Systems and methods of the present disclosure relate to calibration of a resistivity tool. A method for in-situ calibration of a resistivity logging tool, comprises transmitting signals with transmitters of the resistivity logging tool; measuring voltages at two or more receivers located at different distances to the transmitters of the resistivity logging tool; decoupling two or more sets of multi-component tensors at two or more receivers based on the measured voltages; calculating a ratio signal from two or more sets of multi-component tensors; obtaining an apparent resistivity based on the ratio signal; simulating a dipole response tensor at the first receiver based on the apparent resistivity; comparing the first set of multi-component tensor with the dipole response tensor to acquire an in-situ calibration factor; and applying the in-situ calibration factor to multi-components for an inversion input.

Embodiments of an invention disclosed herein relate to methods for performing formation evaluation of a formation or formation's surrounding to identify and characterize the abundance and morphology of non-ionic conductor grains, “c-grains”, within the formations that are evaluated by formation evaluation (FE) tools. The methods and related systems as disclosed herein are directed to correcting any existing FE logs that can be adversely affected by the presence of c-grains in the detection volume of FE tools, and/or obtaining new FE information that is unavailable by the application of existing FE methods.

Embodiments of an invention disclosed herein relate to methods for performing formation evaluation of a formation or formation's surrounding to identify and characterize the abundance and morphology of non-ionic conductor grains, “c-grains”, within the formations that are evaluated by formation evaluation (FE) tools. The methods and related systems as disclosed herein are directed to correcting any existing FE logs that can be adversely affected by the presence of c-grains in the detection volume of FE tools, and/or obtaining new FE information that is unavailable by the application of existing FE methods.

A method for a multichannel geophysical data acquisition system is provided in the field of electrical resistivity tomography. Individual and autonomous node operating systems are provided. Separate communication channels for upstream and downstream data transfer, high voltage transfer and synchronization signals are provided. A novel use of high voltage isolation barriers is also provided. A direct memory access data transfer process is provided.

A method for a multichannel geophysical data acquisition system is provided in the field of electrical resistivity tomography. Individual and autonomous node operating systems are provided. Separate communication channels for upstream and downstream data transfer, high voltage transfer and synchronization signals are provided. A novel use of high voltage isolation barriers is also provided. A direct memory access data transfer process is provided.

A method includes deploying a logging tool in a borehole formed in a subsurface formation, the logging tool having a transmitter and a receiver, wherein a condition that is present during logging comprises at least one of a shape of the borehole is non-circular and the logging tool is off-center within the borehole. The method includes emitting, by the transmitter, a signal into subsurface formation and detecting, by the receiver, a response to the signal being propagated through the subsurface formation. The method includes creating, from the response, a borehole image that includes features in the subsurface formation and correcting the features, wherein correcting the features comprises mapping points of a non-circular shape in the borehole image into a plane substantially perpendicular to an axis of the borehole.

A method includes deploying a logging tool in a borehole formed in a subsurface formation, the logging tool having a transmitter and a receiver, wherein a condition that is present during logging comprises at least one of a shape of the borehole is non-circular and the logging tool is off-center within the borehole. The method includes emitting, by the transmitter, a signal into subsurface formation and detecting, by the receiver, a response to the signal being propagated through the subsurface formation. The method includes creating, from the response, a borehole image that includes features in the subsurface formation and correcting the features, wherein correcting the features comprises mapping points of a non-circular shape in the borehole image into a plane substantially perpendicular to an axis of the borehole.

A method for determining tortuosity, e.g., in an oilfield well includes obtaining a planned trajectory for a hole, and obtaining a first survey of the hole using a sensor deployed into the hole. The first survey includes a first surveyed position at a first depth of the hole and a second surveyed position at a second depth of the hole, and no surveyed positions between the first and second depths. The method further includes simulating a second survey of the hole between the first and second depths using a model. The second survey includes a plurality of simulated positions of the hole between the first and second depths. The method includes determining that the simulated position at the second depth is proximal to the second surveyed position, and visualizing a trajectory of the hole based on the first and second surveys.

An application method of a device for accurately evaluating the vertical content distribution of an undersea hydrate reservoir includes the following steps: assembling the device into a whole and screwing it into an undersea well; activating natural gas hydrates to produce gaseous substances; opening a directional guide channel corresponding to a thermal excitation system in a working state in S2, so that gaseous natural gas hydrates generated in this horizon enter a screw-in long sleeve through the directional guide channel; collecting, by a gas collection system, the gaseous natural gas hydrates; analyzing and recording components and contents in a box by an optical ranging unit and a resistivity unit; repeating S4 and S5 till the end of one collection cycle; and performing data processing and analysis. In this way, accurate evaluation of the vertical content distribution of undersea hydrates is realized.

An application method of a device for accurately evaluating the vertical content distribution of an undersea hydrate reservoir includes the following steps: assembling the device into a whole and screwing it into an undersea well; activating natural gas hydrates to produce gaseous substances; opening a directional guide channel corresponding to a thermal excitation system in a working state in S2, so that gaseous natural gas hydrates generated in this horizon enter a screw-in long sleeve through the directional guide channel; collecting, by a gas collection system, the gaseous natural gas hydrates; analyzing and recording components and contents in a box by an optical ranging unit and a resistivity unit; repeating S4 and S5 till the end of one collection cycle; and performing data processing and analysis. In this way, accurate evaluation of the vertical content distribution of undersea hydrates is realized.