Dr. Nathan Deisman, Research Associate at the University of Alberta, presents his talk "Permeability Measurements in Low Permeability Rocks: Approaches, Challenges, and Solutions" on behalf of his co-authors, Stephen Talman, Francy Guerrero Zabala, and Richard Chalaturnyk.
Abstract: Our work will present an exploration into the use of the transient pulse decay method for measuring permeability and specific storage in low-permeability rocks. We will investigate why this method is important and what it may offer in terms of understanding hydraulic properties. Our presentation starts with a comparative analysis of approaches to solving the differential equations for transient pulse applications. We will look at the assumptions and value of the common analytical solutions of Brace et al. (1968) and Hsieh et al. (1980). Special attention will be given to the use of differential pressure measurements and the application of upstream and downstream pressure measurements and their implications in various experimental configurations.
We will discuss crucial aspects of the testing configuration and specimen loading, including sample preparation, specimen drying, re-saturation, the impacts of test conditions on sensors, and their implications on the measurements and permeability solutions. Also, common problems such as sample homogeneity, leaks, temperature stability, and issues associated with extremely low permeability, such as the impacts of poroelastic waves, will be addressed. Furthermore, we will present new approaches for the solution of the transient pulse decay to account for 'imperfect experimental systems' through the 'Leaky Brace' and 'Leaky Hsieh' models, how we use them, and the potential for interpretation errors.
Throughout the presentation, we will show results from a completed testing program on granites with permeability ranging from 1e -19 m^2 to 1e-22 m^2, tested under isotropic confining stress up to 30MPa and at 40°C. Based on our learnings and experimental results from this program, we will present our optimized pulse decay measurement system design and build, including our approaches for dead volume optimization, efficient data logging systems, and effective sensor selection and placement
Speaker Bio: Nathan Deisman is a Research Associate in Professor Chalaturnyk's Reservoir Geomechanics Research Group. He started in the group in 2002 and has worked in the field, laboratory and on numerical simulations. His projects include core retrieval from remote locations in -45C, downhole tool development and deployment for nuclear waste and CO2 storage, laboratory testing of oil sands, coal, shale, sandstones, and hard rock, and numerical simulation using Itasca'sPFC and FLAC3D and CMGs to solve geotechnical and coupled THM problems.
23 ноя 2023
