A New Discovery on the Deformation Behavior of Shale Gas Reservoirs Affecting Pore Morphology in the Juhugeng Coal Mining Area of Qinghai Province, Northwest China

Objective The Juhugeng mining area in Qinghai Province of northwest China has attracted wide attention among geologists for it hosts typical coal measure gases.The shale gas reservoirs were reformed by intensive structural movements during geological periods,

Reflectivity forward modeling and a CSSI method seismic inversion study of igneous intrusive area,coked area,and gas-enriched area located within a coal seam

We applied the reflectivity method and the constrained sparse spike inverse modeling(CSSI) method to the interpretation of coal field lithologic seismic data.After introducing the principles of these two methods we discuss some parameters of a geological model involving possible gas enriched areas or intruded igneous rock.The geological model was constructed and a 60 Hz seismic response profile was obtained looking for igneous rock intrusion and coked areas of the coal seam using the reflectivity method.Starting from synthesized logging data from two wells and a synthesized seismic wavelet we calibrated the model to show accurate strata.Finally,we predicted the lithology within a 10 m igneous rock area,a 3 m coal seam area,and a coked area using the CSSI technique.The results show that the CSSI technique can identify hard to recognize lithologic features that normal profil-ing methods might miss.It can quantitatively analyze and evaluate the intrusive area,the coked area,and the gas-enriched area.

Determining areas in an inclined coal seam floor prone to water-inrush by micro-seismic monitoring

The failure depth of the coal seam floor is one important consideration that must be kept in mind when mining is carried out above a confined aquifer.Determining the floor failure depth is the essential precondition for predicting the water-resisting ability of the floor.We have used a high-precision microseismic monitoring technique to overcome the limited amount of data available from field measurements. The failure depth of a coal seam floor,especially an inclined coal seam floor,may be more accurately estimated by monitoring the continuous,dynamic failure of the floor.The monitoring results indicate the failure depth of the coal seam floor near the workface conveyance roadway（the lower crossheading） is deeper and that the failure range is wider here compared to the coal seam floor near the return airway（the upper crossheading）.The results of micro-seismic monitoring show that the dangerous area for water-inrush from the coal seam floor may be identified.This provides an important field measurement that helps ensure safe and highly efficient mining of the inclined coal seam above the confined aquifer at the Taoyuan Coal Mine.

Behaviors of overlying strata in extra-thick coal seams using top-coalcaving method

Accidents such as support failure and excessive deformation of roadways due to drastic changes in strata behaviors are frequently reported when mining the extra-thick coal seams Nos.3e5 in Datong coal mine with top-coal caving method,which significantly hampers the mine's normal production.To understand the mechanism of strata failure,this paper presented a structure evolution model with respect to strata behaviors.Then the behaviors of strata overlying the extra-thick coal seams were studied with the combined method of theoretical analysis,physical simulation,and field measurement.The results show that the key strata,which are usually thick-hard strata,play an important role in overlying movement and may influence the mining-induced strata behaviors in the working face using top-coal caving method.The structural model of far-field key strata presents a 'masonry beam' type structure when'horizontal O-X' breakage type happens.The rotational motion of the block imposed radial compressive stress on the surrounding rock mass of the roadway.This can induce excessive deformation of roadway near the goaf.Besides,this paper proposed a pre-control technology for the hard roof based on fracture holes and underground roof pre-splitting.It could effectively reduce stress concentration and release the accumulated energy of the strata,when mining underground coal resources with top-coal caving method.

An improved rotated staggered grid fi nite difference scheme in coal seam

A coal seam is thin compared to the wavelength of seismic waves and usually shows strong anisotropy.It may form special geological formations,such as goafs and collapses,in coal mines.The existence of these formations may lead to instability in numerical simulations of the goaf area in a coal seam.The calculation speed of simulations is always a factor that restricts the development of simulation techniques.To improve the accuracy and effi ciency of seismic numerical simulations of goaf areas,an improved vacuum method has been incorporated into a rotated staggered grid scheme and calculations implemented by combining parallel computing and task parallelism.This ensures that the proposed numerical simulation method can be utilized in a geological model with large differences in elastic parameters among layers and improve the performance of a parallel application by enabling the full use of processor resources to expedite the calculations.We set up anisotropic coal seam models and then analyze numerically the characteristics of synthetic seismograms and snapshots of diff erent goaf areas with or without collapse.The results show that the proposed method can accurately simulate the goaf area and the calculation method can run with a high speed and parallel efficiency.The research will further advance the technology of anisotropic seismic exploration in coal fi elds,provide data for seismic inversion and build a theoretical support for coal mine disaster prediction.

