratories, utilizing a wide variety of instruments. Drift in the measured attenuation response has been identified and been shown to shift CT values. This reduces the accuracy and reliability of CT results and hinders comparison of data. During the 1994 SCA workshop on CT scanning, routine calibration against attenuation standards was recommended to increase integrity, validity and comparability of results. This paper discusses the need for standards and presents methods used by three different laboratories. Overall recommendations for minimization of errors induced by drift are provided.