A method for formation evaluation may comprise forming one or more model parameters from one or more priori geological information and one or more downhole measurements, identifying one or more inversion controls, and performing a forward model operation using a piecewise polynomial model (PPM). The method may further comprise performing an optimization using at least the forward model operation, the one or more model parameters, and the one or more inversion controls, determining if a misfit between the one or more downhole measurements and the one or more model parameters is greater than or less than a threshold, and updating the forward model operation or the one or more priori geological information based at least in part on the misfit.

A method for formation evaluation may comprise forming one or more model parameters from one or more priori geological information and one or more downhole measurements, identifying one or more inversion controls, and performing a forward model operation using a piecewise polynomial model (PPM). The method may further comprise performing an optimization using at least the forward model operation, the one or more model parameters, and the one or more inversion controls, determining if a misfit between the one or more downhole measurements and the one or more model parameters is greater than or less than a threshold, and updating the forward model operation or the one or more priori geological information based at least in part on the misfit.

Methods are provided for determining a depositional environment of a sample of a subterranean environment. An example method includes measuring intensities for a crystallographic plane (CP) 100 peak and a CP 101 peak for quartz in a diffractogram, calculating a ratio of the intensities of the CP 100 peak to the CP 101 peak, and identifying a depositional environment for the sample from the ratio.

Methods are provided for determining a depositional environment of a sample of a subterranean environment. An example method includes measuring intensities for a crystallographic plane (CP) 100 peak and a CP 101 peak for quartz in a diffractogram, calculating a ratio of the intensities of the CP 100 peak to the CP 101 peak, and identifying a depositional environment for the sample from the ratio.

The systems and method described in this specification relate to at least partially restoring carbonate core samples. The systems and methods include extracting a carbonate core sample from a subterranean formation. The extracted carbonate core sample is inserted into a core flooding test machine. A first brine permeability of the extracted carbonate core sample is measured. A fluid is pumped through the extracted carbonate core sample to flood the carbonate core sample. The fluid includes at least one of a high-molecular weight polymer solution and a gel particle solution. The systems and methods include at least partially restoring the porosity and the brine permeability of the flooded carbonate core sample by pumping an oxidizing solution through the carbonate core sample and heating the carbonate core sample to a temperature of at least 60° C. after pumping the oxidizing solution through the carbonate core sample.

The present disclosure describes a method that includes: accessing production logs at a well location of the carbonate reservoir, the production logs comprising data encoding a flow meter profile and a ratio of water and oil (WOR) at each depth of a range of depths; accessing measurements of core samples extracted from each depth within the range of depths; based on the measurements of core samples, determining a relationship of permeability and porosity at each depth within the range of depths; based on the production logs, analyzing the WOR to determine a derivative WOR′ (dWOR/dt) at each depth within the range of depths; and characterizing at least one productive zone at the well location based on a combination of the WOR, the WOR′, the flow meter profile, and the relationship of permeability and porosity at each depth within the range of depths.

Provided herein are various embodiments of determining a cation exchange capacity of a rock sample. One embodiment of a method of determining a cation exchange capacity of a rock sample comprises equilibrating the rock sample to a relative humidity, performing a dielectric permittivity measurement on the rock sample at the relative humidity, and determining a cation exchange capacity of the rock sample based on the dielectric permittivity measurement. One embodiment of a method of determining a cation exchange capacity of a rock sample comprises receiving a dielectric permittivity measurement on the rock sample, and determining a cation exchange capacity for the rock sample based on the dielectric permittivity measurement of the rock sample and a relationship between cation exchange capacity and dielectric permittivity measurements for mineral mixtures corresponding to a range of cation exchange capacity values.

Embodiments of the disclosure can include systems, methods, and devices for determining saturation pressure of an uncontaminated fluid. Downhole saturation pressure measurements and downhole OBM filtrate contamination of a contaminated fluid may be obtained and a relationship may be determined between the saturation pressure measurements and OBM filtrate contamination. The relationship may be extrapolated to zero OBM filtrate contamination to determine the saturation pressure of the uncontaminated fluid. In some embodiments, OBM filtrate contamination may be determined from downhole saturation pressure measurements during pumpout of a fluid.

Methods, systems, devices, and products for downhole operations. Embodiments include downhole tools comprising an outer member configured for conveyance in the borehole; a pressure barrel positioned inside the outer member; a substantially cylindrical pod positioned inside the pressure barrel; and at least one downhole electronic component mounted between the exterior surface and the frame. The pod comprises at least one rigid outer surface forming an exterior surface of the pod and supported by a central frame extending across a diameter of the pod, such as a plurality of outer rigid surfaces. The pod may include a plurality of coupled rigid elongated semicircular metallic shells, wherein each shell of the plurality comprises a rigid outer surface of the plurality of outer rigid surfaces. Each of the at least one downhole electronic component may be sealingly enclosed within a corresponding shell.

A method of fabricating a ferrite for use in a resistivity logging tool includes providing an uncured ferrite material, and pressing the uncured ferrite material into a channel to form the ferrite. The channel is defined on a surface of a bobbin associated with the resistivity logging tool, and the channel can be arcuate and extend at an angle offset from a central axis of the bobbin. The uncured ferrite material is then cured in place within the channels on the bobbin.