Surrounding rock control of gob-side entry driving with narrow coal pillar and roadway side sealing technology in Yangliu Coal Mine

Gob-side entry driving can increase coal recovery ratio, and it is implied in many coal mines. Based on geological condition of 10416 working face tailentry in Yangliu Coal Mine, the surrounding rock deformation characteristics of gob-side entry driving with narrow coal pillar is analysed, reasonable size of coal pillar and reasonable roadway excavation time after mining are achieved. Surrounding rock control technology and effective roadway side sealing technology are proposed and are taken into field practice. The results showed that a safer and more efficient mining of working face can be achieved. In addition, results of this paper also have important theoretical significance and valuable reference for surrounding rock control technology of gob-side entry driving with narrow coal pillar under special geological condition.

Can sealing of rock hosting a repository for highly radioactive waste be relied on?

Multibarrier systems are commonly proposed for effective isolation of highly radioactive waste (HLW). Presently considered concepts take the host rock as a barrier claiming it to retard migration of possibly released radionuclides from HLW containers to the biosphere. This capacity is small unless water-bearing fracture zones intersecting the blasted waste-containing tunnels and excavation-disturbance zones around them can be sealed by grouting and construction of bulkheads, but this is effective only for a very limited period of time as explained in the paper. The disturbed zones thence make the entire repository serve as a continuous hydraulic conductor causing quick transport of released radionuclides up to the biosphere. The dilemma can be solved by accepting the shortcircuiting function of the disturbed zones along the tunnels on the condition that totally tight waste containers be used. Deep holes bored in the site selection phase through the forthcoming repository can be effective pathways for radionuclides unless they are properly sealed. They are small-scale equivalents of tunnels but do not have any excavation damage and can be effectively sealed by using clay and concrete of new types. Applying this principle to very deep boreholes with a diameter of a few decimeters would make it possible to safely store slim, tight HLW canisters for any period of time.

Thermo-hydro-mechanical behavior of clay rock for deep geological disposal of high-level radioactive waste

In the context of deep geological disposal of radioactive waste in clay formations, the thermo-hydro- mechanical （THM） behavior of the indurated Callovo-Oxfordian and Opalinus clay rocks has been extensively investigated in our laboratory under repository relevant conditions： （1） rock stress covering the range from the lithostatic state to redistributed levels after excavation; （2） variation of the humidity in the openings due to ventilation as well as hydraulic drained and undrained boundary conditions; （3） gas generation from corrosion of metallic components within repositories; and （4） thermal loading from high-level radioactive waste up to the designed maximum temperature of 90 ~C and even beyond to 150 ~C, Various important aspects concerning the long-term barrier functions of the clay host rocks have been studied： （1） fundamental concept for effective stress in the porous clay-water system; （2） stress- driven deformation and damage as well as resulting permeability changes; （3） moisture influences on mechanical properties; （4） self-sealing of fractures under mechanical load and swelling]slaking of clay minerals upon water uptake; （5） gas migration in fractured and resealed claystones; and （6） thermal impact on the hydro-mechanical behavior and properties, Major findings from the investigations are summarized in this paper,

Sealing of fractures in claystone

The sealing behavior of fractures in clay rocks for deep disposal of radioactive waste has been comprehensively investigated at the GRS laboratory. Various sealing experiments were performed on strongly cracked samples of different sizes from the Callovo-Oxfordian argillite and the Opalinus clay under rel- evant repository conditions. The fractured samples were compacted and flowed through with gas or synthetic pore-water under confining stresses up to 18 MPa and elevated temperatures from 20 ℃ to 90℃. Sealing of fractures was quantified by measurements of their closure and permeability. Under the applied thermo-hydro-mechanical （THM） conditions, significant fracture closure and permeability decrease to very low levels of 10^-19 to 10^-21 m^2 were observed within time periods of months to years. The properties of the resealed claystones are comparable with those of the intact rock mass. All test results suggest high sealing potentials of the studied claystones.

