The dead volume effect on the elastic moduli measurements using the forced‐oscillation method

Mikhaltsevitch, Vassili; Lebedev, Maxim; Chavez, R.; Pervukhina, Marina; Glubokovskikh, Stanislav; Vargas, Edson

doi:10.1111/1365-2478.13173

“…Drained State to Undrained State. When fully fluidsaturated rock transits from drained state to undrained state and global fluid flow mechanism dominates, similar to the partially fluid-saturated condition, shear modulus keeps constant, while bulk modulus increases with frequency [15,[29][30][31]. The corresponding Poisson's ratio also increases monotonously with frequency, and its associated attenuation is positive with one peak [29,30].…”

Section: Fully Fluid-saturated Conditionmentioning

confidence: 93%

The Frequency Dependence of Poisson’s Ratio in Fluid-Saturated Rocks

Zhao

¹

,

Chen

²

,

Zhang

³

et al. 2022

Geofluids

1

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We investigated the frequency dependence of Poisson’s ratio ν in partially/fully fluid-saturated rocks. Based on one dominant fluid flow mechanism at each condition, we theoretically summarized that (1) when a rock is partially saturated or transits from drained state to undrained state at full saturation, ν increases monotonously with frequency, and the associated attenuation 1 / Q ν is positive with one peak. (2) When the rock transits from undrained state to unrelaxed state at full saturation, there are three cases: 1) ν increases monotonously with frequency and has positive 1 / Q ν with one peak, 2) ν keeps constant with frequency and has no attenuation, 3) and ν decreases monotonously with frequency and has negative 1 / Q ν with one peak. In this condition, the dependence is influenced by the concentrations of stiff and soft pores, the aspect ratio of soft pores, and the pore fluid bulk modulus. (3) When it comes to the transition from drained state to unrelaxed state at full saturation, ν can exhibit two shapes with frequency: 1) step shape with two positive attenuation peaks and 2) bell shape with one positive attenuation peak and one negative attenuation peak. Then, we conducted a numerical example to indicate the effect of influence factors (the concentrations of stiff and soft pores, the aspect ratio of soft pores, and the pore fluid bulk modulus) on Poisson’s ratio from undrained state to unrelaxed state, and validated the theoretical analysis by the published experimental data. In addition, based on 1 / Q ν , we reanalyzed and validated the relationship between different attenuation modes (i.e., bulk attenuation 1 / Q K , P-wave attenuation 1 / Q P , extensional attenuation 1 / Q E , and S-wave attenuation 1 / Q S ): (1) when 1 / Q ν is positive, the relationship between them is 1 / Q K > 1 / Q P > 1 / Q E > 1 / Q S ; when 1 / Q ν is 0, the relationship between them is 1 / Q K = 1 / Q P = 1 / Q E = 1 / Q S ; and when 1 / Q ν is negative, the relationship between them is 1 / Q K < 1 / Q P < 1 / Q E < 1 / Q S . The relationship between different attenuation modes does not depend on saturation state (partial or full saturation) or ν but on 1 / Q ν . This research provides the frequency dependence of Poisson’s ratio in partially/fully saturated rocks, which helps better understand Poisson’s ratio at different frequencies and saturation states and can be used to improve the accuracy of geophysical data interpretation, such as lithology identification, hydrocarbon characterization in conventional reservoir, and brittleness evaluation of shale/tight sandstones in unconventional reservoir.

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“…The topology of the original backward oscillatory search algorithm is combined with the ring topology by V-values. The algorithm initially has high population diversity and uses the primal iterative process for fast convergence to near the optimal value [6] . When the population diversity decreases to a certain level, the ring topology is invoked to increase the population diversity and avoid falling into local optima.…”

Section: ( )mentioning

confidence: 99%

An oscillatory search method for relay protection logic diagrams based on sequential traversal

Wu¹,

Li*²,

Zhang³

et al. 2023

International Conference on Computer, Artificial Intelligence, and Control Engineering (CAICE 2023)

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The current conventional oscillatory search algorithm for relay protection logic diagram is prone to fall into local optimum due to the late population diversity reduction, which leads to poor search results. In this regard, a sequential traversal-based oscillation search method for relay protection logic diagrams is proposed. The oscillation search algorithm is optimized by finding the second-order oscillation factor, optimizing the topology of the algorithm, and constructing the relay protection logic diagram model to obtain a library of graph elements. The experimental results show that the proposed oscillation search algorithm converges faster and has a more desirable search effect.

