UNIAXIAL MECHANICAL PRESSURE EFFECT TO THE PORE STRUCTURE DEFORMATION ON AN ALTERED BRECCIA ROCK
Annisa Nadhira (a*), Iqbal Assidiq(a), Selly Feranie(a), Fourier Dzar Eljabbar Latief(b)
a) Department of Physics Education, Indonesia University of Education Jalan Setiabudi No. 229
Bandung 40154, West Java, Indonesia
*its.annisanadhira[at]gmail.com
b) Physics of Complex Systems, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jalan Ganesha 10
Bandung 40132, West Java, Indonesia
Abstract
Knowledge about the physical parameters of rocks is important in order to understand the properties associated with the fact that porous rocks are fluid storage media. The amount of the contained fluid can be estimated roughly by analyzing the pore fraction of rocks. To investigate the pore evolution, a series of uniaxial compression test was conducted on an altered breccia rock sample. The sample was obtained from a potential geothermal area at Kadidia-Sigi, Sulawesi Tengah. The uniaxial compression treatment started from the natural pressure 438,468 N/m2 then, 629,079 N/m2, 1,887,238 N/m2, 3,145,396 N/m2, 4,403,554 N/m2, and 5,032,633 N/m2. Digital image processing and analysis method were applied to record and analyze the deformation of pore and fracture structure. Qualitative analysis was conducted by investigating the produced 2D and 3D images, and it was shown that the pore intensity and the fractures intensity increases as the pressure increase. Quantitative analysis was conducted by investigating the porosity and specific surface area as a function of the applied pressure. It was found that porosity {ϕ(P)} is in the function of a positively second-degree polynomial and specific surface area {SA(P)} is in the function of a negative second-degree polynomial.
Keywords: pore structure; uniaxial mechanical pressure; an altered breccia rock
Topic: Physics