Air Tests on Low-Permeability Claystone Formations. Experimental Results and Simulations

Ultra-low permeability rocks have plenty of microfractures. The stress-dependent permeability has a significant impact on the seepage. Previous studies are mainly on the permeability variation with stress in low permeability reservoir. But few are involved in ultralow permeability cores. In this paper, the experiment of stress sensitive ultralow permeability cores which are fabricated (both matrix cores and microfracture cores) is conducted. The experimental results shows that the permeability of microfracture low permeability cores which are fabricated increases greatly while the porosity of low permeability cores is little affected. This indicates that the fabricated microfracture cores are in line with that of the real situations of fracture media reservoir. By comparison, the permeability stress sensitive hysteresis degree of microfracture cores is not apparent and the permeability recovery degree is high in the unloading cycle. This study is of great benefit to reveals the stress sensitivity features of ultralow permeability reservoir

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Experiments and Modeling on the Influence of Interfacial Tension on Imbibition Height of Low-Permeability Reservoir

Geofluids ◽

10.1155/2020/8837897 ◽

2020 ◽

Vol 2020 ◽

pp. 1-10

Author(s):

Xiaoxia Ren ◽

Aifen Li ◽

Piyang Liu ◽

Bingqing He

Keyword(s):

Interfacial Tension ◽

Oil Recovery ◽

Dominant Role ◽

Fractal Theory ◽

Experimental Results ◽

Viscous Force ◽

Low Permeability ◽

Rock Samples ◽

Constant Rate ◽

Low Permeability Reservoirs

Low-permeability reservoirs have tiny pores with winding and complicated pore throats. The oil recovery efficiency of low-permeability reservoirs can be enhanced through the displacement of reservoir oil through imbibition. In the present study, experiments were conducted to investigate variations in the imbibition height of hydrophilic and weakly-hydrophilic rock samples under different interfacial tensions. An imbibition model considering imbibition resistance and bending of pore throats was established based on fractal theory. According to the experimental results, variations in the imbibition height of low-permeability rock samples with time can be divided into three stages. In the first stage, the capillary force plays a dominant role, while the viscous force and gravity have very slight effects. The imbibition height first increases rapidly and then levels off to a constant rate. With the increase in interfacial tension, the imbibition rate in the first stage increases, the ultimate imbibition height increases initially and then decreases, and the contribution of the imbibition height in the first stage to the ultimate imbibition height becomes greater. There is an optimal interfacial tension that causes the ultimate imbibition height to reach its maximum. The calculated results obtained from the proposed imbibition model are consistent with the experimental results, indicating that the model can accurately reflect the change in the imbibition height in low-permeability reservoirs in the first stage.

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Optimization of injection parameters for temperature time response gel plugging agent

Journal of Physics Conference Series ◽

10.1088/1742-6596/2109/1/012020 ◽

2021 ◽

Vol 2109 (1) ◽

pp. 012020

Author(s):

Wei Yan ◽

Ruibo Cao ◽

Yingxue Ma

Keyword(s):

Water Injection ◽

Experimental Results ◽

Time Response ◽

Low Permeability ◽

High Permeability ◽

Injection Volume ◽

Injection Speed ◽

Injection Parameters ◽

Medium Permeability ◽

Temperature Time

Abstract Aiming at the temperature time response gel plugging agent developed by Daqing exploration and development institute. In this paper, the injection volume, injection speed and injection concentration are optimized. The experimental results show that: the temperature time response gel can achieve the best plugging effect under the injection volume 0.1PV, injection concentration 1000mg/L and injection speed 0.6ml/min. In the subsequent water injection stage, the conductivity of high permeability layer decreases from 72.7% to 0.7%, that of low permeability layer increases from 4.1% to 14.3%, and that of medium permeability layer increases from 23.2% to 85%.

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Experimental Study of Improving the CO2 Flooding Development Effect in Ultra-Low Permeability Reservoir

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.594-597.2470 ◽

2012 ◽

Vol 594-597 ◽

pp. 2470-2474 ◽

Cited By ~ 1

Author(s):

Lei Zhang ◽

Feng Lan Zhao ◽

Ji Rui Hou

Keyword(s):

Resistance Coefficient ◽

Differential Pressure ◽

Experimental Results ◽

Low Permeability ◽

Oil Reservoir ◽

Breakthrough Time ◽

Displacement Effect ◽

Residual Resistance ◽

Before And After ◽

Gas Channeling

In order to improve the development effect of Chang-6 Oil Reservoir, five sets of different production pressure (1MPa, 2MPa, 3MPa, 4MPa, 5MPa) was designed to do CO2 immiscible flooding experiment to analyze the channeling laws. The experimental results showed that gas breakthrough time and gas channeling time were all shortened with the increasing of the pressure difference, but the ultimate recovery had a fluctuation change, increasing first and decreasing afterwards. And the production sharply increased in the gas breakthrough before and after. The best displacement effect was in 3MPa differential pressure. Then plugging experiment was made under the condition of 3MPa differential pressure, isopropyl amine was as plugging channeling agent. The experimental results: the residual resistance coefficient of plugging channeling agent was 8.56, and the range of enhancing recovery efficiency was 15%.

