Method and apparatus for measuring a cement sample using a single

Abstract

A sample-holding container having a structure that may be heated and internally pressured with water to subject the sample to its anticipated working conditions as the sample is tested. A single, oil-encapsulated transducer transmits acoustic energy waves through a chamber containing the sample and receives reflections of the waves from the chamber floor. The transducer converts the received reflected acoustic waves to an electrical signal that is analyzed to evaluate the sample. Pressurized water in contact with the sample is employed in the chamber to pressurize the sample during the test. A movable, pressure-responsive barrier between the oil encapsulating the transducer and the water pressurizing the sample maintains the transducer and the sample at the same pressure. A thin membrane between the transducer and the sample permits the transducer to be in physical contact with the sample while protecting the transducer from chemical exposure. Pressure differentials across sensitive components are prevented with a self-resetting pressure relief system. The sample material may be a cement slurry with the speed of the acoustic energy waves traveling through the sample and reflected back to the transducer being analyzed to determine the compressive strength of the cured cement. Acoustic energy signal optimization is achieved by maintaining the transducer in contact with the sample, limiting the emitted acoustic energy wave to a primary signal, calibrating the transducer with the chamber, detecting abnormal pressure conditions and fluid movement, and preventing pressure differentials from developing across sensitive components during a pressure leak.