39 Advances in Petrophysics in California Reservoirs
Wednesday, 11 April 2001
10:25 AM - 11:30 AM
MONITORING OIL SATURATION CHANGE WITH CARBON/OXYGEN LOGS IN COMPLEX WELLBORE ENVIRONMENTS IN CALIFORNIA, NIGERIA, AND ANGOLA
Paper number: 39-4
Program: THEME SESSIONS
Time: 11:10 AM – 11:30 AM
Authors
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Dale JulanderChevron USA Production Co, Bakersfield, CA
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Dave BelangerChevron Overseas Petroleum Inc, San Ramon, CA
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Ahmed BadruzzamanChevron Petroleum Technology Co, San Ramon, CA
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Tahmina BadruzzamanPacific Consultants and Engineers, Anaheim, CA
Abstract
One of the primary limiting factors in the estimation of water saturation from Carbon/Oxygen (C/O) ratios is the level of accuracy in the understanding and characterization of the wellbore environment. C/O logs are often run in complex wellbores that are outside the normal range of conditions characterized by the service companies. This paper shows examples of C/O logs from Kern River (California), Angola, and Nigeria that have been recorded in complex wellbore environments, such as: (a) through tubing-casing annuli, (b) large wellbores, (c) through gravel packs, (d) oil-contaminated observation wells, and (e) gas columns. Such environments are not yet characterized by the service companies. The examples serve to document what can be achieved in less than ideal C/O logging conditions.