Entries |
Document | Title | Date |
20080284441 | UNDERWATER ELECTRIC FIELD ELECTROMAGNETIC PROSPECTING SYSTEM - The present invention, in various embodiments, is directed to a geophysical system and method in which a transmitter coil is oriented with its axis horizontally, and a sensor is positioned below the coil to measure an ambient electrical and/or magnetic parameter associated with a conductive medium surrounding the at least one transmitter coil. | 11-20-2008 |
20080309346 | ELECTROMAGNETIC DETECTOR FOR MARINE SURVEYING - A detector for underwater electromagnetic surveying is described. The detector comprises first, second, third and fourth electrodes which are arranged to define first, second and third electric dipole antennae extending between pairs of the electrodes. Each dipole antennae extends between a pair of the electrodes and the fourth electrode is common to all three dipole antennae. Thus the first electrode is separated from the fourth electrode along a first direction to provide the first dipole antenna, the second electrode is separated from the fourth electrode along a second direction to provide the second dipole antenna, and the third electrode is separated from the fourth electrode along a third direction to provide the third dipole antenna. The electrodes are arranged so that the first, second and third directions are inclined at an angle of between 20 and 70 degrees to a surface on which the detector rests when in normal use. | 12-18-2008 |
20090001985 | Methods for Electromagnetic Measurements and Correction of Non-Ideal Receiver Responses - A method for determining formation electrical properties includes deploying one or more receivers for electromagnetic logging; obtaining measurement data indicative of the formation electrical properties using the deployed receivers; correcting the measurement data for receiver imperfection; and inverting the corrected measurement data to obtain one or more parameters of formation electrical properties. | 01-01-2009 |
20090085569 | Method and Device for Sea Electrical Survey of Oil-and-Gas Deposits - A sea electrical survey method for carbohydrates deposits, situated under seabed not exceeding 10 meters of depth, is disclosed, comprising: providing a plurality of multi-channel bottom systems with receiving lines having at least three electrodes and capable to register electromagnetic signals, excitation means generating a series of alternating-sign pulses controlled by a computer a horizontally positioned dipole, synchronizing the excitation means and bottom systems, submerging the systems upon the seabed along a predetermined direction, aligning the receiving lines, moving the dipole within the survey zone, excitation of the pulses, registering signals measuring the potentials difference and the spatial derivatives of the signals during the pulses and the pauses, recording data, analyzing the data with accounting the fields behavior in time and in space simultaneously, determining the environment resistivity and environment polarizability based on a predetermined mathematical model, and compiling the deposit prognosis. Preferable distance, time, and angular parameters are specified. | 04-02-2009 |
20090096457 | Method for determining earth vertical electrical anisotropy in marine electromagnetic surveys - A method is disclosed for determining earth vertical electrical anisotropy from offshore electromagnetic survey measurements. The method requires both online and offline data, which includes at least one electromagnetic field component sensitive at least predominantly to vertical resistivity and another component sensitive at least predominantly to horizontal resistivity. Using a horizontal electric dipole source, online E | 04-16-2009 |
20090121719 | "METHOD OF MARINE ELECTROMAGNETIC SURVEY USING FOCUSING ELECTRIC CURRENT (VARIANTS)" - Two embodiments of marine geo-electric probe methods for hydrocarbon deposits survey comprise—excitation of electromagnetic field in a surveyed medium by transmitting two rectangular current pulses therethrough, the first—during forward traveling of a probe device along a profile and the second—during backward traveling thereof, —measuring instant values of the first and second electric potential differences during the time between the pulses, wherein, the equal-zero condition of the electric potential differences along the profile is ensured, —calculating three sets of normalized electrical parameters based on difference values, —solving an inverse problem via a differential equation for the dipole source voltage in an electrochemically polarizable medium using the parameters, —producing data according to said electrical parameters, and—determining conductivity of the medium, induced-polarization factor and decay time constant of the polarization potential difference. The first embodiment is deployed for circular survey profiles, the second is for linear profiles. | 05-14-2009 |
