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Papers by Douglas Waples
Concentrations of organic and inorganic nitrogen have been measured on Leg 80 sediments. The inor... more Concentrations of organic and inorganic nitrogen have been measured on Leg 80 sediments. The inorganic nitrogen content is relatively constant, 0.02-0.03 wt.%. Because most of the inorganic nitrogen occurs as NH3 or (NH4)+ fixed on clays, clay-poor sediments have lower inorganic nitrogen contents.Organic nitrogen content depends upon both the type and the quantity of organic matter present. In Leg 80 sediments, woody kerogens contain much less organic nitrogen than do kerogens of algal origin. Furthermore, pelagic samples of low organic carbon content have less organic nitrogen than predicted, because of loss during diagenesis.DSDP shipboard analytical procedures do not distinguish between organic and inorganic nitrogen. Great caution must therefore be exercised in interpreting C/N ratios.
Natural resources research, Jun 1, 2004
Heat capacities of the rocks within a sedimentary basin can significantly influence geothermal gr... more Heat capacities of the rocks within a sedimentary basin can significantly influence geothermal gradients if sedimentation or erosion is rapid. This paper provides data on specific heat capacities of minerals and nonporous rocks at 20 • C, derives equations for calculating specific heat capacities of minerals and nonporous rocks at temperatures between 0 • C and 1200 • C, and shows that pressure effects on heat capacities of solids can be neglected. It derives an equation for estimating specific heat capacity of any mineral or nonporous rock as a function of density. Finally, it shows how to calculate the specific heat capacity of any mixture of solid materials. A companion paper discusses specific heat capacities of the fluids in pore spaces of rocks and of fluid-filled porous rocks. The data for minerals and rocks provided herein can be incorporated directly into existing modeling software by users. However, the temperature-dependent equations would have to be incorporated by software developers.
Springer eBooks, 1985
This book explains how to apply geochemical principles to petroleum exploration. Analytical techn... more This book explains how to apply geochemical principles to petroleum exploration. Analytical techniques used in geochemistry, the evaluation of sedimentary rocks which have already expelled hydrocarbons, and factors affecting the composition of bitumen and petroleum are among ...
Researches in organic geochemistry, Sep 25, 1992
Although determination of kinetic parameters for individual source-rock samples is currently very... more Although determination of kinetic parameters for individual source-rock samples is currently very popular, the accepted mathematical method of deconvolving raw pyrolysis data in order to obtain activation-energy distributions and frequency factors, will often yield results which are not chemically or physically reasonable. The inadequacy of such kinetic parameters is demonstrated here, using a data set consisting of a number of samples of the same kerogen type, but at different levels of maturity. Use of these incorrect kinetic parameters in modeling studies, can lead to disastrous errors in predictions of hydrocarbon generation under subsurface conditions. We also briefly outline general aspects of an alternative new method of determining kinetic parameters from raw pyrolysis data. This method is based much on the laws of thermodynamics and on empirical data about chemical reactions, rather than on mathematical curve fitting.
Petroleum Exploration Society of Australia (PESA), 2018
Marine and Petroleum Geology, 2022
Geochemistry in Petroleum Exploration, 1985
Geochemistry in Petroleum Exploration, 1985
Concentrations of organic and inorganic nitrogen have been measured on Leg 80 sediments. The inor... more Concentrations of organic and inorganic nitrogen have been measured on Leg 80 sediments. The inorganic nitrogen content is relatively constant, 0.02-0.03 wt.%. Because most of the inorganic nitrogen occurs as NH3 or (NH4)+ fixed on clays, clay-poor sediments have lower inorganic nitrogen contents.Organic nitrogen content depends upon both the type and the quantity of organic matter present. In Leg 80 sediments, woody kerogens contain much less organic nitrogen than do kerogens of algal origin. Furthermore, pelagic samples of low organic carbon content have less organic nitrogen than predicted, because of loss during diagenesis.DSDP shipboard analytical procedures do not distinguish between organic and inorganic nitrogen. Great caution must therefore be exercised in interpreting C/N ratios.
Natural resources research, Jun 1, 2004
Heat capacities of the rocks within a sedimentary basin can significantly influence geothermal gr... more Heat capacities of the rocks within a sedimentary basin can significantly influence geothermal gradients if sedimentation or erosion is rapid. This paper provides data on specific heat capacities of minerals and nonporous rocks at 20 • C, derives equations for calculating specific heat capacities of minerals and nonporous rocks at temperatures between 0 • C and 1200 • C, and shows that pressure effects on heat capacities of solids can be neglected. It derives an equation for estimating specific heat capacity of any mineral or nonporous rock as a function of density. Finally, it shows how to calculate the specific heat capacity of any mixture of solid materials. A companion paper discusses specific heat capacities of the fluids in pore spaces of rocks and of fluid-filled porous rocks. The data for minerals and rocks provided herein can be incorporated directly into existing modeling software by users. However, the temperature-dependent equations would have to be incorporated by software developers.
Springer eBooks, 1985
This book explains how to apply geochemical principles to petroleum exploration. Analytical techn... more This book explains how to apply geochemical principles to petroleum exploration. Analytical techniques used in geochemistry, the evaluation of sedimentary rocks which have already expelled hydrocarbons, and factors affecting the composition of bitumen and petroleum are among ...
Researches in organic geochemistry, Sep 25, 1992
Although determination of kinetic parameters for individual source-rock samples is currently very... more Although determination of kinetic parameters for individual source-rock samples is currently very popular, the accepted mathematical method of deconvolving raw pyrolysis data in order to obtain activation-energy distributions and frequency factors, will often yield results which are not chemically or physically reasonable. The inadequacy of such kinetic parameters is demonstrated here, using a data set consisting of a number of samples of the same kerogen type, but at different levels of maturity. Use of these incorrect kinetic parameters in modeling studies, can lead to disastrous errors in predictions of hydrocarbon generation under subsurface conditions. We also briefly outline general aspects of an alternative new method of determining kinetic parameters from raw pyrolysis data. This method is based much on the laws of thermodynamics and on empirical data about chemical reactions, rather than on mathematical curve fitting.
Petroleum Exploration Society of Australia (PESA), 2018
Marine and Petroleum Geology, 2022
Geochemistry in Petroleum Exploration, 1985
Geochemistry in Petroleum Exploration, 1985