Jerry D. Childs

An Ultrasonic Device for Nondestructive Testing of Oilwell Cements at Elevated Temperatures and Pressures

This paper describes a measuring technique and a hardware system that automatically monitors and records the complete history of compressive strength development and initial set of oil well cement slurries under high pressures and high temperatures (HP/HT). The design is based on the transmission characteristics of ultrasonic compressional waves through cement slurries. In principle, an analyzer measures the transit time (reciprocal of velocity) of an ultrasonic wave pulse through a slurry sample, converts it to apparent compressive strength, and records the results continuously. Compressive strengths, determined from ultrasonic transit time data, have shown deviations equal to or better than those obtained from mechanical tests. Since specimens are not removed and exposed to atmospheric pressure, the results should be more representative of actual downhole conditions. Also, the process promises to be well-suited to strength retrogression studies since there are no time gaps in the test results. Further experimental and analytical work is being carried out to evaluate the potential of this technique for measuring other slurry properties.

The dislociation of iodine monobromide in carbon tetrachloride

Abstract A visible spectral method has been employed to investigate the equilibrium I2 + Br2 = 2IBr in CCl4 solution. The values of the formation constant (K) and the absorptivities of IBr at various wavelengths were inferred from the data. The value of K at 25°C is reported to be 495 ± 42, which corresponds to a degree of dissociation of 8·25 ± 0·34 per cent. This result is intermediate between the two values reported previously. Absorptivities of IBr are given at a number of wavelengths in the range 390–590 nm.