Transport and seismoelectric properties of porous permeable rock : numerical modeling and laboratory measurements

The objective of this thesis is to better understand the transport and seismoelectric (SE) properties of porous permeable rock. Accurate information of rock transport properties, together with pore geometry, can aid us to better quantify the frequency dependence of its SE coupling coefficient. With the development of micro-CT (pCT) scanners, microstructure of the sedimentary rock can now be obtained in three dimensions at micron level resolution. Pore scale modeling on the rock 3-D pCT images provides us the ability to obtain different rock properties all at once and without much ambiguity. In this thesis, we build numerical tools to compute a range of transport properties and pore geometry parameters (e.g., porosity, electrical conductivity, hydraulic permeability, pore surface area) on the microstructures from basic physical laws. A staggered-grid finite difference (FD) scheme is used to solve the Laplace equation for electrical conductivity and the Stokes equation for hydraulic conductivity. The Laplace solver can handle different levels of conductivity contrast so that different saturations (gas, oil and brine) can be modeled. A three-phase conductivity model developed on the binary representation of the microstructure, which is based on the geometric average of free electrolyte conductance and surface conductance in the EDL, is illustrated. Two different edge detection methods are applied to recognize surface voxel in a binary image. One is a gradient based, first order differential method and the second one is a connectivity-number-based edge detection (CNED) method. Computations are done for a family of synthetic sand packs - Finney pack with low, medium to high porosities - to provide a benchmark of numerical tools and to compare with analytic solutions. Then, the numerical methods are used to calculate properties of Berea Sandstone 500 (BS500) with 23.6% porosity, whose 3-D microtomograms with 2.8 micron resolution are available. Using the numerical methods, rock porosity, pore surface area, (cont.) electrical conductivity and permeability are calculated.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2010

Author dc:creator

• Zhan, Xin

Advisor dc:contributor.advisor

• M. Nafi Toksöz.

• Earth, Atmospheric, and Planetary Sciences.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/57794

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/57794