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“…FO is applied to measure properties of all sedimentary rock types: sandstones [21,33,43,79,89,90,, carbonates [21,33,64,79,92,99,100,119,120,[136][137][138][139][140][141][142][143][144][145][146][147][148][149], and shales [75,100,119,[150][151][152][153][154][155][156][157][158][159][160]. FO is also applied to igneous rocks [21,70,71,73,[161][162][163]…”

Section: Forced-oscillation (Fo)mentioning

confidence: 99%

“…Riabokon et al [146] also studied the non-linearity of dry carbonates. Mikhaltsevitch et al [147] is the continuation of Mikhaltsevitch et al [143,144] whose results are also modelled by modified Gassmann theory. Sun et al [148] studied the impact of partial saturation by (i) drying and (ii) imbibition: P-wave dispersion (and attenuation) is significant for (i) but not for (ii) whereas S-wave dispersion (and attenuation) is insignificant for both (i) and (ii) at > 80% RH.…”

mentioning

confidence: 93%

“…Borgomano et al [142] found dispersion at around 200 Hz affecting all moduli but G in water-saturated Lavoux specimens. Mikhaltsevitch et al [143,144,147] demonstrated that non-ideal boundary conditions (enforced by varying dead volumes) caused significant dispersion in fully decane-saturated Savoinnière specimens if the dead volume exceeds the pore space. Borgomano et al [145] interpreted the observed dispersion and attenuation of Coquina, Rustrel, and Indiana (intact and thermally cracked) specimens in terms of transitions between drained, undrained and unrelaxed fluid-flow regimes at water and glycerine-saturated conditions.…”

mentioning

confidence: 99%

See 1 more Smart Citation

On Frequency-Dependent Rock Experiments: A Comparative Review

Rørheim¹

2022

Preprint

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Rock properties are environment-and condition-dependent which render field-laboratory comparisons ambiguous for a number of known and unknown reasons that constitute the upscaling problem. Unknowns are first transformed into knowns in a controlled environment (laboratory) and second in a volatile environment (field). Causality-bound dispersion and attenuation are respectively defined as rock properties that are frequency-and distance-dependent: dispersion implies non-zero attenuation and vice versa. Forced-Oscillation (FO), Resonant Bar (RB), and Pulse-Transmission (PT) are the customary techniques to measure rock properties at Hz, kHz, and MHz frequencies. Notably FO has emerged as the current champion in bridging the fieldlaboratory void in recent years. Not only is FO probing seismic (Hz) frequencies but with ∼ 10 −6 strain amplitudes it is also similar to field seismic. RB and PT are concisely however FO is verbosely elaborated by chronologically compiling most (if not all) FO studies on sedimentary rocks and comparing all available FO measurements on reference materials such as lucite, aluminium, and PEEK. First of its kind, this inter-laboratory comparison may serve as a reference for others who seek to verify their own results. Differences between FO are discussed with alternative strain and stress sensors being the focal points. Other techniques such as Resonant Ultrasound Spectroscopy (RUS), Laser UltraSonics (LUS), and Differential Acoustic Resonance Spectroscopy (DARS) that are similar to FO, RB, and PT are also described. Only time will tell what the future holds for FO but plausible improvements for the future are ultimately given which may elevate it even further.

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The dead volume effect on the elastic moduli measurements using the forced‐oscillation method

Cited by 5 publications

References 20 publications

The Frequency Dependence of Poisson’s Ratio in Fluid-Saturated Rocks

The Frequency Dependence of Poisson’s Ratio in Fluid-Saturated Rocks

An oscillatory search method for relay protection logic diagrams based on sequential traversal

On Frequency-Dependent Rock Experiments: A Comparative Review

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