深部煤层气储层地质力学研究与进展

Study and Progress of Reservoir Geomechanics within Deep Coalbed Methane

摘要

深部煤层气资源潜力巨大，是中国非常规天然气未来规模性增储上产的重要领域.储层地质力学在深部煤层气勘探开发过程中起到至关重要的作用，是实现效益开发的关键支撑.为查明深部煤层气储层地质力学研究现状与进展，论文在深部煤层气储层地质力学特性、关键技术分析基础上，探讨未来发展方向.结果显示：（1）深部“三高”（高地温、高地应力、高流体压力）地质环境主导控制煤岩力学行为变化，是从浅部脆性向深部脆‒延性乃至延性转变的关键因素，是造成储层低孔‒特低渗、强非均质性和各向异性的核心研究挑战，开展考虑深部“三高”环境与裂缝非均质发育特征的流‒固‒热耦合分析是深部煤层气储层地质力学分析的重要研究内容；（2）基于多数据融合的原位地应力场精细反演、基于CT/深度学习算法的数字裂缝网络模型构建、多场耦合数值模拟是深部煤层气储层地质力学研究的重要技术方法，智能化和实时监测是深部煤层气开发降本增效的关键技术；（3）未来深部煤层气地质研究应当突破传统单一学科界限，重点发展融合地质力学‒渗流‒经济性的多目标协同优化算法，构建起数字孪生系统，实现深部煤层气安全、高效与经济开发.

Abstract

Deep coalbed methane (CBM) resources have great potential and are significant fields for China’s future large-scale increase in reserve and production of unconventional natural gas. Reservoir geomechanics plays a vital role in the exploration and development of deep CBM and is the key support for achieving efficient development. In order to find out the current status and progress of geomechanical research within deep CBM reservoirs, in this paper it explored the future development direction based on the analysis of geomechanical characteristics and key technologies of deep CBM reservoirs. The results show follows. (1) The deep geological environment shows characteristics of high geotemperature, high in-situ stress and high fluid pressure, which dominates and controls the changes in the mechanical behavior of coal and rock, and is the key factor in the transition from shallow brittleness to deep brittle-ductile and even ductile. It creates the core research challenges of low porosity/ultralow permeability, strong heterogeneity and anisotropy in the reservoir. Fluid-solid-thermal coupling analysis considering the heterogeneous development characteristics of cleats is an important research content in the geomechanical analysis of deep CBM reservoirs. (2) Fine inversion of in-situ stress field based on multi-data fusion, digital fracture network model construction based on CT/deep learning algorithm, and multi-field coupling numerical simulation are important technical methods for the geomechanical research of deep CBM reservoirs. Intelligent and real-time monitoring technology is the key to reducing costs and increasing efficiency in deep CBM development. (3) Future research should break through the boundaries of traditional single disciplines and focus on developing multi-objective collaborative optimization algorithms that integrate geomechanics, seepage, and economy, building a digital twin system, and realizing the safe, efficient, and economic development of deep CBM.

Graphical abstract

关键词

储层地质力学 / 深部煤层气 / 进展 / 力学特性 / 数值模拟.

Key words

reservoir geomechanics / deep coalbed methane / progress / mechanics / numerical simulation

0 引言

全球煤层气资源量超260×10¹² m³，其中，中国自然资源部第四次资源评价结果显示，中国煤层气探明资源量达30.05×10¹² m³，可采资源量为12.5×10¹² m³，居世界第三（徐凤银等，2019）.中国深部煤层气资源丰富.初步评价结果表明，埋深大于2 000 m的煤层气地质资源量达40.71×10¹² m³，其中，埋深2 000~3 000 m的煤层气资源量约为18.47×10¹² m³（Li et al.，2023）.

随着全球浅层油气资源日渐殆尽以及对能源需求的增长，油气开发逐渐向深部扩展，深部煤层气这一清洁能源或将成为未来新型能源结构转型的重要支撑（苏现波等，2023；Wan et al.，2024；李熹微等，2025）.深部煤层气井投产初期即有较高的产量，通常无需经历漫长的排水采气阶段，随着产水量的迅速衰减，压裂液反排阶段可能出现自喷现象.相较于浅部煤层气藏，深部煤层具有更高的原始含气饱和度、更完整的原生煤体结构以及更好的保存条件，其单井日均产能亦更高（唐书恒等，2025）.

当前，关于深部煤层气赋存深度的定义存在争议，秦勇（2023）认为存在三类界定标准：①依据煤层气开采水平而设定的临界深度，如1 500 m（徐凤银等，2025a）；②基于深部煤层气开发试验突破经验，将埋深超过2 000 m的煤层气视为深部煤层气（郭广山等，2015）；③强调温度与地应力的双重控制，综合考虑煤层吸附气含量由增大到降低的“临界深度”和地应力机制的转换深度定义深、浅煤层气的划分界线（图1a；秦勇等，2012；秦勇和申建，2016；Qin et al.，2018；Li et al.，2023），其变化幅度极大，在500~ 2 200 m范围，多为800~1 500 m（秦勇，2023）.

中国深部煤层气分布广泛，主要产气盆地/地区包括鄂尔多斯盆地、准噶尔盆地、泌水盆地、四川盆地、渤海湾盆地、滇东黔西地区等（表1）（明盈等，2024；徐凤银等，2024；鞠玮等，2025）.不同盆地/地区的深部煤层气，受其构造、沉积等综合作用控制，呈现“高含气量、低渗透率、煤阶高但区域分异大”的总体特征（表2）.具体而言：

（1）区域分布及埋藏深度差异性显著.深部煤层气赋存于西北、东北、华北、华东及西南等多个含煤盆地/地区，埋深跨度极大，从800 m延伸至5 500 m，大多数主力区块集中在1 000~2 500 m深度段.

（2）煤阶分异明显，整体以高煤阶为主.鄂尔多斯、沁水、四川等地区多为高阶煤，镜质体反射率普遍大于2.0%，部分地区（如四川盆地、鄂尔多斯延川南）超过3.0%，西北地区的准噶尔和新疆阜康则表现为低阶煤特征.