20090160444 | Low temperature squid transient electromagnetic receiver system - A receiver system ( | 06-25-2009 |
20090184715 | Determining Orientation For Seafloor Electromagnetic Receivers - Apparatus and method for estimating the 3D orientation angles for remotely deployed devices with flexible arms such as dipole antennas of receivers used in marine controlled-source electromagnetic surveys to explore for hydrocarbons. Acoustic transponders or transducers, or other positioning sensors such as attitude sensors or strain-sensitive fiber optic cables are placed on each electrode arm of the receiver. Acoustic sensors ( | 07-23-2009 |
20090195251 | APPARATUS, SYSTEM AND METHOD FOR RECEIVING A VERTICAL COMPONENT OF A SIGNAL AND FOR DETERMINING A RESISTIVITY OF A REGION BELOW A GEOLOGIC SURFACE FOR HYDROCARBON EXPLORATION - A system for determining resistivity of a region below a geologic surface by transmitting a signal from a marine location above the sea floor to a receiver comprises a vertical dipole, vertical coil, or other antenna. The receiver may have a vertical dipole, including a first conductor structure and a second conductor structure, as well as a first member. The first conductor structure may be disposed below the sea floor and the second conductor structure may be disposed above the first conductor structure. The receiver may receive the signal at the sea floor. The system may be used in a method that includes releasing the remote reader from a surface vessel, activating a drive head on the remote reader, creating a hole in the sea floor, and disposing a first conductor structure within the hole. | 08-06-2009 |
20090219029 | METHOD FOR HYDROCARBON RESERVOIR MAPPING AND APPARATUS FOR USE WHEN PERFORMING THE METHOD - A method is proposed for a marine electromagnetic survey based on the TM mode, for the purpose of prospecting for and detecting subsurface hydrocarbon reservoirs. The method includes an electromagnetic field source ( | 09-03-2009 |
20090278541 | Electromagnetic Method on Shallow Water Using a Controlled Source - A method for analysing acquired electromagnetic measurements (R) made at or in a sea ( | 11-12-2009 |
20090278542 | Method For Detection Of Signal Source Using Estimation Of Noise Statistics - A method for noise signal analysis and communication with an underground transmitter. The method comprises the steps of measuring a noise floor when no signal is transmitted from a transmitter, detecting a signal when the transmitter is transmitting, and estimating the noise free component of the signal by removing the noise floor measurement. The measurement of the noise floor and detecting the signal from the transmitter may be done using a root mean square technique. The noise floor measurement can be removed from the measured signal by subtracting the noise floor measurement from the measured signal or alternatively by calculating the square root of the difference between the square of the measured signal and the square of the noise floor measurement. The noise estimation technique may be used in connection with, a differential phased shift keying communication scheme or other modulation techniques. | 11-12-2009 |
20090302849 | ELECTROMAGNETIC EXPLORATION - A system and method include receiving electromagnetic energy emanating from a target using a plurality of receivers, and generating a pseudo-source based at least in part on a location of one or more of the plurality of receivers and the received electromagnetic information. | 12-10-2009 |
20090309599 | Method for subsurface electromagnetic surveying using two or more simultaneously actuated electromagnetic sources - A method for electromagnetic exploration includes imparting a first electromagnetic signal into subsurface formations from a first location and imparting a second electromagnetic signal into the formations from a second location substantially contemporaneously with imparting the first electromagnetic signal. The first and second electromagnetic signals are substantially uncorrelated with each other. A combined electromagnetic response of the formations to the first and second imparted electromagnetic signals is detected at a third location. A response of the formations to each of the first and the second imparted signals is determined from the detected response. | 12-17-2009 |
20100045295 | METHOD AND APPARATUS FOR DETERMINING THE NATURE OF SUBMARINE RESERVOIRS - A method of producing a survey report on the presence and nature of a subterranean strata: includes simultaneously towing an EM field transmitter and a seismic source behind a vessel, towing at least one streamer behind the vessel, said streamer or streamers having EM field receivers for measuring an electric field and seismic receivers for measuring a seismic response, applying an EM field to the strata using the EM field transmitter and detecting an EM field response using the EM field receivers, applying a seismic event to the strata using the seismic source and detecting the seismic response using the seismic receivers, analysing the EM field response, analysing the seismic responses and reconciling the EM field response and the seismic response to produce the survey report. | 02-25-2010 |
