Fracture Sustainability Test, Pre- and Post-Test Photomicrographs

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The primary objective of this research is to understand how different rock types, mineral and fluid compositions, and fracture surface textures determine the longevity of fracture apertures, so that selection of reservoir rock can be economically optimized to reduce future refracturing. We are performing laboratory tests to study this in a custom apparatus at conditions relevant to EGS, with temperatures up to 250 degrees C (design maximum 300 degrees C). Our approach is to perform a number of long term (up to several months) laboratory experiments using relevant rock samples with different mineralogies to explore fracture sustainability under EGS conditions. We use an apparatus that allows direct application of a normal force on the fracture faces of a single fracture in a sample having a sheared, tensile fracture. We flow brine of a specified composition through the aperture, and simultaneously measure the fracture permeability and closure. We collect the effluent water for chemical and isotopic analysis. We are numerically modeling our tests and comparing experimental and numerical results.

This submission includes photomicrographs of pre-test (unreacted) and post-test (reacted) samples from Brady well BCH-03 at various depths, Desert Peak well DP 35-13, and samples of Stripa granite. The photomicrographs are provided using uncrossed and crossed polarized light (xpl). UN is uncrossed nicols, CN and xpl are crossed nicols (crossed polars). The magnification listed is just referring to the objective lens that was used, not the total magnification of the images. With a 5x objective, the bottom dimension of an image is 1.75 mm. With 10x the bottom dimension of an image is 0.875 mm, and with 2x the bottom dimension of an image is 4.375 mm.

Citation Formats

Lawrence Berkeley National Laboratory. (2016). Fracture Sustainability Test, Pre- and Post-Test Photomicrographs [data set]. Retrieved from https://dx.doi.org/10.15121/1666365.
Export Citation to RIS
Dobson, Pat, Nakagawa, Seiji, and Kneafsey, Tim. Fracture Sustainability Test, Pre- and Post-Test Photomicrographs. United States: N.p., 26 Sep, 2016. Web. doi: 10.15121/1666365.
Dobson, Pat, Nakagawa, Seiji, & Kneafsey, Tim. Fracture Sustainability Test, Pre- and Post-Test Photomicrographs. United States. https://dx.doi.org/10.15121/1666365
Dobson, Pat, Nakagawa, Seiji, and Kneafsey, Tim. 2016. "Fracture Sustainability Test, Pre- and Post-Test Photomicrographs". United States. https://dx.doi.org/10.15121/1666365. https://gdr.openei.org/submissions/1234.
@div{oedi_1234, title = {Fracture Sustainability Test, Pre- and Post-Test Photomicrographs}, author = {Dobson, Pat, Nakagawa, Seiji, and Kneafsey, Tim.}, abstractNote = {The primary objective of this research is to understand how different rock types, mineral and fluid compositions, and fracture surface textures determine the longevity of fracture apertures, so that selection of reservoir rock can be economically optimized to reduce future refracturing. We are performing laboratory tests to study this in a custom apparatus at conditions relevant to EGS, with temperatures up to 250 degrees C (design maximum 300 degrees C). Our approach is to perform a number of long term (up to several months) laboratory experiments using relevant rock samples with different mineralogies to explore fracture sustainability under EGS conditions. We use an apparatus that allows direct application of a normal force on the fracture faces of a single fracture in a sample having a sheared, tensile fracture. We flow brine of a specified composition through the aperture, and simultaneously measure the fracture permeability and closure. We collect the effluent water for chemical and isotopic analysis. We are numerically modeling our tests and comparing experimental and numerical results.

This submission includes photomicrographs of pre-test (unreacted) and post-test (reacted) samples from Brady well BCH-03 at various depths, Desert Peak well DP 35-13, and samples of Stripa granite. The photomicrographs are provided using uncrossed and crossed polarized light (xpl). UN is uncrossed nicols, CN and xpl are crossed nicols (crossed polars). The magnification listed is just referring to the objective lens that was used, not the total magnification of the images. With a 5x objective, the bottom dimension of an image is 1.75 mm. With 10x the bottom dimension of an image is 0.875 mm, and with 2x the bottom dimension of an image is 4.375 mm.}, doi = {10.15121/1666365}, url = {https://gdr.openei.org/submissions/1234}, journal = {}, number = , volume = , place = {United States}, year = {2016}, month = {09}}
https://dx.doi.org/10.15121/1666365

Details

Data from Sep 26, 2016

Last updated May 17, 2021

Submitted Sep 7, 2020

Organization

Lawrence Berkeley National Laboratory

Contact

Tim Kneafsey

510.486.4414

Authors

Pat Dobson

Lawrence Berkeley National Laboratory

Seiji Nakagawa

Lawrence Berkeley National Laboratory

Tim Kneafsey

Lawrence Berkeley National Laboratory

DOE Project Details

Project Name Sustainability of Shear-Induced Permeability for EGS Reservoirs

Project Lead Lauren Boyd

Project Number FY13 AOP 5.1

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