Petroleum system modeling of the Sabinas Basin, Northeastern Mexico; Part 2: geochemical implications in 2D integrated basin modeling

Potentially hydrocarbon-bearing formations in the Sabinas basin of northeastern Mexico are siliciclastic-carbonate units with Type II-III dispersed organic matter. The kerogen derived from the organic matter of the La Casita Fm is wholly transformed because the vitrinite reflectance reaches values higher than 2%. In this second part, we propose the integration of 2D Simic sections in combination with petrographic and geochemical studies, which is necessary to make a more accurate 2D geochemical and 3D geometric modeling, called Integrated Basin Modeling, which allows inferences about the evolution of hydrocarbon generation, migration and trapping in over mature basins, as well as the construction of its genesis along its burial history and the location of oil opportunities. The methodology used allowed for estimating the initial oil potential (TOC° - IH°) of the source rocks, using the sedimentation rate as a function of the conservation rate of deposited organic matter. For the Sabinas Basin, the COT° - IH° for the La Casita Formation was estimated to be at least 3% but no more than 6%, with a minimum IH° of 250 and a maximum of 500. While for the La Peña Formation, its COT° ranged from 1.5% to 3%, with a minimum IH° of 90 and a maximum of 240. An integration of two kinetics capable of generating CO2 was necessary. This combination of pre-existing kinetics matches the 2D geochemical model results for CH4 and CO2 generated from the following parameters: For gas generation, E (kcal/mol) = 55.68 - 75.68, A (s-1) = 1.96e16 and an IH = 76.59. For oil generation; E (kcal/mol) = 46.50 - 62.50, A (s-1) = 4.978e14 and a HI = 256.41. For CO2 generation; E (kcal/mol) = 46.50 - 56.50, A (s-1) = 4.956e12 and a HI = 37