Controlling Effects of Surrounding Rock to Coal Seam Gas Occurrence

Surrounding rock of coal seam was one of the important factors to gas occurrence. The coal seam gas occurrence was studied by the index of roof strata thickness or sand content rate;we found that there were certain shortcomings. In order to reasonably evaluate the influence of coal seam surrounding rock on gas occurrence in Panji mining area, we quantitatively evaluated the effect of coal seam surrounding rock on gas occurrence by influence coefficient of roof strata thickness, and built six mathematical models of the variational gas content in the mining area which is divided into six gas geological units. The results shows that the coal seam gas content is mainly influenced by 20 mroof strata in each gas geological unit, the gas content presents the tendency of increase, and with the influence coefficient of strata thickness increases, they exist a significant linear relationship.

Ground pressure law of fully mechanized large cutting height face in extremely-soft thick seam and stability control in tip-to-face area

When stepped coal getting technology was applied to high seam mining working face, with field observations the following aspects of working face were analyzed based on the inherent conditions of extremely soft thick seam mined by Liangbei Mine, such as the brokenness and activity law of rock seam in the working face, the law of load-bearing of its supports, and the instability character of coal or rock in tip-to-face area. The following are the major laws. Pressure intensity of roof in high seam mining with extremely soft thick seam is stronger than one in slicing and sublevel-caving as a whole. But the greater crushing deformation of coal side makes pressure intensity of roof in the middle of working face be equivalent to one in sublevel-caving. In the middle of working face the roof brokenness has less dynamic load effect than roof brokenness in the two ends of working face. The brokenness instability of distinct pace of roof brings several load-bearings to supports. In condition of extremely soft thick seam, the ratio of resistance increment of supports in two ends of working face is obviously greater than that of supports in the middle. Most sloughing in coal side is triangular slop sloughing caused by shear slipping in high seam mining with extremely soft thick seam. Ultrahigh mining is the major reason for roof fall. Instability of coal or rock in tip-to-face area can be controlled effectively with the methods such as improving setting load of supports, mining along roof by reinforcing floor and protecting the immediate roof in time, and so on.

Study on detecting spatial distribution availability in mine goafs by ultra-high density electrical method

The purpose of this research is to explore the spatial distribution and influence range of the mined-out area of a coal mine in Hebei Province,the advantages of ultra-high density resistivity method,such as large data volume,high efficiency and high precision,are brought into full play,the abnormal patterns of dislocation and partial drainage area of shallow continuous aquifer caused by subsidence zone are detected,and then the spatial distribution patterns of subsidence and fractures caused by deep mining subsidence zone are deduced,this method not only extends the exploration range of high-density resistivity method in mining subsidence disaster assessment,but also improves the accuracy of measurement,the distribution and influence range of mined-out area are revealed accurately,and good exploration results have been obtained in this project.How to select reasonable geophysical prospecting methods and give full play to the role of geophysical prospecting methods according to the geological characteristics of the study area,this exploration work is not only a good combination of geophysical prospecting methods and actual geological conditions,it also provides a valuable reference version for the exploration work under the same geological conditions.

“Exploring petroleum inside source kitchen”: Connotation and prospects of source rock oil and gas

