Abstract: A method for estimating a permeability of a formation surrouning a borehole comprises applying transient well-test conditions to the borehole. A portion of the formation is excited with an acoustic signal. The acoustic response corresponding to the acoustic exciting is measured with an acoustic receiver located within the borehole. The permeability of the formation is estimated using the acoustic response.

Abstract: Certain embodiments of the present invention provide a system for improved signal processing within a remote sensor system. The system includes a detection component and a processing component. The detection component is adapted to detect an event and generate a signal based at least in part on the event. The processing component adapted to determine an envelope of the signal based at least in part on a situation. Certain embodiments of the present invention provide a method for improved signal processing within a remote sensor system. The system includes detecting an event, generating a signal based at least in part on the event, and determining an envelope of the signal based at least in part on a situation.

Abstract: A method, apparatus and system for acquiring land seismic data includes acquiring seismic data with a first autonomous seismic data acquisition unit and a second autonomous seismic data acquisition unit wherein each acquisition unit comprises a plurality of digitally controlled temperature-compensated crystal oscillators. Oscillator-based timing signals are acquired that are associated with the plurality of digitally controlled temperature-compensated crystal oscillators and a time correction is determined to apply to the seismic data acquired with the first autonomous seismic data acquisition unit. The time correction is determined using the oscillator-based timing signals from the first and second autonomous seismic data acquisition units.

Abstract: A seismic survey apparatus includes a plurality of serially connected electrical nodes; a power supply capable of supplying power to the electrical nodes and detecting a voltage leakage among the electrical nodes; and a software component capable of locating the leakage upon its detection. A method for use in seismic surveying includes powering a plurality of serially connected electrical nodes in a seismic surveying system; automatically detecting a voltage leakage among the electrical nodes on the power domain; and automatically locating the detected voltage leakage.

Abstract: A marine seismic exploration method and system comprised of continuous recording, self-contained ocean bottom pods characterized by low profile casings. An external bumper is provided to promote ocean bottom coupling and prevent fishing net entrapment. Pods are tethered together with flexible, non-rigid, non-conducting cable used to control pod deployment. Pods are deployed and retrieved from a boat deck configured to have a storage system and a handling system to attach pods to cable on-the-fly. The storage system is a juke box configuration of slots wherein individual pods are randomly stored in the slots to permit data extraction, charging, testing and synchronizing without opening the pods. A pod may include an inertial navigation system to determine ocean floor location and a rubidium clock for timing. The system includes mathematical gimballing. The cable may include shear couplings designed to automatically shear apart if a certain level of cable tension is reached.

Abstract: A method of extracting desired features from a cellular image including the steps of: (a) selecting an initial cell within the image; (b) selecting an additional cell, near the initial cell, appearing to be associated with a desired feature; (c) repeating step (b) for further cells, near at least one of the previously selected cells, appearing to be associated with said feature, until selection termination criteria are satisfied; and (d) repeating steps (a) through (c) for other initial cells. The method is particularly adept at extracting relatively weakly defined features in relatively noisy images, such as extracting faults or geologic horizons from 2D or 3D seismic data. A method of editing/filtering the features utilizing a stereo net is also disclosed. Related computer system and computer program products for implementing the method are also described.

Abstract: A method of predicting earthquakes includes the step of positioning a first transducer array adjacent to a seismically active region and below the water table, i.e., within the zone of saturation. The first transducer array includes a first plurality of seismometers, at least one first clock, and at least one first digitizer. The at least one first clock is in communication with at least one of the first plurality of seismometers, and the at least one first digitizer also is in communication with at least one of the first plurality of seismometers. The method also includes the steps of detecting a plurality of wave movements resulting from dilation of the crust of the Earth prior to an earthquake, and converting at least one of the wave movements into a first voltage. The method further includes the step of discriminating between wave movements resulting from dilation of the crust of the Earth and movements resulting from at least one other event.

Abstract: A method and apparatus for estimating a seismic velocity field from seismic data including time-amplitude representations associated with source-receiver locations spaced apart by an offset distance and having a midpoint therebetween, the seismic data being arranged into common midpoint (CMP) gathers associated with respective CMP locations. A control plane having an edge intersecting a plurality of the CMP locations is defined, an initial velocity field for the control plane is produced, the initial velocity field including a plurality of time-velocity values for each of the CMP locations; and an optimized velocity field for the control plane is produced by adjusting the time-velocity values for each of the CMP locations in response to trends, relative to offset distance, in time values, associated with common seismic events, until said optimized velocity field satisfies a condition.

