Rex P. Hjelm, a scientist with the New Mexico Consortium and Los Alamos National Laboratory recently published his latest research in the ACS Journal, Energy and Fuels, titled Small-angle Neutron Scattering (SANS) Characterization of Clay- and Carbonate-rich Shale at Elevated Pressures.
Conventional hydrocarbon resources are decreasing over time as we use them. Fortunately, new technologies now allow for increased production of oil and gas from shale and other tight rock formations. The unconventional oil and gas from shale formations are currently some of the fastest growing energy resources in the United States. They provide cleaner energy to consumers and they reduce our reliance on energy imports.
In order to properly harness this valuable energy resource, researchers are working to fully understand the nanopore structure of associated shales, especially under hydraulic fracturing conditions, where the shales are exposed to both overburden compressive and hydrostatic fluid pressures.
This study used small-angle neutron scattering (SANS) to differentiate pore structure. This included looking at porosity, pore accessibility, and pore size distribution, in the 1−100 nm regime at elevated pressures. This research used the mineralogically distinct clay- and carbonate-rich shales from the Permian Basin.
The researchers found that porosity of the clay-rich shale was 7.7%, compared to 0.51% for the carbonate-rich shale. However, only 2.6% of the nanopores in the carbonate-rich shale were inaccessible to water at 8 kPSI (55.1 MPa) compared to 7.8% for the clay-rich shale. The study also found that the closed pores fall within distinct size ranges, which probably corresponds to the chemical nature of the pore host material. These results give important insight into the effects of shale petrophysical properties on hydrocarbon extraction from unconventional reservoirs.
These new findings add to the basic understanding of shale nanopore characteristics, and can also be used by industry to guarantee more effective hydraulic fracturing.
To read the entire article see:
Small-angle Neutron Scattering (SANS) Characterization of Clay- and Carbonate-rich Shale at Elevated Pressures. Chelsea W. Neil, Rex P. Hjelm, Marilyn E. Hawley, Erik B. Watkins, Cody Cockreham, Di Wu, Yimin Mao, Timothy B. Fischer, M. Rebecca Stokes, and Hongwu Xu.vEnergy & Fuels Article ASAP. DOI: 10.1021/acs.energyfuels.0c01009