Application of Continuous Velocity Logs to Determination of Fluid Saturation of Reservoir Rocks

Abstract

Recent studies of continuous acoustic velocity logs indicate that these logs may provide important assistance in differentiating gas, oil, and water saturations in reservoir rocks. In general, velocities are appreciably lower in sands carrying oil or gas than in water‐saturated sands of otherwise similar character. Specific examples from field logs illustrate this application. Laboratory measurements have been made of acoustic velocity of synthetic and natural rocks. Published studies, both empirical and theoretical, of other workers concerned with the transmission of sound in porous media have been considered. All of these at least qualitatively confirm the conclusions drawn from field data.

Study on P-wave and S-wave velocity in dry and wet sandstones of Tushka region, Egypt

“…Hicks and Berry [14] list the parameters influencing velocities in rocks which may be summarized as follows; (1) Rock framework as elastic constant of grains, density of grains, type of cementing material, pressure on skeleton lithology and porosity, (2) Fluid contained in pore spaces as density of fluid, pressure on fluid, and compressibility of fluid and (3) Temperature of medium, where the change in temperature over the range from 25-150°C causes velocity change in dry rock either shale or sandstone causing 5-7% reduction in velocity for saturated cores under equal hydrostatic and skeleton pressure [15]. (4) Depth and elevated overburden pressure, where the velocity increases logarithmically with increasing in depth and rock pressure as well [5].…”

Processing and interpretation of time-lapse seismic data from a heavy oil field, Alberta, Canada

“…They observed lower P-wave velocities in water-saturated rocks at high pressure than in non-saturated equivalents. Hicks and Berry (1956) furthered this work, reporting that decreasing the differential pressure of reservoir rocks resulted in a decrease in P-wave velocity. The increase in differential pressure can be related to SAGD production, where the injection of steam into a reservoir increases the pore fluid pressure, thus reducing the differential pressure between the pore fluid pressure and overburden pressure (Wang & Nur, 1988;.…”

A deep low-velocity body under the Yellowstone caldera, Wyoming: Delineation using teleseismic P-wave residuals and tectonic interpretation

“…(1956,1958) and Hicks and Berry (1956) investigated compressional velocityporosity relations in porous rocks (equant-inclusion case), and Nur and Simmons (1969a) Pokorny (1965) also ,reported results for Woad's metal whose composition was not specified, but was not eutectic. The behavior of velocity is quite similar to that described for systems above.…”

“…In particular, wave velocity and both for compressional and shear waves (Hicks and Berry, 1956;Banthia and others, 1965;King, 1966;Desai and others, 1969). (1956,1958) and Hicks and Berry (1956) investigated compressional velocityporosity relations in porous rocks (equant-inclusion case), and Nur and Simmons (1969a) Pokorny (1965) also ,reported results for Woad's metal whose composition was not specified, but was not eutectic.…”