Experimental studies of electrokinetic conversions in fluid‐saturated borehole models

Geophysics ◽  
1999 ◽  
Vol 64 (5) ◽  
pp. 1349-1356 ◽  
Author(s):  
Zhenya Zhu ◽  
Matthijs W. Haartsen ◽  
M. Nafi Toksöz
Keyword(s):  
Seismic Wave ◽  
Saturated Porous Medium ◽  
Electric Pulse ◽  
Experimental Studies ◽  
Ground Surface ◽  
Well Logging ◽  
Borehole Wall ◽  
Stoneley Wave ◽  
Apparent Velocity ◽  
Homogeneous Formation

Experimental and theoretical studies show that there are electromagnetic (EM) fields generated by seismic waves with two kinds of conversion mechanisms in a fluid‐saturated, porous medium. Within a homogeneous formation, the seismic wave generates a seismoelectric field that exists only in the area disturbed by the seismic wave and whose apparent velocity is that of the seismic wave. At an interface between differing formation properties, the generated seismoelectric wave is a propagating EM wave that can be detected everywhere. An electrode, used as a receiver on the ground surface, can detect the propagating EM wave generated at an interface, but cannot detect the seismoelectric field generated in a homogeneous formation. When the electrode is in a borehole and close to a porous formation, it can detect both the EM waves and the seismoelectric field. In this paper, electrokinetic measurements are performed with borehole models made of natural rocks or artificial materials. Experimental results show that the Stoneley wave and other acoustic modes, excited by a monopole source in the borehole models, generate seismoelectric fields in fluid‐saturated formations. The electric components of the seismoelectric fields can be detected by an electrode in the borehole or on the borehole wall. The amplitude and frequency of the seismoelectric fields are related not only to the seismic wave, but also to formation properties such as permeability, conductivity, etc. Comparison between the waveforms of the seismoelectric signals and acoustic logging waves suggests that seismoelectric well logging may explore the different properties of the formation. Electroseismic measurements are also performed with these borehole models. The electric pulse through the electrode in the borehole or on the borehole wall induces Stoneley waves in fluid‐saturated models that can be received by a monopole transducer in the same borehole. These measurement methods (seismoelectric logging or electroseismic logging) might directly apply to well logging to investigate formation properties related to the pore fluid flow.

Evaluation of Properties of Constructed Tubular-Steel Cast-in-Place Pilings

2013 ◽  
Vol 2363 (1) ◽  
pp. 36-46
Author(s):  
Devin K. Harris ◽  
Amir Gheitasi ◽  
Theresa M. Ahlborn ◽  
Kevin A. Mears
Keyword(s):  
Compressive Strength ◽  
Experimental Studies ◽  
Ground Surface ◽  
Axial Loading ◽  
Steel Shell ◽  
Deep Foundations ◽  
Element Analysis ◽  
Concrete Core ◽  
Geometrical Properties ◽  
Wisconsin Department

Bridge foundations contribute significantly to the serviceability and efficiency of in-service transportation networks. Foundation failure may lead to catastrophic failure of the entire structure, which in turn results in system failure, loss of life, and detours. When the soil within ground surface layers fails to satisfy the bearing capacity requirements, deep foundations such as tubular-steel concrete-filled piles are commonly used in practice. A challenge that often exists with these systems is the uncertainty surrounding in-service capacity as well as condition, which is difficult to determine from the surface. As a consequence, transportation agencies such as the Wisconsin Department of Transportation use conservative approaches, such as neglecting the tubular-steel contribution or bounding the compressive strength of the core concrete, to design these systems. This approach, while effective for safety, can yield overly conservative and costly designs. The main purpose of this investigation was to evaluate the behavior of tubular-steel, concrete-filled, cast-in-place pilings, with a concentration on the compressive strength and composite behavior between concrete core and steel shell. In this regard, a series of experimental studies, including composite and noncomposite compression loading, core samples, push-through, and flexural testing together with a compatible finite element analysis, were conducted on a series of field-cast piles with different geometrical properties. The results indicated that the steel shell made a significant contribution to the axial loading capacity of the cast-in-place piles. Moreover, no evidence of bond loss was observed during the corresponding experimental studies.

