摘要:
A method for subsurface Earth surveying includes acquiring seismic data over a selected region of the Earth's subsurface. Seismoelectric data are acquired over a selected region of the Earth's subsurface. Electroseismic data are also acquired over a selected region of the Earth's subsurface. At least one type of electromagnetic survey data is acquired over a selected region of the Earth's subsurface. Survey volumes of the seismic data, the seismoelectric data, the electroseismic data and the electromagnetic data are matched, and a model of the Earth's subsurface is generated that accounts for all of the seismic data, the seismoelectric data, the electroseismic data and the electromagnetic data.
摘要:
A method for subsurface Earth surveying includes acquiring seismic data over a selected region of the Earth's subsurface. Seismoelectric data are acquired over a selected region of the Earth's subsurface. Electroseismic data are also acquired over a selected region of the Earth's subsurface. At least one type of electromagnetic survey data is acquired over a selected region of the Earth's subsurface. Survey volumes of the seismic data, the seismoelectric data, the electroseismic data and the electromagnetic data are matched, and a model of the Earth's subsurface is generated that accounts for all of the seismic data, the seismoelectric data, the electroseismic data and the electromagnetic data.
摘要:
A method for determining a component of electric field response to a time varying electromagnetic field induced in the Earth's subsurface involves measuring magnetic field gradient in at least two orthogonal directions in response to the induced electromagnetic field and determining an electric field response in a direction normal to the magnetic field gradient measurements. A method for determining a component of electric field response of the Earth's subsurface to a time varying electromagnetic field induced in the Earth's subsurface involves measuring electric field response along a substantially closed pattern on at least one of the Earth's surface and the bottom of a body of water and determining an electric field response in a direction normal to the measured electric field response using electric field response measurements made at opposed positions along the closed pattern.
摘要:
A method for determining a component of electric field response of the Earth's subsurface to a time-varying electromagnetic field induced in the Earth's subsurface is provided. The method includes measuring electric field response along a nonlinear pattern on at least one of the Earth's surface and the bottom of a body of water. The method includes measuring magnetic field response in three directions along the nonlinear pattern on at least one of the Earth's surface and the bottom of the body of water. The method further includes determining an electric field response in a direction normal to the measured electric field response using the electric field response and magnetic field response measurements.
摘要:
An instrument is disclosed for measuring resistivity of Earth formations from within a conductive pipe inside a wellbore drilled through the formations. The instrument includes a plurality of housings connected end to end and adapted to traverse the wellbore. At least one electrode is disposed on each housing. Each electrode is adapted to be placed in electrical contact with the inside of the pipe. The instrument includes a source of electrical current, a digital voltage measuring circuit and a switch. The switch is arranged to connect the source of electrical current between one of the electrodes and a current return at a selectable one of the top of the pipe and a location near the Earth's surface at a selected distance from the top of the pipe, and to connect selected pairs of the electrodes to the digital voltage measuring circuit. The pairs are selected to make voltage measurements corresponding to selected axial distances and selected lateral depths in the Earth formations.
摘要:
A method for controlled source electromagnetic Earth surveying includes deploying a plurality of electromagnetic sensors in a selected pattern at the top of an area of the Earth's subsurface to be surveyed. At least one of a transient electric field and a transient magnetic field is applied to the Earth in the vicinity of the sensors at a plurality of different positions. At least one of electric field amplitude and magnetic field amplitude at each of the sensors is recorded each time the transient electric field and/or magnetic field is applied. Each recording is adjusted for acquisition geometry. An image is generated corresponding to at least one sensor position using at least two stacked, adjusted recordings.
摘要:
A method of determining resistivity of an earth formation penetrated by a wellbore having conductive casing. The preferred embodiment includes inserting a sonde into the wellbore, the sonde having a plurality of electrodes at axially spaced apart locations adapted to electrically contact the casing, applying electrical current between a first and a second one of the electrodes and measuring the current, measuring a first voltage between a first pair of electrodes axially disposed between the first and second electrodes and measuring a second voltage between a second pair of electrodes also axially disposed between the first and second electrodes and disposed externally to the first pair to determine casing resistance in between the pairs of electrodes. A second difference between the first and second voltages is also measured. Current is applied between other electrodes axially disposed to exclude a third pair of electrodes therebetween, and a third voltage is measured between the third pair to determine characteristic impedance. Current is applied between the first electrode and a surface return electrode, a fourth voltage is measured between the first pair of electrodes, a fifth voltage is measured between the second pair of electrodes, an additional second difference of voltages between the fourth voltage and the fifth voltage is measured, and formation resistivity is determined by combining the first voltage, the second voltage, the third voltage, the fourth voltage, the fifth voltage, the current measurements, the second difference and the additional second difference of the voltages.
摘要:
A sensor cable system for measuring electromagnetic response of the Earth's subsurface includes a sensor cable deployable on the bottom of a body of water. The sensor cable has a plurality of electromagnetic sensing devices thereon at spaced apart locations. A system control unit is in signal communication with the sensing elements. The system control unit includes a transceiver for communicating signals to and from a corresponding sensor cable system. The system control unit includes a global positioning system signal receiver. The system control unit includes a processor configurable to receive signals detected by sensing elements in the corresponding sensor cable system. The processor is configurable to compute stacked signals from the sensing elements in the sensor cable and from sensing elements in the corresponding system. The processor is configurable to calculate a statistical measure of the stacked signals. The system control unit is disposed in a flotation device.
摘要:
A marine electromagnetic acquisition apparatus includes a sensor module having at least one sensor associated therewith. A sensor arm assembly is coupled to the sensor module. The sensor arm assembly has at least one sensor arm and at least one sensor disposed along the at least one sensor arm. An actuator is coupled to the sensor arm assembly for moving the sensor arm assembly between a folded position and an unfolded position.
摘要:
A sensor cable system for measuring electromagnetic response of the Earth's subsurface includes a sensor cable deployable on the bottom of a body of water. The sensor cable has a plurality of electromagnetic sensing devices thereon at spaced apart locations. A system control unit is in signal communication with the sensing elements. The system control unit includes a transceiver for communicating signals to and from a corresponding sensor cable system. The system control unit includes a global positioning system signal receiver. The system control unit includes a processor configurable to receive signals detected by sensing elements in the corresponding sensor cable system. The processor is configurable to compute stacked signals from the sensing elements in the sensor cable and from sensing elements in the corresponding system. The processor is configurable to calculate a statistical measure of the stacked signals. The system control unit is disposed in a flotation device.