Based on the transitional background of the global energy structure, exploration and development of unconventional oil and gas, and investigation of key basins, the unconventional oil and gas resources are divided into three types: source rock oil and gas, tight oil and gas, and retention and accumulated oil and gas. Source rock oil and gas resources are the global strategic supplies of oil and gas, the key resource components in the second 150-year life cycle of the future petroleum industry, and the primary targets for "exploring petroleum inside source kitchen". The geological connotation of source rock oil and gas was proposed, and the models of source rock oil and gas generation, expulsion and accumulation were built, and five source rock oil and gas generation sections were identified, which may determine the actual resource potential under available technical conditions. The formation mechanism of the "sweet sections" was investigated, that is, shale oil is mainly accumulated in the shale section that is close to the oil generation section and has higher porosity and permeability, while the "sweet sections" of coal-bed methane(CBM) and shale gas have self-contained source and reservoir and they are absorbed in coal seams or retained in the organic-rich black shale section, so evaluation and selection of good "sweet areas(sections)" is the key to "exploring petroleum inside source kitchen". Source rock oil and gas resources have a great potential and will experience a substantial growth for over ten world-class large "coexistence basins" of conventional-unconventional oil and gas in the future following North America, and also will be the primary contributor to oil stable development and the growth point of natural gas production in China, with expected contribution of 15% and 30% to oil and gas, respectively, in 2030. Challenges in source rock oil and gas development should be paid more attention to, theoretical innovation is strongly recommended, and a development pilot zone can be established to strengthen technology and promote national support. The source rock oil and gas geology is the latest progress of the "source control theory" at the stage of unconventional oil and gas. It will provide a new theoretical basis for the new journey of the upstream business in the post-industry age.

富水沟谷区浅埋煤层导水裂隙演化特征

富水沟谷区域下浅埋煤层赋存条件特殊,采场上覆岩层导水裂隙发育演化特征复杂。为了揭示沟谷区浅埋煤层在回采扰动作用下覆岩裂隙演化规律,以朱家峁煤矿1305-2工作面过沟谷区回采阶段为工程背景,采用理论分析、物理相似模拟、数值模拟与现场效果验证的方法,建立了覆岩裂隙−渗流场概念模型,开展了覆岩结构发育与微震能量演化研究,分析了覆岩变形与塑性破坏分布特征,提出了针对沟谷区下浅埋煤层导水裂隙防治措施,并应用于现场工程实践。结果表明:开采扰动下裂隙−渗流场模型呈“梯台”结构,并依次划分为初渗区域、稳渗区域、紊渗区域3个区域;将所研究矿井的工况数据代入模型结构,计算出各个渗透区域范围,并根据计算结果对矿井的稳渗区域采取注浆措施。工作面回采至沟谷区段,覆岩裂隙域形态呈现“拱形-梯形-复合梯形”的扩展演化特征,裂隙纵向发育高度达到163 m,并与沟谷区地表贯通。随工作面推进,地表裂隙依次经历“滑移-挤压-撕裂”过程;沟谷区域位移云图呈现出滞后开采“高位梯形”破断形态,在沟底处下沉位移最大,达3.47 m。针对开采导致的裂隙大范围扩展贯通,提出在地面进行采动裂缝注浆处理,在工作面上覆岩层进行注浆封堵,实现过沟谷区开采“井上−井下”联合防治,保证安全开采。该研究结果可为浅埋煤层的过沟谷区开采、采动裂隙防治及富水区“保水采煤”提供新的科学依据。

新集矿区深部1煤层底板奥灰岩溶突水危险性评价

奥灰岩溶裂隙含水层是影响华北型煤矿深部开采的重要水害,在水-岩相互作用下奥灰含水层易导致煤层底板突水。为进一步认识奥灰岩溶突水问题,文章以新集矿区深部1煤层开采为例,利用矿区近些年最新积累的奥灰钻孔资料,选取断层强度指数、断层交叉点与尖灭点、含水层水压、富水性、隔水层等效厚度、脆塑比7个因素作为奥灰岩溶突水的主控因素,并结合层次分析法(analytic hierarchy process,AHP)确定各主控因素影响权重。运用地理信息系统(geographic information system,GIS)空间分析功能建立各主控因素专题图,通过对专题栅格图归一化处理,将各主控因素按照权重进行空间复合叠加,最终获得1煤层底板奥灰岩溶突水危险性评价分区结果。将评价结果与突水系数法计算结果对比分析可知,基于GIS的煤层底板突水危险性评价方法更符合矿区实际地质情况,可以为矿区深部煤层开采与水害防治工作提供参考依据。