（3）储层低孔低渗特征明显，受构造影响大.随着埋深增加，地应力增大，储层物性普遍变差.绝大多数区块孔隙度低于5%，渗透率集中在（0.01~0.1）×10^-3 μm³范围，属于典型的特低渗‒致密储层.然而，煤体结构对渗透率有重要影响：在原生结构煤为主的背景下，受构造运动影响发育碎裂煤的地区（如安徽两淮），渗透率可异常升高至5.72×10^-3 μm³；而构造破坏严重的“碎粒煤”发育区，则可能面临渗透性复杂化的问题（表2）.

（4）深部煤储层含气量普遍较高，资源潜力巨大.截至目前，中国深部煤层气研究和产业发展依次经历了初期探索阶段、缓慢发展阶段、稳中求进阶段和快速发展阶段（图1b；鞠玮等，2025）.“十四五”以来，中国深部煤层气勘探开发实现了产量不断突破，鄂尔多斯盆地延川南区块单井日产气量介于（0.8~2.2）×10⁴ m³，年产气量达4×10⁸ m³，累计产气28.8×10⁸ m³，是我国第一个规模化投入商业开发的深部煤层气田（周德华等，2022；常闯等，2023；何希鹏等，2025；霍超等，2025）；沁水盆地榆社‒武乡地区预测煤层气资源量达2 414×10⁸ m³，其中，60%以上潜在资源量为深部煤层气资源量（宋慧波等，2021）；准噶尔盆地白家海地区测试最高日产气量

为5.7×10⁴ m³，稳产日产气量为2.0×10⁴ m³（周德华等，2022）；鄂尔多斯盆地东缘大宁‒吉县区块直井单井日产量突破2×10⁴ m³，水平井单井日产量突破10×10⁴ m³，区块年产能可达15×10⁸ m³（李勇等，2024a；徐凤银等，2024），截至2025年5月，该区块备案探明地质储量达到2 112×10⁸ m³（田文广等，2025）；鄂尔多斯盆地东缘神府区块2023年提交的深部煤层气探明地质储量超过千亿立方米.深部煤层气领域将成为中国煤层气资源战略接替与天然气产能规模增长的关键方向（秦勇等，2022）.

然而，我国在深部煤层气勘探开发方面仍处于初级阶段，在理论、技术、措施等方面存在瓶颈和挑战.理论方面，我国在浅层煤层气勘探开发上有着相当丰富的经验，但是在深层煤层气理论指导上适用性不强，尤其是在精细储层评价、富集成藏条件和成藏模式、气水渗流机理等问题的研究.技术方面，由于深部煤层气地质条件的复杂性，对钻井技术有较高要求，我国深部煤层气钻井技术尚有不足.目前，我国钻井技术在深部煤层气开发方面仍处于试验探索阶段.在增产技术上也仍有欠缺，缺乏针对复杂地质条件的理论认识和技术体系，缺乏水平井压裂井网优化设计方法体系（秦勇等，2022；Xu et al.，2023；霍超等，2025；鞠玮等，2025）.

1 深部煤层气储层地质力学研究现状

1.1　储层地质力学研究对煤层气开发的核心作用

煤储层地质力学条件作为煤层气开发的关键因素之一，直接影响煤层气井开发效率，其包括两个方面：一是煤储层自身力学性质（如岩石力学性质等）；二为煤储层外部力学条件（地应力场、孔隙流体压力等）（Zoback，2010；章朋，2020）.煤岩力学特征参数是煤岩成分和结构的集中体现，深部高温、高地应力条件对于储层改造具有决定性影响（申建等，2014）.中国不同盆地/地区深部煤层气储层地质条件存在显著差异（表2和表3），鄂尔多斯盆地东缘大宁‒吉县区块二叠系8号煤储层埋深在 2 000~2 600 m、温度为57.68~72.53 ℃、最大主应力梯度约为1.95~2.53 MPa/100m（皇甫展鸿等，2024；徐凤银等，2024）；准噶尔盆地白家海凸起侏罗系八道湾组煤储层埋深在1 000~5 500 m、地温梯度介于1.8~3.0 °C/100m（陈刚等，2016）、最大主应力梯度平均值约为2.42 MPa/100m.中国含煤盆地的地温梯度主要在2.5~3.6 °C/100m，1 500 m深处煤储层温度约为40~60 °C，2 000 m深处的温度可达70 °C以上.深部煤储层普遍处于高地应力环境，最大主应力梯度普遍大于2.0 MPa/100 m.

煤储层压裂时，其自身的力学性质、渗透性，以及原岩地应力状态、储层压力等地质力学参数共同决定了煤储层压裂效果，影响煤层气井产能（图2；Rajabi et al.，2017；Liu et al.，2022）.目前，深部煤层气开发方案制定中涉及岩石力学、地应力等关键指标仍缺乏理论指导，不同的岩性组合对煤岩力学性质变化的影响仍有待深入研究，储层地质力学对深部煤层气开发的理论支撑显得愈发重要.

煤岩力学强度是控制压裂裂缝扩展的关键参数.相较于顶底板砂岩、泥页岩，煤储层通常表现出较低的力学强度.在相同原位地应力场作用下，若煤储层与顶底板岩层之间的强度差异显著，则压裂裂缝易受顶底板应力限制，呈现层内发育特征；反之，若强度差异较小，压裂裂缝则可能突破岩性界面而延伸至顶底板砂岩、泥页岩层，影响压裂效果.煤储层天然裂缝的发育亦对压裂效果具有显著的影响效应.煤储层天然裂缝网络密度高、渗透率大，将加剧压裂液滤失速率与滤失总量，致使井底压力快速衰减，不利于维持压裂裂缝的扩展（Cheng et al.，2020；章朋，2020；李国欣等，2025）.深部游离气在宏观天然裂缝微距运移，受控于顶底板封盖特性和地应力条件，与此同时，地应力也是控制压裂裂缝破裂压力、起裂位置及扩展形态样式的核心地质要素，直接影响压裂改造效果.唐书恒等（2025）基于数值模拟与真三轴物理实验耦合分析，系统揭示了地应力对煤储层压裂裂缝启裂、扩展及空间展布的控制规律：高应力差背景下，压裂裂缝倾向于沿垂直最小主应力方向起裂并线性延伸；在低应力差条件下，压裂裂缝易沟通煤储层天然裂缝系统，形成复杂网状缝网结构.此外，地应力机制类型亦能显著影响压裂裂缝形态（孟召平等，2010；Rajabi et al.，2017）.

