. Early geophysical papers of the Society of Exploration Geophysicists. Petroleum; Prospecting. ADVANCES IN OIL PROSPECTING 153 ment by the Swedish American Prospecting Corporation. As seen from Figure 20, in electrical vertical drilling by the Racom method, forma- tion boundaries are represented by peaks in the ratio curves. Plotting the data as done in Figure 35, that is, ratios higher than one, on the right, and ratios lower than one, on the left, a comparison with Figure 20 shows that a peak on the right means a poor conductor below that peak, and a peak on the left means a good conductor
. Early geophysical papers of the Society of Exploration Geophysicists. Petroleum; Prospecting. ADVANCES IN OIL PROSPECTING 153 ment by the Swedish American Prospecting Corporation. As seen from Figure 20, in electrical vertical drilling by the Racom method, forma- tion boundaries are represented by peaks in the ratio curves. Plotting the data as done in Figure 35, that is, ratios higher than one, on the right, and ratios lower than one, on the left, a comparison with Figure 20 shows that a peak on the right means a poor conductor below that peak, and a peak on the left means a good conductor below the peak. Thus it is readily seen that the sandstones are poorer conductors than the shales, which is in accordance with an observation which was 3»« >Ti - Xee _ isn _. Fig. 35.—Results of electrical vertical drilling and corresponding geologic section at Spring Coulee, Alberta, Canada. Potential-drop-ratio method was used. (From pamphlet of Swedish American Prospecting Corporation.) previously made when discussing the results represented in Figure 31. It is also seen from Figure 35 how well the electrical results check the well data and how the electrical vertical drilling by means of the potential-drop-ratio method may be used to advantage in carrying the structural data obtained from wells into unknown territory. 3. RESISTIVITY CORRELATION IN WELLS In discussing the results which have been obtained on structure with the resistivity and potential-drop-ratio methods the experience obtained by measuring resistivities in wells should by no means be overlooked. In the first place, the results obtained by determining the resistivities in situ at the depths reached by the drill, give very 483. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Society of Exploration Geophysicists. Tulsa
Size: 2030px × 1230px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bo, bookcentury1900, booksubjectpetroleum, booksubjectprospecting
