不同含水率煤体液氮致裂渗透率变化规律
及应力敏感性分析

doi:10.16285/j.rsm.2021.0754

岩土力学 ›› 2022, Vol. 43 ›› Issue (S1): 107-116.doi: 10.16285/j.rsm.2021.0754

不同含水率煤体液氮致裂渗透率变化规律及应力敏感性分析

张磊^{1, 2}，田苗苗^{1, 2}，卢硕^{1, 2}，李明雪³，李菁华^{1, 2}

1. 中国矿业大学矿业工程学院，江苏徐州 221116；2. 中国矿业大学煤炭资源与安全开采国家重点实验室，江苏徐州 221116； 3. 中国矿业大学材料与物理学院，江苏徐州 221116

收稿日期:2021-05-20 修回日期:2022-03-09 出版日期:2022-06-30 发布日期:2022-07-13
作者简介:张磊，男，1986年生，博士，教授，博士生导师，主要从事绿色开采与智能开采等方面的研究。
基金资助:
国家自然科学基金（No.52174129）；中国科协“青年人才托举工程”项目（No.2017QNRC001）。

Analysis of permeability variation and stress sensitivity of liquid nitrogen fracturing coal with different water contents

ZHANG Lei^{1, 2}, TIAN Miao-miao^{1, 2}, LU Shuo^{1, 2}, LI Ming-xue³, LI Jing-hua^{1, 2}

1. School of Mines, China University of Mining and Technology, Xuzhou, Jiangsu 221116, China; 2. State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Xuzhou, Jiangsu 221116, China; 3. School of Materials Science and Physics, China University of Mining and Technology, Xuzhou, Jiangsu 221116, China

Received:2021-05-20 Revised:2022-03-09 Online:2022-06-30 Published:2022-07-13
Supported by:
This work was supported by the National Natural Science Foundation of China (52174129) and the Young Elite Scientists Sponsorship Program by CAST (2017QNRC001).

摘要/Abstract

摘要：

液氮致裂煤体技术是一种新型的煤层增透技术，含水率、煤阶、温度梯度等因素都会影响液氮的增透作用。其中，煤体含水率对液氮致裂的增透效果影响尤为显著。为研究含水率对液氮致裂的影响效果和机制，对含水率分别为0%、2%、4%及6%的4组煤样进行液氮溶浸处理，使用渗透率测试仪进行气相渗透率测试，对不同压力点煤样渗透率及应力敏感性变化规律进行讨论分析。试验结果表明：（1）在相同围压条件下，煤体气相渗透率随有效应力的变化趋势整体上符合负指数函数k = ae^−b^s + c，拟合后相关指数均大于0.95；（2）当有效应力超过一定临界值，煤体气相渗透率会受克林伯格效应影响，随有效应力的增大呈现上升趋势；（3）煤体自身含水率的增加会对液氮致裂效果产生明显促进作用，最明显的是，当含水率从2%提升到4%时，煤样液氮致裂前后渗透率增幅从92.88%增大到357.12%；（4）对液氮致裂前后煤样的渗透率进行归一化处理后，发现煤体水分同时具有阻碍渗流的消极作用与提升致裂效果的促进作用，在水分的复合作用下致裂前后煤样归一化渗透率变化规律比较复杂；（5）在相同孔隙压力下，煤体有效应力敏感性随有效应力的增大逐渐减小，液氮致裂后，煤体的有效应力敏感性显著提高。

关键词: 含水率, 液氮致裂, 渗透特性, 应力敏感性

Abstract:

At present, the technology of fracturing coal by liquid nitrogen is a new type of anti-reflection technology of coal seam. Water content, coal rank and temperature gradient all affect the anti-reflection of liquid nitrogen. Among them, water content has a significant effect on the anti-reflection effect of liquid nitrogen cracking. In order to study the effect and mechanism of water content on liquid nitrogen cracking, four groups of coal samples with water contents of 0%, 2%, 4% and 6% were treated by liquid nitrogen leaching respectively, permeability tester is used to test gas phase permeability of coal samples, and the permeability and stress sensitivity of coal samples at different pressure points were discussed and analyzed. Some findings were obtained. (i) Under the same confining pressure, the variation trend of gas phase permeability with effective stress generally accords with negative exponential function k = ae^−b^s + c, and the correlation indexes are all greater than 0.95. (ii) When the effective stress exceeds a certain critical value, the gas permeability of coal sample is affected by Klinkenberg effect and presents an upward trend with the increase of the effective stress. (iii) The increase of water content of coal sample can significantly promote the fracturing effect of liquid nitrogen. The most obvious is that when water content increases from 2% to 4%, the increase of permeability before and after fracturing increases from 92.88% to 357.12%. (iv) The normalized permeability of coal samples before and after liquid nitrogen fracturing is treated, and it is found that coal moisture has both a negative effect of blocking seepage and a promoting effect of improving the fracturing effect. The normalized permeability of coal samples before and after fracturing is complicated under the combined effect of moisture. (v) Under the same pore pressure, the effective stress sensitivity of coal decreases gradually with the increase of effective stress, and it can be significantly improved by liquid nitrogen fracturing.