Abstract: A universal seismic data acquisition module includes independent environmental isolation chambers for essential signal processing circuitry and for cable connection unions. Cable connection unions are rapidly replaced without opening the main protective chamber. Different connector types required for the many data transmission cable designs needed to service a wide range of survey conditions are more easily accommodated than in conventional single chamber designs. The module is rugged and suitable for operating in a wide range of physical environments including lake or sea immersion to substantial water depths, desert, arctic and others. Need for investment in multiple module types for varying survey conditions is thereby reduced without compromising capacity.

Abstract: Methods are disclosed employing seismic waves having infrasonic frequencies in the range of about 0.1–20 Hz for generating electromagnetic waves of similar infrasonic frequency in hydrocarbon bearing subterranean formations located at depths up to about 5000 meters, said electromagnetic waves having sufficient voltage amplitudes for detection at the earth's surface. Also disclosed are seismic sources capable of generating infrasonic seismic waves of sufficient amplitude for generating electromagnetic waves in hydrocarbon bearing formations at depths up to 5000 meters, said electromagnetic waves having voltage amplitudes sufficient for detection at the earth's surface.

Abstract: The invention is a method for performing a stratigraphically-based seed detection in a 3-D seismic data volume. The method incorporates criteria that honor the layered nature of the subsurface so that the resulting seismic objects are stratigraphically reasonable. The method may be used to extract from a seismic data volume all seismic objects that satisfy the input criteria. Alternatively, the method may be used to determine the size and shape of a specific seismic object in a seismic data volume.

Abstract: A plurality of heavy mass irregularities attached to an inner wall of the drill collar attenuate waves traveling through the collar. The plurality of heavy mass irregularities are spaced and sized for the maximum attenuation of acoustic pulses in a predetermined frequency range. The mass irregularities may be rings firmly coupled to the outer surface of the collar. Alternatively, the mass irregularities may be rings firmly coupled to the outer collar surface by neck pieces, extending inwardly from the inner circumference of the ring. The mass irregularities may be made of steel or tungsten. In another preferred embodiment, the mass irregularities are asymmetrically coupled to an outer collar wall for providing preferential directional attenuation.

Abstract: A seismic data acquisition module includes a motherboard that is environmentally protected as a independent unit by an integral sheath, envelope or encapsulating cover. The motherboard unit is suitably configured for rapid and frequent manual removal from the interior cavity of a protective outer housing for compact and more secure packaging as well as more convenient transport over great distances, if necessary, to successively different survey sites. At a new survey site, the motherboard units may be inserted into more bulky but also more rugged or waterproof outer housings that are provided with environmentally tight cable connectors. The outer housings, having a capital value of only a fraction of the electronic motherboard units, may have arrived at the new site at a different time and may even be distributed in the new survey field at the time the motherboard units arrive.

Abstract: Method for operating and testing a sensor assembly (210). The sensor assembly (210) preferably includes accelerometers with axes of sensitivity orthogonal to each other. The method preferably includes determining sensor tilt angle, determining the position of the sensor, and synchronizing the operation of the sensor.

Abstract: A method of predicting earthquakes includes the step of positioning a first transducer array adjacent to a seismically active region and at least about 3 meters below the surface of the crust of the Earth. The first transducer array includes a first plurality of seismometers, at least one first clock, and at least one first digitizer. The at least one first clock is in communication with at least one of the first plurality of seismometers, and the at least one first digitizer also is in communication with at least one of the first plurality of seismometers. The method also includes the steps of detecting a plurality of wave movements resulting from dilation of the crust of the Earth prior to an earthquake, and converting at least one of the wave movements into a first voltage. The method further includes the step of discriminating between wave movements resulting from dilation of the crust of the Earth and movements resulting from at least one other event.

Abstract: The present invention relates to an apparatus and a method for analyzing the correlation geophysical data and seismic data, physical data monitoring apparatus and method, and an earthquake monitoring method.

Abstract: An apparatus (10) and method are disclosed for eliminating a noise signal from at least one source during an acoustic measurement of a subsurface geological formation or borehole. The apparatus (10) includes a longitudinal body for positioning in the borehole and a transmitter (22) supported by the body for transmitting acoustic signals into the formation and borehole. A sensor (23), substantially isolated within the body, is used to detect one or more noise signals and a receiver (24) is carried by the body for receiving acoustic signals traversing the formation and borehole, and for receiving one or more noise signals.