煤层顶板间接压裂裂缝扩展机制及影响因素

碎软低渗煤层在我国普遍发育,制约煤层气单井产气量提高和产业发展。间接压裂是通过在邻近层产生垂直裂缝沟通煤层进而实现煤层有效改造的一种压裂方式,可以有效应对钻井塌陷、煤粉产出、压裂液滤失和煤层厚度薄等不利因素。通过间接压裂物理模拟试验和扩展有限元数值模拟分析,揭示煤层顶板间接压裂裂缝扩展影响因素,明确裂缝扩展机制,以期为间接压裂技术提供指导。通过直接压裂煤层和不同起裂位置、垂向应力和施工排量影响下间接压裂试验表明,起裂压力高,更易产生长裂缝,且受原生裂缝影响程度减小;但起裂点距离煤层越远,起裂所需能量越大,高破裂压力会对煤层造成粉碎性破坏;大施工排量下,起裂压力对应升高,起裂时间变短,原生裂缝影响程度变小。考虑地应力、起裂位置、岩石力学和施工排量等参数的数值模拟结果显示,在模型参数设置条件下,最大水平主应力和垂向应力差在<4 MPa,煤层与顶板有效应力差>3 MPa、弹性模量差<15 GPa的地层和岩性组合适合间接压裂,起裂位置距离煤层最优距离为<6 m,施工排量需要根据力学性质、断裂能密度等参数确定最优范围。

鄂尔多斯盆地中东部地区石炭系本溪组煤岩气储层特征

近年来,鄂尔多斯盆地多口风险探井在石炭系本溪组煤岩中获得工业气流,展示出该盆地煤岩气良好的勘探前景,但关于该盆地煤岩气储层特征的研究较少,煤岩气储层分布规律认识不清,制约了下一步勘探部署。为此,以本溪组8号煤为例,综合岩心、扫描电镜及物性等分析化验资料,对盆地深层煤岩的宏观煤岩类型、显微组分、煤质特征、孔-裂隙发育特征、物性特征和甲烷吸附能力等储层特征开展了系统研究,建立煤岩气储层评价标准,并预测了煤岩气的有利分布区。研究结果表明:①8号煤以原生结构的光亮煤、半亮煤为主,显微组分中镜质组含量高,灰分平均值为17.77%,镜质体最大反射率为1.08%~2.23%,以肥煤-贫煤为主。②8号煤储集类型以胞腔孔、气孔和裂隙为主,其中裂隙包括宏观割理和微裂隙;孔裂隙体积分布以“U”字形结构为主,微孔贡献最大,其次为微裂隙;比表面积分布呈“L”字形,呈现出微孔单峰。③8号煤氦气法孔隙度平均值为6.25%,渗透率平均值为4.21 mD,煤岩在地层状态下具有良好的渗透性。④8号煤空气干燥基兰氏体积为7.79~26.08 m^(3)/t,平均值为18.60 m^(3)/t,兰氏压力为2.03~4.17 MPa,平均值为3.12 MPa,煤岩吸附能力与灰分含量呈负相关性,与成熟度呈正相关性。结论认为,鄂尔多斯盆地本溪组8号煤发育2类有利区,其中横山-米脂-绥德一带为Ⅰ类有利区,面积约11200 km^(2);乌审旗西和榆林北为Ⅱ类有利区,面积约13300 km^(2),2类有利区资源量超过4.5×10^(12) m^(3),可形成煤岩气规模增储上产的现实领域。