Experimental Examination of Fluid Flow in Fractured Carbon Storage Sealing Formations

This report describes a series of experiments where CO2-saturated-brine flow through fractured seal rocks from three sites within the continental United States that are being considered, or are actively being used, for CCUS pilot studies were examined. The experiments were performed over multiple weeks by injecting CO2 saturated brine through fractured samples, and were scanned with a computed tomography scanner at regular intervals over the course of the experiment while kept at representative reservoir pressures. The goal was to evaluate the change in the fracture flow that would result from a CO2 leakage event so that accurate relationships can be implemented in numerical models to assess risk. Of the three different formations studied in this series of fractured seal formation CO2-saturated-brine flow through experiments, only one formation had a reaction that was greater than the noise in the system. Reactions within the Tuscaloosa claystone sample appeared to reduce the transmissivity of the fracture slightly over the 39 day experiment. The change in the geometry of the fracture was not great enough to view with the medical CT images that were captured during the experiment. All other tests showed a minimal amount of change in the fracture and fracture flow properties.

Thermal effects on clay rocks for deep disposal of high-level radioactive waste

Thermal effects on the Callovo-Oxfordian and Opalinus clay rocks for hosting high-level radioactive waste were comprehensively investigated with laboratory and in situ experiments under repository relevant conditions:(1) stresses covering the range from the initial lithostatic state to redistributed levels after excavation,(2) hydraulic drained and undrained boundaries, and(3) heating from ambient temperature up to 90℃-120℃ and a subsequent cooling phase. The laboratory experiments were performed on normal-sized and large hollow cylindrical samples in various respects of thermal expansion and contraction, thermally-induced pore water pressure, temperature influences on deformation and strength, thermal impacts on swelling, fracture sealing and permeability. The laboratory results obtained from the samples are consistent with the in situ observations during heating experiments in the underground research laboratories at Bure and Mont-Terri. Even though the claystones showed significant responses to thermal loading, no negative effects on their favorable barrier properties were observed.

新疆东天山造山带西段海豹滩岩浆硫化物铜镍矿床多期次侵入与成矿关系

新疆东天山地区造山带中发育大量与镁铁-超镁铁岩有关的铜镍矿,本次研究的海豹滩镁铁-超镁铁岩体就是其中之一。与其他区域形成的铜镍矿大地构造背景不同,东天山铜镍矿均产于中亚造山带南部的岛弧构造环境,通过本次研究识别出海豹滩镁铁-超镁铁质杂岩体的不同侵入期次,圈出岩体范围,大致查明不同含矿期次岩体的规模、形态、产状等,突破了以往对该类岩体含矿性差的认识,为该区寻找同类型矿床提供新的勘查思路和方向。

自控型粒子冲击钻井系统研制与现场试验

我国油气资源勘探开发中常规钻井技术在钻遇石英砂岩、燧石、高硅质砂岩、黄铁矿和火成岩等难钻地层时,面临“钻速慢、进尺短”的钻井瓶颈。为此,基于粒子高频冲击破岩原理,借鉴高层建筑混凝土配浆-注浆和常压混凝土储存方法,设计了双活塞换向机构、防粒子沉淀物料罐、动态回收储存装置、高效分离装置和2D/3D自动化监控系统,研制了1套自控型粒子冲击钻井系统,并在江沙X1井对其进行了现场试验。试验结果表明:该系统运行稳定可靠,粒子回收率达到98.7%,平均机械钻速15 m/h,与邻井同地层螺杆配PDC钻头钻进方式相比平均机械钻速提高1.52倍。所得结论可为深层及复杂坚硬地层钻井提速提供技术支撑。