Abstract: The invention provides an instrument suitable for measuring seismic waves in an environment which comprises a wave guide through which a seismic wave may propagate substantially without dispersion wherein the wave guide is provided with means for measuring its deformation.

Abstract: An earth penetrating apparatus includes a cutting tool and a sensor housing. A radar unit, rate sensor unit, processor, and transmitter are provided in the sensor housing. An antenna arrangement is coupled to the radar unit and configured for transmitting and receiving electromagnetic signals in a relatively forward and/or lateral looking direction relative to a distal end of the cutting tool. The rate sensor unit may include one or both of a gyroscope and an accelerometer. The processor receives radar data from the radar unit indicative of subsurface strata and obstacles respectively located generally forward and/or lateral of the cutting tool, and receives displacement data from the rate sensor unit indicative of one or both of longitudinal and rotational displacement of the cutting tool. The transmitter is configured for transmitting one or both of the radar data and the displacement data to an aboveground location.

Abstract: A method of monitoring microseismic events in a hydrocarbon production reservoir provided with a well comprising inner production tubing and an outer casing. The method includes providing one or more microseismic sensors in contact with the outer casing of the well, and taking steps to enhance the ability of the microseismic sensors to detect microseismic signals over the background noise generated by fluid flow inside the inner production tubing is enhanced. An installation suitable for carrying out such a method is also disclosed.

Abstract: A method of monitoring a microseismic event includes detecting the event to produce a first signal dependent on the event. The first signal includes noise at a frequency of, for example 50 Hz. A first sample of the first signal is taken. Then a second sample of the first signal is taken, the second sample occurring n/f seconds after the first sample, where n is an integer (e.g. 1). Subtracting the first and second samples from each other produces a farther signal dependent on the event in which the noise has been at least partly compensated for.

Abstract: A body device includes: a plurality of sound sources; a speaker and a headphone for outputting sound signals from those sound sources; and a mode setting unit capable of setting a single mode, in which the sound signals from one sound source are output in response to an operation from a front operation unit, and a dual mode in which, while the sound signals from one sound source are being output from the speaker, the voice signals from another sound source are output from the headphone; an external connection unit for connecting an external DVD device with the outside; and a control unit for controlling a mode setting unit so that the body device may be turned ON in the dual mode when a power ON demand signal from the external DVD device or a rear operation unit is detected.

Abstract: A clamp mechanism for actively coupling an in-well seismic station to the casing of a well is disclosed. The clamp mechanism is capable of associating a sensor to production tubing for deployment in the well and is capable of actively coupling the sensor to the casing of the well. The clamp mechanism includes a body capable of being coupled to the deployment member. A carrier mechanism is attached to the sensor and positions adjacent the body. A release mechanism releases the carrier mechanism when subjected to a predetermined pressure in the well or when subjected to fluid in the well for a predetermined amount of time. A biasing mechanism is disposed between the body and the carrier mechanism and displaces the carrier mechanism with attached sensor towards the surface of the casing when released. A guiding mechanism guides the displacement of the carrier mechanism towards the surface of the casing.

Abstract: The invention comprises a system for processing seismic data to estimate time shift resulting from velocity anisotropy in the earth's subsurface. A gather of seismic data traces is formed and selected seismic data traces included in said gather within selected time windows are cross-correlated to estimate the time shift in the seismic data traces included in said gather resulting from velocity anisotropy in the earth's subsurface.

Abstract: A system for sensing subterranean acoustic waves emitted from an acoustic source includes a plurality of laser sources, a plurality of subterranean optical sensors, at least one optical detector, and electronics. The laser sources each emit light at a different frequency. The subterranean optical sensors receive the light and alter the light in response to the acoustic waves. The optical detector receives the altered light and outputs an electrical signal. The electronics receives the electrical signal and converts it into seismic data format. The hydrophone for sensing the acoustic signals is able to operate at pressures of at least 5,000 psi and temperatures of at least 130 degrees Celsius. A hydrophone may be housed in a cable having a diameter of less than about 1.5 inches. The hydrophone's sensor preferably includes a reference mandrel, two sensing mandrels, and a telemetry can, all of which are aligned in a coaxial, end-to-end configuration to reduce the profile of the hydrophone.

Abstract: The invention is a method for performing a stratigraphically-based seed detection in a 3-D seismic data volume. The method incorporates criteria that honor the layered nature of the subsurface so that the resulting seismic objects are stratigraphically reasonable. The method may be used to extract from a seismic data volume all seismic objects that satisfy the input criteria. Alternatively, the method may be used to determine the size and shape of a specific seismic object in a seismic data volume.

