A thermo-mechanical simulation for the stability analysis of a horizontal wellbore in underground coal gasification

IF 4.2 Q2 ENERGY & FUELS

Petroleum Pub Date : 2024-06-01 DOI:10.1016/j.petlm.2023.11.003

Mohammadreza Shahbazi , Mehdi Najafi , Mohammad Fatehi Marji , Ramin Rafiee

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Abstract

The stability analysis of horizontal wells is essential for a successful underground coal gasification (UCG) operation. In this paper, a new 3D coupled thermo-mechanical numerical modeling is proposed for analyzing the stability of UCG horizontal wells. In this model, the effect of front abutment stresses, syngas pressure, syngas temperature and thermal stresses is considered to predict the mud weight window and drilling mud pressure during UCG process. The results show that the roof caving in UCG panel has a greatest impact on the stability of horizontal well. Moreover, when the time of coal gasification is increased, the well convergence increases and for more stability it is necessary to increase the drilling mud pressure. This research was carried out on the M2 coal seam in Mazino coal deposit (Iran). The results showed that the mud weight window for horizontal well drilling is between 0 and 33 MPa. The appropriate stress for the maximum stability of the horizontal well, taking all the thermal and mechanical parameters into account, is 28 MPa. The suggested numerical method is a comprehensive and consistent way for analyzing the stability of horizontal wells in UCG sites.

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地下煤炭气化过程中水平井筒稳定性分析的热力学模拟

水平井的稳定性分析对于地下煤气化（UCG）的成功运行至关重要。本文提出了一种新的三维热力-机械耦合数值模型，用于分析 UCG 水平井的稳定性。在该模型中，考虑了前支墩应力、合成气压力、合成气温度和热应力的影响，以预测 UCG 过程中的泥浆重量窗口和钻井泥浆压力。结果表明，UCG 面板顶板塌陷对水平井稳定性的影响最大。此外，当煤炭气化时间增加时，井的收敛性增加，为了提高稳定性，有必要增加钻井泥浆压力。这项研究是在伊朗 Mazino 煤矿的 M2 煤层进行的。结果表明，水平井钻井的泥浆重量窗口在 0 至 33 兆帕之间。考虑到所有热参数和机械参数，水平井最大稳定性的适当应力为 28 兆帕。所建议的数值方法是分析铀转化天然气（UCG）场地水平井稳定性的一种全面、一致的方法。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Petroleum Earth and Planetary Sciences-Geology

CiteScore

9.20

自引率

0.00%

发文量

审稿时长

124 days

期刊介绍： Examples of appropriate topical areas that will be considered include the following: 1.comprehensive research on oil and gas reservoir (reservoir geology): -geological basis of oil and gas reservoirs -reservoir geochemistry -reservoir formation mechanism -reservoir identification methods and techniques 2.kinetics of oil and gas basins and analyses of potential oil and gas resources: -fine description factors of hydrocarbon accumulation -mechanism analysis on recovery and dynamic accumulation process -relationship between accumulation factors and the accumulation process -analysis of oil and gas potential resource 3.theories and methods for complex reservoir geophysical prospecting: -geophysical basis of deep geologic structures and background of hydrocarbon occurrence -geophysical prediction of deep and complex reservoirs -physical test analyses and numerical simulations of reservoir rocks -anisotropic medium seismic imaging theory and new technology for multiwave seismic exploration -o theories and methods for reservoir fluid geophysical identification and prediction 4.theories, methods, technology, and design for complex reservoir development: -reservoir percolation theory and application technology -field development theories and methods -theory and technology for enhancing recovery efficiency 5.working liquid for oil and gas wells and reservoir protection technology: -working chemicals and mechanics for oil and gas wells -reservoir protection technology 6.new techniques and technologies for oil and gas drilling and production: -under-balanced drilling/gas drilling -special-track well drilling -cementing and completion of oil and gas wells -engineering safety applications for oil and gas wells -new technology of fracture acidizing