氦气资源的盖层特征探究--以塔里木盆地为例

良好的盖层封盖条件是氦气资源得到保护的关键,在氦气资源潜力评估中有着重要的意义。目前对于氦气资源盖层特征的研究仍处于空白阶段,笔者等对盖层的封盖机理及宏观-微观特征与氦气封盖效果之间的关系进行了探究,认为氦气在地层中保存的封盖机理主要包括物性、压力、浓度三重封闭。盖层对于氦气的封盖效果受一系列微观特征(孔隙度、渗透率、突破压力、中值半径)与宏观特征(岩性、厚度、成岩作用、连续性、构造作用)影响,含氦气藏载体气类型的不同也会使盖层对于氦气的封闭能力产生差异。基于笔者等归纳出的盖层特征与氦气封盖效果的关系,对塔里木盆地内具有一定的生氦潜力的和田河区块、雅克拉区块、古城区块的氦气资源盖层条件进行评估,评估结果对应实际勘探中含氦气藏的分布情况。综合分析塔里木盆地含氦气藏盖层特征,发现常规评价油气藏封盖条件的方法并不完全适用于氦气资源盖层条件的评估,精准化分析含氦气藏盖层条件的方法仍需进一步探索。

含水层地下储氢圈闭盖层密封性评价——以Y含水圈闭为例

结合国内外含水层储气库建设中影响盖层密封性的关键指标,构建含水层地下储氢圈闭盖层密封性评价体系,分析得出适合中国含水层盖层密封性评价方法——层次分析法,并运用层次分析法和多因子综合评价法相结合的方法定性分析了华东某油气区内的Y含水圈闭盖层静态密封能力。结果表明:(1)盖层静态密封性评价体系中直接盖层厚度、岩石脆性等传统评价因素占比较高,其次为地层水的酸碱性、矿物类型等特殊因素。(2)基于层次分析法和多因子综合评价法分析可知,Y含水圈闭的盖层在静态条件下具备一定的封气能力,能够在一定程度上封隔储集层中的氢气,避免氢气逸散。研究表明,该评价体系可为初步评价含水层地下储氢盖层密封性提供一定的指导与理论依据。

储气库运行上限压力的确定方法及在板中北储气库的应用

大港油田板中北储气库位于板桥断层上升盘,为断层切割的半背斜构造,属于断块型储气库,断层和盖层的承压能力决定了储气库运行的上限压力。针对缺乏考虑力学完整性的储气库上限压力的研究现状,从地质力学角度出发,综合三维地震解释成果、XMAC测井地应力解释成果、岩石力学测试等资料,基于岩石脆性破裂理论对研究区盖层的水力封闭能力和断层的稳定性进行了评价,以确定考虑力学完整性的储气库安全运行上限压力。结果表明:板中北储气库盖层水力封闭能力上限为39.30 MPa,断层稳定性薄弱点位于2条断层的交叉位置,最小活化压力为30.57 MPa;综合盖层水力封闭能力上限和断层稳定性可知,板中北储气库运行上限压力为30.57 MPa,而设计运行上限压力为30.50 MPa,设计较为合理。研究成果对于储气库上限压力的设计具有指导意义。

试样内置传感器密封引出装置设计与实现

针对岩石力学领域高温高压环境中内置传感器引出和保护问题,设计了一套传感器密封引出装置。该装置主要由垫块、限位座、压块、顶盖、套筒和环形卡箍等组成。验证试验结果表明,该装置实现了试样内部温度等参数的实时测量,保护了传感器及导线不受高温高压环境侵蚀,提高了大尺寸试样力学试验的稳定性及测试数据的准确性和可靠性。

