Abstract: A quantitative simulation process for producing quantitative model predictions of hydrocarbon composition. The quantitative simulation may include measuring a chemical and isotopic composition of a hydrocarbon sample from a hydrocarbon reservoir.

Abstract: A quantitative simulation process for producing quantitative model predictions of hydrocarbon composition may comprise: measuring a chemical and isotopic composition of a hydrocarbon sample from a hydrocarbon reservoir; measuring geochemical data, geophysical data, and/or geological data for the hydrocarbon reservoir and/or source rock; deriving temperature versus time relationships from a basin model for the hydrocarbon reservoir and/or source rock based on the geochemical data, geophysical data, and/or geological data; generating estimated source-rock maturity parameters based on the temperature versus time relationships; generating an estimated compositional yield for hydrocarbon fractions based on the temperature versus time relationships and the chemical composition of the hydrocarbon sample; and generating, using a mass-conserving isotopic fraction (MCIF) simulator, an estimated isotopic composition of the hydrocarbon fractions based on the estimated compositional yield and the isotopic composition of t