煤层气开发活动导致煤储层地质力学参数呈现动态演化特征，原始地应力场受到工程扰动，打破储层应力平衡状态.这种应力场再平衡的过程极易诱发煤岩体剪切破裂，进而导致井壁失稳等井下复杂工况，显著制约煤层气开采效率.在深部煤层气开采过程中，随储层流体的持续产出，地应力系统呈现衰竭趋势，应力状态随之改变，井周地应力场发生再分布，这种动态演化最终影响安全钻井液密度窗.若仍依据开发前原地应力场参数设计钻井液密度，极易诱发井壁失稳，表现为井壁坍塌或压裂液漏失等井下复杂事件.此外，地应力场的动态调整亦可能影响原生储层结构稳定性及含断层/天然裂缝储层系统的活化风险（Zoback，2010；章朋，2020；Zhang et al.，2020）.

1.2　国内外储层地质力学实践应用

在深部煤层气勘探开发中，储层地质力学研究在优化钻井轨迹、流体注入、维持井筒稳定性以及提高产量等方面均起着至关重要的作用，储层地质力学的应用往往与煤体性质直接关联（Gentzis，2011；Liu et al.，2017；鞠玮等，2022；彭文春等，2025）.在澳大利亚库珀盆地、加拿大阿尔伯塔平原、美国圣胡安盆地以及沁水盆地等盆地/地区，储层地质力学性质已被证实是深部资源开发中的核心控制因素.随着埋深增加，高应力环境下的原位地应力场对储层流体流动模式、井筒稳定性以及钻完井工程设计具有显著的制约作用，任何钻探方法的设计和修改，都必须考虑目标煤层的地质力学特性（Gentzis，2011；Rajabi et al.，2017；Salmachi et al.，2021）.

在储层动态响应机制方面，深部煤储层地应力状态与流体渗流之间存在复杂的非线性耦合关系.随着排采进行，孔隙压力的变化会导致储层渗透率呈现非线性动态演化：在高压阶段渗透率增长受限，而当压力降至特定临界值以下时，渗透率往往显著回升（Wu et al.， 2010）.同时，排采过程中储层地应力场与井壁围岩的应力动态响应规律，也是评估储层稳定性及制定排采制度的关键依据（章朋，2020）.针对深部煤层气的工程改造难题，当前研究已从单一参数测定转向构建多物理场（地应力‒温度‒渗流）耦合下的综合评价体系.通过深入剖析煤储层的岩石力学性质、脆性指数及天然裂缝发育状况，建立储层可压性评价模型并划分可压性等级，已成为优化水力压裂设计、预测生产特征的重要手段，在准噶尔盆地白家海凸起侏罗系西山窑组、鄂尔多斯盆地东部石炭‒二叠系等深部煤储层研究时已获得实践应用（彭文春等，2025；徐凤银等，2025b）.

储层地质力学参数对深部煤层差异化气藏工程设计、大规模压裂方案优化及单井产能大幅提升具有重要控制作用，闫霞等（2025）以鄂尔多斯盆地大宁‒吉县区块深部煤储层为例，探讨岩石力学性质、顶底板岩性组合、煤层厚度等因素对地应力的影响机制，结果显示：顶灰底砂组合下的煤岩水平最小主应力最小、顶泥底泥组合下的煤岩水平最小主应力最大，顶底板与煤层力学性质相差越大，煤岩应力值越小.其他条件相同时，随着煤层厚度的增大，煤岩水平主应力、水平主应力差总体呈增大趋势，厚度变化对煤层厚度小于4 m的薄煤层的应力影响更为敏感，当煤层厚度大于4~6 m后，水平主应力、水平主应力差的增幅趋于平缓，由此，水平井开发时的深部煤层厚度下限建议为4 m（图3）.

在此基础上，相关理论进一步向多学科融合方向发展，提出了“岩石力学地层（学）”概念.该方法体系融合了沉积学、地层学与地质力学原理，构建了包含岩石力学地层模式、成藏地质模型及开发地质力学模型在内的综合架构.通过聚焦储层的渗透性、连通性与可改造性三大核心要素，并结合定性分析与定量算法，实现了对深部煤层气“甜点”层段的一体化精准预测，为深部复杂地质条件下的煤层气资源开发提供了系统性的理论支撑（桑树勋等，2023）.

2 深部煤层气储层地质力学特性

2.1　煤岩力学行为特征

随着埋深增加，煤层气储层温度、地应力及流体压力持续升高，围岩属性显著改变，不仅调控煤岩吸附/解吸效率，更极度强化储层非均质性，导致深部煤岩基本力学特性与浅部呈现明显差异（表3）（左建平等，2011；秦勇等，2012；徐凤银等，2024）.这种差异表现为宏观力学行为上弹性模量、泊松比等参数随深度动态变化，煤岩逐渐由脆性向脆‒延性、乃至延性转变，塑性显著增强（秦勇和申建，2016）；同时，高地应力压缩煤储层孔隙与天然裂缝系统，造成渗透率呈指数式衰减（李志强等，2009），形成“低孔‒特低渗”储层特征（李勇等，2024b）.

深部储层具有煤矸交互叠置、微幅构造发育、宏观天然裂缝与微孔系统空间异质性，以及黏土/石英与镜质组/惰质组有机质非均匀分布等特征（赵庆波，2004；秦勇，2021），共同加剧煤岩力学行为的非均质性（闫霞等，2021）.此外，高地温梯度与高地层压力环境不仅制约煤岩吸附、解吸动力学效率，还会进一步加剧储层各向异性，促使煤岩塑性变形倾向性显著增强.高地应力状态对煤储层渗透率亦产生显著制约效应，导致渗透率数量级显著降低（孟召平等，2023；Tao et al.， 2023；王瑞等，2025）.

