Отправлено: 04.02.09 07:12. Заголовок: Formation water saturation from drilling fluid filtrate invasion: comparison of displacement modelli

Journal of Petroleum Science and Engineering
Vol: 15, Issue: 2-4, August, 1996 Bibliographic Page pp. 251-259

Title: Formation water saturation from drilling fluid filtrate invasion: comparison of displacement modelling and induction well log response
Authors: Bilardo, U.a; Alimonti, C.a; Chiarabelli, A.b; Caetani, F. Colacicchia
Affiliations: a. Universitа di Roma “La Sapienza”, Fac. Ingegneria, Dip. I.C.M.M.P.M. 18, via Eudossiana, 00184, Roma, Italy
b. AGIP S.p.A., Servizio LOGE, 20097 S. Donato Milanese (MI) P.O. Box: 12069-20100, Milano MI, Italy
Abstract (English): One goal of log measurements is to determine the degree of water saturation in oil- and gas-bearing beds, which can be calculated using resistivity logs and Archie's equation if the formation resistivity (Rt) is known. The measurement of Rt presents many difficulties:

(1) During drilling, the penetration of drilling fluids into the formation will influence the measured resistivity values; this is known as the invasion effect.

(2) In oil- and gas-bearing beds having a thickness less than the vertical resolution of the log instrument, the measured resistivity value will also be influenced by the presence of more conductive clayey layers; this is known as the shoulder effect.


This paper presents a numerical model that aids in the interpretation of log results from thinly-layered formations, giving water saturation curves for the units of interest.

For a series of gas-bearing horizons, the simulated water-content distribution has been compared with the saturation values obtained using a resistivity log instrument; this comparison has allowed an assessment of the shoulder and invasion effects.

Publisher: Elsevier Science
Language of Publication: English
Item Identifiers: 10.1016/0920-4105(95)00079-8 0920-4105(95)00079-8
Publication Type: Article
ISSN: 0920-4105
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