Characteristics and Evaluation of the High-Quality Source Rocks of Cretaceous Continental Shale Oil in Tonghua Basin, China

The presence of shale oil in the Cretaceous Hengtongshan Formation in the Tonghua Basin, drilled by the well TD-01, has been discussed in this geological investigation for the first time. To evaluate the high-quality source rocks of Cretaceous continental shale oil, the distribution characteristics and the evolution of the ancient environment, samples of shale were systematically analyzed in terms of sedimentary facies, organic geochemistry, and organic carbon isotopic composition. The results demonstrate that a TOC value of 1.5% represents the lower-limit TOC value of the high-quality source rocks. Source rocks have an aggregate thickness of 211 m and contain abundant organic matter, with TOC values of 2.69% on average and a maximum value over 5.44%. The original hydrocarbon-generative potential value(S_1+S_2) is between 0.18 mg/g and 6.13 mg/g, and the Ro is between 0.97% and 1.40%. The thermal maturation of the source rocks is relatively mature to highly mature. The δ^(13)C value range is between -34.75‰ and -26.53‰. The ratio of saturated hydrocarbons to aromatic hydrocarbons is 1.55 to 5.24, with an average of 2.85, which is greater than 1.6. The organic types are mainly type Ⅱ_1, followed by type Ⅰ. The organic carbon source was C_3 plants and hydrophytes. The paleoclimate of the Hengtongshan Formation can be characterized as hot and dry to humid, and these conditions were conducive to the development of high-quality source rocks. A favorable paleoenvironment and abundant organic carbon sources provide a solid hydrocarbon generation base for the formation and accumulation of oil and gas in the shale of the Tonghua Basin.

Growth behavior and resource potential evaluation of gas hydrate in core fractures in Qilian Mountain permafrost area, Qinghai-Tibet Plateau

The Qilian Mountain permafrost area located in the northern of Qinghai-Tibet Plateau is a favorable place for natural gas hydrate formation and enrichment,due to its well-developed fractures and abundant gas sources.Understanding the formation and distribution of multi-component gas hydrates in fractures is crucial in accurately evaluating the hydrate reservoir resources in this area.The hydrate formation experiments were carried out using the core samples drilled from hydrate-bearing sediments in Qilian Mountain permafrost area and the multi-component gas with similar composition to natural gas hydrates in Qilian Mountain permafrost area.The formation and distribution characteristics of multi-component gas hydrates in core samples were observed in situ by X-ray Computed Tomography(X-CT)under high pressure and low temperature conditions.Results show that hydrates are mainly formed and distributed in the fractures with good connectivity.The ratios of volume of hydrates formed in fractures to the volume of fractures are about 96.8%and 60.67%in two different core samples.This indicates that the fracture surface may act as a favorable reaction site for hydrate formation in core samples.Based on the field geological data and the experimental results,it is preliminarily estimated that the inventory of methane stored in the fractured gas hydrate in Qilian Mountain permafrost area is about 8.67×1013 m3,with a resource abundance of 8.67×108 m3/km2.This study demonstrates the great resource potential of fractured gas hydrate and also provides a new way to further understand the prospect of natural gas hydrate and other oil and gas resources in Qilian Mountain permafrost area.

Rapid intelligent evaluation method and technology for determining engineering rock mass quality

The evaluation of engineering rock mass quality is fundamental work for the engineering activities of rock mass.The increasing scale of rock mass engineering necessitates higher intelligence,timeliness,and accuracy in engineering rock mass quality evaluation.As the core aspects of engineering rock mass quality evaluation,the structural characteristics,mechanical characteristics,and quality classification of rock mass have been innovated in recent years.The non-contact measurement technology for rock mass structure and rapid interpretation of rock mass structure information enables the intelligent extraction and analysis of rock mass structure parameters.The modular backpack laboratory system of rock mechanics provides an effective means to acquire rock mechanical parameters on-site conveniently.The theory of statistical mechanics of rock mass(SMRM)integrates various factors such as the rock mass properties,geological environment,and engineering disturbance,providing a theoretical basis for accurately evaluating the weakening and anisotropy of rock mass.The cloud computing platform established based on SMRM can provide technical support for the rapid calculation of rock mass parameters and instant evaluation of the rock mass quality.The development of intelligent evaluation method and technology is altering the conventional technical state of qualitative and semi-quantitative evaluation of engineering rock mass quality,supporting the realization of rock mass engineering construction with intellectualization and informatization.