2.1.1　高压高应力作用下的煤岩脆‒延性转变

高地应力驱动煤岩发生脆‒延性转变的本质机制在于应力对煤岩力学行为的深度重塑.在不同煤级中，应力始终是影响煤岩力学性质最显著的因素（杨永杰等，2006）.随着围压升高，煤岩微观结构发生系统性重组：孔隙、天然裂缝系统受压闭合使煤岩刚性增强，弹性模量和抗压强度初期呈线性增长（He et al.，2022；Shan et al.，2023；图4）；当应力持续增大至临界值，煤岩内部破裂萌生导致力学强度转弱，弹性模量与抗压强度由增转降（刘泉声和许锡昌，2000）.这一转变过程使深部煤储层力学属性从浅部的脆性特征逐渐转化为延性特征，呈现出“高可压缩性、低渗透性、强黏塑性”的软岩大变形行为（王路军等，2018；谢和平，2019；何满潮，2021；He et al.，2022；Shan et al.，2023）.从浅部脆性向深部延性的转化是一个受地应力、温度和孔隙压力共同控制的渐进过程，不存在一个绝对的、全球统一的“界限深度”.根据中国主要含煤盆地的勘探实践：在埋深<1 000 m时，脆性行为占主导，以弹性变形为主，破裂样式主要为脆性剪切破坏或拉张破坏；脆‒延性转化过渡带（1 000~2 000 m）开始出现局部塑性屈服，天然裂缝的闭合效应增强；当埋深超过 2 000 m时，煤岩的延性行为占主导，呈现出显著的强流变性和高可压缩性，整体以塑性流动和蠕变为主（米洪刚等，2024；徐凤银等，2025b）.

微观上，脆‒延性转变受控于双重机制：煤中方解石等充填矿物的塑性化吸收变形能，抑制天然裂缝形成；镜质组等有机质在持续应力下的分子链蠕变引发时间依赖性变形.真三轴实验进一步证实，高围压下煤岩破坏模式从张裂主导转向剪切滑移，屈服强度随围压线性递增，且临界条件受围压、温度与煤阶等多因素协同调控（崔聪等，2018）.

2.1.2　流‒固‒热耦合效应

地温场作为煤层气勘探开发的关键地质因素，不仅控制着煤层气赋存状态与储层渗透率，更能通过流‒固‒热耦合效应显著影响储层力学特性.随着埋深增加导致地层温度升高，煤岩热演化程度与生烃能力增强，其中气体吸附/解吸过程引发的基质收缩是最典型的力学属性动态改变特征（李松等，2016；Yu and Meng，2021；Cai et al.，2022；徐立富等，2025）.温度对煤岩力学行为的调控呈现显著的有效应力依赖性：低有效应力状态下，升温驱动煤体膨胀与孔隙扩张，渗透率增大，但同时削弱了其力学强度；高有效应力状态下，煤体表现出更强的塑性，此时高应力加载会显著抑制温度诱发的膨胀倾向，转而增强煤体压缩性，导致渗透率降低，力学强度则出现反常提升（李志强等，2009；Guo and Cheng，2013；李松等，2016；Yu and Meng，2021）.

煤储层热膨胀效应随温度升高呈现阶段性的演化规律.初期（25~100 ℃）温度上升驱动煤层气解吸，吸附量减少引发煤基质收缩，同时天然裂缝增生，共同削弱煤岩的力学强度，表现为抗压强度与弹性模量持续降低；过渡至100~200 ℃区间时，煤岩整体膨胀造成小尺度天然裂缝张开，但对大尺度宏观天然裂缝产生压实效应，促使抗压强度、弹性模量增大，泊松比下降，储层脆性阶段性增强；当温度升至200~300 ℃区间时，持续膨胀最终诱发煤岩热开裂，热损伤主导力学性能，抗压强度与弹性模量再度显著衰减（马占国等，2005；李松等，2016；王公忠等，2016；Shen et al.，2024）.温度影响效应的全过程表明，温度通过吸附解吸诱导的基质应变、热膨胀引发的裂缝系统重组以及热开裂导致的损伤破裂三重机制，动态重构煤岩力学属性，形成深部煤层气开发中不可忽视的流‒固‒热耦合效应.

2.1.3　煤储层地质力学非均质性及其影响因素

深部高地应力背景下，煤岩力学性质及地应力分布具有强非均质性，受控于微幅构造与天然裂缝系统的空间分异（闫霞等，2021），是决定深部煤储层可改造性与开发效果的关键地质因素.随深部载荷增强，煤体变形依次经历先存天然裂缝闭合、新微裂缝产生、新宏观裂缝形成、沿破裂面破坏及流变破坏5个阶段，每个阶段对应独特的煤体结构和裂缝特征，其在深部环境中因高温高压作用而更为复杂.在正向微构造部位发育张性裂缝，表现为弹性模量低、渗透性好、压裂改造效果较优；而负向微构造和挤压部位应力集中，具有弹性模量高、渗透性差、可改造性差的特征.

割理作为煤储层中重要的裂缝类型，是天然的储集空间、渗流通道与力学弱面，其可进一步划分为近乎垂直的面割理与端割理，二者的空间构型直接控制着煤岩力学和渗流特性，以及深部煤层中压裂裂缝的扩展路径与形态（闫霞等，2021；Liu et al.，2022）.受差异沉积条件、构造应力等因素影响，割理发育程度、开度、间距和连通性呈现显著的空间非均质性，直接决定煤岩强度、变形破裂特征及渗透率分布.Hou et al.（2020）研究认为，单轴抗压强度和抗张强度均随着割理密度的增大而降低，弹性模量与泊松比随割理密度的增大分别呈降低和增高趋势（图5）.此外，当最大主应力平行于端割理方向加载时，煤岩破坏模式以剪切破坏为主（Paul and Chatterjee，2011；刘翰林等，2024；Huang et al.，2025）.

