Abstract: Systems, methods, and apparatuses to generate a crosswell data set are described. In certain aspects, a method includes producing a first electromagnetic field at the earth's surface with a transmitter at a first location, detecting in a first borehole a first field signal induced by the first electromagnetic field, detecting in a second borehole a second field signal induced by the first electromagnetic field, and generating a crosswell data set from the first field signal and the second field signal. A formation model may be created from the crosswell data set.

Abstract: An electromagnetic (EM) data acquisition method for a geological formation may include operating EM measurement devices to determine phase and amplitude data from the geological formation. The EM measurement devices may include at least one first EM measurement device within a borehole in the geological formation, and at least one second EM measurement device at a surface of the geological formation. The method may further include processing the phase data independent from the amplitude data to generate a geological constituent map of the geological formation, and identifying different geological constituents in the geological constituent map based upon the measured amplitude data.

Abstract: A technique that is usable with a well includes providing a model so predict measurements that are received by receivers due to transmissions by sources based on estimated positions of the receivers relative to the sources. The estimated positions each have at least two dimensions. At least some of the receivers and the sources are located in the well. On a computer, the estimated positions are automatically refined based on a comparison of the predicted measurements and actual measurements that are obtained by the receivers.

Abstract: To process measurement data representing a subterranean structure, a derivative of the measurement data collected by at least one survey receiver is computed, with respect to frequency. A response representing the subterranean structure is then computed based on the derivative of the measurement data, where the response contains an air-wave component that has been suppressed due to computing the derivative of the measurement data relative to at least another component that is sensitive to the subterranean structure.

Abstract: To process subterranean survey data, measurement data is collected by a receiver positioned in deep water, where the collected measurement data is responsive to signals emitted by at least one signal source located at or near an air-water interface of the body of water. The measurement data is processed to reduce a predetermined signal component.

Abstract: 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.

Abstract: A technique includes using a first sensor to perform a first electromagnetic field measurement to obtain first data, which is indicative of the presence of a resistive body. The first data is relatively sensitive to an effect that is caused by an air layer boundary. The technique includes using a second sensor to perform a second electromagnetic field measurement to obtain second data, which is indicative of the presence of the resistive body. The second data is relatively sensitive to the effect, and the first and second sensors are either both magnetic field sensors or both electric field sensors. The technique includes combining the first and second data to generate third data, which is relatively insensitive to the effect and is indicative of the presence of the resistive body.

Abstract: To process measurement data representing a subterranean structure, a derivative of the measurement data collected by at least one survey receiver is computed, with respect to frequency. A response representing the subterranean structure is then computed based on the derivative of the measurement data, where the response contains an air-wave component that has been suppressed due to computing the derivative of the measurement data relative to at least another component that is sensitive to the subterranean structure.

Abstract: 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.

Abstract: The 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.

Abstract: A technique includes performing first electromagnetic field measurements to obtain a first set of data and performing second electromagnetic field measurements to obtain a second set of data. The first set of data is relatively sensitive to an effect caused by an air layer boundary and is relatively insensitive to the presence of a resistive body. The second set of data is relatively insensitive to the effect and is relatively sensitive to the presence of the resistive body. The technique includes combining the first and second sets of data to generate a third set of data, which is relatively insensitive to the effect and is relatively sensitive to the presence of the resistive body.

Abstract: To process subterranean survey data, measurement data is collected by a receiver positioned in deep water, where the collected measurement data is responsive to signals emitted by at least one signal source located at or near an air-water interface of the body of water. The measurement data is processed to reduce a predetermined signal component.

Abstract: A technique that is usable with a well includes providing a model so predict measurements that are received by receivers due to transmission by sources baaed on estimated positions of the receivers relative to sources. The estimated positions each have at least two dimensions. At least some of the receivers and the sources are located in the well. On a computer, the estimated positions are automatically refined based on a comparison of the predicted measurements and actual measurements that are obtained by the receivers.

Abstract: The 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.

Abstract: To perform a survey of a subterranean structure behind a subsea surface, at least one sensor module is provided in a subsea environment, where the at least one sensor module comprises at least one magnetic field sensor. Measurement data is received from the magnetic field sensor, and an electric field along a particular direction is determined based on the measurement data to perform the survey of the subterranean structure, wherein the particular direction is generally orthogonal to the subsea surface.

Abstract: To survey a subterranean structure, first measurement data according to a first electromagnetic survey technique and second measurement data according to a second, different electromagnetic survey technique are received. An output value for surveying the subterranean structure is computed based on the first and second measurement data.

Abstract: To survey a subterranean structure, first measurement data according to a first electromagnetic survey technique and second measurement data according to a second, different electromagnetic survey technique are received. An output value for surveying the subterranean structure is computed based on the first and second measurement data.

Abstract: A technique includes performing first electromagnetic field measurements to obtain a first set of data and performing second electromagnetic field measurements to obtain a second set of data. The first set of data is relatively sensitive to an effect caused by an air layer boundary and is relatively insensitive to the presence of a resistive body. The second set of data is relatively insensitive to the effect and is relatively sensitive to the presence of the resistive body. The technique includes combining the first and second sets of data to generate a third set of data, which is relatively insensitive to the effect and is relatively sensitive to the presence of the resistive body.

Abstract: A technique includes using a first sensor to perform a first electromagnetic field measurement to obtain first data, which is indicative of the presence of a resistive body. The first data is relatively sensitive to an effect that is caused by an air layer boundary. The technique includes using a second sensor to perform a second electromagnetic field measurement to obtain second data, which is indicative of the presence of the resistive body. The second data is relatively sensitive to the effect, and the first and second sensors are either both magnetic field sensors or both electric field sensors. The technique includes combining the first and second data to generate third data, which is relatively insensitive to the effect and is indicative of the presence of the resistive body.