3D Static Modeling and Petrographic Aspects of the Albian/Cenomanian Reservoir,Komombo Basin,Upper Egypt

Natural Resources Research - The Albian/Cenomanian reservoir is one of the two main reservoirs composing the petroleum system in the Komombo Basin. However, these reservoirs have not previously...     

The spacetime gravitational field of a deformable body

The high-resolution analysis of orbit perturbations of terrestrial artificial satellites has documented that the eigengravitation of a massive body like the Earth changes in time, namely with periodic and aperiodic constituents. For the space-time variation of the gravitational field the action of internal and external volume as well as surface forces on a deformable massive body are responsible. Free of any assumption on the symmetry of the constitution of the deformable body we review the incremental spatial (“Eulerian”) and material (“Lagrangean”) gravitational field equations, in particular the source terms (two constituents: the divergence of the displacement field as well as the projection of the displacement field onto the gradient of the reference mass density function) and the `jump conditions' at the boundary surface of the body as well as at internal interfaces both in linear approximation. A spherical harmonic expansion in terms of multipoles of the incremental Eulerian gravitational potential is presented. Three types of spherical multipoles are identified, namely the dilatation multipoles, the transport displacement multipoles and those multipoles which are generated by mass condensation onto the boundary reference surface or internal interfaces. The degree-one term has been identified as non-zero, thus as a “dipole moment” being responsible for the varying position of the deformable body's mass centre. Finally, for those deformable bodies which enjoy a spherically symmetric constitution, emphasis is on the functional relation between Green functions, namely between Fourier-/ Laplace-transformed volume versus surface Love-Shida functions (h(r),l(r) versus h ^′(r),l ^′(r)) and Love functions k(r) versus k ^′(r). The functional relation is numerically tested for an active tidal force/potential and an active loading force/potential, proving an excellent agreement with experimental results. Received: December 1995 / Accepted: 1 February 1997     

Water status in winter wheat grown under salt stress

1 IntroductionSalinization is one of the major problems in arid and semi-arid regions in relation to land use and in particular to agricultural production[1]. Excessive salinity leads to toxicity in crops and reduction of the availability of water to crops, by reducing the osmotic potential of the soil solution[2]. Movement of soil water induces solute transport, and solutes are transferred towards the ground surface by the upward soil-water movement caused by evaporation, resulting in an accu…     

Rock physics template (RPT) analysis of well logs and seismic data for lithology and fluid classification in Cambay Basin

The Cambay Basin is 450-km-long north–south-trending graben with an average width of 50 km, having maximum depth of about 7 km. The origin of the Cambay and other Basins on the western margin of India are related to the break up of the Gondwana super-continent in the Late-Triassic to Early-Jurassic (215 ma). The structural disposition of the Pre-Cambrian basement—a complex of igneous and metamorphic rocks exposed in the vicinity of the Cambay Basin—controls its architecture. The principal lineaments in the Basin are aligned towards NE-SE, ENE-WSW and NNW-SSE, respectively. Rock physics templates (RPTs) are charts and graphs generated by using rock physics models, constrained by local geology, that serve as tools for lithology and fluid differentiation. RPT can act as a powerful tool in validating hydrocarbon anomalies in undrilled areas and assist in seismic interpretation and prospect evaluation. However, the success of RPT analysis depends on the availability of the local geological information and the use of the proper model. RPT analysis has been performed on well logs and seismic data of a particular study area in mid Cambay Basin. Rock physics diagnostic approach is adopted in the study area placed at mid Cambay Basin to estimate the volume in the reservoir sands from 6 wells (namely; A, B, C, D, E and F) where oil was already encountered in one well, D. In the study area, hydrocarbon prospective zone has been marked through compressional (P wave) and shear wave (S wave) impedance only. In the RPT analysis, we have plotted different kinds of graphical responses of Lame’s parameters, which are the function of P-wave velocity, S-wave velocity and density. The discrete thin sand reservoirs have been delineated through the RPT analysis. The reservoir pay sand thickness map of the study area has also been derived from RPT analysis and fluid characterization. Through this fluid characterization, oil-bearing thin sand layers have been found in well E including well D. The sand distribution results prove that this methodology has able to perform reservoir characterization and seismic data interpretation more quantitatively and efficiently.     

