71 results about "Geophysical survey" patented technology

A method of data acquisition for geophysical surveys. The method includes the steps of providing a least one magnetic sensor unit for sensing and recording magnetic field fluctuations; providing a plurality of electric sensor units for sensing and recording electric currents induced by the magnetic field fluctuations; receiving a satellite based timing signal and responsively synchronizing and bag a position for each of the plurality of electric sensor units and the at least one magnetic sensor unit; and synchronously recording the positions, the magnetic field fluctuations and the electric currents for downloading for processing.

The presently disclosed technique includes a method for geophysical survey having at least one source and one receiver, wherein the survey has two sets of survey locations within the survey area, one set of survey locations for the source(s) and the other set of survey locations for the receiver(s), wherein the survey locations in one set are randomized.

Method for reducing the time needed to perform geophysical inversion by using simultaneous encoded sources in the simulation steps of the inversion process. The geophysical survey data are prepared by encoding (3) a group of source gathers (1), using for each gather a different encoding signature selected from a set (2) of non-equivalent encoding signatures. Then, the encoded gathers are summed (4) by summing all traces corresponding to the same receiver from each gather, resulting in a simultaneous encoded gather. (Alternatively, the geophysical data are acquired from simultaneously encoded sources.) The simulation steps needed for inversion are then calculated using a particular assumed velocity (or other physical property) model (5) and simultaneously activated encoded sources using the same encoding scheme used on the measured data. The result is an updated physical properties model (6) that may be further updated (7) by additional iterations.

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 (195) are placed near each electrode (26, 27), and means (197, 198) are provided for correcting the electrodes to be at the same elevation with azimuth aligned with the source tow line (11) and the electrode mid-point positioned over the source tow line, based on instantaneous location information from the sensors. The streamer (28) connecting the electrodes may also be monitored for shape by sensors, with corrections made by lateral and vertical control means disclosed herein. The invention can be applied to any marine streamer used in geophysical surveys, including a towed streamer (191) of electromagnetic or seismic receivers (192).

A method and apparatus of constructing a signal for a controlled source electromagnetic survey is described. In one embodiment, a method is described that includes determining a first waveform and a second waveform, the first waveform and second waveform related to a combined frequency spectrum and bandwidth associated with a geophysical survey line. Then, a signal is constructed by sequencing the first waveform with the second waveform. This signal may be utilized in a transmitter, which may be pulled by a vessel along the geophysical survey line.

An improved seismic method comprises the steps of generating seismic waves by exploding an explosive device in a subterranean formation, wherein the explosive device comprises a plurality of explosive elements whereby there is a time delay between the detonations of the individual explosive elements, and detecting the seismic waves and / or reflections thereof with seismic detectors. Also disclosed are geophysical survey systems that comprise a seismic energy source comprising an explosive device that comprises a plurality of explosive elements, the seismic energy source being located in a subterranean formation, and a plurality of seismic detectors that are adapted to detect seismic waves and / or reflections generated when the seismic energy source explodes.

An apparatus and procedure for passively performing a geophysical survey. The RAP Equipment complex comprises an A / D Conversion Device, an external sensor, an external 12 volt battery, and a Notebook Computer in which resides a Fourier analysis program. The A / D Conversion Device is connected to the serial port of the Notebook Computer. The A / D Conversion Device comprises an Analog / Digital Converter modified to replace its quartz resonator with a Frequency Generator for providing a predetermined sampling rate, and a Signal Amplifier. An external sensor is attached by a cable to the input of the Signal Amplifier. A 12 volt power supply powers the Signal Amplifier, the modified A / D converter, and the Notebook Computer. In use, the external sensor is placed on the ground at the first spot it is desired to take a reading. The ground is then lightly tapped in the near vicinity of the sensor either with one's finger or a hammer. This tap causes the natural vibrations within the subsurface layers to be amplified. The sensor picks up these vibrations from the resonating layers, passes them on to the Signal Amplifier which in turn amplifies these signals and passes them on to the A / D Conversion Device. The A / D conversion Device converts these acoustical signals from analog form to digital form and passes them on to the serial port of the Notebook Computer which in turn creates a file of these digital signals.

An airborne geophysical surveying system comprising a receiver coil assembly for towing by an aircraft, the receiver assembly including a receiver coil for sensing changes in a magnetic field component of a magnetic field, and a receiver coil orientation sensing system for sensing orientation changes of the receiver coil. A controller receives signals representing the sensed changes in the magnetic field component from the receiver coil and the sensed orientation changes from the receiver coil orientation sensing system and corrects the sensed changes in the magnetic field component to provide a signal that is corrected for noise caused by changing orientation of the receiver coil in a static geomagnetic field.

