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.
Pixelated amorphous silicon arrays used for detecting X-rays have a number of special requirements for the readout electronics. Because the pixel detector is a high density array, custom integrated circuits are very desirable for reading out the column signals and addressing the rows of pixels to be read out. In practice, separate chips are used for readout and addressing. This paper discusses a custom integrated circuit for processing the analog column signals. The chip has 32 channels of low noise integrators followed by sample and hold circuits which perform a correlated double sample. The chip has several programmable features including gain, bandwidth, and readout configuration.
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