Extraction of Petroleum Hydrocarbons from the Marcellus Shale with Liquid CO2

Palma Jarboe
University of Maryland, Department of Geology, College Park, MD, U.S.A.
[email protected]

Shale is now successfully exploited as a hydrocarbon resource. Due to the high degree of geochemical and petrophysical variability both between shale reservoirs and within a single reservoir, there is a growing need to find more efficient methods of extracting petroleum compounds (oil, natural gas, bitumen) from potential source rocks.

The primary goal of this study is to determine the quantity and distribution of recoverable petroleum hydrocarbons that can be extracted from kerogen-bearing Marcellus Shale cores using carbon dioxide (CO2). Initial Rock-Eval pyrolysis results of core cuttings from wells in western Pennsylvania indicate a TOC distribution ranging from 1-5-6.2 wt%. Solid bitumen reflectance confirms a high degree of thermal maturity for these cores, ranging from 2.2-2.6% Ro. Preliminary CO2-extractions of ground core splits (18-35 mesh) at in situ pressure and temperature conditions achieved successful extractions of n-alkane hydrocarbons in the range of n-C11 to n-C22. Future extractions will assess how extraction efficiency varies as a function of TOC and carbonate contents, exposed shale surface area of different particle size fractions, and extraction duration. Additional Devonian black shale cores of lower maturity will also be analyzed, to examine the effect of thermal maturity on the distribution of extractable hydrocarbons.

Results will of this project will help to gain a better understanding of the use of CO2 as an extraction fluid for petroleum hydrocarbons from the Marcellus Shale and other potential source rock formations.

AAPG Search and Discovery Article #90183©2013 AAPG Foundation 2013 Grants-in-Aid Projects