scholarly journals A time domain induced polarization relaxation time spectrum inversion method based on a damping factor and residual correction

2014 ◽  
Vol 11 (4) ◽  
pp. 519-525 ◽  
Author(s):  
Xiaonan Liu ◽  
Li Kong ◽  
Kaibo Zhou ◽  
Pu Zhang
Geophysics ◽  
2006 ◽  
Vol 71 (3) ◽  
pp. N33-N40 ◽  
Author(s):  
Maosong Tong ◽  
Li Li ◽  
Weinan Wang ◽  
Yizhong Jiang

An appropriate form of induced polarization (IP) acts as a bridge between the structure of a water-saturated core plug and its transport properties. The induced-polarization decay curves of natural rocks can be modeled as a weighted superposition of exponential relaxations. A singular-value decomposition method makes it possible to transform the induced-polarization decay data of the shaley sands into relaxation-time spectrum, defined as plot of weight versus the relaxation-time constant. We measured the induced-polarization decay curves of core samples from a formation of Daqing oil field using a four-electrode method. The decay curves were transformed to relaxation-time spectra that were used to estimate the capillary-pressure curves, the pore-size distribution, and the permeability of the shaley sands. The results show that salinity ranges from [Formula: see text] have little effect on the IP relaxation-time spectra. A pseudocapillary pressure curve can be derived from the IP relaxation-time spectrum by matching the pseudocapillary curve with that from HgAir. The best-matching coefficients of the studied cores change slightly for the samples. Defined as the value of pressure at which the injected mercury saturation is 5%, entry pressures of the cores can be estimated well from IP-derived capillary-pressure curves. Pore-size distributions generated from induced polarization and mercury capillary-pressure curves are comparable. Permeability can be predicted from IP measurements in the form of [Formula: see text], where [Formula: see text] is the estimated permeability from IP relaxation spectrum in millidarcies (md), [Formula: see text] is the porosity in percentage, and [Formula: see text] is average time constant of IP relaxation-time spectra in millis (ms). The constants and exponents from various rock formations are slightly different.


1995 ◽  
Vol 60 (11) ◽  
pp. 1815-1829 ◽  
Author(s):  
Jaromír Jakeš

The problem of finding a relaxation time spectrum best fitting dynamic moduli data in the least-squares sense is shown to be well-posed and to yield a discrete spectrum, provided the data cannot be fitted exactly, i.e., without any deviation of data and calculated values. Properties of the resulting spectrum are discussed. Examples of discrete spectra obtained from simulated literature data and experimental literature data on polymers are given. The problem of smoothing discrete spectra when continuous ones are expected is discussed. A detailed study of an integral transform inversion under the non-negativity constraint is given in Appendix.


1954 ◽  
Vol 27 (1) ◽  
pp. 36-54 ◽  
Author(s):  
W. Kuhn ◽  
O. Künzle ◽  
A. Preissmann

Abstract By rapid deformation of a medium in which linear molecules are present, various changes are produced simultaneously in the latter. These changes are more or less independent of one another, and can release independently and totally or partially by rearrangement of valence distances and valence angles in the chain molecules. By virtue of such relaxation processes, a portion of the stress originating in the rapid deformation disappears, with a changing time requirement for the various portions. A relaxation time spectrum is thus formed. The relaxation time spectrum consists of a finite number of restoring force mechanisms with proper relaxation times or of a continuous spectrum. Both the creep curves (the dependence of the length of a body on time at constant load), and stress relaxation (decay of the stress observed in test sample kept at constant length after rapid deformation), as well as the total visco-elastic behavior, especially the behavior at constant periodic deformation of the test sample, are determined by the relaxation time spectrum. The appropriate Quantitative relationships were derived.


1983 ◽  
Vol 51 (10) ◽  
pp. 911-914 ◽  
Author(s):  
L. Lundgren ◽  
P. Svedlindh ◽  
P. Nordblad ◽  
O. Beckman

1995 ◽  
Vol 407 ◽  
Author(s):  
Fernando C. Perez-Cardenas ◽  
Hao Gan

ABSTRACTGlasses are amorphous solids that exhibit an intricate structural relaxation. A broad relaxation time spectrum always emerges when these systems are perturbed. By using a Langevin-type differential equation to describe the structure dynamicsof these materials, it is depicted how the broad relaxation time spectrum arises due to the stochastic noise and how this affects the system's structure evolution as it is cooled down into the glass transition region. This stochastic model provides a macroscopic as well a microscopic view of the glass relaxation process.


1999 ◽  
Vol 139 (1) ◽  
pp. 69-86 ◽  
Author(s):  
K. Wieczerkowski ◽  
J. X. Mitrovica ◽  
D. Wolf

1992 ◽  
Vol 31 (1) ◽  
pp. 75-82 ◽  
Author(s):  
M. Baurngaertel ◽  
M. E. De Rosa ◽  
J. Machado ◽  
M. Masse ◽  
H. H. Winter

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