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.

Abstract: An free water measurement apparatus and device for measuring the free water that separates from the cement slurry as a matter of time during curing. There is also provided an apparatus and method for measuring the free water that separates from the cement slurry under the temperature and pressure conditions the cement slurry will encounter in the well-bore of an oil and gas well. The apparatus and method provided may further measure the compressive strength measurement of the cement slurry as it is cured.

Abstract: An apparatus and method for using swept frequency energy to inspect a casing or other body is disclosed. A transducer (75) transmits a swept frequency pulse at a casing and receives the reflection resulting from the pulse's impact against the casing. The reflected energy is translated to a reflection signal and analyzed by a signal processor having an envelope detector (240) which translates the reflection signal into an envelope signal. A microprocessor (260) located within the signal processor analyzes the envelope signal to compute data such as the thickness of the casing and the quality of the cement bond holding the casing.

Abstract: A method and apparatus are disclosed for cleaning the wellbore and the near wellbore region. A sonde is provided which is adapted to be lowered into a borehole and which includes a plurality of acoustic transducers arranged around the sonde. Electrical power provided by a cable is converted to acoustic energy. The high intensity acoustic energy directed to the borehole wall and into the near wellbore region, redissolves or resuspends the material which is reducing the permeability of the formation and/or restricting flow in the wellbore.

Abstract: An acoustic formation apparatus is set forth. It utilizes the drill bit on a drill stem as the acoustic source. At a common azimuth and spaced vertically along the drill stem, first and second acoustic transducers are installed. They connect to first and second amplifiers, first and second band pass filters, first and second clipping circuits, a single delay circuit and a cross correlating circuit. The signals are received, filtered, amplified, clipped, one delayed, and then cross correlation is made utilizing variable time delays. The resulting cross correlation function is analyzed using a microprocessor which removes stationary correlation peaks and ignores very short correlation delay times.

Abstract: A porosity measuring MWD system utilizing a source and two detectors is set forth. The source and two detectors are preferably mounted in a stabilizer fin on a drill collar. A standoff measuring device is also included. Dependent on dynamically measured standoff, output pulses from the two detectors are input to storage counters; different counters are selected for different ranges of standoff. Porosity measurements are determined from the counts for variations in standoff measurements; this provides a near/far ratio for ranges of standoff; as the standoff range varies, the counts are directed to different counters. Near/far ratios are determined and represent the apparent porosity; a corrected value of porosity is then determined for each particular range of standoff.

Abstract: An acoustin transducer system for a borehole televiewing apparatus is set forth. In the preferred embodiment, a ceramic circular disc is used and is divided by grooves selected thereon into a set of N concentric rings where N is a whole number integer. Each ring has its own associated transmitter and they are fired in a controlled sequence. Each ring operates as a receiver, and they form output signals which are amplified and controlled delay at the respective delay lines, the several output signals are summed. This assures that the illuminated regions of the borehole is in focus and has a greater depth of field. And a method is also described whereby multiple simultaneous electronically formed acoustic beams are utilized in a differential mode to achieve high spatial resolution in time of flight measurements.

Abstract: A method and apparatus are disclosed for measurement of earth formation dip utilizing sonic techniques. At least three electroacoustic devices are utilized, each having an electroacoustic transmitter and a pair of electroacoustic receivers. The electroacoustic receivers are both located on one side of the transmitter and are preferably located vertically adjacent along a line with the transmitter. Transmitted acoustic energy is detected by the receivers and the elapsed time between detection by a first receiver and detection by a second receiver is determined. A correlation of the variations in elapsed times for each of the three electroacoustic devices is then utilized to calculate the formation dip at various depths.

Abstract: A method and apparatus are disclosed for acoustically investigating a borehole casing cement bond. A sonde is provided which is adapted to be lowered into a borehole and which includes a plurality of acoustic transducers arranged in a helical array around the sonde. A short duration acoustic pulse is directed at the borehole casing from each transducer and the reflection signal generated thereby is coupled to an autoregressive adaptive filter which automatically adjusts its filter coefficients to achieve a desired output signal. The adjusted filter coefficients are then utilized to determine the frequency and decay rate of the reflection signal and the frequency and decay rate of the reflection signal may be utilized to determine selected characteristics of the casing and the cement bond. In a preferred embodiment of the present invention, an additional transducer is mounted a selected distance from a fixed reflector to obtain standard transmission characteristics.