20100052688 | ELECTROMAGNETIC SURVEYING - A method of determining the nature of subterranean strata. The transmitter antenna is towed by vessel at a distance h above the sea floor. The antenna omits a wave field whose strength is proportional to the current delivered to the antenna and this is monitored. The input voltage to the antenna is also measured and changes in antenna impedance are calculated. Changes in antenna impedance are used together with seismic information to determine the nature of the subsea strata. | 03-04-2010 |
20100060286 | METHOD TO MAINTAIN TOWED DIPOLE SOURCE ORIENTATION - Apparatus and method for a steerable horizontal electric dipole source system for underwater deployment as a moving source in electromagnetic surveying of subsurface regions for hydrocarbons. Position locating sensors ( | 03-11-2010 |
20100073001 | SYSTEM AND METHOD FOR DETERMINING SUB SURFACE GEOLOGICAL FEATURES AT AN EXISTING OIL WELL SITE - An array of electromagnetic receiver antennae is arranged and operated in conjunction with the operation of an array of far field electromagnetic transmitter antennae for mapping subsurface features of an existing well site reservoir. Mapping is performed according to the relative intensities, frequencies, phase shifts, and/or other reflected signal parameters of the reflections received by the receiver antennae (relative to the transmit signals) associated with a given location or target area within a reservoir so as to aid in determining the geological features about an oil deposit for an existing oil well. | 03-25-2010 |
20100090701 | MARINE EM EXPLORATION - A method for estimating the effects of an airwave in marine electromagnetic data measured using a source and at least one receiver. The method involves measuring the electromagnetic response at two different under water source-receiver separations and using measurements at the larger separation to estimate the airwave response at that separation. The airwave effect in the response measured at the shorter separation can then be determined using the estimated airwave response at the larger separation. | 04-15-2010 |
20100102820 | Method for determining electromagnetic survey sensor orientation - A method for determining orientation of an electromagnetic survey sensor includes deploying the sensor at a selected position on the bottom of a body of water. An electromagnetic field is generated at a selected position in the body of water. A portion of the electromagnetic field is detected along at least two orthogonal directions at the sensor. A portion of the detected electromagnetic field is selected as having traveled only in a vertical plane which includes both source position and sensor position. The polarization direction of the selected portion of the electromagnetic field is determined from the selected portion. The determined polarization direction is used to determine the sensor orientation. | 04-29-2010 |
20100102821 | SURVEYING METHOD USING AN ARRANGEMENT OF PLURAL SIGNAL SOURCES - A survey technique for use in a marine environment to survey a subterranean structure includes providing an arrangement of plural signal sources in a body of water to produce corresponding signals. The signals of the signal sources in the arrangement are set to cause reduction of at least one predetermined signal component in data received by a receiver in response to the signals. | 04-29-2010 |
20100109671 | Method for acquiring controlled source electromagnetic survey data to assist in attenuating correlated noise - A method for acquiring transient electromagnetic survey signals includes applying a transient electric current to an electromagnetic transmitter disposed above a portion of the Earth's subsurface to be surveyed. Electromagnetic signals are detected at spaced apart locations above the portion of the subsurface in response to an electromagnetic field induced in the Earth's subsurface by the applying transient current. Electromagnetic signals are detected at least one position proximate a position of the electromagnetic transmitter such that the subsurface transient response is substantially always identifiable therefrom. | 05-06-2010 |
20100134110 | MARINE EM EXPLORATION - A method for removing the effects of an airwave from marine electromagnetic data comprising providing an electromagnetic source and at least one receiver in the water; measuring the electromagnetic response at a first source-receiver separation; determining a scaled version of the airwave response at a source-receiver separation where the earth response is negligible and using the scaled airwave response to determine the earth response measured at the first separation. Using this method, an improved estimate of the earth's response can be achieved. | 06-03-2010 |
