Abstract: A method of seismic data processing is described in which a particular wavelet is selected from a plurality of wavelets as being most characteristic of a received seismic signal. A subtracted signal can be determined by subtracting a weighted signal of the particular wavelet from the received signal. From the subtracted signal, an additional particular wavelet can be chosen. The process of subtracting a signal and determining an additional particular one of the plurality of wavelets can be repeated until a criterion is met. The method can be repeated at several depths. The resultant spectral analysis can be used to determine, for example, an absorption coefficient.

Abstract: A tool which is capable of measuring parameters of a multi-phase flowstream without substantially restricting the flow in the wellbore is disclosed. The tool is comprised of a plurality of extendable arms which are radially spaced around and pivotably mounted in a housing so that each arm is extendable from the housing into the flowstream in the wellbore. Various types of sensors, e.g. flow sensors, capacitance sensors, temperature sensors, etc., can be used either alone or in combination which are carried at or near the outer ends of each of the arms whereby the sensors will be deployed from the housing into the flowstream by the arms without substantially restricting the flowstream through the wellbore.

Abstract: A fluid flow measuring or so-called production logging instrument for fluids produced in a well includes an inflatable packer for forming a seal in the wellbore to require diversion of wellbore fluid through a passage formed in the instrument whereby fluid flow rate and other fluid properties may be measured. The inflatable packer receives pressure fluid from the tubing string and may be remotely controlled to inflate and deflate, at will, through signals conducted from the surface to the instrument by way of a cable extending through the tubing string. The instrument includes a main wellbore fluid flow passage in which a shutoff valve is disposed for controlling the flow of fluid through the passage and which may be automatically closed or opened in response to actuation of the packer seal.

Abstract: A downhole flowmeter tool adapted to be lowered into a wellbore and expanded to provide a restricted flow annulus around the tool. One or more flow-sensing means are positioned within the annulus to measure flow therethrough.

Abstract: A method for acoustically measuring wall thickness of tubular goods utilizes an acoustical transducer with a large bandwidth and high resonant frequency to measure the thickness of thin walls. The transducer is exposed directly to fluids in the tubular goods and is rotatable 360 degrees to scan the entire circumference of the tubular goods. The transducer is excited and generates an acoustic waveform from the wall under investigation. The acoustic return has a reverberation portion which results from the reverberation of the generated acoustic waveform in the wall. The harmonic frequency content of the reverberation portion is determined and the frequency difference between two adjacent harmonics is determined, from which the wall thickness is determined.

Abstract: A borehole televiewer apparatus includes a housing section having a cavity for the disposition of an acoustic signal transmitting and receiving transducer. An elongated threaded rod is disposed in the cavity and held stationary relative to the housing and supports a nut, a slipring assembly, the transducer and a drive motor assembly for axially translating the transducer and rotating the transducer while precluding rotation of the motor and a support plate therefor relative to the rod. The support plate is keyed to the rod by an elongated key and keyway configuration to prevent rotation of the motor and the support plate while permitting axial translation of the motor and support plate along the rod.

Abstract: Data received from a sonde in a borehole is enhanced by first measuring the relative travel time of a signal transmitted from the sonde and reflected from an area in the wall of a borehole. This measurement is repeated for a plurality of angles in a horizontal plane. From this plurality of travel times a best fit ellipse or circle is calculated and the travel times are correlated with the best fit ellipse or circle to provide corrected travel times and to determine the eccentricity of the sonde in the borehole. The corrected travel times are displayed as images to indicate the detailed shape properties of the borehole.

Abstract: Method and apparatus for measuring formation compressional and shear wave velocities characterized by a downhole tool having an attenuation chamber between a transmitter and a receiver and a plurality of receivers spaced from the transducer so as to discriminate through the amplitude of the reflected compressional wave the critical angles for the respective formation compressional and shear wave velocities, thereby determining the formation compressional and shear wave velocities. Also disclosed are preferred embodiments in which the plurality of connectors connected between the receivers are also connected with a recorder for recording gated time interval signals. A discriminator and gate are provided for discriminating the largest amplitude of received acoustic energy signals received during the gating period.

Abstract: A borehole tool incorporates an ultrasonic flow measuring device which enables calculation of the rate of flow of material through various perforated intervals of a well casing as a function of depth. Fluid flow rate is proportional to the difference in travel time of a pulse-type ultrasonic signal over a fixed distance in opposite directions through the fluid.

Abstract: Apparatus and method for sonic borehole logging using a continuous wave transmitted signal. The transmitted signal is received at a plurality of points distributed along the borehole axis and sampled synchronously with the transmitted signal. The resulting sampled signal is analyzed, for example, by Fourier analysis, to identify each spatial frequency component. Each frequency component identified indicates the velocity of a particular acoustic wave path from the transmitter to the receiver.

Abstract: In the present invention, characteristics of fractures or microcracks in earth formations surrounding a borehole are detected by use of conventional sonic logging devices used in combination with internal variations of wellborne pressure. A sonic logging tool is first used to generate a log of acoustic velocity at a first pressure. Borehole pressure is then changed and a second log is obtained. Significant changes in formation velocity in response to the pressure change indicates the presence of fractures.