Rifle, CO, United States
Rifle, CO, United States

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Vyazovkin S.,University of Alabama at Birmingham | Burnham A.K.,American Shale Oil LLC | Criado J.M.,University of Seville | Perez-Maqueda L.A.,University of Seville | And 2 more authors.
Thermochimica Acta | Year: 2011

The present recommendations have been developed by the Kinetics Committee of the International Confederation for Thermal Analysis and Calorimetry (ICTAC). The recommendations offer guidance for reliable evaluation of kinetic parameters (the activation energy, the pre-exponential factor, and the reaction model) from the data obtained by means of thermal analysis methods such as thermogravimetry (TGA), differential scanning calorimetry (DSC), and differential thermal analysis (DTA). The recommendations cover the most common kinetic methods, model-free (isoconversional) as well as model-fitting. The focus is on the problems faced by various kinetic methods and on the ways how these problems can be resolved. Recommendations on making reliable kinetic predictions are also provided. The objective of these recommendations is to help a non-expert with efficiently performing analysis and interpreting its results. © 2011 Elsevier B.V.


Peters K.E.,Schlumberger | Peters K.E.,Stanford University | Burnham A.K.,American Shale Oil LLC | Walters C.C.,ExxonMobil
AAPG Bulletin | Year: 2015

Some recent publications promote one-ran, open-system pyrolysis experiments using a single heating rate (ramp) and fixed frequency factor to determine the petroleum generation kinetics of source-rock samples because, compared to multiple-ramp experiments, the method is faster, less expensive, and presumably yields similar results. Some one-ramp pyrolysis experiments yield kinetic results similar to those from multiple-ramp experiments. However, our data for 52 worldwide source rocks containing types I, II, IIS, II/III, and III kerogen illustrate that one-ramp kinetics introduce the potential for significant error that can be avoided by using high-quality kinetic measurements and multiple-ramp experiments in which the frequency factor is optimized by the kinetic software rather than fixed at some universal value. The data show that kinetic modeling based on a discrete activation energy distribution and three different pyrolysis temperature ramps closely approximates that determined from additional runs, provided the three ramps span an appropriate range of heating rates. For some source rocks containing well-preserved kerogen and having narrow activation energy distributions, both single- and multiple-ramp discrete models are insufficient, and nucleation-growth models are necessary. Instrument design, thermocouple size or orientation, and sample weight likely influence the acceptable upper limit of pyrolysis heating rate. Caution is needed for ramps of 30-50°C/min, which can cause temperature errors due to impaired heat transfer between the oven, sample, and thermocouple. Compound volatility may inhibit pyrolyzate yield at the lowest heating rates, depending on the effectiveness of the gas sweep. We recommend at least three pyrolysis ramps that span at least a 20-fold variation of comparatively lower rates, such as 1, 5, and 25°C/min. The product of heating rate and sample size should not exceed ∼100 mg °C/min. Our results do not address the more fundamental questions of whether kinetic models based on multiple-ramp open-system pyrolysis are mechanistically appropriate for use in basin simulators or whether petroleum migration through the kerogen network, rather than cracking of organic matter, represents the rate-limiting step in expulsion. Copyright © 2015. The American Association of Petroleum Geologists. All rights reserved.


Burnham A.K.,American Shale Oil LLC
Thermochimica Acta | Year: 2014

The derivation of chemical kinetics by the thermal analysis community has a checkered past, with numerous papers published using substandard methodology. The ICTAC kinetics committee has taken on the task of upgrading the quality of thermal analysis kinetics through a series of workshops and publications. However, the resulting publications from those efforts by design do not cover all important aspects in detail. This paper explores two issues in greater depth'the optimum selection of heating rates for kinetic determination based on statistical error considerations and the importance of using a diverse set of thermal histories, including but not limited to isothermal and linear heating, to better constrain and validate global models. © 2014 Elsevier B.V. All rights reserved.


Burnham A.K.,American Shale Oil LLC | McConaghy J.R.,Antero Engineering LLC
Energy and Fuels | Year: 2014