冀中坳陷文安斜坡顺向及反向断层侧向封闭性差异分析

为揭示含油气盆地中断层对油气成藏与分布的控制作用,以冀中坳陷文安斜坡为研究靶区,从顺向及反向断层控制油气富集部位及规模的差异出发,综合滑入断裂带内围岩成分及断裂带内部结构的不对称性等特征,分析不同配置类型断层的泥质含量与风险断距的差异及其对侧向封闭性的控制作用。研究结果表明:(1)在地层沉积环境相近的情况下,断层断距小于单层砂泥岩厚度和断层断距为单层砂泥岩层厚度的奇数倍时,反向断层目的点的泥质成分明显高于顺向断层;断层断距为单层砂泥岩层厚度的偶数倍时,反向断层目的点的泥质成分与顺向断层相等;在文安斜坡沙一段内反向断层的断层岩泥质含量平均值较顺向断层高6%。(2)为封闭较厚的上盘破碎带,顺向断层形成封闭时所需的临界断距明显大于反向断层,文安斜坡顺向断层风险断距的平均值约为反向断层的1.8倍。(3)理论与实例分析共同证实,反向断层更容易形成侧向封闭,这与油气主要富集在反向断层附近相吻合,但在文安斜坡内断层断距约为单层砂泥岩层厚度的偶数倍,断层岩泥质含量近似相等。这可能是导致文安斜坡顺、反向断层封闭烃柱高度近于一致的主要原因。上述结论可为油气田勘探开发提供有利的指导。

地下水封洞库洞室智能动态设计方法研究与实践

总结分析地下水封洞库工程地质特征,综合考虑工程地质勘察与监测信息等已知条件与设计目标、约束条件,提出考虑洞室断面收缩、岩体结构模型与力学参数同步反馈修正的地下水封洞库洞室智能动态设计方法.该方法在初步设计阶段,应用反映场地岩体结构等效特征的岩体离散介质模型构建技术,结合不同模型条件下岩体、结构面力学参数综合确定方法与围岩稳定性、水封性评价指标,并充分利用进化神经网络算法等智能优化方法进行洞室设计;在施工图设计与施工阶段,应用反映开挖区段岩体结构真实特征的岩体离散介质模型动态反馈修正数值模型,并基于多场监测数据开展岩体与结构面力学参数智能反演以进行洞室设计,同时提出洞室断面收缩调整策略.选取浙江某地下水封洞库作为典型案例,分别从两阶段介绍设计方法应用过程与成效,结果表明该方法具有较高可行性与可靠性.

二氧化碳气动破岩封孔方法及力学模型研究

为完善新型二氧化碳气动破岩技术,对其封孔方法及力学模型展开研究,通过依托岩方清理工程,采用不同封孔材料进行气动破岩试验对比,最终得出最优的封孔方案,同时根据岩石的强度理论建立孔内压力与冲孔强度、拉伸破坏强度以及剪切破坏强度的关系,并给出实现理想破岩效果的压力关系条件,为施工人员计算破岩参数提供一个切实可行的方向。最终得到以下结论:①快干水泥和水的混合砂浆可满足封孔强度需要,铺碎石垫层可有效防止冲孔;②满足冲孔压力>破岩峰值压力>剪切破坏孔压≥拉伸破坏孔压时破岩效果最为理想。可见该种封孔方法对二氧化碳气动破岩效果得到增强。

苏北盆地刘庄储气库密封性评价研究

对储气库密闭性进行评价是其建设与运行的重要任务,苏北盆地刘庄储气库属于断层控制的断鼻构造边水储气库,通过岩石力学实验与理论分析相结合的方法,从盖层和断层2个方面综合评价刘庄储气库的密封性;从宏观、微观和力学方面评价盖层密封强度;从侧向和垂向评价断层密封能力。研究表明:阜宁组二段一砂组与阜宁组三段二砂组泥岩为研究区内的巨厚盖层,该盖层全区分布且区域分布稳定,岩性组合优越,其黏土矿物含量在30%以上,储气库盖层杨氏模量和脆性指数整体相对较低,杨氏模量普遍小于20 GPa,脆性指数普遍小于45%,黏土矿物组成以伊蒙混层矿物为主,遇水易膨胀,盖层具有良好的油气封堵性。刘①断层断距和倾角均较大,结合研究区内断层面正压力法和上覆地层埋深的经验得出控藏断层垂向密封;砂泥对接定性方法和泥岩涂抹因子定量方法均证明刘庄控藏断层具有较强的侧向封堵性。