基于BWO-RF模型的岩体质量评价方法

岩体质量分级是地下工程初期设计和施工的基础。为了更加高效准确地开展岩体质量评价,提出了一种基于白鲸优化(BWO)随机森林的岩体质量评价模型——BWO-RF模型,同时构建了麻雀搜索算法优化随机森林(SSA-RF)、粒子群优化随机森林(PSO-RF)和未优化随机森林(RF)的岩体质量评价模型进行对比。在模型构建前,建立了包含131组工程实例数据的数据库,运用该数据库最终完成了4种模型的训练和测试。基于模型测试结果,采用准确率、查准率、召回率、F1值和AUC值5个评价指标对模型进行对比优选。研究结果表明:BWO-RF模型各项评价指标均优于其余3种模型,具有更优的评价性能;经过工程实例验证,本研究所提出的BWO-RF模型预测准确率达90%,可为实际工程建设提供参考依据,具备实际工程应用价值。

基于加权隶属度矩阵的岩体质量优化分级及支护研究

巷道围岩质量分级是巷道围岩稳定性分析、合理支护设计与施工的基础。提高分级结果的准确性,是提升支护效果和巷道围岩稳定性的关键途径。以RMR法为基础,以某一测点的分级因素指标值为例,构建RMR法各分级指标的隶属度矩阵,再结合熵值法确定分级指标的权重,得到加权隶属度矩阵,构造优化后的评分公式,进行指标优化评分和围岩质量分级,然后根据围岩质量分级结果及松动圈监测结果设计支护参数,利用FLAC3D进行模拟计算以巷道围岩塑性区体积和顶底板收敛量为评价指标,研究优化前后的支护效果。研究结果表明:经过优化后的指标评分和围岩等级更加准确,巷道支护参数设计更加合理,数值模拟结果显示其能有效地提升围岩的稳定性,并将优化后的支护设计参数应用于工程,取得了良好的效果。研究成果可有效解决巷道围岩分级因素指标值位于分级边界或分级跨度大的问题,为矿山岩体质量分级与支护设计提供参考。

基于优化组合赋权的可拓学磷矿山岩体质量评价

为解决岩体质量评价相邻等级之间指标参数模糊不确定性问题,引入可拓学理论,提出基于优化组合赋权的可拓学岩体质量分级模型,对昆阳二矿磷矿山地下开采的岩石进行质量评价。首先,根据矿山地质特征选取岩石单轴饱和抗压强度(Rc)、岩石质量指标(RQD)、节理间距(Jd)、结构面条件(Jf)、地下水状态(W)和地应力影响系数(Z)6个影响指标,将每个指标划分为5个等级;然后通过改进的层次分析法和熵权法分别确定指标的主观和客观权重,引入矩估计法对主客观权重进行优化组合;最后应用修正的RMR法和Q系统法对岩体质量进行评价,将分级结果与基于优化组合赋权的可拓学岩体质量分级结果进行比较。研究表明:5个待评价岩体中,除上矿体N3的模型分级结果与修正RMR法存在差异之外,其余岩体的分级结果与修正RMR法相同,使用Q系统法的评价结果整体偏低。此外,该模型可得出岩体质量等级偏向于相邻等级的程度,分级结果符合昆阳二矿磷矿山生产勘探地质报告岩体质量范围,比修正RMR法和Q系统法更加准确,验证了本文方法的可靠性,为地下矿山开采提供了技术支撑。

基于数字钻探与多尺度模型融合的隧道岩体完整性自动解译技术研究及应用

在多岩性与多指标钻探数据收集的基础上,综合考虑解译精度与预报效果,借助机器学习工具,提出一种基于数字钻探与多尺度模型融合的隧道岩体完整性自动解译技术。首先,对原始钻探数据有针对性的进行降噪与等距分割(0.5,1,2 m)等预处理,形成多尺度、高质量机器学习数据集;然后,进行模型参数自动寻优、训练、评估与可解释性等操作,验证模型的准确性与可靠性;最后,采用加权平均的方法进行多尺度模型解译结果的融合,以增强该技术的工程实用效果。为方便实际工程应用,以上述技术为核心开发轻量化数字钻探智能解译平台,经多条灰岩与砂岩隧道应用结果表明:对比地质雷达与常规钻探解译,多尺度模型融合解译在解译效率、预测效果等方面总体表现优异,可为隧道施工的开挖与支护提供可靠的岩体完整性信息。

