Services - Kinetics
Wildcat Technologies is now providing source rocks kinetic measurements. Compositional kinetic assessments for primary generation from kerogen and bitumen can be provided for C1, C2-C4, C5-C14, and C15+ components using curve fitting techniques coupled with yields from gold tube pyrolysis experiments (e.g., Behar et al., 1997).
Kinetics data acquisition
Other than the presence of reservoir and seal rocks together with appropriate timing of trap formation relative to generation and migration of hydrocarbons, one other essential component of a petroleum system is undoubtedly hydrocarbon charge. During progressive burial and subsequent maturity of source rocks, it is the break-down of the kerogen and kerogen-derived bitumen that generates hydrocarbons.
Kinetic measurements on source rock samples quantify the rate at which kerogen decomposes into petroleum under increasing temperature together with the attendant pressure regime changes under geological conditions. Petroleum generation can then be related to measured thermal-maturity parameters such as vitrinite reflectance, Tmax and other thermal maturity parameters.
The kinetics of petroleum generation can be defined by the Arrhenius equation which expresses the quantitative relationship between the rate of a reaction (k) and temperature (T in Kelvin) as depicted in the equation:
k = A × exp(Ea /RT)
where A is a constant called the Arrhenius factor (or probability factor or frequency factor) , Ea is the activation energy, and R is the universal gas constant (8.314 × 10-3 KJ mol-1 K-1)
Wildcat Technologies offers the proven Pyromat technique used by Lawrence Livermore National Laboratory measuring organic matter decomposition rates that pertain to the decomposition of source rocks into petroleum. Using our automated Pyromat instrument, source rock samples are decomposed to petroleum and the rate of generation is measured using a flame ionization detector (FID). The source rock samples that we analyze on the Pyromat instrument can either be whole rock or isolated kerogen but extracted whole rock samples are preferred to minimize secondary cracking effects. Duplicate analyses at various heating rates are utilized with two minimum heating rates but three to five rates preferred. Heating rates can range from (0.2 °C/min to 30°C/min). Typical rates are 1, 5, and 30oC/minute. Quality control procedures require that duplicate analyses give true Tmax values within ± 1 °C.
Kinetic calculations are completed using the Gaussian and discrete mathematical models in Kinetics05 software. Gaussian models are completed with a fixed and free reaction order and discrete models are computed with free and fixed A factors.
We are currently in the process of developing a source rock and shale resource database and would be glad to apprise you of its availability - contact us.
Kinetics05 software (http://geoisochem.com/software/05/index.html)
The Kinetics05 software used in processing kinetic measurements was developed by A. K. Burnham and R. L. Braun at the Lawrence Livermore National Laboratory (Braun and Burnham, 1987) . Using this Kinetics05 software, the kinetic parameters can be used to extrapolate laboratory reaction behavior to the lower temperatures and heating rates of natural burial. The kinetics of the thermal decomposition of kerogen are typically expressed as a distribution of activation energies (Ea) with a single fixed frequency factor (A). Tests on these extrapolations can be done by comparing the kinetic results to actual oil/gas field data.
List of cited References:
Behar, F., M. Vandenbroucke, Y. Tang, F. Marquis, and J. Espitalie, 1997, Thermal cracking of kerogen in open and closed systems: determination of kinetic parameters and stoichiometric coefficients for oil and gas generation, Org. Geochem., Vol. 26, No. 5/6, pp. 321-339.
R. L. Braun and A. K. Burnham, 1987, Analysis of Chemical Reaction Kinetics Using a Distribution of Activation Energies and Simpler Models: Energy & Fuels, Vol. 1, pp. 153-161.