A new ASTM International standard for measuring the reflectance of vitrinite in sedimentary rocks will help improve predictions of the location, quantity and quality of undiscovered hydrocarbon resources.
D7708, Test Method for Microscopical Determination of the Reflectance of Vitrinite Dispersed in Sedimentary Rocks, was developed by Subcommittee D05.28 on Petrographic Analysis of Coal and Coke, part of ASTM International Committee D05 on Coal and Coke.
“Vitrinite is the primary component of coal and measuring the reflectance of vitrinite eroded from coal beds and dispersed into sedimentary rock is considered the most robust assay for determination of thermal maturity in hydrocarbon exploration,” says Paul C. Hackley, research geologist, U.S. Geological Survey, and chairman of D05.28. “However, there was no standardized methodology available until the new test method was developed.”
D7708 will provide a framework and reference to understand the most common measurement used to determine whether a source rock is immature, mature or overmature with respect to the generation of hydrocarbons.
All interested parties are invited to participate in a planned interlaboratory study to develop a precision and bias statement for D7708. In addition, Hackley notes that the development of an online photomicrograph database that will supplement the standard is ongoing. All are welcome to submit photomicrographs showing dispersed organic materials in sedimentary rocks or samples of sedimentary rock containing organic matter.
Technical Information: Paul C. Hackley, U.S. Geological Survey, Reston, Va.
ASTM Staff: Scott Orthey