在微观尺度上，有机质与矿物质的非均匀分布进一步加剧了储层的多尺度非均质性，煤岩显微组分与矿物组分是决定储层微观力学性质非均质性的根本内因，进而显著制约宏观岩石力学行为与压裂裂缝的形成扩展（Wu et al.，2024；赵石虎等，2025）.研究表明，不同显微组分的力学强度与变形特征存在显著差异，构造煤中不同有机显微组分的变形差异本质源于其大分子结构的演化，镜质组通常表现出较高的脆性和割理发育程度，而惰质组则相对致密坚硬，这种微观力学性质的差异导致煤体在应力作用下产生非均匀变形（赵庆波，2004；侯晨亮等，2025；赵石虎等，2025）.在矿物组分方面，石英、长石及碳酸盐等脆性矿物含量直接正向影响煤岩弹性模量与脆性指数，有利于压裂裂缝的起裂与扩展；相反，高含量的粘土矿物则会增强储层的塑性特征，增加压裂液滤失并抑制裂缝的复杂程度（王士国等，2022）.此外，煤岩组分还控制割理发育与闭合，镜质组含量高的亮煤条带往往发育高密度的割理系统，为压裂提供了天然的渗流通道和应力弱面，易于形成复杂的缝网结构，而富含矿物的暗煤或夹矸层则往往充当压裂裂缝扩展的屏障（Abrar et al.，2025）.

2.1.4　煤层结构的地质力学影响效应

不同煤层结构对其宏观力学行为、地应力分布及压裂裂缝扩展模式具有根本性的影响（杨兆中等，2021；Zhang et al.，2023；陈国庆等，2025；闫霞等，2025），其主要源于各种结构造成的非均质性和各向异性，它们直接改变了煤岩的力学响应、地应力场形态，以及压裂裂缝的起裂与延伸路径.

（1）单一厚煤层：在单一厚煤层中，结构相对均一，但其内部往往发育有随机的天然裂缝网络.此条件下煤岩宏观力学性质表现出明显的各向异性，含不同倾角天然裂缝的煤体，其应力传递效率和宏观力学性能随裂缝角度具显著变化.地应力分布主要受天然裂缝的方位和密度控制，容易在裂缝尖端产生应力集中.压裂裂缝扩展路径受天然裂缝强烈影响，易沿原有裂缝延伸或发生转向，形成复杂的裂缝网络，而非单一的平面裂缝（Lan et al.， 2025）.

（2）薄互层结构：薄互层由煤层与薄层砂岩、泥岩等频繁互层构成，强烈的垂向非均质性是其核心特征.不同岩性岩石力学性质（如弹性模量、抗压强度）差异显著，导致整体力学行为表现为多层复合材料的特性.不同顶底板岩性与煤层的组合，地应力分布呈现明显差异特征（图3），层间应力差是控制压裂裂缝垂向扩展的关键地质因素（闫霞等，2025）.压裂裂缝在垂向扩展时，遇到岩性界面会发生穿透、停止、转向或沿界面滑移等多种复杂的传播行为，提高施工排量或压裂液粘度有助于压裂裂缝穿透隔层.

（3）含多层夹矸或叠置煤层：此结构存在大量强弱交替的力学界面.煤与夹矸的力学性质差异，使得压裂裂缝在扩展至界面时需要消耗更多能量.各层地应力大小可能不同，形成应力屏障.研究表明，原地应力差和界面强度越大，压裂裂缝穿过砂煤岩界面并在砂岩层中扩展的可能性也越大（图6；杨兆中等，2021）.压裂裂缝能否穿透夹矸层是扩展的核心问题.成功的穿层需要克服界面强度和应力差形成的屏障.如果压裂裂缝沿界面扩展，则界面处的压裂裂缝宽度会远小于煤层中的压裂裂缝宽度（杨兆中等，2021；Liu et al.，2022；Zhang et al.，2023）.

（4）分叉合并等复杂结构：受复杂地质构造影响，可能导致煤层出现分叉、合并或陡倾.在这种结构中，地应力场方向可能发生偏转，尤其在构造活动区域.压裂裂缝扩展方向不仅受当前现今地应力场控制，还强烈受原生地质结构面（如层理、断层）的制约.

2.2　关键参数表征方法

2.2.1　原位地应力场反演

地应力场对深部煤储层水力压裂改造起核心控制作用，其大小、方向及组合特征深刻影响着压裂裂缝的延伸路径、扩展模式以及最终形态（鞠玮等，2022；牛然等，2024）.精确获取深部煤层的地应力场信息是进行井筒优化设计和压裂施工方案制定的根本基础.在传统方法中，微地震监测技术扮演着关键角色，它通过捕捉和分析压裂过程中诱发的微震事件的时空分布特征，能够直接反演出储层在动态扰动下的应力状态，这是其显著优势.

目前针对深部煤储层内部复杂的微构造、煤层顶底板不同岩性组合的力学响应差异、煤岩层厚度变化、夹矸层厚度及其分布等因素对应力场的影响机制尚未完全明确.煤岩内部结构的高度复杂性是其宏观力学响应呈现多样性的根本原因.在深部外部荷载作用下，煤岩的宏观变形响应显现出显著的各向异性、非连续性和向脆‒延性转变等特征（龚爽等，2025）.因此，在精细反演深部煤储层原位地应力场时，需综合考虑高温高压条件下煤岩延性、塑性特征，以及天然裂缝发育导致的强储层非均质性.

以构建的岩石物理模型为约束条件，综合利用测井数据和地震资料进行储层物性参数（如孔隙度、渗透率）和弹性参数（如纵横波速度、密度）的定量反演，已成为刻画深部煤储层参数和精准描绘地应力特征的强有力手段（Gong et al.，2024；刘军等，2024）.通过开展煤岩高温高压岩石力学实验、地应力测试或压裂小压分析获取弹性模量、泊松比、地应力等基本参数，结合测井岩石力学参数计算、天然裂缝描述测量以及裂缝弱化岩石力学性质数值模拟分析，建立裂缝弱化效应影响下的岩石力学剖面（图7）和现今地应力剖面，据此结合地震数据体实现三维地应力场精细反演计算（图8）.

