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Distinguished Seminar Series: Multi-Scale Formation Evaluation of Unconventional Reservoirs

February 16 @ 10:00 am - 11:00 am

Zoya Heidari headshotZoya Heidari

Assistant Professor, University of Texas at Austin

Complex pore geometry, rock fabric, and rock composition as well as heterogeneous and anisotropic nature of organic-rich mudrocks significantly affect physical properties of the rocks (e.g., electrical resistivity, dielectric permittivity, and acoustic properties) and consequently their interpretation for assessment of formation properties such as hydrocarbon reserves. Conventional well-log-based methods for assessment of hydrocarbon reserves using electrical measurements (e.g., shaly-sand resistivity models and volumetric techniques such as the Complex Refractive Index Model (CRIM)) do not take into account the impact of rock fabric, complex pore-structure (e.g., organic and inter-granular pores), pyrite, and kerogen networks. Complex geochemistry of organic-rich mudrocks is also overlooked in the existing rock physics models. The aforementioned limitations cause significant uncertainties in estimates of hydrocarbon reserves and formation evaluation. The focus of this presentation is on rock physics models for interpretation of electrical properties.

In this presentation, the effects of complex pore structure, rock fabric, geochemistry, and directional connectivity of kerogen, pyrite, and pore networks on electrical properties of organic-rich mudrocks will be discussed. Furthermore, new rock physics models/workflows will be introduced that take into account rock fabric as well as the type and the spatial distribution of all conductive components of the rocks to improve reserves evaluation. Comparison of the new method against a conventional method (i.e., Waxman-Smits model) shows that estimates of water saturation can be improved by up to 35%, when a quantitative and realistic spatial distribution of all the conductive components (e.g., pyrite, clay, and kerogen) is taken into account. Laboratory experiments of electrical properties complement numerical simulations by estimating model input parameters and validating the assumptions. The results also demonstrate the importance of taking into account rock fabric and geochemistry in rock physics models used for formation evaluation of unconventional resources.


Zoya Heidari is an assistant professor in the Department of Petroleum and Geosystems Engineering at The University of Texas at Austin. Before joining The University of Texas at Austin, she was an assistant professor at Texas A&M University in College Station and the Chevron Corporation faculty fellow in Petroleum Engineering from September 2011 to August 2015.  Zoya has been the founder and the director of the Texas A&M Joint Industry Research Program on “Multi-Scale Formation Evaluation of Unconventional and Carbonate Reservoirs” from 2012 to 2015 and the University of Texas at Austin Industrial Affiliates Research Program on “Multi-Scale Rock Physics” since 2016.

She received a Ph.D. (2011) in petroleum engineering from The University of Texas at Austin. Zoya is one of the recipients of the 2017 SPE (Society of Petroleum Engineers) Cedric K. Ferguson Medal, the 2016 SPE regional Formation Evaluation award, the 2014 TEES (Texas A&M Engineering Experiment Station) Select Young Faculty Fellows award from the College of Engineering at Texas A&M University and the 2012 SPE Petroleum Engineering Junior Faculty Research Initiation Award. She is also one of the recipients of the 2015 SPE Innovative Teaching Award. She is the holder of Anadarko Petroleum Corporation Centennial Fellowship #1 in Petroleum Engineering at UT Austin since 2016. Zoya’s research interests include Petrophysics, Borehole Geophysics, Well Logging, Formation Evaluation, Rock Physics, Inverse Problems, Integrated Reservoir Characterization of Carbonates and Unconventional Resources, and Completion Petrophysics. Zoya is currently serving as the Vice President of Education for SPWLA.


February 16
10:00 am - 11:00 am
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Marquez Hall
1600 Arapahoe St.
Golden, CO 80401 United States


Room Number
MZ 108