Fracture mechanics of oil shale: some preliminary results

Technical Report · Tue Feb 01 04:00:00 EST 1977

DOI:https://doi.org/10.2172/7119762· OSTI ID:7119762

Results of a comprehensive series of fracture toughness tests on oil shale from Anvil Points are presented. Since oil shale is layered and transversely isotropic, three-point-bend specimens representing 20 and 40 gal/ton were tested in the three principal crack orientations--divider, arrester, and short transverse. These specimens were fatigue cracked to produce a sharp natural crack in a stable manner by means of loading between fixed limits of the crack opening displacement. Crack front position was marked by immersing the specimen in a penetrating dye so that the crack length could be determined after final failure. Load-to-failure records of load vs. crack opening displacement showed evidence of crack surface interference or crack closure. Fracture toughness was found to decrease by approximately 40 percent for an increase in kerogen content from 20 to 40 gal/ton. Highest values of fracture toughness were found for the divider geometry, lowest for short transverse, and intermediate for arrester with the actual values varying from 0.3 to 1.1 MN m/sup -/sup 3///sub 2/.

• Research Organization: Sandia Labs., Albuquerque, NM (USA)
• DOE Contract Number: EY-76-C-04-0789
• OSTI ID: 7119762
• Report Number(s): SAND-76-0727
• Country of Publication: United States
• Language: English

Related Subjects

04 OIL SHALES AND TAR SANDS
040300* -- Oil Shales & Tar Sands-- Drilling
Fracturing & Mining
040500 -- Oil Shales & Tar Sands-- Properties & Composition
BITUMINOUS MATERIALS
CARBONACEOUS MATERIALS
CRACKS
ENERGY SOURCES
FATIGUE
FOSSIL FUELS
FRACTURE PROPERTIES
FUELS
MECHANICAL PROPERTIES
OIL SHALES