Abstract: A model seismic image of a subsurface seismic reflector is constructed, wherein a set of source and receiver pairs is located, and a subsurface velocity function is determined. Specular reflection points are determined on the subsurface seismic reflector for each of the source and receiver pairs. A Fresnel zone is determined on the subsurface seismic reflector for each of the specular reflection points, using the subsurface velocity function. One or more seismic wavelets are selected and a set of image points is defined containing the subsurface seismic reflector. A synthetic seismic amplitude is determined for each of the image points by summing the Fresnel zone synthetic seismic amplitude for all of the Fresnel zones that contain the image point, using the seismic wavelets. The model seismic image of the subsurface seismic reflector is constructed, using the synthetic seismic amplitudes at the image points.

Abstract: A method for seismic exploration using nonlinear conversions between electromagnetic and seismic energy, with particular attention to the electromagnetic source waveform used. According to the invention, seismic returns from a source waveform are correlated with a reference waveform, with both waveforms custom designed to minimize both correlation side lobes and interference from linear electroseismic effects. A waveform element is selected which may be sequenced by a binary or similar digital code embodying the desired custom design to generate an input sweep with the needed depth penetration and noise suppression. Correlation of the seismic response with the reference waveform in a data processing step mathematically aggregates the seismic response from the input sweep into a single wavelet. Preferred binary digital codes include prescribed variations of maximal length shift-register sequences. Also, an apparatus for generating the desired waveforms.

Abstract: A universal seismic data acquisition module includes independent environmental isolation chambers for essential signal processing circuitry and for cable connection unions. Cable connection unions are rapidly replaced without opening the main protective chamber. Different connector types required for the many data transmission cable designs needed to service a wide range of survey conditions are more easily accommodated than in conventional single chamber designs. The module is rugged and suitable for operating in a wide range of physical environments including lake or sea immersion to substantial water depths, desert, arctic and others. Need for investment in multiple module types for varying survey conditions is thereby reduced without compromising capacity.

Abstract: A method of seismic surveying comprising the steps of actuating the or each vibrator in a first vibrator group at time T0, and subsequently actuating the or each vibrator in a second vibrator group at time T1 that satisfies T0<T1<T0+S1+L where S1 is the sweep time of the first vibrator group and L is the listening time. At least one of the first vibrator group and the second vibrator group comprises at least two vibrators. The first group and the second group of vibrators may be the same group, or they may be different groups. This method enables the time required to complete a seismic survey to be reduced compared to the prior art “simultaneous shooting” and “slip-sweep shooting” techniques.

Abstract: A sensor for detecting an acceleration on a surface. The sensor exchanging messages with a computing means through a communication interface. The sensor comprises an accelerometer for outputting a signal representative of the acceleration and an interface unit comprising a transmitting circuit. The interface unit receives the signal representative of the acceleration and modulates the same for transmission to the computing means.

Abstract: An energy impulse generator for transferring an energy pulse to a surface. The generator exchanges messages with a computing means through a communication interface. The generator comprises a housing. The generator further comprises an impact assembly movably mounted within the housing between at least a resting position, a latched position and an impact position. In the impact position, the impact assembly transfers the energy pulse to the surface. The generator also includes an energy storage means attached to the impact assembly. In the latched position, the energy storage means is capable of releasing a specified amount of energy to the impact assembly such that upon release of the specified amount of energy the impact assembly moves from the latched position to the impact position then returns to the resting position. The computing means controls the release of the specified amount of energy to the impact assembly.

Abstract: A method and device for emitting radial seismic waves in a material medium by electromagnetic induction, used notably for generating seismic waves in cased or uncased wells or in a water mass is disclosed. Emission of radial waves is essentially obtained by radially expanding a metal tube (1) under the effect of a magnetic pressure generated by electromagnetic induction with elastic waves being created in the medium under the effect of this expansion. The magnetic pressure is obtained by connecting a coil (2) in line with the tube to a current generator (3). The winding pitch of coil (2) can be constant or variable. Tube (1) can for example be added into a well or hole or it can be a tube portion of a cased well.