20100148783 | MULTI-COMPONENT MARINE ELECTROMAGNETIC SIGNAL AQUISITION CABLE AND SYSTEM - A marine electromagnetic sensor cable includes a plurality of sensor modules disposed at spaced apart locations along a cable. Each module includes at least one pair of electrodes associated therewith. The electrodes are arranged to measure electric field in a direction along the direction of the cable. A plurality of spaced apart magnetic field sensors is associated with each module and arranged to enable determining an electric field amplitude in a direction transverse to the direction of the cable from magnetic field gradient. | 06-17-2010 |
20100171501 | PROVIDING A TOW CABLE HAVING PLURAL ELECTROMAGNETIC RECEIVERS AND ONE OR MORE ELECTROMAGNETIC SOURCES - To perform marine electromagnetic (EM) surveying of a subterranean structure, a marine cable system is provided including a tow cable, a plurality of electromagnetic (EM) sources coupled to the tow cable, and a plurality of EM receivers coupled to the tow cable. The system is configured for deployment in a body of water to perform marine EM surveying of a subterranean structure. | 07-08-2010 |
20100201367 | Short-offset transient electromagnetic geophysical surveying - A method for electromagnetic surveying subsurface formations includes inducing an electromagnetic field in the subsurface formations by passing electric current through a transmitter. Response of the subsurface formations to the induced electromagnetic field is detected at a first plurality of spaced apart positions disposed longitudinally within a bipole length of the transmitter. A direct induction response is removed from the detected response. | 08-12-2010 |
20100271029 | Method and Device for Induced Polarization Mapping of Submarine Hydrocarbon Reservoirs - This invention is directed toward an electromagnetic surveying method based on detection of induced polarization effect and evaluation of its characteristics for mapping marine hydrocarbon targets. The method includes the steps of vertical deployment in a body of water of at least one electric wire which forms an electromagnetic transmitter which emits electromagnetic energy arranged to excite an electromagnetic field in the body of water and underlying medium, the same wire being used as a receiver for measurements of the vertical component of the electric field; (b) providing survey data as the spatial distribution of the vertical component of the electric field and the medium response in the form of apparent resistivity versus time in the body of water; (c) performing a space/time analysis of the vertical component of the electric field and response with the purpose of detecting induced polarization effect and determine its intensity and relaxation times; and (d) mapping the anomalous zones described by the characteristics perspective of the induced polarization for the exploration of an underground hydrocarbon reservoir. There is also described equipment for use when practising the method. | 10-28-2010 |
20110006774 | SUBSURFACE POSITIONING SYSTEM AND METHOD FOR MONITORING MOVEMENT UNDERGROUND - A system for monitoring movement in a subsurface environment, which may be used to determine flow dynamics within a fluid mass such as an ore body, or track subsurface persons or moving assets. A plurality of underground positioning system (UPS) elements in the subsurface environment transmit characteristic signals to a plurality of antennas, which transmit the signals to a data processing apparatus. The system thus determines changes in the positions of the UPS elements to derive an indication of the motion of the fluid mass or the locations and movement of subsurface persons or assets. | 01-13-2011 |
20110050231 | METHOD OF DETERMINING ELECTRICAL ANISOTROPY IN A SUBSURFACE FORMATION - Method of determining electrical anisotropy in a subsurface formation, wherein electromagnetic field data from a multi-offset electromagnetic survey obtained by using an electromagnetic source and a plurality of electromagnetic receivers at varying offset distances from the source is provided. The electromagnetic field data comprises a first set of multi-offset response signals received at each receiver with the electromagnetic source emitting at a first frequency, and at least one additional set of multi-offset response signals received at each receiver with the electromagnetic source emitting at a different frequency. The presence of electrical anisotropy in the subsurface formation is determined using the first and at least one additional sets of multi-offset response signals. This may comprise comparing the first set and the at least one additional set of multi-offset response signals and determining the presence of electrical anisotropy in the subsurface formation from the comparison of the sets of multi-offset response signals. | 03-03-2011 |
