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[en] To introduce the application of nuclear logging, it is appropriate to provide a motivation for the use of nuclear measurement techniques in well logging. Importance aspects of the geological sciences are for instance grain and porosity structure and porosity volume of the rocks, as well as the transport properties of a fluid in the porous media. Nuclear measurements are, as a rule non-intrusive. Namely, a measurement does not destroy the sample, and it does not interfere with the process to be measured. Also, non- intrusive measurements are often much faster than the radiation methods, and can also be applied in field measurements. A common type of nuclear measurement employs neutron irradiation. It is powerful technique for geophysical analysis. In this research we illustrate the detail of this technique and it's applications to well logging and oil industry. Experiments have been performed to investigate the possibilities of using neutron attenuation measurements to determine water and oil content of rock sample. A beam of 14 MeV neutrons produced by a 150 KV neutron generator was attenuated by different samples and subsequently detected with plastic scintillators NE102 (Fast counter). Each sample was saturated with water and oil. The difference in neutron attenuation between dry and wet samples was compared with the fluid content determined by mass balance of the sample. In this experiment we were able to determine 3% of humidity in standard sample model (SiO2) and estimate porosity in geological samples when saturated with different fluids. (Author)
[en] This paper discusses a method of measuring the porosity of core samples using gamma-ray attenuation. Equations for the uncertainty in the measurements are presented. The effect of unknown lithologies and fluid saturations is also discussed. The method has been experimentally validated against porosities measured with Archimedes' method on a variety of lithologies and over a range of porosities. The method was used to successfully characterize the porosity of 80' of core from a heterogeneous dolomite reservoir. Measuring porosity with gamma-ray attenuation has some significant advantages over traditional methods:it is fast, non-destructive, and provides a much better characterization of small scale heterogeneities in porosity. Its accuracy is limited, however, if the lithology or fluid saturations are not known. (Author)
[en] Standard models of two-phase flow in porous media have been shown to exhibit several shortcomings that might be partially overcome with a recently developed model based on thermodynamic principles (Hassanizadeh and Gray, 1990). This alternative two-phase flow model contains a set of new and non-standard parameters, including specific interfacial area. By incorporating interfacial area production, destruction, and propagation into functional relationships that describe the capillary pressure and saturation, a more physical model has been developed. Niessner and Hassanizadeh (2008) have examined this model numerically and have shown that the model captures saturation hysteresis with drainage/imbibition cycles. Several static experimental studies have been performed to examine the validity of this new thermodynamically based approach; these allow the determination of static parameters of the model. To date, no experimental studies have obtained information about the dynamic parameters required for the model. A new experimental porous flow cell has been constructed using stereolithography to study two-phase flow phenomena (Crandall et al. 2008). A novel image analysis tool was developed for an examination of the evolution of flow patterns during displacement experiments (Crandall et al. 2009). This analysis tool enables the direct quantification of interfacial area between fluids by matching known geometrical properties of the constructed flow cell with locations identified as interfaces from images of flowing fluids. Numerous images were obtained from two-phase experiments within the flow cell. The dynamic evolution of the fluid distribution and the fluid-fluid interface locations were determined by analyzing these images. In this paper, we give a brief introduction to the thermodynamically based two-phase flow model, review the properties of the stereolithography flow cell, and show how the image analysis procedure has been used to obtain dynamic parameters for the numerical model. These parameters include production/destruction of interfacial area as a function of saturation and capillary pressure. Our preliminary results for primary drainage in porous media show that the specific interfacial area increased linearly with increasing gas saturation until breakthrough of the displacing gas into the exit manifold occurred.
[en] We investigate the effects of the saturation boundary on small-x evolution at the next-to-leading order accuracy and beyond. We demonstrate that the instabilities of the next-to-leading order BFKL evolution are not cured by the presence of the nonlinear saturation effects, and a resummation of the higher order corrections is therefore needed for the nonlinear evolution. The renormalization group improved resummed equation in the presence of the saturation boundary is investigated, and the corresponding saturation scale is extracted. A significant reduction of the saturation scale is found, and we observe that the onset of the saturation corrections is delayed to higher rapidities. This seems to be related to the characteristic feature of the resummed splitting function which at moderately small values of x possesses a minimum.
