METHOD FOR MEASURING SOUND VELOCITY AND SAMPLE HOLDER

摘要

Method of measuring the velocity of sound in small pieces of rock, in particular drill cuttings of fine grain rock such as clay shale resulting from drilling for oil or gas. Each rock piece (10) is machined on at least two sides in order to form parallel and plane surfaces (10A, 10B) for engagement of ultrasonic transducer heads (1, 2). A transducer head is placed against each of said surfaces, and to one transducer (1) there is applied a drive voltage (3A) which is swept through a frequency range, whereas the other transducer (2) is adapted to receive resulting ultrasonic waves in the rock piece. Corresponding output signals from the other transducer are applied to a recording unit (8) for determination of resonance peaks in the output signal, and the frequency difference DELTA fm between at least two adjacent resonance peaks is taken as a basis for calculating the velocity of sound according to the formula v = 2L DELTA fm, where L is the distance between said parallel and plane surfaces (10A, 10B).