2.2.2　基于数字建模的裂缝网络模型

数字煤岩建模技术是揭示和量化深部煤层气储层复杂微观结构的核心手段，为应对其强非均质性和极低渗透性提供了关键解决方案.该技术依托微米级计算机断层扫描（CT）对煤岩样品进行三维高精度成像，精准重构深部煤储层在高地应力环境压缩改造后的孔隙‒裂缝系统，实现从微观尺度对储集空间的数字化表征（Yao et al.，2009；李伟等，2014；Dong et al.，2024）.针对深部煤岩组分复杂、天然裂缝多被挤压闭合或矿物充填的特点，基于深度学习的U⁃Net图像分割算法被广泛用于智能识别有机质、矿物质及天然裂缝，从而精确提取孔隙率、连通性等关键参数，为深部煤储层渗透能力和力学稳定性评价提供定量依据（Košek et al.，2024；王刚等，2024；Mahmoudi et al.，2025；Tian et al.，2025）.

在提取裂缝产状（长度、倾角、方位角）并分析其统计规律基础上，结合地震资料预测区域裂缝发育情况，利用多约束随机模拟技术可构建从岩心至区块尺度的离散裂缝网络（DFN）模型.深部煤层中天然裂缝通常服从幂律长度分布和Fisher倾角分布（陈健翔等，2024），DFN模型依托地质统计数据，在三维空间生成符合实际地质特征的裂缝系统，真实反映深部煤储层天然裂缝非均质性和各向异性，为井位布置和压裂设计提供地质模型基础.基于裂缝网络DFN模型可进一步构建渗流‒力学耦合数值模型，模拟深部高地应力、高孔隙压力条件下的压裂裂缝扩展规律及应力‒流体动态交互机制（Tan et al.，2021），对优化深部煤层气压裂设计、预测缝网形态和评估产能至关重要（段永强等，2015；徐凤银等，2024）.

3 研究进展与关键技术

3.1　储层改造地质力学理论

深部煤层气储层水力压裂面临复杂的地质力学环境.压裂裂缝扩展不再遵循经典PKN或KGD模型的简单二维模式，而是受强地应力非均质性、天然裂缝网络、煤岩力学性质各向异性及层理界面的综合控制（陈勉等，2008；周健等，2008；杨兆中等，2021；高向东等，2022；韩文龙等，2024）.压裂裂缝转向现象普遍，尤其当压裂裂缝尖端遭遇高强度遮挡层、大尺度天然裂缝或显著应力差界面时，易发生剧烈偏转甚至分叉，形成非平面复杂缝网（张士诚等，2014；Weng，2015）.压裂裂缝竞争扩展是另一核心挑战，压裂液在多个潜在起裂点或天然裂缝系统和薄弱面间的非均匀分流，导致强烈的应力阴影效应（于永军等，2017；仝少凯等，2019），其抑制邻近压裂裂缝的宽度增长与纵向延伸，加剧了“无效”裂缝的形成，显著降低主缝的有效改造体积（He et al.，2017；Zhou et al.，2017）.精确预测深部煤储层压裂裂缝形态需构建嵌入精细地质力学属性的全三维扩展模型，并考虑流‒固耦合效应及近井筒复杂效应，为优化射孔方案、压裂液粘度及排量设计提供关键理论支撑.

深部煤层气井产能递减后，重复压裂是重要的增产措施，其成功高度依赖于初始压裂诱导的应力场重分布建模精度（图9）（秦勇等，2012；Gong et al.，2016；姜伟等，2017；张遂安等，2021）.首次形成的支撑压裂裂缝网络及其诱发的大范围储层变形，会显著改变近场及远场的应力大小与方向，形成复杂的应力扰动区，且在形成的“应力笼区”孔隙与天然裂缝闭合，渗透率降低（He et al.，2017；郑春山等，2024）.初次压裂施工规模不足导致裂缝不能有效延伸，生产过程中煤粉堵塞、裂缝闭合以及煤层基质水锁等因素会进一步降低压裂裂缝导流能力，使得煤层气井不能达到理想的产气效果.上述问题使深部煤层气井由初次压裂向重复压裂技术方向发展（倪小明等，2012；杨兆中等，2020）.煤层气井重复压裂技术的关键是要解决选井问题.通过科学选井和精准的应力场建模，重复压裂工艺可有效治理由孔隙喉道堵塞、支撑裂缝闭合及近井地带污染等诱发的导流能力衰退问题，显著提升煤层气井产能（李阳等，2005；倪小明等，2016；梁智飞等，2022）.

评估重复压裂可行性需构建高精度的流‒固耦合数值模型，模拟初始压裂裂缝支撑剂嵌入、煤基质收缩/膨胀、孔隙压力变化及储层压实等多因素共同作用下的应力场动态演化.暂堵与转向理论相结合的暂堵转向压裂工艺研究为煤层气井重复压裂技术指出了新的方向（杨国威等，2014；张遂安等，2021）.关键评估指标包括新形成的压裂裂缝能否突破原有应力屏蔽区、能否有效沟通未充分改造的储层区或新发现的甜点区、是否引发原有支撑缝失效（王成旺等，2018；张万春等，2022）.