煤层底板含水层区域注浆改造浆液扩散范围现场示踪试验

近年来,为解放底板高承压灰岩水上煤炭资源,华北煤田普遍采用地面定向钻技术,对太原组薄层灰岩进行区域性注浆加固改造(习称“底板区域治理”),以全面封堵灰岩岩溶裂隙并阻断垂向导水通道。该技术中,与浆液扩散范围(半径)密切相关的“水平分支孔”孔间距设计问题,一直备受学界和业界的广泛关注。皖北矿区底板区域注浆工程量大,特别是深部资源开采,将有数十亿元的注浆工程,有必要查清浆液扩散范围真实数据。为此,以皖北矿区恒源煤矿为研究基地,依托Ⅱ63采区底板区域治理工程,设计并实施浆液扩散范围示踪试验,在中间的水平分支孔(Z8-7)投放荧光剂(示踪剂),在两侧的水平分支孔(Z8-6、Z8-8)以及交叉分支检测孔(Z8JC)取岩屑样鉴别荧光水泥,以获得浆液扩散范围,进而在浆液扩散影响因素分析基础上,构建恒源煤矿底板区域注浆治理浆液扩散范围计算公式。结果表明:①综合岩屑现场及室内鉴别结果分析,获得恒源煤矿Ⅱ63采区底板区域注浆浆液扩散范围为38.3~44.0 m,且水泥分布密集区在水平分支孔浆液扩散范围30 m以内,该区域内注浆效果最佳。②通过现场岩屑快速鉴别与室内岩屑精准鉴别,取得的浆液扩散范围基本一致,证明了荧光示踪浆液扩散范围的有效性。③通过对比分析,认为在计算参数、边界约束等符合实际注浆工况条件下,浆液扩散范围理论计算和数值模拟结果,与现场示踪试验实测结果较为接近。④利用示踪试验过程中的压水试验及注浆参数、钻遇构造及水文地质响应等数据,考虑重力、构造、地下水径流等因素影响,借助SPSS非线性拟合软件,得到恒源煤矿Ⅱ63采区底板区域注浆浆液扩散范围计算公式。⑤基于恒源煤矿受注层实际地质、水文地质条件,利用拟合的浆液扩散范围计算公式得出Ⅱ63采区Z8场地浆液扩散范围为37.8~42.9 m,与浆液扩散范围示踪试验实测结果相近,计算公式可在类似条件下推广应用。本次煤矿底板区域注浆浆液扩散范围现场示踪工程试验,不仅取得了浆液扩散范围的真实数据,而且阐明了浆液扩散与多种地质、水文地质因素之间的内在联系,揭示了超深、超长定向钻注浆浆液扩散机理,构建了浆液扩散范围计算公式,为类似条件下底板区域治理工程水平分支孔孔间距的合理设计提供了参考依据。

平顶山矿区多煤层卸压立体抽采模式与工程示范

平顶山矿区多煤层发育、含气层段多,仅靠井下进行瓦斯治理工程量大、难度高。为了开辟平顶山矿区瓦斯抽采新模式,达到“采一层抽多层”的目的,采用气测录井与含气量测试相结合的方法精准判识了煤系主要含气层段和含气量;采用体积法评价了东部5对矿井采动区和采空区的煤系气资源量。基于“O”形圈理论和“防-抗-让”思想,分别优化设计了采动井、采空井的井位、层位和井身结构,构建了采动区、采空区多煤层卸压立体抽采模式并进行了工程示范。结果表明:(1)二_(1)煤层顶板200 m范围内存在四煤组、三煤组、二_(1)煤层顶板60 m范围内的砂岩/泥质砂岩互层段等3处主要含气段。平顶山矿区东部5对矿井的采动区和采空区资源量分别为26.36×10~8 m^(3)和20.00×10~8 m^(3)。(2)采动井最佳井位为0.17~0.28倍采长,且靠近回风巷条带区域;走向上,采动井的间距一般为80~100 m。创建了“大口径、避开岩体变形强烈区、P110梯型扣套管”的采动直井稳孔技术体系和“下行水平轨迹+提高套管强度”的采动L型水平井稳产技术体系,保证了产气通道的畅通性。采空井一般布置在距离回风巷30~50 m的区域,完钻位置一般为二_(1)煤层顶板40~60 m的范围;筛管布置在四煤段顶板至裂隙带底部。(3)建立了“地面采动直井/定向井-采动L型水平井-采空井”联作的卸压立体抽采模式,实现了多气源立体抽采。截至2024年4月30日,累计抽采纯量达5258.8万m^(3),总利用量达到3735.4万m^(3),率先在河南省实现了煤系气产业化开发,示范和引领带动作用显著。

海孜煤矿深部勘查区中组煤层气储层物性特征分析

【目的】煤层气储层的物性特征是进行煤层气开发研究的关键因子。【方法】重点对海孜煤矿深部勘探区域中组煤储层的物性参数进行调查,以对井田内中组煤储层物性特征进行研究。【结果】研究表明,煤层的物性特征适宜开采,其中有机显微组分占优,无机显微组分次之。该煤层含气量多,虽然煤层渗透率相对较小,但符合煤层气开采条件。煤层开采时的吸附作用一般,但有利于煤层气储集和缩短煤层气的开发周期。【结论】研究结果可为该研究区煤层气抽采提供可靠的技术参考。

深煤层气井低伤害完井液分析

深煤层气井的开采通常是采用水敏损害的完井液,但这类完井液存在着严重的伤害问题,对煤层气井的开采效率有着不利影响。在煤层气开采过程中,需要不断向井底注入液体,在注入过程中不可避免地会对煤层造成一定的伤害。从深煤层气井开采过程中出现的问题出发,对煤层气井中常见的完井液进行了分析和讨论,并在此基础上提出了相应的低伤害完井液方案。分析结果表明:低伤害完井液能有效降低深井煤层气开采过程中出现的问题。