20110050232 | REMOVING EFFECTS OF NEAR SURFACE GEOLOGY FROM SURFACE-TO-BOREHOLE ELECTROMAGNETIC DATA - A method that involves developing an electromagnetic property model of a near surface area and using this electromagnetic property model and electromagnetic data acquired using one or more electromagnetic transmitters located above the near surface area and one or more electromagnetic receivers located within a wellbore to determine one or more electromagnetic properties of a subsurface area. Also an electromagnetic data acquisition system that includes one or more electromagnetic transmitters capable of being operated on the earth's surface, one or more first electromagnetic receivers capable of being operated within a wellbore and capable of receiving signals from the one or more electromagnetic transmitters, and one or more second electromagnetic receivers capable of being located on the earth's surface near the one or more electromagnetic transmitters and capable of receiving signals from the one or more electromagnetic transmitters. Related embodiments are also described. | 03-03-2011 |
20110121835 | LOCATING TECHNIQUE AND APPARATUS USING AN APPROXIMATED DIPOLE SIGNAL - Location determination is performed using a transmitter including an elongated generally planar loop antenna defining an elongation axis. The elongation axis is positioned along at least a portion of a path. A magnetic field is then generated which approximates a dipole field. Certain characteristics of the magnetic field are then determined at a receiving position radially displaced from the antenna elongation axis. Using the determined certain characteristics, at least one orientation parameter is established which characterizes a positional relationship between the receiving position and the antenna on the path. The magnetic field may be transmitted as a monotone single phase signal. The orientation parameter may be a radial offset and/or an angular orientation between the receiving position and the antenna on the path. The antenna of the transmitter may be inserted into a first borehole to transmit the magnetic field to a receiver inserted into a second borehole. | 05-26-2011 |
20110210742 | Subsea, Vertical, Electromagnetic Signal Receiver For A Vertical Field Component And Also A Method Of Placing The Signal Receiver In Uncompacted Material - A vertical receiver antenna device includes first and second receiving electrode units interconnected by a receiver antenna cable and connected to means for the electromagnetic surveying of electrically resistive targets potentially containing hydrocarbons. The receiver antenna is arranged in a tubular, non-magnetic antenna housing arranged vertically in subsea uncompacted material, and one of the first and second receiving electrode units being connected in a electrically conductive manner to the underlying structure, and the other one of the first and second receiving electrode units being arranged in a portion of the antenna housing distantly from the first one of said first and second receiving electrode units. A method of installing a vertical receiver antenna in subsea uncompacted material is also described. | 09-01-2011 |
20110273179 | Multiple component electromagnetic survey signal acquisition method - A method for marine electromagnetic surveying includes transmitting a first electromagnetic field oriented in a first direction into a body of water. A second electromagnetic field oriented in a second direction is transmitted into the body of water, wherein the second direction is substantially transverse to the first direction. A parameter related to electromagnetic field amplitude is detected at a plurality of longitudinally and laterally spaced apart positions behind a vessel. The components of the detected electromagnetic field parameter are resolved into components along the first and second directions by using the geometrical symmetries and asymmetries of the transmitting source. Systems for implementing such methods are also provided. | 11-10-2011 |
20110279120 | Electromagnetic survey systems and methods with rotation-corrected motion compensation - A disclosed electromagnetic survey system includes one or more streamer(s) having multiple electromagnetic sensors and motion sensing units. Each motion sensing unit has one or more accelerometer(s) to measure motion perpendicular to an axis of the streamer, and a rotation sensor to measure rotation about the axis. The measurements of the accelerometer are adjusted based on measurements from the rotation sensor. The survey system also includes one or more processor(s) that determine, for each electromagnetic sensor, a motion signal based on the adjusted measurements. A described electromagnetic survey method includes processing acceleration and rotational motion measurements to obtain an orientation of motion sensing units as a function of time. The measured acceleration is manipulated based on the orientation to obtain one or more velocity signal(s) for each motion sensing unit. Interpolation is performed on the velocity signals to determine at least one velocity signal for each electromagnetic sensor. | 11-17-2011 |
