Changes

Among these, the optical method is omitted from the following discussion because it is confined to boreholes with clear borehole fluids and is rarely used in the petroleum industry.

Among these, the optical method is omitted from the following discussion because it is confined to boreholes with clear borehole fluids and is rarely used in the petroleum industry.

Table 1 summarizes the main characteristics of the two tools discussed in this chapter. The currently available borehole image methods provide only semiquantitative physical measurements and therefore are not suitable for the estimation of bulk rock properties as is done with wireline logs. Because of the two-dimensional nature of borehole images, the principal information is structural, that is, it is pertinent to the geometrical arrangement of rock layers caused by sedimentary and tectonic forces. This makes borehole images powerful tools in the hands of petroleum geologists and reservoir engineers in determining lithofacies types, folds, faults, and fractures influencing reservoir compartmentalization, extent, and performance.

Table 1 summarizes the main characteristics of the two tools discussed in this article, and in the related articles in the ''See Also'' section. The currently available borehole image methods provide only semiquantitative physical measurements and therefore are not suitable for the estimation of bulk rock properties as is done with wireline logs. Because of the two-dimensional nature of borehole images, the principal information is structural, that is, it is pertinent to the geometrical arrangement of rock layers caused by sedimentary and tectonic forces. This makes borehole images powerful tools in the hands of petroleum geologists and reservoir engineers in determining lithofacies types, folds, faults, and fractures influencing reservoir compartmentalization, extent, and performance.

{| class = "wikitable"

{| class = "wikitable"

==Ultrasonic reflection technique: the borehole televiewer==

==Ultrasonic reflection technique: the borehole televiewer==

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file:borehole-imaging-devices_fig1.png|'''Figure 1.''' Borehole televiewer technique.<ref name=pt04r23>Zemanek, J., Caldwell, R. L., Glenn, E. E., Holcomb, S. V., Norton, L. J., Straus, A. J. D., 1969, The Borehole Televiewer—a new logging concept for fracture location and other types of borehole inspection: Journal of Petroleum Technology, v. 21, p. 762–774., 10., 2118/2402-PA</ref>

file:borehole-imaging-devices_fig1.png|'''Figure 1.''' Borehole televiewer technique.<ref name=pt04r23>Zemanek, J., Caldwell, R. L., Glenn, E. E., Holcomb, S. V., Norton, L. J., Straus, A. J. D., 1969, The Borehole Televiewer—a new logging concept for fracture location and other types of borehole inspection: Journal of Petroleum Technology, v. 21, p. 762–774, DOI: [https://www.onepetro.org/journal-paper/SPE-2402-PA 10.2118/2402-PA].</ref>

file:borehole-imaging-devices_fig2.png|'''Figure 2.''' Drill marks (arrow) on borehole televiewer images.

file:borehole-imaging-devices_fig2.png|'''Figure 2.''' Drill marks (arrow) on borehole televiewer images.

file:borehole-imaging-devices_fig3.png|'''Figure 3.''' Borehole televiewer Image showing fracture (arrow) crossing the wellbore.

file:borehole-imaging-devices_fig3.png|'''Figure 3.''' Borehole televiewer Image showing fracture (arrow) crossing the wellbore.

==Electrical borehole scanning: the formation microscanner==

==Electrical borehole scanning: the formation microscanner==

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file:borehole-imaging-devices_fig6.png|{{figure number|6}}Formation MicroScanner technique.<ref name=pt04r5>Ekstrom, M. P., Dahan, C., Chen, M.-Y., Lloyd, P., Rossi, D., 1987, Formation imaging with microelectrical scanning arrays: The Log Analyst, v. 28, p. 294–306.</ref>

file:borehole-imaging-devices_fig6.png|{{figure number|6}}Formation MicroScanner technique.<ref name=pt04r5>Ekstrom, M. P., Dahan, C., Chen, M.-Y., Lloyd, P., Rossi, D., 1987, [https://www.onepetro.org/journal-paper/SPWLA-1987-v28n3a4 Formation imaging with microelectrical scanning arrays]: The Log Analyst, v. 28, p. 294–306.</ref>

file:borehole-imaging-devices_fig7.png|{{figure number|7}}Formation MicroScanner images of cross-bedded sequence showing drill marks (d.m.) at WSW and sawtooth effects (s.e.) on some layers.

file:borehole-imaging-devices_fig7.png|{{figure number|7}}Formation MicroScanner images of cross-bedded sequence showing drill marks (d.m.) at WSW and sawtooth effects (s.e.) on some layers.

file:borehole-imaging-devices_fig8.png|{{figure number|8}}Formation MicroScanner images showing dipping unconformity at contact (arrow) of Cretaceous clastic rocks with Mississippian carbonates.

file:borehole-imaging-devices_fig8.png|{{figure number|8}}Formation MicroScanner images showing dipping unconformity at contact (arrow) of Cretaceous clastic rocks with Mississippian carbonates.