scholarly journals Sensitivity of Acoustic Emission Triggering to Small Pore Pressure Cycling Perturbations During Brittle Creep

2019 ◽  
Vol 46 (13) ◽  
pp. 7414-7423 ◽  
Author(s):  
K. Chanard ◽  
A. Nicolas ◽  
T. Hatano ◽  
F. Petrelis ◽  
S. Latour ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Pore Pressure ◽  
Pressure Cycling ◽  
Brittle Creep ◽  
Small Pore

Improvement of Reliability Assessment of Gas Pipeline Using Acoustic Emission Technique

2013 ◽  
Author(s):  
Giuseppe Giunta ◽  
Sergio Budano ◽  
Antonio Lucci ◽  
Roberto Piancaldini ◽  
Luca Prandi
Keyword(s):  
Acoustic Emission ◽  
Magnetic Particles ◽  
Acoustic Emission Technique ◽  
Gas Industry ◽  
Pressure Cycling ◽  
Aggressive Environment ◽  
Initiation And Propagation ◽  
Acoustic Transient ◽  
Transient Energy ◽  
Full Scale Tests

Among NDE techniques for monitoring damages on pipelines in service, the Acoustic Emission (AE) technique is effective to check initiation and propagation of critical defects under stress and exposed to aggressive environment. To investigate both reliability and applicability of the AE technique to pipelines used in Oil&Gas industry, different full scale tests have been designed and performed as significant items. A pilot line (48″ diameter and length 194m), formed from pipes made of both steels grade API 5L X80 and X100, has been buried and monitored for about 16 months by using AE technique. External defects (dent & gouge type) have been executed on each pipe. A pressure cycling test has been provided giving pressure in the range 135–150 bar for simulating gas transport operation over many years. By means of AE technique the source localization of defects and correlation between the damage growing and the acoustic transient energy have been analyzed. The growth in the crack areas has been also periodically controlled using NDT inspections (US and magnetic particles). The results provide good perspective for using AE technique as advanced methodology to improve the reliability of pipeline.

Initiation of Acoustic Emission in Fluid-Saturated Rock Samples under Electric Current Action

2021 ◽  
Author(s):  
Alexander Ponomarev ◽  
Vladimir Smirnov ◽  
Andrey Patonin ◽  
Tatyana Kartseva
Keyword(s):  
Acoustic Emission ◽  
Electric Current ◽  
Pore Pressure ◽  
Electrical Power ◽  
Radial Strain ◽  
Electrical Current ◽  
Sample Volume ◽  
Radial Deformation ◽  
Saturated Rock ◽  
Current Action

<p>We present the results of the laboratory studies of the activization of acoustic emission in fluid-saturated and uniaxial stressed sandstone and granite samples under the electrical current action. The experiments were carried out at the Geophysical observatory “Borok” of Schmidt Institute of Physics of the Earth (Russian Academy of Sciences) using servocontrolled press INOVA-1000 under strain control.</p><p>We recorded acoustic emission (AE), axial load, axial and radial strain of the sample and controlled the electric current flowing through the sample. The electrodes for creating an electric potential difference were mounted at the ends of the cylindrical samples. The experiments were carried out both in the presence and in the absence of a galvanic contact of the electrodes with the sample. We examined dry cores and partially saturated cores with an aqueous NaCl solution of various concentrations.</p><p>A significant increase in acoustic activity (more than several times) was found during periods of current action, as well as a decrease in activity after termination of electric action. Radial strain increases during periods of electric current flow, which indicates an increase in the sample volume. We did not find acoustic emission initiation on dry samples and on fluid-containing samples in the absence of galvanic contact of the electrodes with the samples.</p><p>The increase in the AE activity depends mainly on the electrical power and the duration of the exposure interval. The product of these parameters gives the amount of Joule heat. This indicates that the mechanism of AE initiation by electric current is of a thermal nature. Acoustic activation increases with an increase in the heat generated by the electric current passing through the sample. This makes it possible to relate the initiation of fracturing by thermal expansion of the fluid in the sample cracks and an increase in pore pressure. Found increasing of the radial deformation during the heating intervals supports this idea. Thus, the discovered phenomenon can be considered as a consequence of an unconventional way of increasing pore pressure in rocks saturated with a conducting fluid.</p><p>The effect of increasing the acoustic emission activity under electric current action is observed both in mechanically stressed samples and in free, unloaded samples.</p><p>The work was supported partly by the mega-grant program of the Russian Federation Ministry of Science and Education under the project no. 14.W03.31.0033 and partly by the state assignment of the Ministry to IPE RAS.</p>

scholarly journals Pore-pressure cycling experiments on Mx80 Bentonite

2014 ◽  
Vol 400 (1) ◽  
pp. 303-312 ◽  
Author(s):  
C. C. Graham ◽  
J. F. Harrington ◽  
R. J. Cuss ◽  
P. Sellin
Keyword(s):  
Pore Pressure ◽  
Pressure Cycling

Acoustic emission induced by pore-pressure changes in sandstone samples

Geophysics ◽  
2011 ◽  
Vol 76 (3) ◽  
pp. MA21-MA32 ◽  
Author(s):  
Sibylle I. Mayr ◽  
Sergei Stanchits ◽  
Cornelius Langenbruch ◽  
Georg Dresen ◽  
Serge A. Shapiro
Keyword(s):  
Acoustic Emission ◽  
Pore Pressure ◽  
Fractured Rock ◽  
Axial Stress ◽  
Spatiotemporal Distribution ◽  
Final Sample ◽  
Macroscopic Fracture ◽  
Emission Activity ◽  
Water Saturated ◽  
Pressure Changes

An understanding of microseismicity induced by pore-pressure changes in stressed rocks is important for applications in geothermal and hydrocarbon reservoirs as well as for [Formula: see text] sequestrations. We have studied the triggering mechanisms of microseismicity (or acoustic emission in the laboratory) as a function of triaxial stress conditions and pore-pressure changes. In investigating the spatiotemporal distribution of acoustic emission activity in water-saturated triaxially stressed Flechtingen Sandstone samples subjected to changes in pore pressure, we assumed that acoustic events were triggered by pore-pressure increase. To estimate pore-pressure changes in the sample, we used an analytical solution of the 1D diffusion equation. A theoretical analysis of the spatiotemporal distribution suggested that for initially insignificantly stressed samples, acoustic events were triggered by the migration of a critical pore-pressure level through the sample. The critical level was controlled by the applied pore pressure of the previous cycle according to an apparent Kaiser effect in terms of pore pressure. This memory effect of the rock vanished if additional axial stress was applied to the sample before the next injection cycle. The behavior of a highly fractured rock in the final stage of the failure experiments was different. During the formation of a final sample-scale fracture, the spatiotemporal distribution of acoustic emission was more likely controlled by propagation of the fracture than by diffusion of a critical pore pressure, showing that the final macroscopic fracture was triggered by low pore pressure. Our work contributes to the characterization of reservoirs using fluid-induced seismicity.

Propagation of acoustic emission signals in metallic fuselage structure

2001 ◽  
Vol 148 (4) ◽  
pp. 169-177 ◽  
Author(s):  
R.P. Dalton ◽  
P. Cawley ◽  
M.J. Lowe
Keyword(s):  
Acoustic Emission
Sign in / Sign up

Export Citation Format

Share Document