Abstract: Disclosed herein are earthquake detection devices capable of initiating a safety response in the event of an earthquake. The earthquake detection devices comprise a plurality of three-component accelerometers for measuring acceleration in three directions; and a processing unit for: receiving acceleration measurements from each of the plurality of accelerometers, determining if the acceleration measurements meet or exceed a predetermined threshold value and sending a signal to one or more transducers.

Abstract: A method for designing 4-D seismic acquisition source and receiver repeatability specifications, the method including: locating, with a computer subsurface anomalies above a target reservoir zone from analysis of high-resolution reflectivity images for the target reservoir zone; determining, with a computer, how the anomalies above the target reservoir zone modify target illumination for variations in the 4-D seismic acquisition source and receiver positions; and determining, with a computer, repeatability specifications for a monitor seismic survey, wherein tolerances for the source or receiver positions varies across an acquisition area based on how the anomalies modify the target illumination.

Abstract: A system in accordance with an embodiment of the present disclosure comprises at least two electrodes coupled to an electromagnetically sensitive bio-organism and control logic configured to predict an earthquake based upon signals produced by the electrodes in response to an electromagnetic signal.

Abstract: A method for re-calibrating installed downhole sensors used in hydrocarbon wells by the application of a calibration string inserted in the wells and deployed in close proximity to the installed downhole sensor.

Abstract: Methods and systems for quality control of seismic data illumination map generation are described. The quality control is based on determined fold differences calculated using the actual position of the sources and receivers in the determination of the seismic illumination. In another aspect, sub-surface complexity is considered in preparing a map of seismic illumination. The seismic data illumination map can be evaluated in real-time onboard a seismic vessel and included as part of an infill reshoot decision making/quality control process.

Abstract: A recording system and method for conducting seismic surveys including cordless battery-operated digital recorders, each employing an integral global positioning system receiver that is only periodically enabled for the purpose of establishing synchronized acquisition clock signals among all the recorders. The satellite receiver adjustment cycle is varied depending on past acquisition clock accuracy and temperature changes. A time stamp is recorded with the digitized seismic data in non-volatile memory. The memory is sized to allow extended periods of operation. Each recorder preferably includes a low-power system timer that may be used as a timer to remotely turn on and off the recorders according to a pre-programmed schedule to conserve power when the system is not in use. Electronic components are idled or de-energized when not needed.

Abstract: A container data center includes a container, a plurality of power supplies, an electric switch system, a plurality of normally closed switches, an alarm device, and a controller. The electric switch system is received in the container. The plurality of normally closed switches are connected between the power supplies and the electric switch system. Each normally closed switch is connected with a corresponding one of the power supplies in series. The controller is connected to the normally closed switches and the alarm device, configured for receiving earthquake information containing an earthquake intensity, and configured for controlling the alarm device to activate alarms and controlling some of the normally closed switches or all the normally closed switches to open when the earthquake intensity is equal to or greater than a predetermined earthquake intensity.

Abstract: Methods and systems utilizing seismic sensors configured or designed for use in seismic signal detection are provided so as to reduce the occurrence of spurious responses of the sensors. A method of seismic surveying using a seismic sensor may include the steps of deploying the seismic sensor at a location for seismic signal detection and acquiring seismic signals. The seismic signals may include high frequency response signals containing spurious response signals at an identifiable bandwith. The method may further include applying spurious response cancellation based on the bandwidth location of the spurious response signals and generating modified seismic waveforms having extended frequency bandwidth.

Abstract: To test a seismic sensor, an output of the seismic sensor in response to a test signal applied by a signal generator is measured. According to a first function that corresponds to a reference response of the seismic sensor and according to a second function that corresponds to a signal containing noise in an environment of the seismic sensor, a filter is created to perform attenuation of the noise. The filter is applied to attenuate noise during testing of the seismic sensor.

Abstract: An apparatus for sensing motion of a surface comprises a stabilised platform comprising a support structure and a moveable mass resiliently suspended with respect to the support structure; a transmitter transducer and a receiver transducer mounted on the moveable mass, the transmitter transducer arranged to transmit an acoustic wave towards the surface, and the receiver transducer arranged to receive a reflected wave from the surface, and detection means for measuring motion of the surface based on a Doppler shift in the reflected wave. The detection means may comprise an amplifier arranged to receive a Doppler modulated signal from the receiver transducer, and a phase detector arranged to receive an amplified signal from the amplifier and to provide a demodulated output signal indicative of the motion of the surface.

Abstract: A method of predicting subsurface properties of a geologic formation includes acquiring seismic data for a subsurface region including the geologic formation of interest, computing seismic attributes of the measured seismic data over at least part of this geologic formation, determining internally consistent rock properties representative of the geologic formation, generating models of the same part of the geologic formation with these rock properties, computing synthetic seismic data from the models, computing the same attributes from these synthetic seismic data, and using Bayesian analysis to predict, from the probability of modeled attributes given the models, the probability of the actual subsurface properties given the measured attributes.

Abstract: A sensor having a mass that moves relative to a structure is disclosed. The mass is attached to the structure by a rigid member such that the mass moves around a pivot point on the structure, the pivot point remaining fixed with respect to the structure as the mass moves. A code scale is attached to the mass. An imaging system that is fixed with respect to the structure forms an image of the code scale. A controller provides an indication of a position of the mass relative to the structure using the code scale image. The rigid member can include a surface having the code scale thereon, the surface rotating about the pivot point as the mass moves such that the surface remains at a fixed distance from the pivot point as the mass moves.