Numerical Modeling of Mud Invasion Profile Based on the Well Logging with the Shallow Depth of Investigation

2012 ◽  
Vol 524-527 ◽  
pp. 148-151
Author(s):  
Yuan Zhong Zhang ◽  
Xiu Ying Miao
Keyword(s):  
Numerical Modeling ◽  
Dynamic Process ◽  
Water Saturation ◽  
Radial Distance ◽  
Well Logging ◽  
Shallow Depth ◽  
Borehole Wall ◽  
Drilling Mud ◽  
Invasion Depth ◽  
Depth Of Investigation

The drilling mud invasion is a dynamic process varying with time and reveal the permeability or the relatively permeability of the formation saturated with fluid. The mud invasion profile denotes the water saturation change with the radial distance from the borehole wall. The logging with the shallow depth of investigation (DOI), such as density logging, neutron logging and shallow electrical logging, often detects the information of the flushed zone. We chose DOI logging to model the slope invasion profile with the hyperbolic secant function, and the calculated logging reading comparing from the real logging reading to optimize the invasion profile. The results show that the mud invasion profile and the invasion depth are strongly affected by porosity, where the invasion depth reduces with porosity adding.

scholarly journals A numerical simulation of the acoustic and elastic wavefields radiated by a source on a fluid‐filled borehole embedded in a layered medium

Geophysics ◽  
1993 ◽  
Vol 58 (4) ◽  
pp. 475-475 ◽  
Author(s):  
Michel Bouchon
Keyword(s):  
Layered Medium ◽  
Borehole Wall ◽  
Stoneley Wave ◽  
Wave Reflections ◽  
Volume Source ◽  
Linear System Of Equations ◽  
Method Of Calculation ◽  
Secondary Sources ◽  
Element Technique ◽  
Discrete Wavenumber Method

We present a method of calculation to simulate the propagation of acoustic and elastic waves generated by a borehole source embedded in a layered medium. The method is formulated as a boundary element technique where the Green’s functions are calculated by the discrete wavenumber method. The restrictive assumptions are that the borehole is cylindrical and that its axis runs normal to the layer interfaces. The physics of the method rely on Huygens’s principle that states that a diffracting boundary—the borehole wall in the present case—can be represented as a distribution of secondary sources. The borehole is discretized into small cylindrical elements and each element is represented by three sources: a volume source representing the wavefield diffracted in the fluid and two surface forces that give rise to the elastic wavefield radiated outside the borehole. The strength of each source is obtained by solving the linear system of equations that describes the boundary conditions at the borehole wall. The method is used to generate synthetic acoustic logs and to investigate the wavefield radiated into the formation. The simulations considered display the Stoneley wave reflections at the bed boundaries and show the importance of the diffraction that takes place where the borehole wall intersects the layer interfaces.

scholarly journals Kinetics of filtration consolidation of water-saturated clay soils

2020 ◽  
pp. 86-95 ◽  
Author(s):  
O. V. Ageikina ◽  
V. V. Vorontsov ◽  
R. R. Sufyanov
Keyword(s):  
Mathematical Model ◽  
Porous Medium ◽  
Saturated Porous Medium ◽  
Experimental Studies ◽  
Saturated Soils ◽  
Consolidation Process ◽  
Filtration Consolidation ◽  
Wide Range ◽  
Water Saturated ◽  
The Mathematical Model

The relevance of the research processes filtration consolidation due to the place of water-saturated soils in various design solutions related to the exploration, production and transportation of hydrocarbons. It should be noted that the diversity of soils led to the emergence of a wide range of mathematical models, obtained on the basis of generalization of experimental data and various assumptions to simplify engineering calculations. The article presents the results of theoretical and experimental studies of the mathematical model of the consolidation process of a water-saturated porous medium. This model is based on simplifying assumptions that are different from those adopted in well-known solutions. A fundamental approach to the formation of the model was developed on the basis of the kinetic representations of chemical reactions used in solving the environmental problems of epoxidation reactions of olefins. We determined the parameters of the mathematical model of the consolidation process of the saturated porous medium of clayey soil and confirmed its adequacy by the research results. In addition, we established the parameters of the field of non-equilibrium filtration, reducing the nonexistent ability of water-saturated soils.

