xx
List of Figures
6.63 Acoustic impedance versus depth display . . . . . . . . . . . . . . . . . . . . . . . 199 6.64 Predicting depth of a seismic reflector (courtesy Geophysical Press, from Hardage, B.A.: “Vertical Seismic Profiling, Part A: Principles,” 1983) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199 6.65 Looking ahead of the bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200 6.66 Offset VSP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201 c 6.67 “D” Sand field and geologic cross-section (Copyright 1988, Society of Petroleum Engineers, from Cramer, P.M.: “Reservoir Development Using Offset VSP Techniques in the Denver-Julesburg Basin,” Journal of Petroleum Technology (February 1988)) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202 c 1988, Society of Petroleum 6.68 Survey modeling (Copyright Engineers, from Cramer, P.N.: “Reservoir Development Using Offset VSP Techniques in the Denver-Julesburg Basin,” Journal of Petroleum Technology (February 1988)) . . . . . . . . . . . . . . . . . . . . . . . . . 203 c 1988, Society of 6.69 Multi-offset VSP field plan (Copyright Petroleum Engineers, Cramer. P. M. “Reservoir Development Using Offset VSP Techniques in the Denver-Julesburg Basin,” Journal of Petroleum Technology) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205 6.70 Correlation between model data and zero-offset VSP (Copyright c 1988, Society of Petroleum Engineers, Cramer. P. M. “Reservoir Development Using Offset VSP Techniques in the Denver-Julesburg Basin,” Journal of Petroleum Technology) . . . . . . . . 205 6.71 Final offset VSP data displays; (a) northwest profile, (b) north profile, (c) northeast profile, (d) west profile, and (e) southwest c 1988, Society of Petroleum Engineers, profile (Copyright from Cramer, P.M.: “Reservoir Development Using Offset VSP Techniques in the Denver-Julesburg Basin,” Journal of Petroleum Technology (February 1988)) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206 c 6.72 Results of interpretation of the VSP data (Copyright 1988, Society of Petroleum Engineers, from Cramer, P.M.: “Reservoir Development Using Offset VSP Techniques in the Denver-Julesburg Basin,” Journal of Petroleum Technology (February 1988)) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207 6.73 Topographic mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208 6.74 Contouring techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209 6.75 General contouring rules (numbers on map are two-way times in ms) 210 6.76 Contouring lows and highs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211 6.77 Contouring steeply sloping surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211 6.78 Contours in the presence of faults. Contour interval 10 ms . . . . . . . . . 212 6.79 Structure map derived from sequence of time slices 4 ms apart (courtesy of Occidental Exploration and Production Company) . . . . . 212 6.80 A typical isochron or two-way time interval map. Contour interval 10 ms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213 6.81 Average velocity map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214