Abstract: A two-port, coaxial, waveguide flowline sensor for transmitting TEM mode electromagnetic radio frequency signals through borehole fluids flowing through a longitudinal flowline cavity of the waveguide. The waveguide flowline sensor responds to changes in the conductivity, dielectric constant, and state of the fluid at high borehole temperatures and pressures. The sensitivity of the sensor is enhanced by impedance mismatches between two feedthrough waveguides comprising the ports of the sensor, and a flowline cavity waveguide.

Abstract: A computer-aided method for providing a de-aliased output data set d.sub.L (t,x.sub.L,y.sub.L) from a spatially aliased, three-dimensional, input data set of known seismic signals, a(t,x,y), where L is an interpolator. The known data set is zero-padded by L. The zero-padded data set is zero-masked. The zero-padded data set is divided by a zero-padded, zero-masked data set to provide an interpolation operator H.sub.L. L-1 zero traces are interleaved between the known traces of data set a(t,x,y) to provide a zero-inserted data set c.sub.L ((t,x.sub.L,y.sub.L) whose transform is C.sub.L (m,k.sub.xL,k.sub.yL). The product of (H.sub.L) with (C.sub.L) is (D.sub.L) which is inverse-transformed to provide the desired de-aliased data set d.sub.L (t,x.sub.L,y.sub.L).

Abstract: An improved check valve for selectively controlling the flow of fluid through a valve seat. A spring biases a plunger against the valve seat when the fluid is stationary. Movement of the fluid pushes the valve plunger against the spring to open the aperture of the valve seat. An actuator selectively exerts a force against the plunger to close the plunger against the valve seat. In one embodiment of the invention, the actuator directs a pressurized fluid against a second end of the plunger, and a seal prevents leakage of such fluid toward the plunger first end in contact with the valve seat. A cavity between the seal and the plunger first end can be vented to the atmosphere to maintain the pressure differential created by the pressurized fluid against the plunger second end.

Abstract: A method of correcting receiver signals in an induction well logging instrument for skin effect. The method includes determining a magnitude of signals induced in an induction receiver at each one of a plurality of different frequencies, determining a relationship of the magnitudes with respect to frequency, and determining a skin effect corrected conductivity by determining a value of the relationship which would obtain when the frequency is equal to zero. In a preferred embodiment, the step of determining the relationship includes calculating a best fit curve of the magnitudes with respect to the frequency, calculating the first derivative of the best fit curve with respect to the frequency, and calculating a correction for the signals at a selected frequency according to the relationship of the first derivative with respect to the frequency. The correction is applied to the signal at the selected frequency to calculate a skin effect corrected signal.

Abstract: A method of measuring the density of an earth formation penetrated by a wellbore. The method includes irradiating the earth formation with gamma rays from a source, detecting Compton scattered gamma rays at a plurality of locations spaced apart from the source along the wellbore, calculating an apparent density of the formation from the detected gamma counting rate at each of the locations, calculating differences in apparent density between pairs of the apparent densities, calculating a correction for the apparent density from a distal one of the locations by scaling the differences in apparent density according to an empirical relationship, and calculating the density by combining the correction with the apparent density from the distal one of the locations.

Abstract: A liner for a shaped charge formed from a mixture of powdered tungsten and powdered metal binder. The liner is formed by compression of the mixture into a substantially conically shaped solid body. In a preferred embodiment of the invention, the mixture comprises a range of approximately 70 to 90 percent by weight of tungsten and 30 to 10 percent of the powdered metal binder. In a specific embodiment of the invention, graphite powder is intermixed with the powdered metal binder and tungsten to act as a lubricant. The powdered metal binder preferably comprises a malleable, ductile metal such as lead, bismuth, tin, zinc, silver, antimony, cobalt, nickel or uranium.