模糊综合评判法在蚀变岩型金矿床岩体质量评价中的应用

对于工程岩体的质量评价,不论是目前常用的Q系统分类法、地质力学RMR分类法还是国标BQ分类法,都存在一定的局限性。为了得到一个更加准确,更贴近真实岩体质量的评价结果,引用模糊综合评判法进行岩体的稳定性评价。以焦家金矿蚀变岩型金矿床为例,对不同蚀变类型的岩性稳定性进行模糊综合评判。结果表明焦家矿区调查区域为-190中段至-330中段之间,除-270以上黄铁绢英岩化花岗岩为Ⅲ类稳定性一般的岩体外,其余蚀变花岗岩的岩体质量均为Ⅳ类较差和Ⅴ类很差的岩体。品位最高的黄铁绢英岩化碎裂岩岩体稳定性最差,在施工到相应岩性的采场时特别要注意做好采场的相关支护工作。

岩矿鉴定和电子探针在矿物药金礞石鉴定及质量评价中的应用

采用薄片鉴定和电子探针测试对来自个6个不同地区的金礞石进行鉴别和质量评价。首先通过薄片鉴定初步确定金礞石样品的主要成分及伴生矿物,进一步利用电子探针技术对金礞石的主要成分、伴生矿物进行半定量分析,再利用电子探针波谱定量分析研究金礞石中Hg、Pb、S、Ge等元素的赋存状态,在这些技术综合鉴定的基础上,对各地的金礞石进行质量评价。研究表明,岩矿鉴定及电子探针技术的结合用于鉴定金礞石矿物药是一种极为有效、可行的办法,具有原位、无损的优点。

某露天矿边坡稳定性及优化研究

文章以广西某露天矿山高陡边坡为研究对象,通过现场调查及室内岩石力学试验,结合矿山地质资料,采用RQD和RMR方法进行岩体质量评价,采用RocLab软件确定岩体力学参数,采用极限平衡法并基于Slide软件进行边坡稳定性及优化研究。研究结果表明:使用推荐的优化参数可使现状边坡的安全性和经济性之间达到最佳平衡,采场边坡参数的选取可作为同类矿山参考之依据。

基于博弈论的密切值法在水电站岩体质量评价中的应用

针对传统岩体质量评价方法所存在的缺陷,将博弈论和密切值法相结合,用于水电站岩体质量评价。根据水电站岩体质量的分级标准和影响因素,运用密切值法建立岩体质量评价模型,依托博弈论的指标赋权法明确对应指标权重,最后根据密切值的分析结果对岩体质量进行评价,并结合实例进行对比分析。研究结果表明:基于博弈论的组合赋权法确定的组合权重不仅科学合理而且有效克服了密切值法权重计算的主观性;另一方面,采用密切值评价方法对岩体质量评价获得的结果与变权欧式距离评价方法结果比较,结果完全一致,与可拓学理论、未确知测度理论评价结果比较也基本相吻合,具有一定的工程实用价值,可以运用于水电站地下洞室岩体质量评价中。

Multiscale hierarchical analysis of rock mass and prediction of its mechanical and hydraulic properties

Engineering geological and hydro-geological characteristics of foundation rock and surrounding rock mass are the main factors that affect the stability of underground engineering. This paper presents the concept of multiscale hierarchical digital rock mass models to describe the rock mass, including its structures in different scales and corresponding scale dependence. Four scales including regional scale,engineering scale, laboratory scale and microscale are determined, and the corresponding scaledependent geological structures and their characterization methods are provided. Image analysis and processing method, geostatistics and Monte Carlo simulation technique are used to establish the multiscale hierarchical digital rock mass models, in which the main micro-and macro-structures of rock mass in different geological units and scales are reflected and connected. A computer code is developed for numerically analyzing the strength, fracture behavior and hydraulic conductivity of rock mass using the multiscale hierarchical digital models. Using the models and methods provided in this paper, the geological information of rock mass in different geological units and scales can be considered sufficiently,and the influence of downscale characteristics(such as meso-scale) on the upscale characteristics(such as engineering scale) can be calculated by considering the discrete geological structures in the downscale model as equivalent continuous media in the upscale model. Thus the mechanical and hydraulic properties of rock mass may be evaluated rationally and precisely. The multiscale hierarchical digital rock mass models and the corresponding methods proposed in this paper provide a unified and simple solution for determining the mechanical and hydraulic properties of rock mass in different scales.

