Source rocks for petroleum 

Azizi Myrie March 23,2023

This Marcellus shale exposure in central New York contains the grey-colored Cherry Valley limestone between the Union Springs and Oatka Creek shales.

Petroleum source rock is fine-grained sediment containing enough organic materials to create and release sufficient hydrocarbons to form a commercial accumulation of oil or gas. The most prevalent source rocks are shales and lime mudstones, which contain many organic materials. Any rock that may develop and release enough hydrocarbons to form an accumulation of oil or gas is considered a petroleum source rock. According to oil generation, source rocks are divided into three types :

Immature source rocks that have yet to produce hydrocarbons.

Mature source rocks in the generation stage.

Post-mature source rocks have already produced all crude oil-type hydrocarbons.

Potential source rocks are immature sedimentary rocks that, at a higher maturity level, might produce and release hydrocarbons.

Potential source rocks are sedimentary rocks that may have produced and released hydrocarbons but whose source potential has not yet been assessed.

Sedimentary rocks are good sources of hydrocarbons because they have produced and released them in the past.

The primary criteria used to assess the hydrocarbon source are the quantity (organic richness), quality (kerogen type), thermal maturation production capability, and distribution of organic matter in the rock. The organic matter composition of the source rock samples (shale, limestone, or marl) can be assessed directly. Yet, indirect approaches based on wireline data allow continuity of sampling of vertically diverse shale sections, are cost-effective and have easy access to data.

Reference

Al-Areeq, Nabil Mohammed. “Petroleum Source Rocks Characterization and Hydrocarbon Generation.” Petroleum Source Rocks Characterization and Hydrocarbon Generation | IntechOpen, 7 Feb. 2018, https://doi.org/10.5772/intechopen.70092.

“Marcellus Shale in Central New York Showing Cherry Valley Limestone | U.S. Geological Survey.” Marcellus Shale in Central New York Showing Cherry Valley Limestone | U.S. Geological Survey, 5 Mar. 2015, www.usgs.gov/media/images/marcellus-shale-central-new-york-showing-cherry-valley-limestone.