20120119743 | MULTI-MODE ELECTROMAGNETIC SURVEYING - A method for providing information about a region below the earth's surface, comprises a) providing data from a system comprising an inductive source providing inductive signals in the region and a plurality of galvanic receivers for receiving galvanic signals resulting from the inductive signals, wherein the galvanic signals are the result of mode conversion occurring in the subsurface region; and b) processing the data. Step b) may include generating at least one galvanic virtual source signal. | 05-17-2012 |
20120146648 | AUTONOMOUS ELECTRICAL METHODS NODE - The present invention relates to a method and apparatus for evaluating and measuring the geometry of a fracture. | 06-14-2012 |
20130088235 | Method for Acquiring and Processing Marine Seismic Data to Extract and Constructively use the Up-Going and Down-Going Wave-fields Emitted by the Source(s) - A method for acquisition and processing of marine seismic signals to extract up-going and down- going wave-fields from a seismic energy source includes deploying at least two marine seismic energy sources at different depths in a body of water. These seismic energy sources are actuated with known time delays that are varied from shot record to shot record. Seismic signals from sources deployed at different depths are recorded simultaneously, Seismic energy corresponding to each of the sources is extracted from the recorded seismic signals. Up-going and down-going wave-fields are extracted from the sources deployed at different depths using the extracted seismic energy therefrom. A method includes the separated up-going and down-going wave-fields are propagated to a water surface or a common reference, the up-going or the down-going wave-field is 180 degree phase shifted, and the signals from these modified up-going and down-going wave-fields are summed. | 04-11-2013 |
20130113489 | STATIONARY STAR-SHAPED ANTENNA METHOD FOR MANIPULATING FOCUSED BEAMFORMED, SHAPED FIELDS AND BEAMSTEERED ELECTROMAGNETIC SIGNAL FROM SUBTEL SEDIMENTARY STRATIGRAPHIC FORMATIONS DEEP IN THE EARTH - A method for electromagnetic geophysical surveying according to one aspect of the invention includes disposing a plurality of electromagnetic receivers in a selected pattern above an area of the Earth's subsurface to be evaluated. An electromagnetic source is repeatedly actuated proximate the electromagnetic receivers. Signals generated by the receivers, indexed in time with respect to each actuation of the at least one electromagnetic energy source, are recorded. The recorded signals are processed to generate an image corresponding to at least one point in the subsurface. The processing includes stacking recordings from each receiver for a plurality of actuations of the sources and beam steering a response of the receivers such that the at least one point is equivalent to a focal point of a response of the plurality of receivers. | 05-09-2013 |
20130147488 | RADIO FREQUENCY ASSISTED GEOSTRUCTURE ANALYZER - The invention relates to instruments designated for geophysical survey, in particular for soil mass exploration using electromagnetic waves. Radio frequency assisted geostructure analyzer comprising transmitting loop ( | 06-13-2013 |
20130162256 | In-Line and Broadside Marine Electromagnetic Surveying - Methods for geophysical surveying include disposing an electromagnetic source and first and second receiver electrodes in water; actuating the source; and detecting a responsive electromagnetic field by measuring a potential difference between the first and second receiver electrodes, wherein: the electromagnetic source defines a source dipole axis; the first and second receiver electrodes define a receiver dipole axis; and the source dipole axis is not substantially parallel to the receiver dipole axis. Systems for geophysical surveying include a first source electrode on a first source cable; a second source electrode on a different second source cable, the first and second source electrodes forming an electromagnetic source and defining a source dipole axis; a first receiver electrode on a first receiver cable; a second receiver electrode on a different second receiver cable, the first and second receiver electrodes defining a receiver dipole axis not substantially parallel to the source dipole axis. | 06-27-2013 |