[en] The dynamics of the growth of interfaces in the presence of noise and when the normal velocity is constant, in the weakly nonlinear limit, are described by the Kardar-Parisi-Zhang (KPZ) equation. In many applications, however, the growth is controlled by nonlocal transport, which is not contained in the original KPZ equation. For these problems we are proposing an extension of the KPZ model, where the nonlocal contribution is expressed through a Hilbert transform and can act to either stabilize or destabilize the interface. The model is illustrated with a specific example from reactive infiltration. The properties of the solution of the resulting equation are studied in one spatial dimension in the linear and the nonlinear limits, for both stable and unstable growth. We find that the early-time behavior has a power-law scaling similar to that of the KPZ equation. However, in the case of stable growth, the scaling of the saturation width is logarithmic, which differs from the power law in the KPZ equation. This dependence reflects the stabilizing effect of nonlocal transport. In the unstable case, we obtain results similar to those of Olami [Phys. Rev. E 55, 2649 (1997)]
[en] Highlights: ► Five 3-D hydrate samples are formed to study CH4–CO2 replacement with liquid CO2. ► Liquid CO2 adapts to hydrate reservoirs with/without underlying gas or free water. ► CH4 replacement rate and amount increase with the increase of hydrate saturation. ► Saturations of water and hydrate have different effect on CH4 replacement percent. ► There exists a phase zone that replacement rate and percent of CH4 are higher. - Abstract: The dynamics of CH4 replacement in natural gas hydrate with liquid CO2 was studied with a high pressure three-dimensional reactor. Five groups of hydrate samples were formed to investigate the effect of hydrate reservoir properties on CH4–CO2 replacement reaction. The results showed that CH4 in the hydrate gradually moves to the liquid CO2 phase while CO2 in the liquid phase penetrates into the hydrate under pressure–temperature conditions not only within the phase zone surrounded by (LCO2–VCO2), (water–HCO2–LCO2), and (water–HCH4–VCH4) curves but also that above (LCO2–VCO2) and (water–HCH4–VCH4) curves. The replacement rate and amount of CH4 increase with the increase of hydrate saturation in the sediments. Compared with injecting gaseous CO2 method, liquid CO2 injection is also benefit for the recovery of CH4 from hydrate reservoir with much free water or that without underlying gas room to the extent that the injection of liquid CO2 is kept by high gas saturation. The replacement percent of CH4 hydrate decreases with the increase of hydrate saturation, but increases with the increase of water saturation. A higher replacement percent is obtained in the zone surrounded by three phase curves of (LCO2–VCO2), (water–HCO2–LCO2) and (water–HCH4–VCH4)
[en] A method to determine liquid saturations in core plugs during flooding is of importance when the relative permeability and capillary pressure function are to be determined. This part of the EFP-93 project uses transmission of γ-radiation to determine these saturations. In γ-transmission measurements, the electron density of the given substance is measured. This is an advantage as compared to methods that use electric conductivity, since neither oil nor gas conducts electricity. At the moment a single 137Cs-source is used, but a theoretical investigation of whether it is possible to determine three saturations, using two radioactive sources with different γ-energies, has been performed. Measurements were made on three core plugs. To make sure that the measurements could be reproduced, all the plugs had a point of reference, i.e. a mark so that it was possible to place the plug same way every time. Two computer programs for calculation of saturation and porosity and the experimental setup are listed. (EG)
[en] The research deals with experimental study of potentiality of wave impacts on monotonous movement of fluids and inclusions (solid particles, drops, bubbles, etc.) in a porous medium. The efficiency of the wave effects on porous media saturated with liquid is shown experimentally. The effect of creating unidirectional movement of liquid and inclusions in a porous medium using the wave impacts has been demonstrated
[ru]Работа посвящена экспериментальному выявлению возможности волновых воздействий на монотонные движения флюидов и включений (твердых частиц, капель, пузырьков и т. п.) в пористой среде. Экспериментально показана эффективность волнового воздействия на пористые среды, насыщенные жидкостью. Продемонстрирован эффект создания однонаправленных движений жидкости и включений в пористой среде с помощью волнового воздействия
[en] A method to determine liquid saturations in core plugs during flooding is of importance when the relative permeability and capillary pressure function are to be determined. This part of the EFP-95 project uses transmission of γ-radiation to determine these saturations. In γ-transmission measurements, the electron density of the given substance is measured. This is an advantage as compared to methods that use electric conductivity, since neither oil nor gas conducts electricity. At the moment a single 137Cs-source is used, but a theoretical investigation of whether it is possible to determine three saturations, using two radioactive sources with different γ-energies, has been performed. Measurements were made on three core plugs. To make sure that the measurements could be reproduced, all the plugs had a point of reference, i.e. a mark so that it was possible to place the plug same way every time. Two computer programs for calculation of saturation and porosity and the experimental setup are listed. (EG)
[en] Using numerical methods, we study the finite-field ground state of an S=1 zigzag ladder. Special attention is paid to the magnetization plateau which appears at a half of the saturation magnetization in the ground-state magnetization curve