CONTENTS xiii 



CBAFTBR FAOB 



10. Electrical Methods (Cont.) 



X. Treasure and Pipe Finders 818 



A. Treasure and Pipe Finders with Separate Excitation 818 



B. (Self-Contained) Treasure Finders 819 



11. Geophysical AVell Testing 825 



I. Electrical Logging 825 



A. Determination of Resistance or Impedance of Formations 825 



B. Determination of Spontaneous Potentials (Porosities) 831 



C. Determination of Resistance of Drilling Mud 834 



D. Measurement of Dip and Strike 834 



E. Determination of Casing Depth 835 



F. Discussion of Results 835 



II. Temperature Measurements 837 



A. Apparatus; Procedure 840 



B. The Universal Geothermal Gradient 845 



C. Thermal Properties of Rocks 847 



D. Heat Generating Processes; Causes of Transient Temperatures. 853 



E. PJffect of Surface Relief and Surface Temperature 860 



III. Seismic Measurements 862 



IV. Miscellaneous Measurements in Wells 863 



A. Determination of Radioactivity 863 



B. Magnetic Measurements 865 



(.'. Acoustic Measurements 866 



D. Fluid-Level Measurements l)y Sound Reflection 867 



K. High-Frequency Measurements in Open Holes 867 



F. Gas Detection 868 



Vx. Photoelecti'ic Measurements 869 



II. Side-Wall Sampler Bulleis 869 



12. Miscellaneous Geophysical Methods 870 



I. Radioactivity Measurements 870 



A. General 870 



B. Radioactivity of Rocks 873 



C. Instruments and Procedure in Radioactivity Exploration 878 



D. Results and Interpretation of Radioactivity Measurements. . . . 883 

 II. Hydrocarbon (Soil and Gas) Analysis 885 



A. Macroscopic and Microscopic Methods 886 



B. Significant Hydrocarbons; Occurrence 888 



C. Gas-Detection Methods 892 



D. Soil Analysis 898 



E. Interpretation and Results of Gas and Soil Analysis 902 



III. Vibration Recording, Dynamic Testing, and Strain Gauging 910 



A. Vibration Recording (Free Vibrations) 912 



B. Dynamic Testing 914 



C. Strain Gauging 928 



IV. Acoustic Methods 934 



A. Atmospheric-Acoustic Methods 935 



B. Marine- Acoustic Methods 943 



C. Geoacoustic Methods 956 



Indexes 965 