Oil shale from the illite-rich Garden Gulch Member of the Green River Formation in Colorados Piceance Basin was pyrolyzed in a self-purging 12 kg batch autoclave. The shale was held within the autoclave in a container open only at the top, and a nitrogen sweep around that container swept the produced gas and oil vapors out of the headspace at a controlled pressure determined by a back-pressure regulator. Oil and water weights and gas composition were measured as a function of time, and oil composition was evaluated by a variety of techniques. Increasing back pressure retarded the evolution of generated oil. This volatilization phenomenon can be fit simply by adjusting the activation energy of the pyrolysis kinetics by 0.67 cal/mol/kPa. Oil yields decreased and gas yields increased with increasing back pressure. Oil quality increases as yield decreased. API gravity was typically above 40, nitrogen content was only 0.5-0.6 wt %, and As, V, and Ni were below detection limits of 0.1 ppm. The quality improvement with lower yield is attributed to longer liquid residence time for coking, which results in less heavy oil being volatilized. Results are consistent with the original work using this approach by Burnham and Singleton (Burnham, A. K.; Singleton, M. F. High Pressure Pyrolysis of Green River Oil Shale. In Geochemistry and Chemistry of Oil Shales; Miknis, F. P., McKay, J. F., Eds.; ACS Symposium Series 230; American Chemical Society: Washington, DC, 1983.), who used Mahogany zone shale from the Anvil Points mine near Rifle, CO. These results demonstrate the common finding in fossil fuel processes that product quality and quantity trade off with each other. © 2014 American Chemical Society.


Bumham A.,American Shale Oil LLC | Fowler T.,Royal Dutch Shell | Symington B.,ExxonMobil
Oilfield Review | Year: 2010

The formation of oil shales, the methods by which they are exploited in various parts of the world, and the techniques currently being developed for tapping the energy they contain, are discussed. The shales are studied to attain source-rock status, achieving full maturity and expelling their oil and natural gas, which then migrate, and under the proper conditions, accumulate and become trapped. The shale, which occurs as 50 beds of organic-rich shallow marine sediments alternating with biomicritic limestone, is produced from open-pit mines at depths to 20 m. Converting volume of rock to volume of recoverable oil requires information on oil shale properties, such as organic content and grade, which can vary widely within a deposit. ExxonMobil and AMSO are some of the various companies pursuing research and development processes for in situ oil shale conversion.


Patent
American Shale Oil LLC | Date: 2010-05-13

A sub-surface hydrocarbon production system comprising an energy delivery well extending from the surface to a location proximate a bottom of the hydrocarbons to be produced. A production well extends from the surface to a location proximate the hydrocarbon and a convection passage extends between the energy delivery well and the production well thereby forming a convection loop. The energy delivery well and the production well intersect at a location proximate the hydrocarbon such that the convection loop is in the form of a triangle. Preferably, the convection passage extends upwardly from a point at which the convection passage intersects the production well. The system also includes a heater, such as an electric heater or down-hole burner, disposed in the energy delivery well.


Patent
American Shale Oil LLC | Date: 2011-03-03

A process for retorting and extracting sub-surface hydrocarbons. The process comprises drilling an energy delivery well extending from the surface to a location proximate a bottom of the hydrocarbons. The hydrocarbons are heated from the bottom to form a retort, the retort extending along a portion of the energy delivery well. A vapor tube is extended to a location proximate the retort, the vapor tube having an entrance corresponding to the region of the retort along the energy delivery well that is nearest the surface exit.


Devices, systems, and processes are provided for retorting and extracting hydrocarbons from oil shale. A heat transfer fluid includes at least one liquefied petroleum gas (LPG) component such as, for example, propane or butane. The heat transfer fluid moves through a heat delivery loop to retort oil shale, thereby facilitating the production of recoverable hydrocarbons. While the heat transfer fluid moves through the heat delivery loop, cracking of a portion of the heat transfer fluid may produce various hydrocarbon materials that may be provided to a product stream.


Patent
American Shale Oil LLC | Date: 2010-05-13

A system and process for extracting hydrocarbons from a subterranean body of oil shale within an oil shale deposit located beneath an overburden. The system comprises an energy delivery subsystem to heat the body of oil shale and a hydrocarbon gathering subsystem for gathering hydrocarbons retorted from the body of oil shale. The energy delivery subsystem comprises at least one energy delivery well drilled from the surface of the earth through the overburden to a depth proximate a bottom of the body of oil shale, the energy delivery well extending generally downward from a surface location above a proximal end of the body of oil shale to be retorted and continuing proximate the bottom of the body of oil shale. The energy delivery well may extend into the body of oil shale at an angle.


A heating system for a subterranean mineral formation according to embodiments of the present invention includes a casing positioned in a bore in the subterranean mineral formation, the casing having an outer surface and an inner surface, a heating element positioned within the casing, a surface connection system having a first end coupled to the heating element within the casing and a second end at a top ground surface above the subterranean mineral formation, a heat transfer fluid contained within the casing, the heat transfer fluid configured to transfer heat between the heating element and the inner surface of the casing, wherein at least a portion of the heat transfer fluid is undergoing phase changes between liquid and gas in order to regulate a temperature of the casing. Fins may be included on the outside of the casing to enhance heat transfer.

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