A method for evaluating gas saturation with pulsed neutron logging in cased holes

Liu, Juntao; Liu, Shucai; Zhang, Feng; Su, Bo; Yang, Haijun; Xu, Yong; Miao, Bin; Li, Hu

doi:10.1016/j.jngse.2018.09.018

Cited by 18 publications

(2 citation statements)

References 7 publications

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“…Over the past decades, a variety of fracture recognition methods have been developed in conventional logging while drilling. Gamma logging [7][8][9] and neutron logging [10][11][12] are used to recognize wellbore fractures. Du et al used electric logging to recognize wellbore fractures [13].…”

Section: Introductionmentioning

confidence: 99%

Wellbore fracture recognition and fracture parameter identification method using piezoelectric ultrasonic and machine learning

Liu,

Luo,

et al. 2024

Smart Mater. Struct.

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Real-time monitoring of wellbore status information can effectively ensure the structural safety of the wellbore and improve the drilling efficiency. It is especially important to recognize the wellbore fractures and identify their parameters, which motivates us to propose a wellbore fracture recognition and parameter identification method using piezoelectric ultrasonic and machine learning. To realize a Self-model Emission Detection (SED), we innovatively utilize a single transducer to act as both an actuator and a sensor, allowing for the efficient acquisition of ultrasonic echo signals of the wellbore. For fracture recognition, we use the wavelet packet transform to extract features from the ultrasonic echo signal, while constructing a Convolutional Neural Network (CNN) model for fracture recognition. Then, we establish the relationships between the fracture width-depth parameter and the echo signal, including the peak value as well as the arrival time difference. The experimental results show that the proposed method effectively recognizes the fractures from the ultrasonic echo signal of the wellbore. At the same time, the established function truly reflects the relationship between the fracture parameters and the echo signal. Therefore, the proposed method can provide an identification function for quantitative monitoring of wellbore fracture parameters. Moreover, the functions can be used as a reference for other structural health monitoring, which has good application prospects.

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Section: Introductionmentioning

confidence: 99%

Wellbore fracture recognition and fracture parameter identification method using piezoelectric ultrasonic and machine learning

Liu,

Luo,

et al. 2024

Smart Mater. Struct.

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“…Shale gas is mainly composed of adsorbed gas and free gas (Curtis, 2002). The factors affecting the gas content of shale gas reservoirs include: total organic carbon (TOC) content (Yang et al, 2019), porosity (Ge et al, 2016;Sun et al, 2016;Zhu et al, 2020), gas saturation (Liu et al, 2018;Pandey et al, 2019;Zhou et al, 2019), adsorbed gas content (Ghazy et al, 2016;Sultan et al, 2018) and total gas content (Guo and Peng, 2019), etc. At present, there are relatively few related studies on the shale of the Lower Carboniferous Luzhai Formation in the central Guangxi area, the gas-bearing characteristics are not yet clear, and there is a lack of quantitative research on the corresponding influencing factors.…”

Section: Introductionmentioning

confidence: 99%

An improved method for improving the calculation accuracy of marine low-resistance shale reservoir parameters

Zhang²

2022

Front. Earth Sci.

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In order to accurately evaluate the shale reservoir of the Lower Carboniferous Luzhai Formation in the central Guangxi area, in view of the influence of the low resistivity of the reservoir and the complex mineral composition on the logging response, taking Well A1 as an example, a method to improve the calculation accuracy of reservoir parameters is studied. The reasons for the low resistance in the study area are analyzed from the aspects of minerals, geochemistry and geology. An improved △log R method based on borehole correction and natural gamma spectroscopy logging was proposed to calculate the total organic carbon content. A calcium-corrected HERRON method is proposed to calculate porosity. The P/S time difference ratio-density neutron log overlap difference is proposed to calculate saturation. Calculation of adsorbed gas content based on organic matter correction. The results show that the improved method greatly improves the prediction accuracy, and has high consistency with the core analysis results, and can accurately evaluate the shale reservoirs of the Lower Carboniferous Luzhai Formation in the central area of Guangxi. The improved new method has good applicability and can be further used in the evaluation of this kind of source rock reservoir.

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Pulsed neutron logging responses of gas-bearing tight sandstone reservoir-numerical analysis and quantitative evaluation

Zhang,

Han,

et al. 2023

J Radioanal Nucl Chem

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A method for evaluating gas saturation with pulsed neutron logging in cased holes

Cited by 18 publications

References 7 publications

Wellbore fracture recognition and fracture parameter identification method using piezoelectric ultrasonic and machine learning

Wellbore fracture recognition and fracture parameter identification method using piezoelectric ultrasonic and machine learning

An improved method for improving the calculation accuracy of marine low-resistance shale reservoir parameters

Pulsed neutron logging responses of gas-bearing tight sandstone reservoir-numerical analysis and quantitative evaluation

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