Numerical and physical simulations of array laterolog in deviated anisotropic formation

Wu, Yan; Wu, Zhi Qiang; Fan, Yiren; Xing, Tao; Li, Chaoliu; Yuan, Chao

doi:10.1016/j.petsci.2022.03.023

Cited by 4 publications

(1 citation statement)

References 16 publications

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“…Additionally, as the angle of fractures increased, the deep lateral resistivity also increased, whereas shallow lateral resistivity remained relatively unchanged. Wu et al proposed a three-dimensional finite element method to simulate array lateral logging and developed a physical simulation system to verify the accuracy of the three-dimensional finite element method [ 25 ]. The effects of anisotropy and inclination on the array lateral logging were then analyzed.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation Study on the Influence of Fracture on Borehole Wave Modes: Insights from Fracture Width, Filling Condition, and Acoustic Frequency

Gao,

Wu,

et al. 2024

Sensors

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Unconventional reservoirs, such as shale and tight formations, have become increasingly vital contributors to oil and gas production. In these reservoirs, fractures serve as crucial spaces for fluid migration and storage, making their precise assessment essential. Array acoustic logging stands out as a pivotal method for evaluating fractures. To investigate the impact of fracture width, fracture-filling conditions, and acoustic frequency on compressional and shear waves, a three-dimensional variable mesh finite difference program was employed for acoustic logging numerical simulation. Firstly, numerical models representing fractured formations with varying fracture widths and distinct fluid-filling conditions were established, and array acoustic logging numerical simulations were conducted at different frequencies. Subsequently, the waveform data were processed to extract acoustic characteristic parameters, such as velocities and amplitude attenuations of compressional and shear waves. Finally, a quantitative analysis was conducted to examine the variation patterns of characteristic parameters of refracted compressional and shear waves in relation to fracture properties. The research results indicate that amplitude attenuation information derived from borehole wave modes is particularly sensitive to the changes in fracture properties. As fracture width increased, we observed a significant amplitude attenuation in both compressional and shear waves, proportional to the logarithm of the attenuation coefficients. Furthermore, when the fracture width was constant, gas-filled fractures exhibited more prominent amplitude attenuation than water-filled fractures, with shear wave attenuation being more sensitive to the filling material. Moreover, from a quantitative perspective, the analysis revealed that the attenuation coefficients of refracted compressional and shear waves exhibited an exponential variation with gas saturation. Notably, once fracture width and filling conditions were established, the amplitudes of compressional and shear waves at the dominant frequency of 40 kHz were significantly reduced compared to those at 8 kHz, accompanied by increased attenuation. Subsequent quantitative analysis revealed that, when the product of fracture width and dominant frequency remains constant, the corresponding attenuation coefficient ratios approach 1. This indicates that the attenuation process of acoustic propagation in fractured media follows the principle of acoustic similarity. The findings of this study provide reference for further research on fracture property evaluation methods based on array acoustic logging data.

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Section: Introductionmentioning

confidence: 99%

Numerical Simulation Study on the Influence of Fracture on Borehole Wave Modes: Insights from Fracture Width, Filling Condition, and Acoustic Frequency

Gao,

Wu,

et al. 2024

Sensors

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Numerical and physical simulations of borehole resistivity logging in high-resistance formation

Wu,

Sun,

Fan

2024

Fourth International Meeting for Applied Geoscience &Amp; Energy

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Detection Performance and Grading-Selection-Based Inversion of Low-Frequency Alternating Current Resistivity Logging in Moderate-High Resistance Formations

Fan

Cai

et al. 2022

SPE Journal

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Summary With the development of high-angle/horizontal well technology, unconventional tight reservoirs with moderate/high resistivity have gradually become the focus of exploration and development. However, in moderate-high-resistance reservoir environments, distorted responses can be observed regularly in the array laterolog curves, which will lead to misjudgment for the oil-gas reservoirs. Therefore, the detection performance of the array lateral instrument powered by low-frequency alternating current urgently needs to be clarified and the true resistivity of the formation is necessary to be analyzed and extracted. In this paper, the reasons for distorted responses are investigated as well as the qualitative and quantitative assessments of the detection performance of low-frequency alternating current lateral instrument in moderate-high resistance formations. Moreover, a rapid inversion method is proposed based on the initial value grading optimization strategy to invert the anisotropic resistivities from the observed data with outliers. Numerical simulation results show that the current flow characteristics vary significantly across stratigraphic models and the distorted responses are primarily caused by the high-resistance characteristics and borehole enlargement. The combination of the initial value grading optimization strategy and the regularization inversion algorithm improves the accuracy of the inverted resistivities even further. Synthetic and field examples are analyzed to illustrate the detailed implementations and the performance of the proposed inversion method.

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Numerical and physical simulations of array laterolog in deviated anisotropic formation

Cited by 4 publications

References 16 publications

Numerical Simulation Study on the Influence of Fracture on Borehole Wave Modes: Insights from Fracture Width, Filling Condition, and Acoustic Frequency

Numerical Simulation Study on the Influence of Fracture on Borehole Wave Modes: Insights from Fracture Width, Filling Condition, and Acoustic Frequency

Numerical and physical simulations of borehole resistivity logging in high-resistance formation

Detection Performance and Grading-Selection-Based Inversion of Low-Frequency Alternating Current Resistivity Logging in Moderate-High Resistance Formations

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