Abstract: Disclosed herein is a method for eccentricity correction. This method may dispose a downhole tool into a borehole. The downhole tool may comprise a measuring assembly that has at least one transducer, determining a beam pattern from the at least one transducer, determining a center of the measurement assembly in the borehole with the beam pattern, calculating a beam pattern factor with at least the beam pattern, calculating an angle factor with at least the beam pattern, calculating an eccentricity factor with at least the beam pattern factor and the angle factor, and creating an eccentricity corrected image with at least the eccentricity factor.

Abstract: A method for generating acoustic images corrected for distortions caused by attenuation of the ultrasonic signal by the mud may comprise disposing a downhole tool into a borehole, transmitting a pressure pulse from at least one transducer into the borehole, recording an echo with the at least one transducer, measuring a travel time, measuring an amplitude, determining a geometry of the borehole, determining a location of the downhole tool in the borehole, calculating an incident angle, mapping a mud attenuation, and correcting an image. A system for generating acoustic images corrected for distortions caused by attenuation of the ultrasonic signal by the mud comprising a downhole tool that may comprise a measuring assembly, wherein the measuring assembly comprises at least one transducer and wherein the at least one transducer is configured to emit a pressure pulse and record an echo. The system may further comprise an information handling system.

Abstract: A method for generating acoustic images corrected for distortions caused by attenuation of the ultrasonic signal by the mud may comprise disposing a downhole tool into a borehole, transmitting a pressure pulse from at least one transducer into the borehole, recording an echo with the at least one transducer, measuring a travel time, measuring an amplitude, determining a geometry of the borehole, determining a location of the downhole tool in the borehole, calculating an incident angle, mapping a mud attenuation, and correcting an image. A system for generating acoustic images corrected for distortions caused by attenuation of the ultrasonic signal by the mud comprising a downhole tool that may comprise a measuring assembly, wherein the measuring assembly comprises at least one transducer and wherein the at least one transducer is configured to emit a pressure pulse and record an echo. The system may further comprise an information handling system.

Abstract: A method for characterizing a sand-pack or gravel-pack in a subsurface formation includes inducing a pressure change to induce tube waves in fluid in a well drilled through the subsurface formation. At a location proximate to a wellhead at least one of pressure and a time derivative of pressure in the well is measured for a selected length of time. At least one of a physical parameter and a change in the physical parameter with respect to time, of the sand-pack or gravel-pack, is determined using the measured pressure and/or the time derivative of pressure.

Abstract: A method for generating acoustic images corrected for distortions caused by attenuation of the ultrasonic signal by the mud may comprise disposing a downhole tool into a borehole, transmitting a pressure pulse from at least one transducer into the borehole, recording an echo with the at least one transducer, measuring a travel time, measuring an amplitude, determining a geometry of the borehole, determining a location of the downhole tool in the borehole, calculating an incident angle, mapping a mud attenuation, and correcting an image. A system for generating acoustic images corrected for distortions caused by attenuation of the ultrasonic signal by the mud comprising a downhole tool that may comprise a measuring assembly, wherein the measuring assembly comprises at least one transducer and wherein the at least one transducer is configured to emit a pressure pulse and record an echo. The system may further comprise an information handling system.

Abstract: A method for characterizing a sand-pack or gravel-pack in a subsurface formation includes inducing a pressure change to induce tube waves in fluid in a well drilled through the subsurface formation. At a location proximate to a wellhead at least one of pressure and a time derivative of pressure in the well is measured for a selected length of time. At least one of a physical parameter and a change in the physical parameter with respect to time, of the sand-pack or gravel-pack, is determined using the measured pressure and/or the time derivative of pressure.

Abstract: A method for processing seismic data includes obtaining a velocity model, determining a critical angle for an interface represented in the velocity model based on a ratio between velocity of the seismic wave on first and second sides of the interface, determining an orientation of a normal vector extending normal to a location of the interface, determining an orientation of an arrival direction vector of a wavefield at the location of the interface, calculating an angle between the normal vector and the arrival direction vector, determining that the angle between the normal vector and the arrival direction vector is greater than the critical angle at the location, and attenuating the wavefield associated with the location in response to determining that the angle between the normal vector and the arrival direction vector is greater than the critical angle at the location.

Abstract: A method comprising for deghosting seismic data is disclosed. The method includes the steps of acquiring seismic data by conducting a survey of a subsurface area of interest wherein the seismic data includes ghost data and estimating a time-varying wave height above the subsurface area of interest during at least a portion of the survey, wherein the estimation of the wave height is based at least in part on a remote measurement of the wave height during the survey. The estimated time-varying wave height is used to characterize the ghost data and deghost the seismic data based at least in part on the characterized ghost data.

Abstract: A method for processing seismic data includes obtaining a velocity model, determining a critical angle for an interface represented in the velocity model based on a ratio between velocity of the seismic wave on first and second sides of the interface, determining an orientation of a normal vector extending normal to a location of the interface, determining an orientation of an arrival direction vector of a wavefield at the location of the interface, calculating an angle between the normal vector and the arrival direction vector, determining that the angle between the normal vector and the arrival direction vector is greater than the critical angle at the location, and attenuating the wavefield associated with the location in response to determining that the angle between the normal vector and the arrival direction vector is greater than the critical angle at the location.

Abstract: A method comprising for deghosting seismic data is disclosed. The method includes the steps of acquiring seismic data by conducting a survey of a subsurface area of interest wherein the seismic data includes ghost data and estimating a time-varying wave height above the subsurface area of interest during at least a portion of the survey, wherein the estimation of the wave height is based at least in part on a remote measurement of the wave height during the survey. The estimated time-varying wave height is used to characterize the ghost data and deghost the seismic data based at least in part on the characterized ghost data.