3.2　复杂含缝模型构建与多场耦合数值模拟

深部煤储层包含大量天然裂缝和层理面，其水力压裂过程涉及大规模断裂形成与岩块运动，连续介质力学方法如有限元FEM、有限体积FVM难以精确模拟.离散元法DEM擅长模拟非连续介质的接触、分离、旋转以及破裂过程，而DFN模型可精确表征复杂天然裂缝网络（Scholtès and Donzé，2012；唐煊赫等，2023；Cheng et al.，2024；Chen et al.，2025）.DFN⁃DEM混合算法将DEM对离散块体力学行为的精细模拟与DFN对天然弱面系统的精确表征结合，能更真实地再现压裂液在天然裂缝中的流动、诱发剪切滑移、新裂缝萌生与贯通、形成复杂缝网的动态过程，并可定量评估天然裂缝属性如密度、产状、强度对压裂效果的影响.结合并行计算技术提升大规模模型计算效率，DFN⁃DEM混合算法已成为研究深部煤层复杂裂缝扩展机制的有力工具（徐凤银等，2025a）.嵌入式离散裂缝模型 （EDFM）是处理复杂裂缝网络的高效工具，其将裂缝作为离散实体，明确其几何形状、方向及属性，在保留基质网格的同时，直接为裂缝网格赋予开度、渗透率等属性，基于非相邻网格连接（NNC）技术，不仅维持传统基质间渗流计算，还构建起基质与裂缝、裂缝与裂缝的流动关系，精准模拟裂缝出水动态与压力变化（朱大伟等，2020）.实测数据显示，相较于传统双孔双渗网格模型及非结构化网格模型，EDFM在运算速度、机理呈现和可视化方面均实现显著性能提升.

深部煤层气开发本质上是高地温场‒渗流场‒地应力场‒化学场（Thermo⁃Hydro⁃Mechanical⁃Chemical，THMC）全过程强烈耦合的复杂系统（Yang et al.，2023；肖智勇等，2024；Mao et al.，2025；张贺龙等，2025）.构建完善的THMC耦合模型是理解储层响应、优化工程方案的核心.模型需充分考虑深部高温高压环境下煤岩物理力学性质的显著变化及其非线性响应.

在当前复杂含缝模型构建与多场耦合数值模拟研究中，方法技术发展仍面临多重挑战与局限：天然/压裂裂缝网络形态、接触关系及渗流特性的数学描述尚不完善，多物理场耦合模拟中强非线性耦合关系的求解面临收敛性与计算效率的瓶颈.此外，跨尺度效应的关联机制也尚未明晰，模型预测精度与工程实际存在偏差.这些局限性共同制约了对含缝介质中复杂多场耦合行为的准确描述与高精度预测.

3.3　智能预测与优化技术

3.3.1　地应力场动态反演

精确掌握地应力场及其动态变化是实现深部煤层气高效开发和灾害预警的核心.深部煤层气储层处于高地应力、高孔隙压力环境，地应力状态不仅控制着储层压裂裂缝的延伸方向和形态，也直接影响井网部署和压裂策略的有效性.当前，将成功应用于页岩气领域的四维地应力反演模拟等技术引入到深部煤层气领域，在理论上是可行的，且在沁水盆地寿阳区块煤层气效益开发的探索性研究中显示出良好的应用潜力（张滨海等，2018；刘英君等，2022），为煤层气排采制度调整、加密井井壁稳定性分析、二次压裂优化设计等提供重要参考.

此外，基于卫星干涉合成孔径雷达（InSAR）的大范围、高精度地表形变监测技术，为地下储层在流体注入/开采过程中的三维应力应变场演化提供了革命性数据源.结合卷积神经网络（CNN）和长短期记忆网络（LSTM）等深度学习算法，可构建端到端模型，从长时间序列的InSAR形变数据中直接学习和反演储层内部三维应力‒应变场的时空演化.该项技术能够实时监测大规模压裂或长期采气所引起的大区域应力扰动，识别潜在断层活化与滑移风险区域，指导注采平衡动态调整；同时，可为重复压裂的靶区优选和区域井网整体优化提供动态应力场依据，支撑“地质体透明化”在深部煤层气开发中的实现，最终提升采收率并降低工程风险（张守仁等，2022）.

3.3.2　机器/深度学习辅助压裂方案设计

压裂方案设计正从经验驱动迈向数据与模型双驱动的智能化阶段.机器/深度学习模型基于大量历史压裂施工数据如泵注程序、压裂液性能、支撑剂参数和对应的微地震监测结果或生产动态响应，可训练监督学习模型如随机森林、梯度提升机、深度神经网络，建立压裂参数与天然裂缝复杂度之间的非线性映射关系，高精度预测特定地质背景下不同压裂设计射孔策略、压裂液体系、支撑剂类型与浓度、泵注程序所能诱导的裂缝网络复杂度.模型能识别关键控制因素如水平应力差、脆性矿物含量、天然裂缝走向与压裂液粘度的交互作用，并量化其对压裂裂缝扩展模式平面缝‒复杂缝和SRV的影响.结合强化学习或混合整数规划等优化算法，系统可自动生成最大化裂缝复杂度与预期产能的个性化压裂设计方案，大幅减少对人工经验的依赖，显著提升设计效率与针对性，实现“地质工程一体化”智能设计（胡秋嘉等，2025；徐凤银等，2025a；周立宏等，2025），尤其适用于地质条件复杂的深部煤层气区块（朱峰等，2021；Wen et al.，2023；黄力等，2024；Wei et al.，2024；张聪等，2024）.

3.3.3　光纤传感实时监测压裂裂缝扩展

分布式光纤传感技术，特别是分布式声波传感（DAS）和分布式温度传感（DTS），为应对深部煤层气储层强非均质性、高地应力以及复杂缝网提供了革命性的实时监测与评估手段.在深部煤层气压裂过程中，DAS通过全井筒捕捉压裂液流动、压裂裂缝动态扩展、支撑剂运移及煤岩破裂产生的声波/振动信号，能够实时诊断压裂裂缝起裂位置、监测纵向高度增长、识别转向行为以及多压裂裂缝竞争现象，尤其适用于评估高地应力条件下非平面缝网的复杂扩展形态.DTS则通过监测注入压裂液导致的温度场异常，精准刻画各射孔簇的进液效率、主压裂裂缝方位及缝网覆盖范围，揭示储层改造的均匀性.

在深部煤层气开发中，DAS与DTS的联合应用可实现压裂全过程“可视化”，精准识别无效簇或早期砂堵段，评价层间/簇间改造差异，并为高地应力、高塑性地层中暂堵时机优化和液量分配提供实时决策依据.该技术极大提升了压裂设计的针对性与调控时效，为深部煤层气储层有效改造和生产制度优化提供了关键数据支撑，是实现智能化压裂和提质增效的核心技术（陈金宏等，2022；宁卫东等，2024；刘永成等，2025；徐凤银等，2025b）.