中国海油低渗及非常规油气藏储层改造技术进展及展望

中国海上低渗及非常规油气开发存在产能低、投资大、操作费用高、收益较低及单井经济任务重等问题。经过技术攻关,中国海油形成了平台压裂、钻井船压裂和拖轮压裂等海上储层改造作业模式,研发出集海上低渗储层改造液体系、海上控水支撑剂技术、低渗储层压裂管柱设计和海上储层改造监测技术为一体的海上低渗储层改造技术,以及适用于陆上深煤层大规模压裂技术。本文综述了中国海上低渗油气储层改造技术及陆上深煤层大规模压裂技术研究进展,展望了未来储层改造重点发展方向,对推动中国海油低渗及非常规油气开发技术进步有重要指导意义。

近浅埋多层厚硬顶板大采高综放工作面矿压显现规律研究

针对榆神矿区近浅埋多层厚硬顶板条件下,“大周期”来压支架立柱下缩量大、煤柱应力集中系数高、稳定性差等强矿压问题,采用了数值计算、微震和煤体应力监测等技术手段,对覆岩破断运动及工作面来压规律进行了分析研究,结果表明:覆岩破断运动上,多层厚硬顶板较大的“垂向离层空间”和“自下而上”的顺次交替垮落孕育了顶板“高+低层位组合破断”的时空基础;“高低层位顶板组合破断”是“大周期”来压增强的关键诱因;同时,煤柱应力的时空演化受控于多层厚硬顶板的破断垮落。矿压显现上,工作面“大周期”立柱下缩量平均可达945 mm,持续距离12.10 m,并可由2~5次连续强来压组成;巷道煤柱应力集中系数达到1.80~2.30,影响范围为工作面前方126 m至后方471.3 m,具有明显的“高强度、大范围、长上升期”特点。针对该条件下的强矿压防治,分别提出了“弱化低位顶板、优化破断结构”和“弱化高位顶板、改变破断次序”的技术思路,并取得的了较好的应用效果。

临兴地区深部煤储层煤体结构定量表征及影响因素分析

煤体结构的定量表征是煤储层研究的热点问题之一。为精细刻画煤体结构的空间分布,查明其差异分布的主控因素,通过煤岩取心观测,借助地质强度因子对煤体结构进行定量表征,结合不同煤体结构的测井响应,构建了基于测井曲线的煤体结构量化表征模型,预测了煤体结构的空间分布,探讨了沉积、构造、地应力、微观力学性能对煤体结构的影响特征。研究结果表明:密度、伽马、声波、井径测井对煤体结构响应灵敏,利用测井多元回归法可以显著提高煤体结构的判识精度。研究区煤体结构以原生-碎裂结构为主,其次为碎裂结构,发育少量的原生结构和碎裂-碎粒结构。整个研究区的煤体结构分布可以归纳为四大类七个小分区。发育在潮道、砂坪、泥坪、三角洲平原、潟湖环境中的煤层,其厚度逐渐变大,但煤体结构与煤层厚度没有明显的关系。然而,灰分含量与煤体结构的完整性呈正相关,研究不同沉积环境中灰分的变化规律是揭示沉积环境对煤体结构控制特征的关键。煤储层变形程度越大,煤体结构越破碎。原生结构煤、原生-碎裂结构煤、碎裂结构煤的平均构造曲率分别为8.4×10^(-6)、18.7×10^(-6)、25.7×10^(-6)m^(-1)。断层发育区,煤体结构以碎裂结构为主。随着埋深增大,原位地应力增大,煤体结构完整性增强,地应力状态在此基础上进一步分化煤体结构。在浅部伸张-压缩过渡带以碎裂-碎粒结构为主;在深部压缩状态以原生-碎裂结构为主;在深部压缩-伸张过渡带碎裂结构的比例有所增加。煤岩微观力学性能受控于煤基质组分和显微孔隙结构。煤岩无机组分力学强度高于有机组分,且无机组分孔隙孔径比有机组分孔隙孔径小,则无机组分含量越高,煤岩力学强度越高,煤体结构越完整。该研究成果为煤层钻井施工、压裂改造、储层评价提供参考。