Downhole core sampling apparatus including first and second sealing elements and at least one pump configured to pump wellbore fluid from the annular space defined by the sealing elements. The downhole core sampling apparatus is capable of obtaining formation fluid saturated core samples for laboratory testing and reservoir evaluation. Method and system for obtaining formation fluid saturated core samples from the sidewall of subterranean wellbores is provided.

A method for predicting a total minimum horizontal stress (σ.sub.h) and a total maximum horizontal stress (σ.sub.H) for an anisotropic formation may comprise: measuring Young's moduli parallel ±15° and perpendicular ±15° to a transverse isotropy plane of a horizontal core sample from the anisotropic subterranean formation; measuring Poisson's ratios parallel ±15° and perpendicular ±15° to the transverse isotropy plane of the horizontal core sample; inputting the measured Young's moduli and Poisson's ratios of the horizontal core sample into a 1-dimensional mechanical earth model (1-D MEM); and calculating, using the 1-D MEM, a predicted total minimum horizontal stress (σ.sub.h) and a predicted total maximum horizontal stress (σ.sub.H).

A method for predicting a total minimum horizontal stress (σ.sub.h) and a total maximum horizontal stress (σ.sub.H) for an anisotropic formation may comprise: measuring Young's moduli parallel ±15° and perpendicular ±15° to a transverse isotropy plane of a horizontal core sample from the anisotropic subterranean formation; measuring Poisson's ratios parallel ±15° and perpendicular ±15° to the transverse isotropy plane of the horizontal core sample; inputting the measured Young's moduli and Poisson's ratios of the horizontal core sample into a 1-dimensional mechanical earth model (1-D MEM); and calculating, using the 1-D MEM, a predicted total minimum horizontal stress (σ.sub.h) and a predicted total maximum horizontal stress (σ.sub.H).

A system for sidewall coring includes a sidewall coring tool lowered into a wellbore for positioning a coring bit inside a subterranean formation, an injection assembly, and an array of sensors. The coring bit is capable of collecting a core sample by rotating with respect to a housing of the sidewall coring tool. The injection assembly injects a plurality of fluids into a sidewall core and is configured to selectively inject a plurality of fluids into the core sample. The array of sensors is embedded within a sidewall cutter enclosure for recording measurements during an injection process. The array of sensors produces information relating to the core sample.

A system for sidewall coring includes a sidewall coring tool lowered into a wellbore for positioning a coring bit inside a subterranean formation, an injection assembly, and an array of sensors. The coring bit is capable of collecting a core sample by rotating with respect to a housing of the sidewall coring tool. The injection assembly injects a plurality of fluids into a sidewall core and is configured to selectively inject a plurality of fluids into the core sample. The array of sensors is embedded within a sidewall cutter enclosure for recording measurements during an injection process. The array of sensors produces information relating to the core sample.

Testing apparatuses and their methods of use for testing core samples with treatment fluids, such as reactive fluids, such as acidic fluids, are provided. The testing apparatuses include a top and a base housing coupled together having a sample recess, a viewing window, and a primary distribution hole. Within the sample recess a core sample assembly is secured and immobilized. The core sample assembly in the testing apparatus is viewable through the viewing window and fluidly accessible through the primary distribution hole. Optionally, a light connector coupled to the testing apparatus provides light into the core sample assembly. Methods of using the testing apparatus include providing a testing apparatus with a core sample assembly secured and immobilized within the sample recess of the testing apparatus, introducing a treatment fluid to the core sample, and detecting the interaction within the testing apparatus of the core sample with the treatment fluid.

Testing apparatuses and their methods of use for testing core samples with treatment fluids, such as reactive fluids, such as acidic fluids, are provided. The testing apparatuses include a top and a base housing coupled together having a sample recess, a viewing window, and a primary distribution hole. Within the sample recess a core sample assembly is secured and immobilized. The core sample assembly in the testing apparatus is viewable through the viewing window and fluidly accessible through the primary distribution hole. Optionally, a light connector coupled to the testing apparatus provides light into the core sample assembly. Methods of using the testing apparatus include providing a testing apparatus with a core sample assembly secured and immobilized within the sample recess of the testing apparatus, introducing a treatment fluid to the core sample, and detecting the interaction within the testing apparatus of the core sample with the treatment fluid.

Methods for determining mineral compositions of materials are described. The methods include obtaining elemental data associated with a geologic sample, calculating a measurement correlation matrix of the geologic sample from the elemental data, calculating an artificial correlation matrix, comparing the measurement correlation matrix and the artificial correlation matrix to determine an error value, minimizing the error value by updating the artificial correlation matrix and comparing the measurement correlation matrix to the updated artificial correlation matrix, and determining a mineral composition of the geologic sample based on the minimized measurement correlation matrix.

Methods for determining mineral compositions of materials are described. The methods include obtaining elemental data associated with a geologic sample, calculating a measurement correlation matrix of the geologic sample from the elemental data, calculating an artificial correlation matrix, comparing the measurement correlation matrix and the artificial correlation matrix to determine an error value, minimizing the error value by updating the artificial correlation matrix and comparing the measurement correlation matrix to the updated artificial correlation matrix, and determining a mineral composition of the geologic sample based on the minimized measurement correlation matrix.

Well completion is accomplished by obtaining a sample of geological material from the subsurface and generating primary data for the sample of geological material. The primary data include textural data, chemical data and mineralogical data. The primary data are used to derive secondary data for the sample of geological material, and the primary data and the secondary data are used to generate tertiary data for the sample of geological material. The tertiary data are a quantification of physical characteristics of the sample of geological material. The primary data, secondary data and tertiary data are used to determine a location of a stage along a well and an arrangement of perforation clusters in the stage.