Abstract: A calibration apparatus includes a motion assembly, which is arranged to move an imaging probe through a calibration point having known coordinates. The imaging probe includes an ultrasound transducer and a position sensor for acquiring concurrently a first sequence of ultrasound images and a second sequence of position measurements. The apparatus further includes a marking circuit, which is arranged to mark an ultrasound image that is acquired by the ultrasound transducer in the first sequence when the imaging probe is at the calibration point. A processor is arranged to calibrate a time offset between the first and second sequences by associating the marked ultrasound image in the first sequence with a position measurement in the second sequence whose coordinates match the coordinates of the calibration point.

Abstract: Information about coupling of a seismic receiver is obtained from a power spectrum for a record acquired at a seismic receiver. In one method, the power spectrum for the record is compared with a reference power spectrum, which may be known a priori or which may be determined from the power spectra of records acquired by a group of receivers. In an alternative method, one receiver of a group of receivers is designated as a reference receiver, and the power spectra of records acquired by other receivers in the group are compared with a power spectrum for the reference receiver. The obtained information about the coupling of a receiver may be used to determine a coupling correction operator for the receiver, and this operator can be applied to seismic data acquired by the receiver to correct for the effects of imperfect coupling of the receiver.

Abstract: Various techniques are described which may be used to facilitate and improve seismic exploration activities. For example, one aspect of the present invention is directed to a technique for enabling in-situ measurement of geophone response parameters. Another aspect of the present invention is directed to a technique for improving geophone calibration and for improving the accuracy of measurement of geophone response parameters. Yet another aspect of the present invention is directed to a technique for compensating geophone response output data in order to improve the accuracy of such data.

Abstract: A method and system for calibrating acoustic receivers (112). The method and system facilitate calibrating the acoustic receivers (112) while they are mounted to a downhole acoustic tool (102). Calibrating the acoustic receivers (112) in situ provides more accurate results than previously available. The method and system provide separate compensation factors for the acoustic receivers (112) at different frequencies and for different transmission sources. The separate compensation factors facilitate more accurate signal acquisition over a wider range of conditions.

Abstract: A vacuum-strength measurement device is utilized to determine vacuum producer system performance specifications and system parameters. A flow ability factor can be determined that represents the effect of system piping and usage area equipment on performance. With the flow ability factor, a vacuum strength requirement can be determined to effect a target vacuum performance. For system design, design parameters can be established based on a relationship between a desired flow ability factor and an amount of vacuum strength required to match target vacuum performance.

Abstract: A method of using a seismic detector including four seismic sensors having axes which are in a substantially tetrahedral configuration, each of the sensors being in a respective signal channel, includes one or more of the following steps: combining outputs from the sensors to check that their polarities are correct; testing to ascertain if one of the sensors is not working and, if so, using the outputs from the other three sensors to obtain an indication of motion in three dimensions; if all four sensors are working, using their outputs to obtain an indication of motion in three dimensions on a least squares basis; checking that the outputs from the sensors are coherent; and checking the gains (or sensitivities) of the four channels.

Abstract: An accelerometer system principally for use in high spatial density urban arrays for near-real-time mapping of strong shaking due to large earthquakes. The present accelerometer system offers research-grade “16-bit resolution” (=90.3 dB dynamic range =20log(215)), and yet it is inexpensive to buy and inexpensive to maintain. A more efficient and accurate calibration and compensation procedure is also disclosed. The improved accelerometer system is ideally suited to any situation requiring large numbers of instruments, low installation costs, high robustness, low maintenance costs, and near-real-time response. The price/performance point achieved by the present invention far exceeds past instrumentation and opens many new markets.

Abstract: A method of estimating a petrophysical property of a subsurface area that includes deriving an acoustic calibration relationship correlating acoustic propagation characteristics of a first subsurface area with a petrophysical property of the first subsurface area determined using nuclear spectroscopy measurements; processing acoustic data acquired from a second subsurface area to determine acoustic propagation characteristics associated with a plurality of regions within the second subsurface area; and estimating the petrophysical property of the regions within the second subsurface area using the calibration relationship and the acoustic propagation characteristics associated with the second subsurface area.

Abstract: A vibration transducer such as a geophone, comprising a central pole piece (110) with a magnet (112) and coil (118) concentrically arranged around it. The position of the magnet (112) is fixed relative to the pole piece (110) and the coil (118) is movable relative to the magnet (112). A method of manufacturing a vibration transducer is characterised in that a bobbin carrying the coils is formed from a substantially tubular body which is positioned on a mandrel and at least one coil is wound around its outer surface, the mandrel being removed from the bobbin when the coil is complete. Another method is characterised in that the coil is formed separately and the bobbin is formed from a substantially tubular body which is positioned inside the coil and expanded to contact the coil when in position.

Abstract: An interferometric geophone includes a freely-falling reference mass and an interferometric arrangement to measure motion of a surface to which the geophone is attached. The mass may fall through an evacuated chamber. A carriage arrangement may reposition the reference mass for another fall. The reference mass has top and bottom retro-reflectors. The interferometric arrangement includes a laser and a beam-splitter that divides the laser beam into two beams directed toward the top and bottom of the reference mass by partially reflecting surfaces on prisms or mirrors. When the beam encounters the first face of each prism or a first mirror it is split again. One of the split beams is directed toward the falling retro-reflector; the other beam passes through the prism or mirror and encounters the second face. The retro-reflector returns the first split-beam to the second face via a lens arrangement.

Abstract: A sensor array includes a fiber optic cable and at least one electro-optical conversion unit connected to the cable. The electro-optical conversion unit includes a housing formed of mating upper and lower covers. The housing includes an interior cavity for receiving a phase modulator module, a strength member and an interferometer formed by fibers connected to various splices and couplers in combination with the phase modulator module. The interior of the housing is filled with a fill material for holding the position of optical fibers to thereby protect against environmental factors such as shock and moisture.

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.