Abstract: A method for detecting alteration of earth formations penetrated by a wellbore. The method includes determining a first arrival velocity of dipole acoustic energy propagated through the earth formations. A first frequency dependent velocity of the dipole acoustic energy is then determined. A first dispersion characteristic is determined from the difference between the first arrival and frequency dependent velocities. The method includes determining a frequency dependent velocity and a first arrival velocity for synthesized waveforms for an unaltered formation. The synthesis uses the first arrival velocity of the dipole acoustic energy as a shear velocity. A second dispersion characteristic, related to a difference between the frequency dependent velocity and the first arrival velocity of the synthesized waveforms is determined. The alteration is detected by finding a difference between the first dispersion characteristic and the second dispersion characteristic.

Abstract: A current switch for borehole logging tools operating at high temperatures with high load currents, which includes a driver unit that responds to an input digital control signal by holding an output field effect transistor in a turn-off state until its gate electrode is fully charged before allowing the transistor to supply current to an inductive or acoustic load, and by effecting a rapid discharge of the gate electrode to turn the transistor off. A digital coupler is inserted between the source of the input digital control signal and the driver unit to electrically decouple the load current from the source. The effects of spurious noise contaminants including power spikes in the load, fly-back coupling, and Miller's capacitance thereby are minimized and a switching action with minimal transition time is achieved.

Abstract: A method for logging a subterranean formation from within a well that has been cased and cemented is disclosed. An acoustic signal is transmitted into the formation from a pulse-echo transducer placed within the wellbore and the first casing echo and the first formation echo are detected. The amplitude and the arrival times of these two echoes, combined with some known information about the wellbore, the casing, and the cement enable several parameters to be calculated. These parameters in turn may be used to image the formation around the well.

Abstract: This invention describes a methodology to image features using an array of multiple piezo-electric elements which employs the selective use of mechanical and electronic beam focusing, electronic beam steering and amplitude shading to increase resolution and overcome side lobe effects. This invention introduces a novel signal reconstruction technique utilizing independent array element transmission and reception, creating focusing and beam steering. Application of the methodology can be used in wireline, measurement while drilling, pipe and pipeline and medical applications. Applications include, but are not limited to Bore hole Caliper, Bore hole Geometry, Bore hole Imaging, Casing Inspection, Cement Evaluation and Volumetric Scanning Applications (e.g. Fluid, Behind Casing and Open Hole). The configuration of the transducer array is preferably cylindrical, but may be conical, biconical, convex, concave or may take the form of a number of suitable geometric configurations.

Abstract: A method for using geometrical data to determine characteristics of a wellbore penetrating a subterranean formation is disclosed. The method involves converting data obtained form acoustic well logging into cartesian coordinates and solving a general quadratic equation by a least squares fit to an elliptical or circular model. More specific information, such as tensor strain and formation compaction along the wellbore may then be obtained from the geometrical data.

Abstract: A method of determining an amount of dissolved gas in a fluid sample is disclosed. The method includes hydraulically confining and expanding the sample while measuring pressure and volume. A first volume and pressure are determined at which the rate of change in pressure with respect to volume deviates from a linear relationship. A second volume and pressure at which continued expansion of the fluid causes substantially no change in pressure is determined. The first pressure and volume are extrapolated by the linear relationship to intersect an extrapolation from the second volume and pressure at no change in pressure, thereby determining a bubble point comprising a bubble point pressure and a bubble point volume. A third pressure corresponding to measured pressure of the fluid sample at the bubble point volume is determined.

Abstract: An apparatus for generating a large perforation in a target such as a wellbore casing. A recess in a housing has a closed end and an open end facing the target. A shaped liner in the recess has an apex facing the recess open end, and has a base end facing the closed end of the recess. The shaped liner defines an interior volume filled with explosive material. The explosive material is detonated and expands the liner against the recess wall and forms a perforating jet which moves toward the recess open end. If the recess open end is circular, the perforating jet exits the recess as an annular jet which impacts the target and cuts a plug section from the target. The penetrating power of the jet is confined to the annular cutting area instead of being focused into a conventional jet shape. Multiple shaped liners can be placed in the recess, and the shape of the perforating jet can be modified by the liner shape and recess dimensions.

