Energy Policy Act of 2005 (Ultra-deepwater and Unconventional Resources Program)
Petrophysical studies of unconventional gas reservoirs using high-resolution rock imaging
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA 94720
Schlumberger, BP, Chevron
The main objective of this work is to determine (a) the physical mechanisms that limit gas recovery from tight rock formations, and (b) the means of extending this recovery as far into the future as possible. Because the mechanisms that block gas flow in the formation and near the wellbore are not fully understood, we propose to use the sophisticated petrophysical imaging tools and theoretical calculation methods at our disposal to elucidate them. Once we better understand the key factors that influence the rate and ultimate level of gas recovery, we will investigate methods of changing the formation properties volumetrically to optimize production in space and in time. The usual approach of highly discounting the future recovery may no longer be applicable in a world in which real energy prices will be growing faster than the local (e.g., state) economies.
We propose to acquire high-resolution images of gas-bearing shale rocks using Advanced Light Source (ALS) facility and Focused Ion Beam (FIB) technology at Lawrence Berkeley National Laboratory (LBNL), and analyze these images using Maximal Inscribed Spheres-type methods in order to estimate gas shale and tight sand flow properties at different, including in situ, conditions. These approaches have been developed at LBNL and University of California at Berkeley (UCB) and have been successfully applied to studies of chalk, diatomite, and sandstone. We will investigate the impact of pore-space geometry in different rock formations on flow properties, including absolute and relative permeabilities, capillary pressure, and Klinkenberg coefficient. We will use the 3D images of the rocks acquired in this project to develop depositional models and to link the petrophysical properties of the rock to the geology and geological history of the reservoir.
A thorough and comprehensive study of existing unconventional gas-bearing formations will create a knowledge base for the development of emerging and frontier developments. The proposed study is fundamental, and acquired knowledge will be equally applicable in short- and long-term technology developments.
Principal Investigator: Dmitriy Silin