| Class / Patent application number | Description | Number of patent applications / Date published |
|---|
| 324336000 | To detect transient signals | 7 |
| 20090243616 | MULTI-COMPONENT MARINE ELECTROMAGNETIC SIGNAL ACQUISITION METHOD - 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. | 10-01-2009 |
| 20100097065 | Method and apparatus for while-drilling transient resistivity measurements - Structure for deep MWD resistivity measurements suitable for both geo-steering and measurements ahead of the drill bit is disclosed. The structure is capable of extracting information about resistivity of formation in the presence of conductive drill. In one embodiment, ahead-of-bit sensing is achieved via transient electromagnetic measurements when current is switched off in the transmitter loop and the transient signal is measured in the receiver loops placed at some distances from the receiver. To reduce a parasitic effect of the currents in the drill three-coil bucking system with magnetic nonconductive shield in combination with a highly conductive copper shield are applied. Specifically, a short (less than 1 m) copper cover and short (less than 0.2 m) ferrite cover are placed in the vicinity of transmitting and receiving coils. A bucking operation followed by an inversion is performed on received signals to obtain data reflecting parameters of the surrounding subsurface formations. | 04-22-2010 |
| 20110298460 | 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. | 12-08-2011 |
| 20130154650 | METHOD AND APPARATUS TO DETECT A CONDUCTIVE BODY - Various embodiments include apparatus and methods to detect and locate conductive bodies and/or provide steam-assisted gravity drainage (SAGD) steering operation. Tools can be configured with receiving sensors ( | 06-20-2013 |
| 20150048834 | TOWABLE TRANSIENT ELECTROMAGNETIC SURVEY DEVICE - A towable transient electromagnetic survey device for connection to a land, water based or an airborne towing vehicle is provided. The towable transient electromagnetic survey device includes a central body structure and a number of booms extending therefrom to interconnect the central body structure to the towing vehicle and suspend a transmitter loop for generating a primary electromagnetic field. Receiving loop(s) and transmitter loop(s) may also be housed in the central body structure. The central body structure may also be configured for switching in and out of connection of various transmitter and receiver loop configurations. In particularly preferred arrangements, the location of a transmitter loop or a pair of transmitter loops relative to a receiver loop is effective for substantially nulling mutual inductance between the transmitter loop(s) and the receiver loop. | 02-19-2015 |
| 20150137818 | METHODS OF TRANSIENT EM DATA COMPRESSION - A system and method to compress transient signals are described. The system includes a transmitter disposed in a borehole to change a transmitted current and induce a current in an earth formation, and a receiver disposed in the borehole to receive the transient signals resulting from the transmitted current. The system also includes a processor to compress the transient signals, the processor compressing the transient signals based on a spline approximation method or an Eigen value method for each transient signal based on whether the spline approximation method or the Eigen value method results in a fewer number of parameters representing the transient signal. | 05-21-2015 |
| 20160041295 | SYSTEMS AND METHODS FOR ACTIVE CANCELLATION OF TRANSIENT SIGNALS AND DYNAMIC LOOP CONFIGURATION - A method and system for active cancellation of transient signals and dynamic loop configuration for geophysical exploration is disclosed. The method includes controlling a transmitter to transmit a waveform in a frequency spectrum during an on-time. The transmitter includes a plurality of turns of wire. The method also includes controlling a plurality of switches to direct an electrical signal through the plurality of turns of wire. The plurality of switches electrically coupled to the plurality of turns of wire. The method further includes controlling a switch of the plurality of switches to direct a first portion of a transient current in an opposite direction from a direction of a second portion of the transient current during an off-time. | 02-11-2016 |
