Measuring ultrasonic characterisation to determine the impact of TOC and the stress field on shale gas anisotropy
Yazeed Altowairqi A , Reza Rezaee B , Milovan Urosevic A and Claudio Delle Piane CA Curtin University
B Department of Petroleum Engineering, Curtin University
C CSIRO
The APPEA Journal 53(1) 245-254 https://doi.org/10.1071/AJ12021
Published: 2013
Abstract
While the majority of natural gas is produced from conventional sources, there is significant growth from unconventional sources, including shale-gas reservoirs. To produce gas economically, candidate shale typically requires a range of characteristics, including a relatively high total organic carbon (TOC) content, and it must be gas mature. Mechanical and dynamic elastic properties are also important shale characteristics that are not well understood as there have been a limited number of investigations of well-preserved samples. In this study, the elastic properties of shale samples are determined by measuring wave velocities. An array of ultrasonic transducers are used to measure five independent wave velocities, which are used to calculate the elastic properties of the shale. The results indicated that for the shale examined in this research, P- and S-wave velocities vary depending on the isotropic stress conditions with respect to the fabric and TOC content. It was shown that the isotropic stress significantly impacts velocity. In addition, S-wave anisotropy was significantly affected by increasing stress anisotropy. Stress orientation, with respect to fabric orientation, was found to be an important influence on the degree of anisotropy of the dynamic elastic properties in the shale. Furthermore, the relationship between acoustic impedance (AI) and TOC was established for all the samples.
Yazeed Altowairqi is a PhD student in the Department of Petroleum Engineering at Curtin University. His research focuses on rock physics of high TOC shale-gas and the seismic response of shale. His study examines various applications of seismic inversion and mulit-attribute analysis though acoustic and shears impedance analysis. Yazeed is also trying to build a rock physics model of shale-gas formations from well log data and calibrating it to laboratory results. Yazeed was awarded his Masters degree in geophysics in 2010 from Curtin University after completing his BSc, also in geophysics, in 2007 from King Abdulaziz University (KAAU). y.altowairqi@postgrad.curtin.edu.au |
Reza Rezaee of Curtin University’s Department of Petroleum Engineering has a PhD (reservoir characterisation). He has more than 25 years of experience in academia. He has supervised more than 60 MSc and PhD students during his university career to date. He has published more than 120 peer-reviewed journal and conference papers and is the author of three books about petroleum geology, logging, and log interpretation. His research has been focused on integrated solutions for reservoir characterisation, formation evaluation, and petrophysics. Presently, he is focused on unconventional gas, including gas shale and tight gas sand studies. He is lead scientist for the WA: ERA (EIS) tight gas and shale gas research projects. He established Curtin University’s unconventional gas research group in 2010. R.Rezaee@exchange.curtin.edu.au |
Milovan Urosevic of Curtin University’s Department of Exploration Geophysics has a PhD in Geophysics. His professional interests are in 3C seismic data processing analysis, 3C Vertical Seismic Profile (VSP) imaging and seismic anisotropy. During his career he has been engaged in several research projects supported by national and international oil and gas companies and these commissions, together with his supervisory work at various universities, have involved a wide range of achievements. He has supervised over 70 MSc and PhD students during his university career to date. He has published more than 80 peer-reviewed journal and conference papers and is the author of one book on Seismic methods. M.Urosevic@curtin.edu.au |
Dr Claudio Delle Piane works at CSIRO-Earth Science Resource and Engineering and comes from a geological and geomechanical background. He has worked in rock mechanics and rock physics in the rock deformation laboratory at the Swiss Federal Institute of Technology (ETH) in Zurich. He has expertise in experimental rock mechanics testing, scanning electron microscopy and a strong structural geological background. Claudio.Dellepiane@csiro.au |
