Abstract
In recent years much energy has been directed toward obtaining equations for predicting physical properties of subsurface formations from indirect measurements. One of the most important examples is in the use of the sonic velocity log for predicting porosity. This log records the travel time through a one foot section of formation and this travel time is used in predicting the porosity of the formation. The purpose of the present study was to determine the effects of various factors on the velocity of sound waves in sandstones and to incorporate the information into an equation for calculating the porosity. The factors considered in this study are temperature, confining pressure, shaliness, water saturation and porosity. The approach to this problem was to measure the velocities of sound through 90 sandstone samples at temperatures through 90 sandstone samples at temperatures of 77, 150 and 300°F and under confining pressures ranging from 1,000 to 15,000 psig and to correlate these velocities with the physical properties of the samples by use of regression analysis. Equations were developed for correlating sonic velocity and porosity. The sonic velocity equations show that the factors studied do have an effect on the velocity of sound in sandstones and when these factors are taken into account the average per cent deviation obtained is substantially less than the deviation obtained from the sonic porosity equation now used in sonic log interpretation.
Marek, Benjamin Frank (1969). An experimental investigation of factors affecting acoustic wave velocities in sandstone. Doctoral dissertation, Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -174775.