Hydration index and hydrated constitutive model of clay shale using acoustic frequency spectrum

Liu, Xiangjun; Ding, Yi; Ranjith, P.G.; Luo, Peng

doi:10.1002/ese3.388

Cited by 11 publications

(5 citation statements)

References 32 publications

(49 reference statements)

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“…Recently, shale has attracted huge attention in the energy industry as a result of the great potential of shale gas. , In the exploitation of shale gas, as a typical phenomenon of the liquid–rock interaction, spontaneous imbibition exists in drilling engineering and well completion. , During drilling operation, shale contacts with drilling fluid at the wall of the wellbore. Spontaneous imbibition is a significant way of fluid invading shale, jeopardizing wellbore stability. , In addition, multistage hydraulic fracturing has been identified as an efficient method of improving gas production . During hydraulic fracturing, a mass of fracturing fluid is injected into the shale reservoir.…”

Section: Introductionmentioning

confidence: 99%

Novel Analytical Model of Shale Spontaneous Imbibition Considering the Hydration Effect

Ding

Liu

et al. 2021

Energy Fuels

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Shale gas has enormous potential and has become a hotspot in recent decades. To exploit shale gas, a variety of working fluids (drilling fluid, fracturing fluid, etc.) have to be applied in drilling and well-completion engineering. When fluid contacts with shale, spontaneous imbibition occurs, affecting wellbore stability, fracturing fluid loss, and shale gas production. In the past few years, numerous researchers conducted studies on shale spontaneous imbibition, yet the vast majority of their works are derived from conventional method based on sandstone and carbonate. One of the characteristics of shale is strong hydration, which has been widely reported. During the interaction between liquid and shale, spontaneous imbibition is accompanied by hydration. Shale hydration mainly involves two aspects, i.e., osmotic pressure and hydration structural damage. Now there is still no research on studying the hydration effect during spontaneous imbibition, and how hydration affects spontaneous imbibition is still not fully understood. Therefore, in this paper, considering osmotic pressure and hydration structural damage, spontaneous imbibition in shale formation has been investigated. Besides, according to the Hagen−Poiseuille law, a novel analytical model has been established by coupling imbibition and hydration. In comparison to experimental data of spontaneous imbibition, practicability of this spontaneous imbibition model has been verified. On the basis of this new model and spontaneous imbibition test, influences of salinity and hydration on shale spontaneous imbibition have been systematically discussed. Results indicate that salinity reduces spontaneous imbibition by lowering the driving force of imbibition and restricting hydration damage. Hydration structural damage is its major influencing mechanism for shale spontaneous imbibition. In the shale exploitation, this model can offer guidance for evaluating fracturing fluid loss and hydration damage, which are practical for drilling and hydraulic fracturing design. Besides, the outcome of this paper is beneficial for improving our understanding on spontaneous imbibition in shale formation.

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Section: Introductionmentioning

confidence: 99%

Novel Analytical Model of Shale Spontaneous Imbibition Considering the Hydration Effect

Ding

Liu

et al. 2021

Energy Fuels

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“…Accordingly, the effects of water should be taken into full consideration when monitoring rock stability. Current researches show that water can reduce the AE energy, count, and other parameters in the process of rock failure [26][27][28][29]. However, there are few studies on the frequency domain characteristics of AE waveforms when waterbearing rocks are failure.…”

Section: Introductionmentioning

confidence: 99%

Acoustic Emission Waveform Analysis of Sandstone Failure with Different Water Content

Shen

et al. 2021

Geofluids

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Previous studies have shown that water can reduce the acoustic emission (AE) energy and other parameters during rock failure. However, the fracture mechanism of rock can be better reflected by analyzing the AE waveform. Therefore, this paper conducted experiments of uniaxial compression on sandstone samples of various water contents and collected AE signals simultaneously. Analyses of fast Fourier transform (FFT) and Hilbert-Huang transform (HHT) were performed on the AE waveform when the sample failed. The results show that as the water content increases, the frequency and intensity of the AE signal will decrease. The influence of water on the intensity of the AE signal is greater than that on the frequency. Through the analysis of the energy mechanism of rock failure, it is pointed out that the frequency and intensity of AE signal are closely related to elastic energy index W ET and burst energy index K E . The research results have guiding significance for the monitoring of rockburst.

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“…e differences between the traditional and generalised RQDs results were discussed. To evaluate the hydration damaging extent of the muddy shale, Liu et al [22] proposed the hydration damaging index. Additionally, the hydration constitutive law was constructed.…”

Section: Introductionmentioning

confidence: 99%

State Judgement Model of the Coal and Rock Medium and Its Engineering Application

Zhu

Wang

Han

2020

Advances in Civil Engineering

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In the loading and failure process of the coal and rock medium, with the increasing of the damaging and failure extent, the medium state gradually changed from the continuous, the quasicontinuous, and the discontinuous to the loose successively. To evaluate the damaging failure extent of the coal and rock mass and distinguish the state of the coal and rock mass medium, first, the medium state index was defined based on the acoustic wave propagation model. Then, based on the coal mass in the working face 8512 in the Chenjiagou Coal Mine in China, the acoustic character and the mechanical character experiments were conducted. Through experiments, the variation law of the ultrasonic wave velocity and the medium state index of the coal mass with the strain under the compressive state were acquired; with the increasing of the strain, the medium state indexes successively experienced the variation process including stabilising around 0, slow increasing, dramatic increasing, and stabilising around 1. Then, based on the variation law of the medium state index, the coal and rock mass medium state judgement model was constructed. This model was applied to judge the coal mass medium state. After it, the mudstones in the roof of the same working face were regarded as the research object, the mudstone medium state was divided into 4 types according to the medium state judgement model, namely, continuous, quasicontinuous, discontinuous, and bulk solid, and the mudstone failure state was basically consistent with the continuous, quasicontinuous, discontinuous, and bulk solid state. The adaptability and rationality of the judgement model was verified. Finally, engineering application of the judgement model was conducted. The distribution law of the top coal with different medium state was acquired. In the top coal that was 186 m away from the working face, it belonged to the continuous medium state. As for the top coal that was 6 m to 186 m far away from the working face, it was under the quasicontinuous medium state. For the top coal that was 3 m to 6 m far away from the working face, it was under the discontinuous medium state. For the top coal that was less than 3 m far away from the working face and behind the working face, it belonged to the bulk solid medium state. The state judgement model can successfully distinguish the medium state of the coal seam and mudstones in the roof in the working face 8512. This provided a new approach to evaluate the damaging failure extent of the coal and rock medium in the Chenjiagou Coal Mine.

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Hydration index and hydrated constitutive model of clay shale using acoustic frequency spectrum

Cited by 11 publications

References 32 publications

Novel Analytical Model of Shale Spontaneous Imbibition Considering the Hydration Effect

Novel Analytical Model of Shale Spontaneous Imbibition Considering the Hydration Effect

Acoustic Emission Waveform Analysis of Sandstone Failure with Different Water Content

State Judgement Model of the Coal and Rock Medium and Its Engineering Application

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