Experimental Study on Vibration-Assisted Grinding

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
Kuan-Ming Li ◽  
Yang-Ming Hu ◽  
Zhong-Yi Yang ◽  
Ming-Yuan Chen
Keyword(s):  
Tool Life ◽  
Surface Finish ◽  
Small Amplitude ◽  
Experimental Studies ◽  
Ground Surface ◽  
Minimum Quantity Lubrication ◽  
Vibration Frequencies ◽  
Surface Finishes ◽  
Amplitude Vibration ◽  
Conventional Grinding

This paper presents experimental studies of vibration-assisted grinding with small-amplitude vibration (in the order of 1 μm) in terms of ground surface finish and tool life. The objectives are to obtain finer surface finishes on molds and longer tool life. The investigation shows that vibration-assisted grinding can improve surface finishes when compared with conventional grinding. Two different vibration frequencies are conducted in the experiments. Results show that surface finish and tool life are influenced by different process parameters. In vibration-assisted grinding, the best surface finish is obtained by using higher frequency of 11.4 kHz and lower feed rates. In this study, vibration-assisted grinding can extend tool life more than twice as that in conventional grinding. It is also shown that tool life in vibration-assisted grinding can be significantly improved by using minimum quantity lubrication (MQL).

scholarly journals Numeric Simulation of Acoustic-Logging of Cave Formations

Energies ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3908
Author(s):  
Fanghui Xu ◽  
Zhuwen Wang
Keyword(s):  
Excitation Frequency ◽  
Scattered Wave ◽  
P Wave ◽  
Borehole Wall ◽  
Stoneley Wave ◽  
S Wave ◽  
P Waves ◽  
Acoustic Logging ◽  
Source Distance ◽  
First Arrival

The finite difference (FD) method of monopole source is used to simulate the response of full-wave acoustic-logging in cave formations. The effect of the cave in the formation of borehole full-waves was studied. The results show that the radius of cave is not only linearly related to the first arrival of the compressional wave (P-wave), but also to the energy of the shear wave (S-wave). The converted S (S–S wave) and P-waves (S–P wave) are formed when the S-wave encounters the cave. If the source distance is small, the S–S and S–P waves are not separated, and the attenuation of the S-wave is not large, due to superposition of the converted waves. The S–P wave has been separated from the S-wave when the source distance is large, so the attenuation of the S-wave increases. The amplitude of the P and S–waves changes most when the distance of the cave to the borehole wall reaches a certain value; this value is related to the excitation frequency. The amplitude of the Stoneley wave (ST wave) varies directly with the radius of cave. If the radius of the cave is large, the energy of ST wave is weak. The scattered wave is determined by the radius and position of the cave. The investigation depth of a monopole source is limited. When the distance of the cave to the borehole wall exceeds the maximum investigation depth, the borehole acoustic wave is little affected by the cave. In actual logging, the development of the cave can be evaluated by using the first arrival of the P-wave and the energy of the S and ST waves.

scholarly journals A Method of Experimental Studies of Heat Transfer Processes between Adjacent Facilities

2018 ◽  
Vol 7 (4.3) ◽  
pp. 288 ◽  
Author(s):  
Vadym Nizhnyk ◽  
Stanislav Shchipets ◽  
Olexandr Tarasenko ◽  
Vitalii Kropyvnytskyi ◽  
Bogdan Medvid
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Test Specimen ◽  
Experimental Studies ◽  
Ground Surface ◽  
Heat Radiation ◽  
Lower Edge ◽  
Specimen Type ◽  
Transfer Processes ◽  
Window Opening

A method of experimental studies of heat transfer processes between adjacent facilities during fire was developed. Equipment necessary for the experimental studies was determined. A new specimen type for studies was created in order to perform experimental studies. Configuration of the specimen for the studies allows simulation of a building fragment with filler structures which is affected by heat radiation emitted by fire. Points of placement of the specimens for studies relative to the heat flux source when conducting experimental studies were substantiated. It was revealed that height of the specimen installation shall be determined so that the test specimen is located below the flame tip in order to take into account the most severe impact of heat radiation coming from the fire bed and to exclude any possibility of irradiation from the ground surface. It was proposed that the test specimens are placed at the level of the lower edge of the window opening of the building fragment at the distances of2 m,4 mand6 mfrom the building fragment. The sequence of conduction of experimental studies of heat transfer processes between adjacent facilities during fire was developed. 

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