Abstract: An underwater cable deployment system includes a series of cables, pre-wound on a set of reels, disposed upon a pallet and connected to a distribution hub on the pallet. The pallet is lowered to the ocean floor and a remotely operated vehicle (ROV) is also lowered to the ocean floor to deploy cables to form a predetermined array on the ocean floor. Preferably, the pallet is delivered to the ocean floor in advance by crane with the reel-mounted sensor array cables being deployed later by ROV. Optionally, the ROV may include a jetting package configured to bury the sensor cable as it is being deployed from the reel on the ROV.

Abstract: In the present invention, a seismic receiver contains an onboard digitizer that samples and converts a signal from detected seismic energy into the digital domain. The receiver contains an analog to digital converter, a transmission circuitry, and a link to the seismic detection circuitry. The signal from the seismic detection circuitry is converted into a digital signal, which is then relayed to the data recorder. These components are all resident to the receiver itself. Additional control circuitry is employed to provide clocking and testing functions. These receivers communicate with one another, and provide sampled seismic data on an individual basis. The components may be prepared on a PCB and put inside the receiver cap. The PCB may be flexible in nature, as to provide a maximum of surface mounted components in the smallest amount of space.

Abstract: In a remote data acquisition system a control unit transmits a radio signal simultaneously to a plurality of remote units. Each remote unit receives the radio signal at different times dependent on various system delay factors. A compensating delay is added in each remote unit in order to trigger each remote unit for data acquisition at the same time.

Abstract: In a three-dimensional exploring method for finding location of a buried object by transmitting a wave signal (4) by means of e.g.

Abstract: A seismic sensor contains a geophone (4) disposed within a housing (12). The sensor is also provided with locking means (14, 19, 21) that can either lock the geophone 4 relative to the housing, or can allow the geophone to rotate within the housing.

Abstract: A method and system for extraction of P-wave and S-wave velocities from multicomponent seismic data by joint velocity inversion is provided. The method and system accurately invert the P-wave and S-wave velocities from multicomponent seismic data via joint velocity inversion. The joint velocity inversion has proven to be an effective tool to extract the interval P-wave and shear wave velocities by decomposition and reconstruction of the P-wave and S-wave velocity fields. The method and inversion process is valid for land and marine seismic data, including surface reflection seismic ocean bottom seismic and vertical cable seismic data.

Abstract: A method for seismic exploration using nonlinear conversions between electromagnetic and seismic energy, with particular attention to the electromagnetic source waveform used. According to the invention, seismic returns from a source waveform are correlated with a reference waveform, with both waveforms custom designed to minimize both correlation side lobes and interference from linear electroseismic effects. A waveform element is selected which may be sequenced by a binary or similar digital code embodying the desired custom design to generate an input sweep with the needed depth penetration and noise suppression. Correlation of the seismic response with the reference waveform in a data processing step mathematically aggregates the seismic response from the input sweep into a single wavelet. Preferred binary digital codes include prescribed variations of maximal length shift-register sequences. Also, an apparatus for generating the desired waveforms.

Abstract: The invention comprises the generation of seismic signals at a survey site at which seismic sensors are deployed by dropping mass units from an overflying aircraft. The mass units will impact the earth's surface at said survey site to generate seismic signals. The seismic sensors are utilized to detect the resulting seismic signals.

Abstract: A method and apparatus for low cost, convenient prospecting and surveys of subsurface structures using seismoelectric signals, as well as laboratory analysis of geological samples. The seismoelectric signals come from seismic waves generated by sources which can be applied or natural. The seismoelectric signals are generated with the same velocity and frequency of the generating seismic waves, then induce secondary electromagnetic signals which travel at their own much higher speed. The seismoelectric signals thus may be measured with electrodes or antennas. Electrodes may be disposed within a borehole or on the surface. The method allows use of geophone data, but does not require it. The it source of the seismoelectric signals, being a moving seismic wave front, conveys continuous, whole body information on the structures underground, in much the same way as seismic ware data, but in the form of simpler, easier to capture seismoelectric signals. Reflection and refraction of seismic waves can be ascertained.

Abstract: The invention is titled Electrical Power from Road Seismic Energy. The invention consists of key concepts and proposed procedures to provide an environmentally friendly alternative source of electrical power. The invention is a description of methodology for producing electrical energy by the placement of transducers near and underneath highways. The seismic energy generated by passing traffic excites the transducers and the output of multiple transducers is combined to produce economically useful amounts of electrical power. The specific implementation of the invention is a battery charger that would also be used as the inventor's tests harness to evaluate the economics of the invention. The amount of potential energy generated by passing traffic on a highway is not generally appreciated. An analogy would be a car passing over a pontoon bridge, the pontoons rising and lowering in the water and generating waves in the water.