Method for enhancing resistive anomalies in electromagnetic geophysical survey data. Scaled values of a measured electromagnetic field parameter are plotted on a depth section at locations related to corresponding source / receiver locations. Scaling is performed relative to a reference signal selected to represent a baseline free of unknown resistive bodies. Scaled values are represented by a color scale in the display, and the color scale may be adjusted to enhance perceived anomalies. The method may be employed in either the frequency domain or the time domain.

Method for enhancing resistive anomalies in electromagnetic geophysical survey data. Scaled values of a measured electromagnetic field parameter are plotted on a depth section at locations related to corresponding source / receiver locations. Scaling is performed relative to a reference signal selected to represent a baseline free of unknown resistive bodies. Scaled values are represented by a color scale in the display, and the color scale may be adjusted to enhance perceived anomalies. The method may be employed in either the frequency domain or the time domain.

Apparatus for conducting geophysical surveys comprising a multiplicity of intelligent electrodes provided on a multi-conductor cable, for receiving a command signal in response to which predetermined electrodes are connected to selected conductors in the cable. Each intelligent electrode is identical in all respects, including its programming, resulting in simplified construction of the cable and easy replacement of the intelligent electrodes. Instead of assigning a unique address code to each switch in a series of take-outs on a multi-conductor cable, each electronic switch is programmed with the same address code. That is, each switch is programmed to be activated when it receives a code command that, for example, is prefaced with a particular address, e.g. the number 1. The second part of the code (y) instructs the switch as to which conductor in the multi-conductor cable is to be connected to the local electrode at the location of the switch. When the controller issues a code command that is prefaced by a number which is larger than 1, (e.g. n), then the first switch in the sequence of switches along the cable decrements the preface number. The first switch then re-transmits the code command, with only the preface portion having been changed, (i.e. to n-1), along the cable to the next switch in the series. Each successive switch performs a similar modification to the preface number, and retransmits the progressively modified code command to the next switch in the series. Ultimately, when the modified command reaches the nth switch, it is prefaced with the number 1, whereupon that switch then recognizes it as a valid command to operate. The second part of the command (y) remains unaltered through the repeated re-transmissions, and determines which conductor in the cable is to be connected to the electrode (i.e. to ground).

A method for the design of VSP surveys for the purpose of imaging a reef in the formations surrounding the well in question. The basic steps include:building a geophysical model;defining receiver locations in the well within the model;defining the target (reef);ray tracing from receivers to surface via target;defining source locations on surface based on ray density pattern; andvalidate by ray tracing from source locations to receiver locations via target.

The presently disclosed technique includes a method for geophysical survey having at least one source and one receiver, wherein the survey has two sets of survey locations within the survey area, one set of survey locations for the source(s) and the other set of survey locations for the receiver(s), wherein the survey locations in one set are randomized.

The invention discloses a multi-block multi-unit three-dimensional geological survey method and belongs to the technical field of geological survey. The method is characterized by including the steps of (1), modeling geological units; (2) building multi-block initial geological structure models; (3), performing field geological research and geophysical survey; (4), modifying models; (5), assembling models; (6) drilling for verification; researching primary model application. The method is mainly applicable to geological survey and research.

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 (195) are placed near each electrode (26, 27), and means (197, 198) are provided for correcting the electrodes to be at the same elevation with azimuth aligned with the source tow line (11) and the electrode mid-point positioned over the source tow line, based on instantaneous location information from the sensors. The streamer (28) connecting the electrodes may also be monitored for shape by sensors, with corrections made by lateral and vertical control means disclosed herein. The invention can be applied to any marine streamer used in geophysical surveys, including a towed streamer (191) of electromagnetic or seismic receivers (192).

A downhole drilling tool is adapted to be placed in a borehole formed in the earth. The downhole drilling tool has mounted thereto at least one of a transmitter for generating and a receiver for sensing at least one component of an electromagnetic field within a distant earth region. The tool also has a device configured to acquire subsurface data from the at least one component of the electromagnetic field; and a device configured to calculate a resistivity distribution of the distant earth region from the subsurface data. A geophysical survey is performed with a downhole drilling tool by transmitting at least one component of an electromagnetic field through the distant earth region; acquiring subsurface data from the at least one component of the electromagnetic field; and calculating a resistivity distribution of the distant earth region from the subsurface data.

A hydrocarbon exploration method for determining subsurface properties from geophysical survey data. Rock physics trends are identified and for each trend a rock physics model is determined that relates the subsurface property to geophysical properties (103). The uncertainty in the rock physics trends is also estimated (104). A geophysical forward model is selected (105), and its uncertainty is estimated (106). These quantities are used in an optimization process (107) resulting in an estimate of the subsurface property and its uncertainty.

Methods and apparatuses are disclosed that assist in sensing underwater signals in connection with geophysical surveys. One embodiment relates to a transducer including a cantilever coupled to a base. The cantilever may include a beam and a first coupling surface angularly oriented from the beam, and the base may include a second coupling surface angularly oriented from the beam and substantially parallel to the first coupling surface of the cantilever. The transducer may further include a sensing material coupled between the first coupling surface of the cantilever and the second coupling surface of the base.

