Summary
Focused resistivity logging tools, such as Laterolog 7, have been used extensively, because they record large deflections—as compared with those for the unfocused normal and lateral sondes—against highly resistive thin formations. These large deflections, however, do not signify any inherent superiority of these tools, but are the result of using a set of fictitious and genetically unrelated currents in the apparent resistivity formulae—currents that do not exist in the ground at the time of measurement, do not ensure the necessary condition for null or near-null of potential, and do not generate the measured potential. When the real currents are used, the apparent superiority disappears altogether. By a suitable manipulation of the apparent resistivity formulae, even the normal or the lateral device can be made to yield large deflections.
It is also demonstrated that (i) the unfocused two-electrode normal sonde has a far larger radius of investigation than the ‘focused’ seven-electrode Laterolog 7 of equal spacing; (ii) the response of any sonde, focused or unfocused, can be synthesised exactly from that of a normal device of suitable spacings; (iii) Laterolog interpretation charts, published by different companies or by the same company at different times, exhibit very wide variations; and (iv) the extraordinarily high refinement of present-day resistivity log interpretation is inconsistent with the drastic simplifications, idealisations and other ambient factors governing the complex logging problems.
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References
ANON. (1950). Interpretation Handbook for Resistivity Logs, Document No. 4, Schlumberger Well Surveying Corporation, USA.
ANON. (1955). Resistivity Departure Curves (Beds of Infinite Thickness), Document No. 7, Schlumberger Well Surveying Corporation, USA.
ANON. (1958). Introduction to Schlumberger Well Logging, Document No. 8, Schlumberger Well Surveying Corporation, USA.
ANON. (1969) (i) Log Interpretation Principles, Schlumberger Limited, USA.
ANON. (1972) (ii) Log Interpretation Charts, Schlumberger Limited, USA.
APPARAO, A. and ROY, A. (1973). Field results for direct-current resistivity profiling with two-electrode array, Geoexploration, 11, 21–44.
ARCHIE, G. E. (1942). The electrical resistivity log as an aid in determining some reservoir characteristics, Petroleum TechnoL, 5, TP 1422, 54–62.
DOLL, H. G. (1951). The laterolog: a new resistivity logging method with electrodes using an automatic focussing system, J. Petroleum TechnoL, 3, TP 3198, 305–16.
Go INTERNATIONAL (1972). Log Interpretation Reference Data Handbook, Gearhart-Owen Industries Inc., USA.
GUYOD, H. (1964). Factors affecting the responses of laterolog type logging systems (LL3 and LL7), J. Petroleum TechnoL, 16, 211–19.
GUYOD, H. (1966). Examples of current distribution about laterolog sondes, Log Analyst, 7, 27–33.
HALLIBURTON OIL WELL CEMENTING COMPANY (1952). Guard Electrode Logging, Electrical Well Services Laboratory Bulletin, April 1952, Duncan, Oklahoma, USA.
LYNCH, E. J. (1962). Formation Evaluation. Harper and Row Publishers, New York, Evanston and London, 422 p.
MORAN, J. H. (1976). Comments on ‘New results in resistivity well logging, Geophysical Prospecting, 23, 426–448’.
MORAN, J. H. (1976). Comments on ‘New results in resistivity well logging, Geophys. Prospecting, 24, 401–2’.
MORAN, J. H. and CHEMALI, R. E. (1979). More on the laterolog device, Geophys. Prospecting, 27, 902–30.
OWEN, J. E. and GREER, W. J. (1951). The Guard Electrode logging system, J. Petroleum Technol., 3, TP 3222, 347–56.
PLRSON, S. J. (1963). Handbook of Well Log Analysis for Oil and Gas Formation Evaluation. Prentice-Hall Inc. USA, 326 p.
ROY, A. (1974). Correction to ‘Radius of investigation in DC resistivity well logging, Geophysics, 36, 754–760’
ROY, A. (1974). Correction to ‘Radius of investigation in DC resistivity well logging, Geophysics, 39, 566’
ROY, A. (1975). New results in resistivity well logging, Geophys. Prospecting, 23, 426–48.
ROY, A. (1977). The concept of apparent resistivity in Laterolog 7, Geophys. Prospecting, 25, 730–7.
ROY, A. (1978). A theorem for direct current regimes and some of its consequences, Geophys. Prospecting, 26, 442–63.
ROY, A. (1980). On some resistivity log interpretation charts, Geophys. Prospecting, 28, 453–91.
ROY, A. and APPARAO, A. (1971). Depth of investigation in direct current methods, Geophysics, 36, 943–59.
ROY, A. and APPARAO, A. (1976). Laboratory results in resistivity logging, Geophys. Prospecting, 24, 123–40.
ROY, A. and APPARAO, A. (1978). Reply to comments on ‘New results in resistivity well logging’ and ‘Laboratory results in resistivity logging’, Geophys. Prospecting, 26, 481–4.
ROY, A. and DHAR, R. L. (1971). Radius of investigation in dc resistivity logging, Geophysics, 36, 754–60.
ROY, A. and DHAR, R. L. (1974). Radius of investigation in dc resistivity logging, Errata in Geophysics, 39, 566
WELEX INCORPORATED, (i) Bulletin A101, Interpretation Charts for Electric Logs and Contact Logs, and (ii) Bulletin A127, Application of Radiation-Guard Surveys to Carbonate Reservoirs, Fort Worth, Texas, USA. Dates of publication not given.
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© 1982 Applied Science Publishers Ltd
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Roy, A. (1982). Focused Resistivity Logs. In: Fitch, A.A. (eds) Developments in Geophysical Exploration Methods—3. Springer, Dordrecht. https://doi.org/10.1007/978-94-009-7349-7_3
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DOI: https://doi.org/10.1007/978-94-009-7349-7_3
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