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Diagnostics of Gold Laser Plasmas

International Astronomical Union Colloquium ◽

10.1017/s0252921100108085 ◽

1988 ◽

Vol 102 ◽

pp. 357-360

Author(s):

J.C. Gauthier ◽

J.P. Geindre ◽

P. Monier ◽

C. Chenais-Popovics ◽

N. Tragin ◽

...

Keyword(s):

Experimental Results ◽

Pure Gold ◽

Electronic Temperature ◽

X Ray ◽

Laser Plasmas ◽

Collisional Radiative Model ◽

Radiative Model

AbstractIn order to achieve a nickel-like X ray laser scheme we need a tool to determine the parameters which characterise the high-Z plasma. The aim of this work is to study gold laser plasmas and to compare experimental results to a collisional-radiative model which describes nickel-like ions. The electronic temperature and density are measured by the emission of an aluminium tracer. They are compared to the predictions of the nickel-like model for pure gold. The results show that the density and temperature can be estimated in a pure gold plasma.

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Observation of Phase Contrast Images in STEM and CTEM Modes by Using 100 kV Field Emission Electron Gun

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100051967 ◽

1974 ◽

Vol 32 ◽

pp. 390-391

Author(s):

Y. Harada ◽

T. Goto ◽

H. Koike ◽

T. Someya

Keyword(s):

Field Emission ◽

Phase Contrast ◽

Image Formation ◽

Fresnel Diffraction ◽

Experimental Results ◽

Electron Gun ◽

Scanning Microscopy ◽

Emission Electron ◽

Lattice Images

Since phase contrasts of STEM images, that is, Fresnel diffraction fringes or lattice images, manifest themselves in field emission scanning microscopy, the mechanism for image formation in the STEM mode has been investigated and compared with that in CTEM mode, resulting in the theory of reciprocity. It reveals that contrast in STEM images exhibits the same properties as contrast in CTEM images. However, it appears that the validity of the reciprocity theory, especially on the details of phase contrast, has not yet been fully proven by the experiments. In this work, we shall investigate the phase contrast images obtained in both the STEM and CTEM modes of a field emission microscope (100kV), and evaluate the validity of the reciprocity theory by comparing the experimental results.

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A new dissociation mode for dislocations in silicon

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100108878 ◽

1978 ◽

Vol 36 (1) ◽

pp. 346-347

Author(s):

A. Ourmazd ◽

G.R. Booker ◽

C.J. Humphreys

Keyword(s):

Detailed Examination ◽

Experimental Results ◽

Dislocation Network ◽

Weak Beam ◽

Phosphorus Doped

A (111) phosphorus-doped Si specimen, thinned to give a TEM foil of thickness ∼ 150nm, contained a dislocation network lying on the (111) plane. The dislocation lines were along the three <211> directions and their total Burgers vectors,ḇt, were of the type , each dislocation being of edge character. TEM examination under proper weak-beam conditions seemed initially to show the standard contrast behaviour for such dislocations, indicating some dislocation segments were undissociated (contrast A), while other segments were dissociated to give two Shockley partials separated by approximately 6nm (contrast B) . A more detailed examination, however, revealed that some segments exhibited a third and anomalous contrast behaviour (contrast C), interpreted here as being due to a new dissociation not previously reported. Experimental results obtained for a dislocation along [211] with for the six <220> type reflections using (g,5g) weak-beam conditions are summarised in the table below, together with the relevant values.

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Multislice calculations of RHEED patterns from vicinal Si (001)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100150836 ◽

1993 ◽

Vol 51 ◽

pp. 1000-1001

Author(s):

Scott Lordi

Keyword(s):

Misorientation Angle ◽

Incident Angle ◽

Incident Beam ◽

Experimental Results ◽

Bragg Condition ◽

Vicinal Surfaces ◽

Kinematic Theory ◽

Step Edges

Vicinal Si (001) surfaces are interesting because they are good substrates for the growth of III-V semiconductors. Spots in RHEED patterns from vicinal surfaces are split due to scattering from ordered step arrays and this splitting can be used to determine the misorientation angle, using kinematic arguments. Kinematic theory is generally regarded to be inadequate for the calculation of RHEED intensities; however, only a few dynamical RHEED simulations have been attempted for vicinal surfaces. The multislice formulation of Cowley and Moodie with a recently developed edge patching method was used to calculate RHEED patterns from vicinal Si (001) surfaces. The calculated patterns are qualitatively similar to published experimental results and the positions of the split spots quantitatively agree with kinematic calculations.RHEED patterns were calculated for unreconstructed (bulk terminated) Si (001) surfaces misoriented towards [110] ,with an energy of 15 keV, at an incident angle of 36.63 mrad ([004] bragg condition), and a beam azimuth of [110] (perpendicular to the step edges) and the incident beam pointed down the step staircase.

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