Abstract: A method includes the steps of receiving a wavefield generated by reflections in a subsurface region and recorded by a plurality of seismic receivers and compensating the recorded wavefield for amplitude attenuation. The method further includes modelling a propagation of a source wavefield forward in time, from an initial time-state to a final time-state through an earth model that is representative of the subsurface region, wherein the modelling includes phase and amplitude effects of attenuation and modelling a propagation of the compensated recorded wavefield backward in time from a final time-state to an earlier time-state through the earth model, wherein the subsurface region has an absorption characteristic that dampens the recorded wavefield wherein the modelling includes phase and amplitude effects of attenuation.

Abstract: A non-compression engine having two or three variable volume mechanisms, an induction-displacer (1) and a combustion-expander (2) or an induction-displacer (1) and a combustion-expander (2) and an atmospheric-cooler (3). A working volume of gas is drawn into the induction-displacer, then displaced into the combustion-expander (2) at substantially constant volume passing through the regenerator (5). The gas in the combustor-expander (2) is further heated by combustion of a fuel then expanded to extract work. The gas is then displaced through the regenerator (5) into the atmospheric-cooler (3) at substantially constant volume, or exhaust from the regenerator at constant pressure. The gas is contracted in the atmospheric-cooler doing atmospheric work. Once the gas has equilibrated with the pressure of the atmosphere it is exhaust from the atmospheric-cooler (3).

Abstract: A method includes the steps of receiving a wavefield generated by reflections in a subsurface region and recorded by a plurality of seismic receivers and compensating the recorded wavefield for amplitude attenuation. The method further includes modelling a propagation of a source wavefield forward in time, from an initial time-state to a final time-state through an earth model that is representative of the subsurface region, wherein the modelling includes phase and amplitude effects of attenuation and modelling a propagation of the compensated recorded wavefield backward in time from a final time-state to an earlier time-state through the earth model, wherein the subsurface region has an absorption characteristic that dampens the recorded wavefield wherein the modelling includes phase and amplitude effects of attenuation.

Abstract: Provided is a three-way valve having and actuator (66) and first (100) and second (102) piston assemblies movable by the actuator (66) and arranged in tandem, wherein each piston assembly (100,102) has a backside (104,106) in fluid communication with a common pressure source for pressure balancing the piston assemblies (100,102). By having the backsides (104,106) in fluid communication with a common pressure source and by isolating the piston assemblies (100,102) from a main chamber, an axial load on the actuator (66) is minimized, thereby allowing for more compact valve designs.

Abstract: Provided is a three-way valve having and actuator (66) and first (100) and second (102) piston assemblies movable by the actuator (66) and arranged in tandem, wherein each piston assembly (100,102) has a backside (104,106) in fluid communication with a common pressure source for pressure balancing the piston assemblies (100,102). By having the backsides (104,106) in fluid communication with a common pressure source and by isolating the piston assemblies (100,102) from a main chamber, an axial load on the actuator (66) is minimized, thereby allowing for more compact valve designs.

Abstract: The invention provides an optical mask (1) for use in blending overlapping tiled images, the optical mask comprising a base (2); an array of elongate sliding elements (10) arranged side by side on the support, each sliding element being independently slidable along an axis and being constrained against lateral translational movement; the mask having a transmission-modifying edge (22) for positioning in a beam of light to modify transmission of the light, the transmission-modifying edge (22) having a profile which is adjustable by moving one or more of the sliding elements (10) along their axes.

Abstract: An objective function is based on covariance of differences in predicted data over multiple sets of candidate model parameterizations that characterize a target structure. A computation is performed with respect to the objective function to produce an output. An action selected from the following can be performed based on the output of the computation: selecting at least one design parameter relating to performing a survey acquisition that is one of an active source survey acquisition and a non-seismic passive acquisition, and selecting a data processing strategy.

Abstract: The invention provides an optical mask (1) for use in blending overlapping tiled images, the optical mask comprising a base (2); an array of elongate sliding elements (10) arranged side by side on the support, each sliding element being independently slidable along an axis and being constrained against lateral translational movement; the mask having a transmission-modifying edge (22) for positioning in a beam of light to modify transmission of the light, the transmission-modifying edge (22) having a profile which is adjustable by moving one or more of the sliding elements (10) along their axes.

Abstract: A non-compression engine having two or three variable volume mechanisms, an induction-displacer (1) and a combustion-expander (2) or an induction-displacer (1) and a combustion-expander (2) and an atmospheric-cooler (3). A working volume of gas is drawn into the induction-displacer, then displaced into the combustion-expander (2) at substantially constant volume passing through the regenerator (5). The gas in the combustor-expander (2) is further heated by combustion of a fuel then expanded to extract work. The gas is then displaced through the regenerator (5) into the atmospheric-cooler (3) at substantially constant volume, or exhaust from the regenerator at constant pressure. The gas is contracted in the atmospheric-cooler doing atmospheric work. Once the gas has equilibrated with the pressure of the atmosphere it is exhaust from the atmospheric-cooler (3).

Abstract: An acoustic source for delivering acoustic energy to a ground formation, particularly a rock formation, the source including (a) a solenoid to generate an electromagnetic field, (b) a bullet positioned within the influence of the electromagnetic field, (c) a casing surrounding and enclosing the solenoid and bullet so that both the solenoid and the bullet are protected from the surrounding environment, in use the solenoid being electrically energized to cause the bullet to be propelled by electromagnetic force so that the bullet impacts an anvil portion of the casing in contact with the ground formation is provided.