SCCS Fall Seminar - Julia Reece
|Date(s):||November 21, 2013|
|Location:||Green Earth Sciences Room 365
Anshul Agarwal |
Matrix Permeability and the Effect of Adsorption: An Example of the Eagle Ford Shale
We measured matrix permeability on a vertically and horizontally oriented sample of the Eagle Ford Shale with both an adsorbing (CO2) and a non-adsorbing pore fluid (Helium) to investigate permeability anisotropy and the effect of adsorption on matrix permeability in both directions. A thorough understanding of these transport processes is critical for defining the interactions between shale and CO2, and the potential risk of CO2 leakage from storage reservoirs. Here, we performed pulse-decay permeability experiments, and additional Darcy flow experiments for the case of the horizontal sample, at a temperature of 38.5°C (± 0.1°C), confining pressures up to 6000 psi, and fluid pressures ranging from 377 to 2000 psi. Results indicate that the apparent permeability using Helium is around 10 nD in the direction perpendicular to bedding and around 1 mD parallel to bedding. This large anisotropy is caused by flow occurring on different scales: through pores versus along microcracks and bedding planes. We show that using CO2 as the pore fluid reduces the vertical permeability by an order of magnitude due to adsorption effects; however, it does not significantly affect the horizontal permeability.