Multiscale Hierarchical Digital Rock Mass Models and Numerical Testing on Mechanical and Hydaulic Properties of Rock Mass

Underground space utilization and exploration is an irreversible trend for promoting sustainable development especially in megacities.Geotechnical engineering safety is always one of the most important issues in all phases,including planning,design, construction and operation,of the underground project.Engineering geological and hydro-geological characteristics of the foundation rock mass

三峡库区碎屑岩岸坡岩体钻孔成像特征及质量评价方法研究

三峡库区地层岩性复杂,岩体赋存环境差异性明显,影响岩体质量的因素较多,在周期性水力作用下碎屑岩岸坡岩体已形成独有的结构特征,对岸坡的长期安全与稳定性不利。在调查统计库区碎屑岩特征的基础上,开展了大量原位钻孔测试,分类总结了库区碎屑岩岸坡岩体典型的钻孔成像特点,详细分析了不同裂隙特征岩体钻孔岩芯的块体尺度与断裂特征。基于岩芯断裂特征与钻孔成像裂隙特征的对应关系,建立了岩体质量评价指标RQ,并与传统的岩石质量指标RQD和声波测试结果进行对比,验证了该指标的适用性。研究结果表明,三峡库区碎屑岩库岸影响岩体质量的钻孔成像特征主要有沉积分层结构、软弱充填结构、原生破碎带及钻孔轴向裂隙切割4种结构类型,RQ考虑了不同结构类型划分块体的长度区间,量化了不同区间岩体占比对岩体质量评价值的贡献,基于岩体内部结构特征可以更客观地评价碎屑岩岸坡的岩体质量,避免了钻孔取芯过程机械损伤引入的误差。研究成果有助于分析三峡库区碎屑岩岸坡岩体的质量分布特征,并为岩体质量演化的量化描述提供理论方法与技术思路。

耦合多源勘察信息的水工岩体完整性智能评价方法

岩体完整性是评价水工岩体质量等级的重要参数,传统方法往往采用的单一指标难以全面反映结构面、地下水、卸荷等地质条件对评判结果的综合影响。提出了一种耦合多源勘察信息的水工岩体完整性智能评价方法。首先利用合成少数类过采样算法对勘察信息数据进行均衡处理,改善数据集结构;进而采用随机森林算法分别对原始岩体完整性数据和预处理后的数据进行预测,结合实际工程数据进行有效性及适用性验证,并针对影响岩体完整性的不同因素对预测结果进行了讨论分析。结果表明,所提出的方法对数据集的均衡处理可有效改善少数类岩体样本完整性的评价准确率,通过耦合并挖掘不同完整性指标中的深层信息,实现岩体完整性的智能评价,为进一步辅助岩体质量评价提供新的方法。

基于综合权重—模糊物元法的岩溶地区隧道围岩质量评价

为科学、准确地对岩溶隧道进行围岩质量分级评价,提出了基于综合权重—模糊物元法的岩溶地区隧道围岩质量评价方法。根据实测数据,采用CRITIC法确定影响岩溶地区隧道围岩质量指标的客观权重,采用改进的层次分析法确定其主观权重,并利用组合赋权计算得出各项指标的综合权重,最终根据模糊物元理论确定围岩的分级。为验证该方法的有效性,将其应用于岩溶地区腾讯七星数据中心隧道群围岩质量评价中。研究结果表明:基于综合权重—模糊物元法的岩溶地区隧道围岩质量评价判定结果与实际现场分级情况吻合较好,说明该方法能够实现对岩溶隧道围岩质量的综合判定。

地下工程岩体质量评判的三支决策方法

为了提高地下工程评判效率,利用三支决策的方法对地下工程岩体稳定性进行质量评判.首先利用模糊相对比较决策对地下工程岩体进行总体排序;其次通过贝叶斯决策规则做出期望损失最小的决策;然后用三支决策对地下工程岩体质量评判,得到分级结果;最后将该模型运用到实际工程中,验证该评判模型的科学性和可行性.为以后计算机在岩体质量评判中更为深入的应用打好理论基础.

