Abstract: A method for imaging non-specular seismic events as well as correlating non-specular events with physically measurable quantites in a volume of Earth's subsurface. Includes entering as input to a computer signals detected by a plurality of seismic sensors disposed above and/or within the volume in response to actuation of at least one seismic energy source above and/or within the volume. Parameter analysis is performed to populate the initial model with point-wise, best-fit wavefront travel-time approximations. Imaging is performed to obtain undifferentiated specular and non-specular representations of the volume. Specular boundaries are mapped using the imaged volume and using the boundaries to form a model of specular components of the volume. Beamforming is used to characterize seismic attributes associated with specular and non-specular reflections as separate and differentiated data sets.

Abstract: A method for imaging the Earth's subsurface includes taking summed recordings of signals acquired by a plurality of seismic sensors disposed above the volume in response to repeated actuations of a seismic energy source. A travel time of seismic energy is determined from a position of the source to a selected image point in the volume and from the image point to each seismic sensor. A time-delayed scanline gather is generated from the travel times using a model of spatial distribution of acoustic properties of formations in the volume. A template image of backscattered energy from the image point is generated based on the model. The flattened scanline gather is singular value decomposed. The template image is projected onto the decomposed time-delayed scanline gather. Components from the projection are used to determine signal and interference. Weights are calculated for beamforming of the determined signal component.

Abstract: A method for locating diffractors in subsurface formations includes actuating at least two seismic energy sources at spaced apart locations. Seismic energy is detected in the formations resulting from actuation of the two sources. Signals corresponding to the detected seismic energy are processed to remove components related to direct arrivals from each source. Arrival times of seismic energy in the signals corresponding to energy diffracted from at least one diffractor are identified. The at least one is located diffractor in a plane using the identified arrival times.

Abstract: A method for seismic surveying includes disposing a plurality of seismic sensors in a selected pattern above an area of the Earth's subsurface. A seismic energy source is repeatedly actuated proximate the seismic sensors. A signal used to actuate the source comprises a linear chirp having a starting frequency and an ending frequency less than twice the starting frequency. Recorded signals are processed to generate an image corresponding to at least one point in the subsurface, the processing includes stacking recordings from each sensor for a plurality of actuations of the source, cross correlating the stacked signals with an expected signal generated by non linearities in the subsurface and beam steering a response of the seismic sensors such that the at least one point is equivalent to a focal point of a response of the plurality of sensors.

Abstract: 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.

Abstract: A method for imaging the Earth's subsurface includes taking summed recordings of signals acquired by a plurality of seismic sensors disposed above the volume in response to repeated actuations of a seismic energy source. A travel time of seismic energy is determined from a position of the source to a selected image point in the volume and from the image point to each seismic sensor. A time-delayed scanline gather is generated from the travel times using a model of spatial distribution of acoustic properties of formations in the volume. A template image of backscattered energy from the image point is generated based on the model. The flattened scanline gather is singular value decomposed. The template image is projected onto the decomposed time-delayed scanline gather. Components from the projection are used to determine signal and interference. Weights are calculated for beamforming of the determined signal component.

Abstract: A method for locating diffractors in subsurface formations includes actuating at least two seismic energy sources at spaced apart locations. Seismic energy is detected in the formations resulting from actuation of the two sources. Signals corresponding to the detected seismic energy are processed to remove components related to direct arrivals from each source. Arrival times of seismic energy in the signals corresponding to energy diffracted from at least one diffractor are identified. The at least one is located diffractor in a plane using the identified arrival times.

Abstract: 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.

Abstract: A method for seismic surveying includes disposing a plurality of seismic sensors in a selected pattern above an area of the Earth's subsurface to be evaluated. A seismic energy source is repeatedly actuated proximate the seismic sensors. Signals generated by the seismic sensors, indexed in time with respect to each actuation of the seismic 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 sensor for a plurality of actuations of the source and beam steering a response of the seismic sensors such that the at least one point is equivalent to a focal point of a response of the plurality of sensors.

Abstract: A method for seismic surveying includes disposing a plurality of seismic sensors in a selected pattern above an area of the Earth's subsurface. A seismic energy source is repeatedly actuated proximate the seismic sensors. A signal used to actuate the source comprises a linear chirp having a starting frequency and an ending frequency less than twice the starting frequency. Recorded signals are processed to generate an image corresponding to at least one point in the subsurface, the processing includes stacking recordings from each sensor for a plurality of actuations of the source, cross correlating the stacked signals with an expected signal generated by non linearities in the subsurface and beam steering a response of the seismic sensors such that the at least one point is equivalent to a focal point of a response of the plurality of sensors.

Abstract: 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.

Abstract: An acoustic energy source for imparting acoustic energy into the Earth's subsurface includes an electrically driven transducer coupled to a source of swept frequency alternating current. A tunable Helmholtz resonator is disposed proximate the transducer. In one example, the resonator has a tuning device configured to maintain a resonant frequency substantially equal to an instantaneous frequency of the alternating current. The tuning device includes an actuator coupled to a sleeve, wherein the sleeve is disposed over selected numbers of openings in a wall of a tube on the resonator. The transducer and the resonator are disposed in a wellbore drilled through rock formations. The wellbore has a plurality of layers of fluid therein, each layer thereof having a different density and/or viscosity.

Abstract: A method for characterizing fluid pumping effects on a subsurface formation includes (a) during pumping of fluid into the subsurface formation, detecting passive seismic signals related to fractures created in the subsurface formation. (b) A place of origin of the passive seismic signals is determined. (c) A seismic energy source is actuated for a plurality of actuations and an output thereof is beam steered toward the place of origin. (d) At least one acoustic property is determined for the place of origin using signals detected as a result of the plurality of actuations. The detected signals are beam steered toward the place of origin and are stacked over the plurality of actuations. (a), (b), (c) and (d) are repeated until the pumping is completed.