琼东南盆地崖城13-A构造潜山天然气成藏条件与成藏模式

琼东南盆地潜山油气藏勘探形势复杂,近年在陵南低凸起、松南低凸起均有勘探失利。为进一步剖析琼东南盆地成藏条件与成藏模式,以YC13-A-A井为主要研究对象,通过包裹体分析、薄片观察、盆地模拟、地震资料和测录井资料,对YC13-A构造成藏条件与成藏模式进行分析。结果表明:YC13-A构造天然气为高成熟-过成熟天然气,天然气来源于崖南凹陷以及莺歌海盆地古近系崖城组烃源岩。中生界潜山顶部风化剥蚀以及内幕形成的孔隙和裂缝作为储层,构造脊、砂体和断层为气体的运移提供了良好的输导条件。受到古潜山上覆巨厚泥岩以及泥岩快速沉降的影响,导致欠压实形成弱超压,从而提供了良好的封盖条件。各成藏控制因素的耦合,为天然气成藏提供了有利成藏条件。YC13-A构造主要由西侧莺歌海盆地、东侧崖南凹陷古近系崖城组烃源岩供烃,供烃动力充足,通过断层、构造脊、砂体向潜山风化壳直接充注,具有双凹供烃、双类输导、双重封堵、晚期成藏的成藏特征。

辽宁锦州南部应力场特征及其对地下水封油库稳定性影响分析

区域应力场是构造运动的驱动力,是地壳应力研究中的重要内容,现今构造应力与地质资源的储存、开采及基础建设工程的设计实施具有密切联系。文章对锦州南部地区9个钻孔进行了翔实的现场水压致裂原地应力测试,并依据强度与应力指标,对应力状态和岩爆风险分别进行了评价与预测。结果表明,测区最大和最小水平主应力量值分别为3.92~17.33 MPa和3.00~8.93 MPa,垂直应力值为0.80~4.58 MPa,最大水平主应力方向在N33°~88°E之间,优势方位为N72°E;地应力评价结果显示为低~很低应力状态,工程区地下厂房附近无岩爆风险。

源断盖配置油气聚集时期预测方法及其应用

为确定含油气盆地油源断裂处油气富集程度,在烃源岩、断裂和盖层配置及油气聚集机制研究基础上,通过油源断裂活动期、烃源岩排烃期和泥岩盖层形成期,建立了一套源断盖配置下的油气聚集期的预测方法,并利用其预测渤海湾盆地歧口凹陷沙一下亚段内油气聚集时期。结果表明,沙三段烃源岩排烃、南大港断裂开启和沙一中亚段区域性泥岩盖层形成,均为馆陶组—明化镇组沉积期,三者配置关系良好且时期较长,有利于沙三段烃源岩排出的油气在沙一下亚段内聚集成藏,预测结果与勘探成果吻合。

地下水封洞库施工期洞室围岩变形松弛典型特征与规律

基于地下水封洞库工程特征与典型洞库工程实例,整理分析大量洞室围岩内部变形、表层变形、波速与锚杆应力等监测数据.结果表明:预埋的多点位移计测点位移主要为0.5~3.0 mm,收敛位移监测值主要为4~8 mm,拱顶沉降监测值主要为3~6 mm,围岩时效变形不明显;围岩变形与爆破开挖有关,当掌子面或后续台阶开挖面接近监测断面时,变形出现陡增;围岩质量越差,开挖面空间效应越不明显.提出洞室围岩损失位移确定方法,发现损失位移占最终收敛位移50%~60%;基于波速变化率提出围岩松弛程度评价指标,发现围岩最大松弛程度约为0.47,松弛深度为1.5 m;洞室围岩锚杆受力普遍较小,锚杆拉应力与围岩变形基本同步变化.