Reconstructing fluvial bar surfaces from compound cross‐strata and the interpretation of bar accretion direction in large river deposits

The interpretation of fluvial styles from the rock record is based for a significant part on the identification of different types of fluvial bars, characterized by the geometric relationship between structures indicative of palaeocurrent and surfaces interpreted as indicative of bar form and bar accretion direction. These surfaces of bar accretion are the boundaries of flood‐related bar increment elements, which are typically less abundant in outcrops than what would be desirable, particularly in large river deposits in which each flood mobilizes large volumes of sediment, causing flood‐increment boundary surfaces to be widely spaced. Cross‐strata set boundaries, on the other hand, are abundant and indirectly reflect the process of unit bar accretion, inclined due to the combined effect of the unit bar surface inclination and the individual bedform climbing angle, in turn controlled by changes in flow structure caused by local bar‐scale morphology. This work presents a new method to deduce the geometry of unit bar surfaces from measured pairs of cross‐strata and cross‐strata set boundaries. The method can be used in the absence of abundant flood‐increment bounding surfaces; the study of real cases shows that, for both downstream and laterally accreting bars, the reconstructed planes are very similar to measured bar increment surfaces.     

Über die Verteilung der aus Gezeitenbeobachtungen bestimmten gravimetrischen Faktoren in Europa

auamaumuu am, n u a¶rt;u nuu n ¶rt;a ₂, ₂, ₁ u ₁ (u. 1–4). na ¶rt;a ¶rt;am au ¶rt;um au an¶rt;u mu naam. a n¶rt;aam unam nu nuu nna m uu u u mmu mam ¶rt; uu u a a mau n.

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Vorgetragen am 2. Internationalen Symposium Geodäsie und Physik der Erde, Potsdam, Mai 1973.     

Specific features of the relativistic electron flux dynamics during the recovery phase of a magnetic storm on April 6, 2000

The energy spectrum of electrons with energies of 0.8–6.0 MeV has been analyzed based on the data of the Express-A2 geostationary satellite and time variations in the fluxes of electrons with energies higher than 0.6 and 2 MeV (according to the GOES-10 satellite data) before and after a weak geomagnetic storm on April 9–10, 2002, which developed during the prolonged (about ten days) recovery phase of a strong magnetic storm on April 6, 2000. The effect of the secondary injection and acceleration caused by an intensification of substorm activity during a weak storm on the electron flux dynamics has been studied for the first time. The energy spectra and time variations in the electron flux dynamics before and after a weak storm have been described based on analytical solutions to the kinetic equation for the electron distribution function with regard to the stochastic acceleration and loss rates. It has been established that there were different acceleration and loss rates before and after the weak storm of April 9–10, 2000.     

Seismic earth pressures on rigid and flexible retaining walls

While limiting-equilibrium Mononobe–Okabe type solutions are still widely used in designing rigid gravity and flexible cantilever retaining walls against earthquakes, elasticity-based solutions have been given a new impetus following the analytical work of Veletsos and Younan [23]. The present paper develops a more general finite-element method of solution, the results of which are shown to be in agreement with the available analytical results for the distribution of dynamic earth pressures on rigid and flexible walls. The method is then employed to further investigate parametrically the effects of flexural wall rigidity and the rocking base compliance. Both homogeneous and inhomogeneous retained soil is considered, while a second soil layer is introduced as the foundation of the retaining system. The results confirm the approximate convergence between Mononobe–Okabe and elasticity-based solutions for structurally or rotationally flexible walls. At the same time they show the beneficial effect of soil inhomogeneity and that wave propagation in the underlying foundation layer may have an effect that cannot be simply accounted for with an appropriate rocking spring at the base.     

The Lyot-coronagraph with 53 cm objective

The new Lyot-coronagraph with 53 cm objective is described. The coronagraph has a grating spectrograph. The solar disk image on the slit of the spectrograph is 12.6 cm. The dispersion is 1 Å/mm in the second order. The coronagraph is situated at the Kislovodsk Station of Pulkovo Observatory, 2050 m above sea level.     

Neutron monitor observations of high-energy solar particles during the new cycle

After a lapse of five years, the first solar events in which particles were emitted with sufficiently high energies to produce intensity enhancements in ground-based neutron monitors occurred on July 7, 1966, and January 28, 1967. Although the magnitude of the first of these increases was too small (<2%) to permit detailed analysis, the later event, which exceeded 18% at sea-level stations in the polar regions, displayed unusual characteristics. The January 28 event is anomalous in that either it represents the first observation of solar particles reaching the earth from the back side of the sun, or it is associated with a feeble flare (1-) in the unfavored eastern hemisphere of the visible disk. The propagation of solar particles in this event was evidently controlled by a diffusion mechanism, and the observations are consistent with predictions based on alternative theoretical models of this process.This work was supported by the U.S. National Science Foundation and the U.S. Air Force Cambridge Research Laboratories, Office of Aerospace Research.