Velocity anisotropy of shales and depth estimation in the North Sea basin

摘要: It is known that in the North Sea basin depths to major reflectors as determined from surface seismic data are often larger than well‐log depths. From a study of sets which tie 21 wells, I found strong correlation between occurrence depth error and presence shales subsurface. Assuming caused by elliptical velocity anisotropy shales, measured comparison sonic interval profile obtained also depth. was two methods measurements agree with each other qualitatively previous laboratory shale samples. The results strongly suggest anomaly shales. A simple method correct given.