3.3.4　自适应暂堵转向压裂

针对深部煤层气储层非均质性强、天然裂缝发育导致压裂液易沿优势通道窜流的问题，自适应暂堵转向压裂技术成为提高改造均匀性与复杂性的关键.其核心在于应用温敏水凝胶、压敏微球、pH响应颗粒等智能响应材料，其在特定井下环境如高温或遭遇高压差下触发相变或膨胀，智能封堵已开启的高导流通道或天然裂缝，迫使后续压裂液转向并开启新的裂缝分支或沟通次级裂缝系统.该技术克服了传统球塞或化学暂堵剂位置不可控、难以适应深井条件的缺点，显著提升缝网复杂度与压裂改造体积SRV，尤其适用于层理发育、应力差小或发育天然裂缝网络的深部煤储层（Ai et al.，2018；Santos et al.，2018；周彤等，2020；霍超等，2025；徐凤银等，2025b；朱庆忠等，2025）.优化智能材料的响应阈值（如相变温度略低于储层温度、强度及降解性）是实现高效、精准、长效转向的核心挑战.

4 未来研究发展方向

4.1　储层地质力学‒渗流‒经济性协同优化算法

当前，深部煤层气储层开发面临诸多挑战：传统压裂施工参数优化过程存在计算复杂度高、求解效率低等问题.随着大数据时代的到来和数据挖掘技术的快速发展，基于算法数据驱动的压裂参数优化方法已成为极具价值的研究方向.在深部煤层气开发领域，随着能源开发与资源利用领域对效率与可持续性的双重诉求不断提升，地质力学、渗流理论和经济性三者之间的多目标协同优化逐渐成为学术界与工业界共同关注的前沿课题.复杂的地质力学环境、尚未完全阐明的渗流机制以及较高的经济风险，使建立储层地质力学‒渗流‒经济性多场耦合的协同优化算法显得尤为迫切.

在深部煤层气储层地质力学研究与勘探开发中，地质力学对孔隙压力分布、应力场演化等关键要素的精确刻画，能够有效提供工程指导（桑树勋等，2023；唐志潭等，2024；闫霞等，2025）；渗流理论聚焦于流体在多孔介质中的传输规律，通过量化流速、流量等参数，助力优化流体采收率与注入策略（Wu et al.，2010；Liu et al.，2016，2017；张邈和刘义坤，2016；朱煜珣和刘金锋，2023）；经济性考量则是将上述理论成果与市场机制、成本预算紧密结合，旨在以最低的成本投入实现最大的资源产出效益.然而，三者之间并非孤立存在，而是相互制约、相互促进的复杂系统.构建一套综合储层地质力学约束、渗流优化目标以及经济性导向的多目标协同优化模型显得尤为关键.地质力学‒渗流‒经济性多目标协同优化需借助先进的数值模拟技术与智能算法，对复杂地下环境进行多维度迭代求解，并通过大量工程实例验证其可行性和优越性，从而为资源开发领域提供一种兼顾安全性、高效性与经济性的创新解决方案，助力实现深部煤层气效益开发.

4.2　数字孪生驱动的储层全生命周期管理

储层数字孪生是动态映射物理储层的数字镜像系统，通过集成实时监测数据、物理模型与机器学习算法，在数字空间中高精度复现储层物理力学行为与属性特征（王芷桁等，2025）.该技术构建起物理数据与虚拟模型的双向映射机制，实现了从勘探开发到废弃处置的全生命周期智能化管理.

在深部煤层气勘探阶段，通过融合地质统计学、地球物理勘探与实时传感数据，构建三维地质力学精细模型，为井位优化部署提供数据支撑（Han et al.，2020；Yao et al.，2020；刘文岭和韩大匡，2022）；开发阶段借助多物理场耦合模型，动态模拟压裂裂缝扩展规律与流体渗流特性，指导压裂工艺参数与井网间距优化设计（刘文岭和韩大匡，2022）；生产阶段依托实时数据驱动模型更新机制，动态调整开采策略以延缓储层渗透率衰减；废弃阶段则通过封存潜力评估模型，为碳封存工程或储气库改造提供技术依据.其核心技术体系涵盖数据治理、跨尺度多物理场耦合建模，以及人工智能驱动的参数反演与闭环优化算法.当前技术挑战集中于数据标准化体系缺失与高性能计算瓶颈，未来将向自主决策系统演进，并深度融合绿色能源开发场景.

5 结论

（1）与浅部相比，受深部“三高”（高地温、高地应力、高流体压力）地质环境影响，深部煤层气储层在地质力学特性上存在显著差异，煤岩力学行为发生本质改变，发生脆‒延性转变，塑性增强、渗透率下降，储层的改造难度增大.原位地应力场精细反演、数字裂缝网络模型构建、多场耦合数值模拟是深部煤层气储层地质力学研究的重要方法.

（2）深部煤层气储层改造是热‒流‒固强烈耦合的结果，多场耦合效应是储层响应的内在核心.地应力场的非均质性、天然裂缝网络的发育情况以及煤岩自身的力学各向异性，共同控制了压裂裂缝的起裂、扩展和最终缝网形态.智能化和实时监测技术是深部煤层气开发降本增效的关键.基于机器/深度学习的参数优化、基于光纤传感的实时监测和基于智能材料的暂堵转向技术，构成压裂过程“可视化、可诊断、可控制”的技术闭环，是提高深部煤储层改造效率的必然方向.

（3）未来深部煤层气储层地质力学的发展应实现多学科协同与全生命周期管理.深部煤层气开发依赖于储层地质力学、渗流与经济性评价等学科深度交叉融合，发展多目标协同优化算法，构建数字孪生系统，是实现深部煤层气规模效益开发的关键路径.

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基金资助

国家自然科学基金面上项目(42372185)

中国石油天然气股份有限公司基础性前瞻性科技项目(2024DJ23)

江苏高校“青蓝工程”优秀青年骨干教师培育项目和中央高校基本科研业务费专项资金项目(2025ZDPY10)