Key words: water content, liquid nitrogen fracturing, permeability characteristics, stress sensitivity

中图分类号:

TU452

张磊, 田苗苗, 卢硕, 李明雪, 李菁华, . 不同含水率煤体液氮致裂渗透率变化规律及应力敏感性分析[J]. 岩土力学, 2022, 43(S1): 107-116.

ZHANG Lei, TIAN Miao-miao, LU Shuo, LI Ming-xue, LI Jing-hua, . Analysis of permeability variation and stress sensitivity of liquid nitrogen fracturing coal with different water contents[J]. Rock and Soil Mechanics, 2022, 43(S1): 107-116.

参考文献

相关文章 15

[1]	汤华, 严松, 杨兴洪, 吴振君, . 差异含水率下全风化混合花岗岩抗剪强度与微观结构试验研究[J]. 岩土力学, 2022, 43(S1): 55-66.
[2]	刘杰, 崔瑜瑜, 卢正, 姚海林, . 分散土分散性影响因素及其判别方法初探[J]. 岩土力学, 2022, 43(S1): 237-244.
[3]	潘振辉, 肖涛, 李萍, . 压实度与制样含水率对压实黄土微结构及水力特性的影响[J]. 岩土力学, 2022, 43(S1): 357-366.
[4]	欧孝夺, 甘雨, 潘鑫, 江杰, 覃英宏, . 重塑膨胀岩热传导性能及影响因素试验研究[J]. 岩土力学, 2022, 43(S1): 367-374.
[5]	张婵青, 何凤飞, 姜顺航, 曾子真, 熊峰, 陈江, . 土体含水率监测的移动点热源法研究[J]. 岩土力学, 2022, 43(7): 2025-2034.
[6]	金宗川, 王雪晴, 乌效鸣, 彭赟, . 土壤热参数及其影响因素测试分析[J]. 岩土力学, 2022, 43(5): 1335-1340.
[7]	郑文红, 施天威, 潘一山, 罗浩, 吕祥锋, . 含水率对岩石电荷感应信号影响规律研究[J]. 岩土力学, 2022, 43(3): 659-668.
[8]	侯乐乐, 翁效林, 李林, 周容名, . 考虑含水率影响的结构性黄土临界状态模型[J]. 岩土力学, 2022, 43(3): 737-748.
[9]	赵志强, 戴福初, 闵弘, 谭晔, . 原状黄土−古土壤中水分入渗过程研究[J]. 岩土力学, 2021, 42(9): 2611-2621.
[10]	刘越, 陈东霞, 王晖, 于佳静, . 干湿循环下考虑裂隙发育的残积土边坡响应分析[J]. 岩土力学, 2021, 42(7): 1933-1943.
[11]	张闯, 任松, 张平, 隆能增, . 水、孔洞及层理耦合作用下的千枚岩巴西劈裂试验研究[J]. 岩土力学, 2021, 42(6): 1612-1624.
[12]	郭智辉, 简文彬, 刘青灵, 聂闻. 基于现场原型试验的斜坡降雨入渗分析及入渗模型研究[J]. 岩土力学, 2021, 42(6): 1635-1647.
[13]	汪时机, 骆赵刚, 李贤, 文桃. 考虑局部含水率效应的浅层土体开裂过程与力学机制分析[J]. 岩土力学, 2021, 42(5): 1395-1403.
[14]	赵奎, 冉珊瑚, 曾鹏, 杨道学, 腾天野, . 含水率对红砂岩特征应力及声发射特性的影响[J]. 岩土力学, 2021, 42(4): 899-908.
[15]	雷学文, 丁豪, 王新志, 沈建华, 孟庆山, . 钙质粉土的固结特性试验研究[J]. 岩土力学, 2021, 42(4): 909-920.

Metrics

Viewed

Full text

Abstract

Cited

Shared

Discussed

不同含水率煤体液氮致裂渗透率变化规律及应力敏感性分析

Analysis of permeability variation and stress sensitivity of liquid nitrogen fracturing coal with different water contents

PDF (Chinese)

摘要/Abstract

引用本文

使用本文

参考文献

相关文章 15

Metrics

本文评价

推荐阅读 10

不同含水率煤体液氮致裂渗透率变化规律 及应力敏感性分析

Analysis of permeability variation and stress sensitivity of liquid nitrogen fracturing coal with different water contents

PDF (Chinese)

摘要/Abstract

引用本文

使用本文

参考文献

相关文章 15

Metrics

本文评价

推荐阅读 10

不同含水率煤体液氮致裂渗透率变化规律及应力敏感性分析