kerogenrich

Kerogenrich, or kerogen-rich, is a descriptor used in geology and petroleum geology to describe sedimentary rocks or organic-rich sediments that contain high amounts of kerogen, the insoluble organic matter that is the precursor to hydrocarbons.

Kerogen is formed from degraded remains of plankton, algae, and sometimes plant material, preserved under anoxic or rapidly deposited conditions. In rocks labeled as kerogen-rich, total organic carbon (TOC) is typically elevated, and kerogen content is characterized by analyses such as Rock-Eval pyrolysis, which yields kerogen type and amount. The kerogen in a rock determines its potential hydrocarbon products and its response to maturation.

Types of kerogen are commonly categorized as Type I (lipid-rich, oil-prone), Type II (plankton-derived, oil and gas-prone), and Type III (gas-prone, humic). Kerogen-rich rocks are often targeted in unconventional resources, such as shale oil and oil shale, where sufficient heating over geological timescales can generate hydrocarbons. However, maturation state is crucial: immature rocks generate little hydrocarbons, while overmature rocks may produce mostly gas or have degraded hydrocarbons.

Measurement and evaluation of kerogen richness involve TOC content, kerogen yield, and maturity indicators from Rock-Eval pyrolsis (such as Tmax and Hydrogen Index). Physical properties like porosity and permeability influence the producibility of any generated hydrocarbons. Therefore, kerogen richness alone does not guarantee economic hydrocarbons; the quality of kerogen, its maturity history, burial and tectonic history, and reservoir characteristics all play essential roles.

Applications of the concept include resource assessment, exploration planning, and modeling of petroleum systems in organic-rich formations, including shale plays and oil shale deposits.