Halliburton Company

Halliburton Energy Services, Inc.

Halliburton Logging Services, Inc.

The Superior Oil Company

A J Mallett

John W Minear

Batakrishna Mandal

James Robert Birchak

Dennis E Roessler

Eugene J Linyaev

Carl A Robbins

David H Weinstein

Monroe Alfred Ashworth, Iii

A LWD tool is disclosed for detecting the existence of and distance to adjacent bed boundaries. A transmitter assembly generates either a short acoustic pulse or a swept frequency signal that is detected by an associated receiver assembly. The received signal(s) are conditioned and converted to high precision digital signals by an A/D converter. The digitized signals are accumulated and transferred to a digital signal processor via a high speed data bus. The digital signal processor also receives a digital signal representing the transmission signal and compares the transmission signal and the received signals together to enable a downhole microprocessor to derive a time lag for the received signals. The microprocessor can transmit the time lag signal to the surface via a mud pulse for real-time control, or can operate as part of a closed loop drilling system to automatically control inclination of the drilling assembly to stay within, or to enter, a pay zone based upon the time lag associated with the received signals, and the measured speed of sound of the formation. In one embodiment, the receivers in the receiver array are steered to investigate various volume cells in the formation. A time delay is determined based on the volume cell, which is used to align and sum the received signals. The maximum sum value then is used as indicative of a bed boundary in that particular volume call.

Acoustic logging while drilling tool to determine bed boundaries

Disclosed is a sonic well tool for performing acoustic investigations of subsurface geological formations penetrated by a borehole, and a method of logging formation data. The well tool generally includes a longitudinally extending body for positioning in said borehole. The tool also includes a transmitter supported by the body for transmitting acoustic energy, and at least two receivers. One of the receivers is positioned on the interior of the sonic tool to receive the acoustic signals that traverse the sonic well tool. The second receiver is positioned on the exterior of the sonic tool and receive sonic signals that traverse the sonic tool and those that traverse the formation. The apparatus further includes a processor for subtracting the well tool signal of the first receiver from the combined well tool and formation signal of the second receiver.

Acoustic noise cancelling apparatus for well logging and method of well

This disclosure is directed to a displacement amplifier for forming acoustic pulses and more particularly to one which incorporates a flexible movable lightweight diaphragm of rectangular configuration. It has upper and lower ends which are connected to opposing piston rods driven by duplicate pistons and double acting cylinders. The cylinders are located at opposite ends of the diaphragm or membrane. They are supported in an elongate tool which positions the flexible membrane in a generally rectangular window. This enables the membrane to flex as the pistons are driven, thereby enabling the flexure of the membrane to form dipole source for radially directed compression waves transmitted from the membrane in the window.

Displacement amplified acoustic transmitter

For use in acoustic logging, an acoustic wave transducer system forming both compression and shear waves is disclosed, the system having the preferred form of a plurality of radially directed magnetostrictive expansion means, being N in number, each having a transducer plate affixed to the outer end thereof and further including means for providing a current to a coil wound thereabout forming flux initiating magnetostrictive expansion and contraction to form compression or shear waves.

Transducer forming compression and shear waves for use in acoustic well

For use in an acoustic logging tool having a sonde adapted to be lowered in a borehole, an improved acoustic transducer comprising a pyramidal frustrum is disclosed. The preferred embodiment incorporates fifteen sides. Each side mounts a piezoelectric crystal for receiving. Mechanical resonant frequencies of the transducer are outside the receiver band width which is about 25 kHz. The resonant frequencies are above 25 kHz, thereby avoiding primary resonant frequencies within the band width.

Wide band acoustic receiver transducer

For use with an acoustic transmitter in an acoustic well logging tool, an improved transducer modification circuit is set forth in the preferred and illustrated embodiment. The circuit of this disclosure modifies the diameter resonant frequency of a piezoelectric transducer, thereby expanding the frequency range downward for the transmitter transducer by moving the diameter resonant frequency.

Resonant frequency modification of piezoelectric transducers

An acoustic energy mode propagation speed or travel time measurement system for use in well logging is disclosed. A downhole sonde is provided with an acoustic transmitter and at least one acoustic receiver. The transmitter is repetitively driven with a unique or characteristic swept frequency signal. Propagated acoustic energy detected at the receiver is cross-correlated with the characteristic transmitter swept frequency signal to provide indications of the arrival of various modes of acoustic energy propagation at the receiver. Logs as a function of borehole depth of the speed of propagation of the various modes of propagation may be derived.

Swept energy source acoustic logging system

A method and apparatus for seismic geophysical exploration including a seismic energy source, a control means, a plurality of geophones, and a plurality of geophone monitoring means, all located in a selected survey area. Each geophone monitoring means is positioned in relatively close physical proximity and electrically coupled to one or more of the geophones forming a set of geophones. The control means is utilized to generate electrical signals containing data initiating the operation of the seismic energy source and the plurality of geophone monitoring means. The electrical signals generated by the various geophones in a set responsive to a particular shot of the seismic energy source are received by the associated geophone monitoring means. Apparatus contained within the associated geophone monitoring means samples such geophone signals and produces representative data in digital form. The digitized data is stored in a memory device contained within the geophone monitoring means. When the geophone monitoring means receives electrical signals from the geophones responsive to a subsequent shot of a seismic energy source, these electrical signals are sampled and digitized. The stored data from the previous shot is withdrawn from the memory device and the data representative of the subsequent shot is summed thereto. The summed data is then accessed to the memory device. The procedure is repeated successively until the data representative of a selected number of shots has been summed. The cumulatively summed data is then accessed to a recording device also contained within the geophone monitoring means and a record is made of such summed data.

Growing community of inventors

Houston, TX, United States of America

A J Mallett