Abstract: A method of determining volumetric flow rates of gas and liquid in a highly inclined conduit. The method includes measuring the velocity the gas, measuring the velocity of the liquid, calculating a fractional amount of the cross-sectional area of the conduit occupied by the gas and occupied by the liquid, and calculating the volumetric flow rates from the measurements of velocity and from the calculated fractional amounts of the cross-sectional area of the conduit occupied by the gas and by the liquid. In a preferred embodiment, the gas velocity is measured by cross-correlating measurements of two spaced apart temperature sensors after momentarily heating the gas. In the preferred embodiment, the liquid velocity is measured by a spinner flowmeter.

Abstract: An electromagnetic well logging tool for imaging the electrical characteristics of a borehole. A tool inserted into the borehole includes the appropriate mechanical apparatus to align a plurality of transmission lines adjacent to the borehole wall without requiring direct electrical contact. Electrical circuitry applies a step or impulse voltage on one end and samples the reflections at the same end of each transmission line, where the reflections indicate the magnitude of any changes of dielectric constant of the material of the borehole wall. The transmission lines are preferably angled relative to the center line of the borehole for a complete mapping of the circumference. The tool is moved at a desired speed through the portion of the borehole where measurement is desired. The sampling rate of the reflections depends on the desired speed of the tool and the desired resolution of the measurements.

Abstract: A seismic data acquisition system utilizing a plurality of remote units, each remote unit being coupled to a plurality of receivers placed spaced apart on the earth's surface is provided. The remote units acquire seismic data from their associated receivers in response to a seismic shock wave induced at a selected point on the earth and transmit the acquired seismic data to a recorder over a separate channel associated with each receiver. A signature device located at a known receiver location transmits a data sequence containing an embedded time-invariant code that is unique to the signature device to the recorded during the recording cycle. The signature device data sequence and its location are pre-recorded in the recorder. The recorder utilizing the stored data sequence and the data sequence transmitted by the signature device during the recording cycle to map the seismic data channels corresponding to the locations of their associated receivers.

Abstract: A sidewall coring tool for wireline use in an earth bore hole is provided which includes an elongated tool body adapted for suspension within the bore hole by the wireline cable at a selected depth, low speed high torque rotary coring bit apparatus mounted within the elongated tool body and cooperating therewith for advancing and retracting a rotary coring bit transversely therefrom for drilling and recovering a large core sample from the sidewall of the bore hole, and decentralizing arm apparatus mounted in the tool body on the side opposite the side of the body from which the rotary coring bit is advanced, the decentralizing arm apparatus spaced above and below the location of the rotary coring apparatus for deploying decentralizing arms from the tool body into contact with the bore hole walls and forcing the side of the tool body from which the rotary coring bit will be advanced into contact with the bore hole wall and for maintaining the tool body in rigid contact during the coring operation.

Abstract: A well perforating apparatus for generating a plurality of material perforating jets. A base has a plurality of recesses or apertures, and a liner is proximate to the base and is indented into each recess or aperture. Explosive charges contact the indented surfaces of the liner to form multiple shaped charges. A detonator activates the explosive material to collapse the liner segments proximate to the explosive charges and to generate a plurality of perforating jets. In one embodiment of the invention, the base initially comprises a planar material that can be formed into a geometric shape for insertion into a cylindrical housing or wellbore. The invention substantially reduces manufacturing costs and is especially useful in permitting a high density shot pattern to be generated by the perforating jets.

Abstract: Method and system for determining position from suppressed carrier signals transmitted by satellites in which a digital representation of the satellite signals is sampled and distributed for simultaneous measurement in synchronous parallel circuits. The phases of suppressed carriers implicit in the signals are combined in a time series of measurements with phase data from a second receiver to determine position.

Abstract: The present invention is a floatation apparatus with a self-deploying mast for use in a marine towing operation. The invention includes a mast assembly. The mast assembly comprises a shaft adapted to pivotally mount in a storage position on the floatation apparatus, a pair of masts mounted on the shaft forming a structure with front and back sides and dividing the masts into a top section above the shaft and a bottom section below the shaft, pairs of arms and legs projecting perpendicularly from the front of the top section of the masts and from the back of the bottom section of the masts, respectively, a crosspiece connecting the arms to each other and another crosspiece connecting the legs to each other.