Inversion of multiple thermal indicators: Quantitative methods of determining paleoheat flux and geological parameters. III. Stratigraphic age determination from inversion of vitrinite reflectance data and sterane isomerization data     

J. Pantano  I. Lerche 《Mathematical Geology》1990,22(3):281-307

Thermal indicator data are used in an inverse mode to determine ages of stratigraphic horizons simultaneously with paleoheat flux. Results from blind tests on wells with horizon ages ranging from Ordovician through Carboniferous and Jurassic to Miocene indicate that thermal indicator inversions are capable of resolving such ages to within about 10% uncertainty. Results using the inversion procedure with one thermal indicator (vitrinite reflectance) were comparable to the results using another independent thermal indicator (sterane isomerization) in the same well. The activation energy for sterane isomerization was determined to be 30±15 kJ mol^–1. In addition: (a) the age of a stratigraphic horizon, the thickness of eroded sediments at an unconformity, and the variation of paleoheat flux with time were determined simultaneously by thermal indicator inversion in a single well; (b) two neighboring wells, less than 10 km apart, provided essentially identical ages for the same formation when tested using the inversion procedure. The ability to determine stratigraphic horizon ages from inversion of thermal indicator data implies that sedimentation rates can be determined; thus, basinal evolution can be inferred to a degree of resolution not previously obtainable from assumed interpolation methods applied to determine the age of horizons between a limited set of stratigraphic horizons of known ages.  相似文献   

Inverse methods and kinetic models of hydrocarbon generation. II. Case histories for residual kerogen analysis     

Jianchang Liu  I. Lerche 《Mathematical Geology》1990,22(8):989-1009

Using the results of the first paper in this series, which dealt with an inverse procedure for hydrocarbon generation, this paper focuses on case histories and numerical implementation of the model. Experimental data on residual kerogen analysis have been used with the inverse procedure to examine the applicability of the model to hydrocarbon generation directly from the degradation of kerogen, and to derive the kinetic parameters for the construction of a prediction equation. Energy-dependent channeling probability distributions are used to exhibit the stability of the model in describing the processes of kerogen degradation. The numerical methods for the solution of the inverse procedure and a sensitivity analysis are also discussed.  相似文献   

Erosion and uplift uncertainties in the Barents Sea, Norway     

I. Lerche 《Mathematical Geology》1997,29(4):469-501

Three different types of methods are used to assess the ability to determine erosion amounts and to provide estimates of uncertainty. In the situation of dynamical indicator methods, such as seismic velocity, sonic logs, density logs, or drilling exponent methods, intrinsic assumptions and parameter values used provide only a broad statement on the resolution of uplift/erosion events. None of the methods is more accurate, at best, to better than ± 1 km and likely much worse. For geological model procedures, exemplified by considerations of Airy isostasy and by bed upturning near a salt dome in the Nordkapp Basin of the Barents Sea, the uncertainties are again of the order of ± 500–1000 m. With thermal indicator procedures, the bulk of the constraint information from available data is needed to determine paleoheat flux with little left over to constrain the erosion, implying a minimum uncertainty of ± 500 m on erosion determinations. No method seems capable of resolving erosional events to better than a minimum uncertainty of ± 500 m, and likely no better than ± 1 km.  相似文献   

Enhanced diffusion in strongly magnetized astrophysical plasmas     

I. Lerche 《Astrophysics and Space Science》1973,23(2):339-346

We demonstrate that the diffusion coefficient for low energy particles, tied to a magnetic field which random walks, may be considerably larger than previously estimated in a strongly magnetized system — like the solar wind or the Galaxy. This is of interest with respect to propagation and lifetime considerations of low energy cosmic rays in the solar wind and the Galaxy.  相似文献   

    

I. Lerche  E. N. Parker 《Astrophysics and Space Science》1970,8(1):140

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Inversion of Apparent Attenuation and Phase Velocity to Determine Scattering Parameters     

I. Lerche 《Geophysical Journal International》1988,95(1):149-161

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One-dimensional modelling of episodic fracturing: a sensitivity study     

S. Cao  I. Lerche  W. G. Lyon 《地学学报》1989,1(2):177-181

Episodic fracturing is discussed in relation to both sedimentary deposition rates and lithology, as well as to pressure release criteria and vertical numerical grid sizes of a one-dimensional fluid-flow/ compaction model. It is shown that the evolution of episodic fracturing is a ruggedly stable pattern for fine-scale gridding, and that a critical fracture pressure of around 0.8 of the lithologic overburden is suggested.  相似文献   

Relativistic and non-relativistic gas flows in astrophysical media: The general symmetric solution in the low pressure limit     

I. Lerche 《Astrophysics and Space Science》1976,45(2):327-336

The dynamical expansion and motion of supernova remnants, double radio galaxies, etc., into and through the surrounding interstellar and/or intergalactic gas are processes of some importance in astrophysics for inferring energy, magnetic fields, particle pressure, etc. in a wide variety of astrophysical situations. We are usually hampered by the fact that it is often difficult to obtain a solution to the equations describing the flow of a gas into a surrounding medium starting from a postulated equation of state. The present paper shows how, by starting with a fluid flow that one believes adequately describes the gas, it is possible to solveby quadratures for the associated pressure and density. And in making these remarks we are implicitly assuming plane, cylindrical or spherically symmetric flow velocities which may be unsteady in time. The fluid speed can be chosen to be either non-relativistic or relativistic, but the method is valid only when the resulting gas pressurep, is small compared to c ², where is the mass density. We illustrate the method by solving a simple problem. In view of the ever increasing number of astrophysical situations where some measure of the fluid flow through an object is becoming available (often from Doppler shifted lines) we believe the present technique shou'd be of some use in helping to unravel the internal dynamical properties of the flowing gas.  相似文献   

South Caspian Oil Fields: Onshore and Offshore Reservoir Properties     

Bagirov  E.  Bagirov  B.  Lerche  I.  Mamedova  S. 《Natural Resources Research》1999,8(4):299-313

Original field data reports from the Azerbaijan sector of the South Caspian Basin have been used to compile statistical histograms of reservoir characteristics for both onshore and offshore oil fields. Two groups of statistics are presented here: the first group discusses reservoir thickness, areas, volumes, and horizon depths for the onshore and offshore fields; the second group discusses permeability, porosity, oil viscosity, oil recovery factor, reserves, and production for the onshore and offshore fields. These statistical distributions have been constructed so that one has available an historical database for use in assessing the range of likely reservoir characteristics in exploration ventures in this basin.  相似文献