20130207661 | LOW NOISE MARINE ELECTRIC FIELD SENSOR SYSTEM - An EM receiver instrument suitable for making underwater electric field measurements. The EM receiver comprises a dipole antenna; an AM modulator for applying modulation to a signal detected by the antenna; a fiber-optic voltage sensor and an application of AM demodulator for applying demodulation to the signal. The fiber-optic sensor may be an interferometric voltage sensor or a phase sensitive voltage sensor. | 08-15-2013 |
20130241559 | Electromagnetic Receiver Assembly for Marine Electromagnetic Surveying - Disclosed is an electromagnetic receiver assembly for marine electromagnetic surveying, the electromagnetic receiver assembly comprising an elongated housing and receiver electrodes mounted at separate points along the elongated housing. An embodiment may include an electromagnetic receive assembly that includes an elongated housing, wherein the elongated housing defines an interior chamber. The electromagnetic receiver assembly may further include receiver electrodes configured to be in contact with water when in operation, wherein the receiver electrodes are mounted at separate points along the elongated housing. The electromagnetic receiver assembly may further include sensor electronics disposed in the interior chamber and electrically coupled to the receiver electrodes. The electromagnetic receiver assembly may be configured for deployment on or near a bottom of a body of water. | 09-19-2013 |
20130320984 | TECHNIQUES FOR SURFACE EXPLORATION AND MONITORING - Techniques for surface exploration and monitoring are presented. In representative embodiments, a system is provided that cars perform multiple types of measurements of a surface. For example a single system of survey probes and one or more survey controllers can be used to offer both seismic and electrical measurements. A survey controller can be configured to automatically poll survey probes to obtain identifiers of the probes aid determine a relative order the probes. Survey probes can be configured to; (a) collect signals associated with a surface; (b) digitize the signals to form digital data; and (c) store the digital data for later transmission to the survey controller. Relative positions of survey probes can be automatically determined using a transmitting beacon or other techniques. Survey probes can automatically disconnect from a power conduit while measuring a surface property and operate using an internal source of power when disconnected, to reduce noise. The survey controller can be remotely accessible through a computer network for remote control of the survey probes. | 12-05-2013 |
20140184227 | COLLECTING AND TRANSMITTING CONTROL SOURCE ELECTROMAGNETIC SIGNALS - Concurrently measuring, correlating, and processing magnetic and electric field data includes measuring base band signals, and then up-converting those band signals to a higher frequency for filtering, while at the same time preserving phase and amplitude information. All timed elements in the system are rigorously synchronized. The increased data set results in improved signal-to-noise ratio and information correlation. | 07-03-2014 |
20140191760 | METHOD AND APPARATUS FOR SUPPRESSION OF THE AIRWAVE IN SUBSEA EXPLORATION - The far zone “airwave” that arises when surveying subsea formations is greatly diminished by deployment of the transmitter combining mutually orthogonal horizontal electric and magnetic dipoles with the electric and magnetic dipole moments being locked in a special relationship. At each of the operating frequencies, the amplitude and phase characteristics of the transmitter electric and magnetic dipole moments are determined either from a supplementary measurement earned out using natural and/or controlled field sources, or by minimization of the vertical magnetic field at a remote receiver. Similar results can be obtained when data acquired in two independent surveys—one with the horizontal electric dipole transmitter pointing in one direction and another with a horizontal magnetic dipole transmitter pointing in the orthogonal direction and towed over the same or close positions—are linearly combined to minimize the vertical component of the combined magnetic field at remote receivers. | 07-10-2014 |
20140239956 | SYSTEM AND METHOD FOR DETECTING A FRACTURE IN A ROCK FORMATION USING AN ELECTROMAGNETIC SOURCE - A surface electromagnetic survey system and method for detecting a fracture or fracture zone in a rock formation are provided. The system includes an electromagnetic source configured to generate an electromagnetic field in the vicinity of or at a surface of the rock formation. The electromagnetic source includes one or more electric dipole sources that are arranged so as to generate a substantially vertical electric field. The system also includes an electromagnetic receiver associated with the electromagnetic source, the electromagnetic receiver being configured to measure a component of the electromagnetic field at the surface of the rock formation; and a processor configured to convert the measured component of the electromagnetic field measured at the electromagnetic receiver into an electromagnetic field response per unit moment of the electromagnetic source. The electromagnetic field response provides information about characteristics parameters of the fracture or fracture zone. | 08-28-2014 |