Abstract: A method and system for determining the location of a microseismic event is disclosed. An electromagnetic sensor measures the electromagnetic energy which is caused by a microseismic event. Seismic data from the microseismic event is measured and recorded using plurality of ground motion sensors. The time at which microseismic event occurred is estimated based at least in part on the time at which electromagnetic energy caused by the microseismic event is received by the electromagnetic sensor. The location of said source of the microseismic event is determined using the estimated occurrence time and the time at which the seismic energy arrived at the ground motion sensors. A method of triggering a seismic recording device is also disclosed. The electromagnetic energy from a microseismic event is measured and recorded using an electromagnetic sensor. The time at which the microseismic event occurred is estimated based on the measured electromagnetic energy.

Abstract: A two-conductor bidirectional digital telemetry interface between a seismic sensor acquisition/conversion module and a seismic data collection module. The data collection module is configured as a master electronics device and the sensor acquisition/conversion module is configured as a slave electronics device in the telemetry system. The master device provides power to the slave device over the two conductors. The master device transmits portions of commands to the slave device at a first time and the slave device transmits portions of a digital seismic data packet to the master at a different second time in a fixed-duration frame. The frames are transmitted at regular intervals. The outbound commands and inbound data are encoded by block codes. A phase-locked loop in the slave is locked to a master clock in the master by deriving a clock and a sync point from the block-coded commands it receives from the master.

Abstract: An electroacoustic transducer 1 is constituted by a base 24 formed of magnetic material; a magnetic core 22 formed of magnetic material and provided erectly on the base 24; a diaphragm 20 formed of magnetic material and supported with an air gap between the diaphragm and a forward end of the magnetic core; a magnet 25 constituting a magnetic circuit together with the base 24, the magnetic core 22 and the diaphragm 20 so as to provide a magnetostatic field; a coil 23 disposed around the magnetic core 22 for applying an oscillating magnetic field to the magnetic circuit; a housing 30 molded integrally with the base 24 and the magnet 25, and so on. The housing 30 has notch holes 38 extending from a bottom surface thereof to the magnet 25.

Abstract: A sonic or acoustic tool having a transmitter and a receiver and further having a receiver testing and calibration device is disclosed. Methods for testing and tuning acoustic receivers dynamically are also disclosed. The calibration device includes an acoustic signal generator in acoustic communication with a receiver or a plurality of receivers, where the generator generates an acoustic calibration signal or test signal which propagates to each receiver. The receiver response is monitored to determine receiver integrity and tune. Based on the response, the processing unit or units can adjust the receiver response or instruct tuning circuitry associated with the receiver to adjust the receiver response.

Abstract: The invention provides for assessing location and/or proximity to a buried or submerged optical fiber cable. A seismic generator creates seismic pulses, at known frequencies, on the ground (or water) at a first location and the synchronous rotation of the polarization state of light transmitted through the optical fiber cable is detected. Other seismic pulses are generated at different locations and the polarization rotation is detected at each such location to locate a closest proximity to the cable, corresponding to a minimum or maximum of polarization rotation. A wireless synchronous signal is generated with the seismic pulses to differentially isolate the polarization rotation signal; and, if desired, to further determine distance between the cable and the source of the seismic pulse.

Abstract: A marine seismic source for generating acoustic source energy. A housing has a continuous exterior perimeter which is moveable to displace water. Movement of the housing can be accomplished by providing alternating convex and concave exterior surfaces connected with inflection points. The composite shape provides movement inwardly or outwardly, and can be moved with different types of actuators. Piezoelectric elements can be activated to move the housing surfaces and to change the internal housing volume. The resulting pressure pulse provides acoustic source energy useful for the evaluation of subterranean geologic formations and for other purposes.

Abstract: A method for surface estimation of reservoir properties, wherein location of and average earth resistivities above, below, and horizontally adjacent to the subsurface geologic formation are first determined using geological and geophysical data in the vicinity of the subsurface geologic formation. Then dimensions and probing frequency for an electromagnetic source are determined to substantially maximize transmitted vertical and horizontal electric currents at the subsurface geologic formation, using the location and the average earth resistivities. Next, the electromagnetic source is activated at or near surface, approximately centered above the subsurface geologic formation and a plurality of components of electromagnetic response is measured with a receiver array. Geometrical and electrical parameter constraints are determined, using the geological and geophysical data.