Gas Shale Permeability and Velocity Measurement at Laboratory Scale

Date

2012-12

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Abstract

Matrix permeability of gas shales is a crucial parameter for their characterization, production potential, and commercial development. Gas shales are an important reservoir type from an economic perspective because of their potential to hold large volume reserves and produce economically over time. However, shale matrix permeability can not be easily acquired from direct field measurements; it can only be measured in the laboratory.

The main goal of this thesis was to characterize the elastic properties and gas transport properties for the Barnett shale which comes from the Fort Worth basin in North Texas, of the United States. We measured density and ultrasonic velocity based on the three plug technique. Matrix permeability and porosity were measured simultaneously by using a specially designed apparatus and a newly developed transient pressure technique invented by Metwally and Sondergeld, 2011.

Measurement results show evidence for strong anisotropy in both velocity and permeability attributes. Nonlinear reduction in permeability and effective porosity with an increase of effective pressure has been observed. Correlation between elastic constant C44 and permeability parallel to the bedding plane has been clearly identified, which may offer an indicator for estimating permeability.

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Keywords

Matrix Permeability, Gas shales, Ultrasonic velocity, Pressure decay

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