20140239957 | Using Low Frequency For Detecting Formation Structures Filled With Magnetic Fluid - A method for mapping a subterranean formation having an electrically conductive wellbore casing therein may include using a low frequency electromagnetic (EM) transmitter and EM receiver operating at a low frequency of less than or equal to 10 Hertz to perform a first EM survey of the subterranean formation, and with either the low frequency EM transmitter or EM receiver within the electrically conductive well-bore casing. The method may further include injecting a magnetic fluid into the subterranean formation, and using the low frequency EM transmitter and EM receiver to perform a second EM survey of the subterranean formation after injecting the magnetic fluid. | 08-28-2014 |
20140312906 | FRACTAL SHAPED ANTENNA FOR DOWNHOLE LOGGING - An apparatus for estimating a subsurface material property includes: a first energy interface device configured to transmit electromagnetic or electrical energy into the subsurface material; a second energy interface device configured to receive return electromagnetic or electrical energy due to the transmitted electromagnetic or electrical energy interacting with the subsurface material; and a processor configured to estimate the property using a signal received from the second device; wherein at least one of the first energy interface device and the second energy interface device is a fractal-shaped antenna comprising a base motif figure and at least one scaled down replication of the base motif figure, the at least one replication being a change from the base motif by at least one of a linear displacement translation and a rotation, and a position of the replication upon the base motif figure is by at least one of rotation, translation, and stretching. | 10-23-2014 |
20150048833 | DUAL COIL FOR ELECTROMAGNETIC SOUNDING OF LAYERED EARTH - Methods and systems for measuring subsurface electrical conductivity, using first and second sensor coils. The second sensor coil has a smaller effective area and a greater bandwidth than the first sensor coil. The first and second sensor coils are positioned with respect to each other to achieve zero or near zero mutual inductance. | 02-19-2015 |
20150309201 | METHOD AND APPARATUS FOR OPTIMIZING DEEP RESISTIVITY MEASUREMENTS WITH MULTI-COMPONENT ANTENNAS - According to aspects of the present disclosure, systems and methods for optimizing deep resistivity measurements are described herein. The method may include obtaining one or more first multi-component measurements from a downhole tool disposed in a bore-hole. The downhole tool may comprise multi-component antennae. A relative structural dip angle, Φ, of the downhole tool relative to formations may be determined, for example, through the use of an additional downhole tool, or computationally using the one or more first multi-component measurements. A tilt angle of at least one of the multi-component antenna may be adjusted, with the adjusted tilt angle being based on the dip angle. The method may further include obtaining one or more second multi-component measurements associated with the adjusted tilt angle, and determining a formation characteristic based, at least in part, on the one or more second multi-component measurements, without including or considering formation anisotropy effects. | 10-29-2015 |
20150378051 | MONITORING SEED CONDITION USING WIRELESS TECHNOLOGY - In one embodiment, a method, comprising directly sensing a condition of a seed entirely buried in soil; changing a first characteristic of a sensing component responsive to the condition of the seed; and responsive to receiving a momentary external excitation, providing by the sensing component a first electromagnetic signal wirelessly to a second device based on the changed first characteristic, the first electromagnetic signal providing an indication of the condition of the seed. | 12-31-2015 |
20160041289 | Method of Mapping Resistive or Conductive Targets onshore or offshore and an Apparatus for Applying the Method - An apparatus of the marine and onshore controlled source electromagnetic survey and a method of applying the apparatus are related. The apparatus comprises at least one signal transmitter and at least one signal receiver. Each transmitter is a solenoid of finite length, and/or each receiver is a toroid coil. | 02-11-2016 |