A system and techniques for detecting near-subsurface voids in the earth use a controlled source electromagnetic transmitter and a plurality of controlled source electromagnetic receivers. Signals received by the plurality of controlled source electromagnetic receivers corresponding to signals generated by the controlled source electromagnetic transmitter are analyzed. Bi-static doublets detected in the received signals are used to identify the location of the near-subsurface voids.

A system and techniques for detecting near-subsurface voids in the earth use a controlled source electromagnetic transmitter and a plurality of controlled source electromagnetic receivers. Signals received by the plurality of controlled source electromagnetic receivers corresponding to signals generated by the controlled source electromagnetic transmitter are analyzed. Bi-static doublets detected in the received signals are used to identify the location of the near-subsurface voids.

A method and system for estimating a resistivity of a formation. A method for estimating a resistivity of a formation may comprise disposing a downhole tool into a borehole, wherein the downhole tool comprises a pad, an injector electrode, and a return electrode, injecting a current signal into the formation from the injector electrode, measuring a voltage signal between the injector electrode and the return electrode; and determining a formation resistivity and a formation dielectric constant from at least one of the voltage signal, at least one property of the downhole tool, and at least one property of the borehole. A system for estimating a resistivity of a formation may comprise a downhole tool. The downhole tool may comprise a pad, wherein the pad comprises an injector electrode and a return electrode. The system may further comprise a conveyance for disposing the downhole tool in a borehole and an information handling system.

A method and system for estimating a resistivity of a formation. A method for estimating a resistivity of a formation may comprise disposing a downhole tool into a borehole, wherein the downhole tool comprises a pad, an injector electrode, and a return electrode, injecting a current signal into the formation from the injector electrode, measuring a voltage signal between the injector electrode and the return electrode; and determining a formation resistivity and a formation dielectric constant from at least one of the voltage signal, at least one property of the downhole tool, and at least one property of the borehole. A system for estimating a resistivity of a formation may comprise a downhole tool. The downhole tool may comprise a pad, wherein the pad comprises an injector electrode and a return electrode. The system may further comprise a conveyance for disposing the downhole tool in a borehole and an information handling system.

Systems and methods of the present disclosure relate to calibration of a resistivity tool. A calibration method comprises deploying a transmitter in a known formation with a known resistivity property with a physical tilted angle θ relative to a longitudinal axis of the tool; deploying receivers in the known formation, wherein a physical tilted angle of a first receiver is θ relative to the longitudinal axis of the tool, and wherein a physical tilted angle of a second receiver is −θ, relative to the longitudinal axis of the tool; transmitting signals with the transmitter and measuring the signals at the receivers; combining measurements at two receivers with respect to a transmitter signal in the known formation; producing synthetic responses of the tool in the known formation using forward modeling; and calculating an effective tilted angle θ′ from real measurements and the synthetic responses.

Systems and methods of the present disclosure relate to calibration of a resistivity tool. A calibration method comprises deploying a transmitter in a known formation with a known resistivity property with a physical tilted angle θ relative to a longitudinal axis of the tool; deploying receivers in the known formation, wherein a physical tilted angle of a first receiver is θ relative to the longitudinal axis of the tool, and wherein a physical tilted angle of a second receiver is −θ, relative to the longitudinal axis of the tool; transmitting signals with the transmitter and measuring the signals at the receivers; combining measurements at two receivers with respect to a transmitter signal in the known formation; producing synthetic responses of the tool in the known formation using forward modeling; and calculating an effective tilted angle θ′ from real measurements and the synthetic responses.

Methods for simulation of hydrocarbon systems having a sharply varying viscosity gradient include receiving, by a computer system, Neutron Magnetic Resonance (NMR) logs for hydrocarbon wells in an oilfield. The computer system identifies viscosity regions of hydrocarbons present within the hydrocarbon wells based on the NMR logs. The computer system determines equation of state (EOS) parameters based on compositional analysis of pressure-volume-temperature (PVT) samples obtained from the hydrocarbon wells. The computer system generates a three-dimensional (3D) model of the oilfield, using as inputs, the viscosity regions, the EOS parameters, and a fluid composition gradient with respect to a depth within each viscosity region. The computer system determines a landing depth from the surface of the Earth for operation of peripheral water injectors based on simulating the 3D viscosity model.

Methods for simulation of hydrocarbon systems having a sharply varying viscosity gradient include receiving, by a computer system, Neutron Magnetic Resonance (NMR) logs for hydrocarbon wells in an oilfield. The computer system identifies viscosity regions of hydrocarbons present within the hydrocarbon wells based on the NMR logs. The computer system determines equation of state (EOS) parameters based on compositional analysis of pressure-volume-temperature (PVT) samples obtained from the hydrocarbon wells. The computer system generates a three-dimensional (3D) model of the oilfield, using as inputs, the viscosity regions, the EOS parameters, and a fluid composition gradient with respect to a depth within each viscosity region. The computer system determines a landing depth from the surface of the Earth for operation of peripheral water injectors based on simulating the 3D viscosity model.

Data is received downhole from a downhole logging tool to produce received data. The received data is processed to produce processed data. A binary formatting option is selected from a group of binary formatting options, wherein applying the selected binary formatting option to the processed data produces fewer bits than applying any other binary formatting option of the group of binary formatting options to the processed data. The selected binary formatting option is applied to the processed data to produce binary data. The binary data is transmitted uphole. The binary data is received uphole. The received binary data is decompressed to produce uncompressed data. The uncompressed data is processed uphole.

Data is received downhole from a downhole logging tool to produce received data. The received data is processed to produce processed data. A binary formatting option is selected from a group of binary formatting options, wherein applying the selected binary formatting option to the processed data produces fewer bits than applying any other binary formatting option of the group of binary formatting options to the processed data. The selected binary formatting option is applied to the processed data to produce binary data. The binary data is transmitted uphole. The binary data is received uphole. The received binary data is decompressed to produce uncompressed data. The uncompressed data is processed uphole.