松辽盆地南部长岭断陷蚀变火山碎屑岩储层质量评价

火山碎屑岩普遍存在蚀变现象,蚀变直接影响火山碎屑岩储层储集性能的定量表征和准确评价。为此,以松辽盆地南部长岭断陷下白垩统火石岭组火山碎屑岩为研究对象,采用岩心观察、薄片鉴定和扫描电镜等手段对储层岩性进行识别,分析储层微观特征,明确储层主要蚀变类型,通过测井曲线建立岩性识别交会图版,并建立蚀变指数计算方法,定量识别储层蚀变程度,再结合储层质量因子对储层质量进行综合评价和分类。研究结果表明:①研究区火山碎屑岩主要蚀变类型包括玻屑脱玻化蚀变、长石溶蚀蚀变和黏土化蚀变3类,其中黏土化蚀变对储层的测井响应和识别影响很大,脱玻化蚀变和溶蚀蚀变对增加孔隙起到了建设性作用,黏土化蚀变既可以形成黏土矿物晶间孔,也可以堵塞原有孔隙,其作用随蚀变程度的增加,孔隙度呈现先增加再减小的变化趋势。②火山碎屑岩储层的测井响应受蚀变影响明显,其中自然伽马、电阻率、声波时差、密度、补偿中子和元素测井曲线为黏土化蚀变敏感曲线,通过常规曲线和元素测井确定蚀变指数,可以定量识别储层蚀变程度。③研究区火山碎屑岩储层可分为3类,其中Ⅰ类储层以粗粒晶屑岩屑凝灰岩为主,钠长石次生溶蚀作用较强,黏土化蚀变程度较弱,蚀变指数低;Ⅱ类储层以中粒晶屑岩屑凝灰岩为主,黏土化蚀变程度中等,蚀变指数较低;Ⅲ类储层包含细粒含泥凝灰岩和极细粒泥质凝灰岩,黏土化蚀变程度强,蚀变指数高。

藏东南铁路弃渣场不同土壤重构模式土壤质量评价

为揭示不同土壤重构模式对土壤性质及植物生长状况影响的差异,寻找适合藏东南铁路弃渣场生态修复需求的土壤重构模式,本研究在色季拉山隧道口弃渣场设置不同材料及覆土厚度的土壤重构模式,并选取当地优势草本高羊茅(Festuca arundinacea)进行种植试验。通过研究高羊茅的生物学性状及重构土体的理化性质,分析不同土壤重构模式下弃渣场的生态恢复效果。结果表明:不同重构材料对土壤理化性质及高羊茅生长状况均产生显著影响(P<0.05),覆土厚度与高羊茅生物量呈正相关关系。添加30%生物堆肥的基质,根际土容重较剥离表土基质降低了21.4%,全氮含量提高了113%,全磷含量增加了90%,有机质含量提高了约3.5倍,高羊茅株高、地上生物量明显提高。添加30%弃渣石的基质,较剥离表土基质碳、磷含量提升,未明显促进高羊茅生长。研究表明,弃渣石和生物堆肥均可作为表土替代材料,覆土厚度增加有利于植物生长,生物堆肥+表土60 cm处理的重构效果最佳。本研究结果为藏东南铁路弃渣场土地复垦与植被恢复提供了科学依据。

某露天矿山破碎岩体高陡岩质边坡稳定性的数值模拟研究

露天矿山高陡岩质边坡的稳定性严重威胁着矿山的安全生产,尤其是对于地质条件复杂、地层分布不均匀且节理裂隙发育的变质岩和侵入岩形成的破碎带发育的边坡更是如此。为确保某矿山的安全生产,通过力学试验的方法确定了岩石的物理力学性质,通过Hoek-Brown强度准则将岩石的力学性质转化为岩体的力学性质并对岩体的质量进行了评价。同时,采用FLAC3D数值模拟技术将高陡岩质边坡进行数值研究。结果表明:终了边坡的安全系数为1.31,边坡总体上处于稳定状态,但是通过对边坡中部的最大主应力分析可知,边坡中部随着开采的进行,可能存在冒落、垮塌或滑坡的风险,针对边坡存在的风险提出了预防措施。研究为矿山的安全生产提供了科学指导,同时为相似矿山的边坡处理提供了科学依据。