An improved seismic method comprises the steps of generating seismic waves by exploding an explosive device in a subterranean formation, wherein the explosive device comprises a plurality of explosive elements whereby there is a time delay between the detonations of the individual explosive elements, and detecting the seismic waves and / or reflections thereof with seismic detectors. Also disclosed are geophysical survey systems that comprise a seismic energy source comprising an explosive device that comprises a plurality of explosive elements, the seismic energy source being located in a subterranean formation, and a plurality of seismic detectors that are adapted to detect seismic waves and / or reflections generated when the seismic energy source explodes.

In one embodiment the invention comprises a system for planning a seismic survey based on a model of a subsurface formation in which a computer simulation is generated having sources and receivers positioned in selected locations with respect to the model. Ray tracing is performed from the sources to estimate a propagation ray path of seismic signals emanating from the source locations, and emergent points are determined at which ray paths reach the earth's surface following reflection from a subsurface area of interest. A survey may then be designed and performed in which receiver positions are concentrated at the areas where the emergent points are concentrated.

The invention discloses a pile extracting construction method, wherein an approximate location of a discarded pile is initially determined by using a seismic geophysical survey, and the specific pile location is detected and determined by using a small screw drill; by using the method, the discarded pile is located more accurately; during a steel pipe sinking procedure, a soil layer beside the pile is washed in a casing pipe by using high pressure jetted gas and water, so that the frictional force on the outer side of the pile is reduced to be minimum, and the pile is convenient to pull out; compared with the traditional method, the pile extracting method is fast in progress; the new foundation bearing capacity in a later period is also ensured.

A hydrocarbon exploration method for determining subsurface properties from geophysical survey data. Rock physics trends are identified and for each trend a rock physics model is determined that relates the subsurface property to geophysical properties (103). The uncertainty in the rock physics trends is also estimated (104). A geophysical forward model is selected (105), and its uncertainty is estimated (106). These quantities are used in an optimization process (107) resulting in an estimate of the subsurface property and its uncertainty.

The present invention relates to a method and system for processing multi-dimensional signal data to determine frequency dependent features therefrom. The multi-dimensional signal data are transformed into space-frequency or time-space-frequency domain, providing second signal data. At predetermined locations of at least a portion of the one of space and time-space of the second signal data a dominant feature corresponding to a largest value of the second signal data is determined. This is followed by the determination of a wave-vector corresponding to the dominant feature at each of the predetermined locations. Finally, a dip map, a frequency map, and an amplitude map are generated using the wave-vectors. The method and system for processing multi-dimensional signal data to determine frequency dependent features therefrom according to the present invention provide a powerful tool for improved and more detailed evaluation of seismic data using dip, frequency, and amplitude maps, resulting in substantially more accurate geophysical surveys.

A method, including: determining, with a computer, point spread functions for a plurality of parameter locations by performing at least a portion of a first iteration of an iterative full wavefield inversion process; determining at least one property for each of the point spread functions; and evaluating a candidate survey design based on the at least one property for each of the point spread functions.

A method for acquiring geophysical data includes connecting a power module comprising a data transfer port and a power transfer port to a geophysical data acquisition device to provide a geophysical sensing node and deploying the geophysical sensing node. While deployed, data is transferred from the geophysical data acquisition device to the power module via the data transfer port and power is transferred from the power module to the geophysical data acquisition device via the power transfer port. The method also includes retrieving the geophysical sensing node and replacing the power module with a newly charged power module to provide a newly charged geophysical sensing node, and deploying the newly charged geophysical sensing node. Corresponding systems are also disclosed herein.

The invention discloses a scale value correction method applied to a shipborne gravimeter. The method comprises the following steps of establishing an error compensation correction model for observinga gravity value by taking the closed gravity data information of the shipborne gravimeter which goes to and from a port of embarkation and stops at a halfway port of recruit as a basic mathematical model, and carrying out error compensation on the observed gravity value; solving a scale value based on the corresponding relationship between the compensated gravity observation value and an absolutegravity value, and compensating the data of the shipborne gravimeter. The method can eliminate the system error caused by the scale value error, can obtain the high-precision voyage number survey result data, and has the important guiding value and practical significance for the marine geophysical survey, especially the marine gravity measurement of deep and far sea voyage numbers.

A system for controlling impulsive sources during a geophysical survey includes a triggering unit that interfaces to an impulsive source and provides an estimated current location for the impulsive source and a shot controller configured to transmit a detonation authorization to the triggering unit. The shot controller or the triggering unit may inhibit detonation of an impulsive source connected to the selected triggering unit if an estimated current location of the impulsive source is substantially different than an intended shot location. A corresponding apparatus and method are also disclosed herein.