Baker Hughes Corporation

Piezotech LLC

Eric Molz

Rocco DiFoggio

Philip Lawrence Kurkoski

Frans Lautzenhiser

Constantyn Chalitsios

Volker Krueger

Douglas J Patterson

Vladimir Dubinsky

Robert Alan Estes

James Dallas

Gamal A Hassan

Qianmei Zhang

Mahesh Matam

Jonathan F Hook

William Madigan

Edgar R Alvarez

James E Leggett, Iii

Hayward Atkinson

Srdja Zekovic

Low frequency pulse-echo ultrasonic transducers are provided especially suited for use in downhole cement bond evaluation, but usable for various applications. One frequency pulse-echo ultrasonic transducer comprises a transducer stack having alternating layers of a piezoceramic element and an ultrasonic attenuating element that is preferably acoustic impedance matched to the piezoceramic elements in order to reduce the Q of the transducer stack. Another low frequency pulse-echo ultrasonic transducer comprises an assembly having the present transducer stack disposed on an acoustic attenuating backing and a front face. Yet another low frequency pulse-echo ultrasonic transducer comprises a transducer composite made from a lead metaniobate. Still another frequency pulse-echo ultrasonic transducer comprises a composite stack. A further low frequency pulse-echo ultrasonic transducer comprises a composite stack, wherein multiple drive elements allow driving individual elements at different times. The transducers may be driven in a multiple-pulse time delayed manner.

Low frequency broad band ultrasonic transducers

A device for acoustic measuring in a medium in a borehole such as velocity of sound in the medium or velocity of the medium, includes at least a first acoustic array situated in a first, slanted sidewall of a measuring area and operating to emit a series of acoustic waveforms across a measuring area. In one form, the device includes a second acoustic array situated in a second, slanted sidewall of the measuring area and operating to receive an acoustic signal resulting from the emitted series of acoustic waveforms or to receive said acoustic signal and emit a second series of acoustic waveforms. A the processor measures a time between when a predefined portion of one of the series of acoustic waveforms was emitted and when a predefined portion of the received acoustic signal corresponding to the predefined portion of one of the series of acoustic waveforms is received by the acoustic receiver, and correlates the measured time to a reference time, then outputs a correlation factor for determining the velocity of sound in the medium in the measuring area. The processor may also calculate transit time for the two emitted acoustic signals or echoes from the first emitted acoustic signals to determine medium flow velocity.

System and device for acoustic measuring in a medium

A stepped reflector on the outside of a bottomhole assembly produces two reflections in response to excitation of a transducer. The velocity of the fluid in the borehole is estimated using the two reflections. Alternatively, a change in the gas content of the borehole fluid is estimated from changes in the electrical impedance of a transducer in contact with the borehole fluid.

Early kick detection in an oil and gas well

An apparatus for measuring radiation in a borehole penetrating the Earth, the apparatus includes: a downhole tool having a structure defining a cavity; and one or more radiation detection components integrated into the cavity and configured to measure the radiation. An apparatus conveyable through a borehole for measuring radiation downhole and a method of producing a downhole apparatus for measuring radiation are provided.

Nuclear detectors built directly into shielding or modulating material

A photodiode whose long-wavelength cutoff is in the short-wavelength range (preferably, between ultraviolet and yellowish-green) having reduced temperature sensitivity is used in downhole applications. It may be matched with scintillation devices having an output matched to the response curve of the photodiode for use with nuclear logging devices. The photodiode may also be used in gyroscopes in which light from an LED matched to the photodiode is reflected from a spinning mass.

Downhole navigation and detection system

A logging-while-drilling density sensor includes a gamma ray source and at least two NaI detectors spaced apart from the source for determining measurements indicative of the formation density. An analytic function based on a heuristic model is used to predict the measured response as a function of offset, mud density and formation density. The model may be used to provide a caliper measurement where acoustic caliper data are unreliable.

Compensated caliper using combined acoustic and density measurements

An acoustic attenuator suppresses acoustic signals traveling along the body of a measurement-while-drilling (MWD) tool, making it possible to obtain acoustic measurements relating to underground formations. Shaped cavities (spherical or cylindrical) filled with a fluid have a resonance frequency that is tuned to be within the band of interest thereby attenuating acoustic signals traveling through the body at these resonance frequencies. The staggered arrangement of the cavities increases the path length for the acoustic signals and provides further attenuation. Attenuation may also be accomplished by use of a composite consisting of cylindrical layers of two different materials with thicknesses that attenuate selected frequencies. Additional attenuation is provided by lengthening the path length of a seismic signal passing through the more competent of the two materials of the composite.

Acoustic body wave dampener

Growing community of inventors

Houston, TX, United States of America

Eric Molz