特提斯喜马拉雅带地热水化学特征与物源机制

西藏地热资源丰富,特别是其南部特提斯喜马拉雅地热带是一条现今仍然十分活跃的地热带。通过对该地热带10处代表性温泉野外调查及采样分析,讨论了水化学特征及水体中异常富集元素的物源机制。根据热储温度、水化学类型及水体中溶解的典型稀有分散性元素浓度,这些温泉可划分为两大类：一类包括卡乌、曲参岗、查巴曲珍和古堆温泉群,这些温泉热储温度均高于120℃,水化学类型以Na-Cl-HCO₃型为主,特征性稀有分散性元素如Li、B和As等显著富集;另一类包括锡钦、哲古和曲果温泉,热储层温度相对较低,变化于60~110℃,水化学类型以CaNa-HCO₃和Na-HCO₃型为主,Li、B和As等元素浓度较低。第一类温泉系统,水化学成分除与水循环深度大、热储温度高导致更强的水岩作用过程密切相关外,水体中异常富集的Li、B和As等特殊化学成分更可能与演化晚期的残余岩浆流体来源有关。相比之下,第二类温泉系统主要代表了水循环深度较浅、地下水更替频繁、冷水混入比例较大的温泉,水化学成分主要受控于水-岩作用的强弱。因此,特提斯喜马拉雅带地热水体异常富集的稀有分散性元素物源机制主要受控于深部富含这些元素的流体混入过程。     

牛D1井复杂构造带绳索取心钻探工艺技术研究

复杂构造带的绳索取心钻探易发生井漏、井塌以及取心困难等难题,处理不当甚至可导致井眼报废。结合牛D1井实例,介绍了绳索取心钻探工艺在复杂地层所遇的施工难点,并分析诱发井漏、井塌以及取心困难的原因,指出常规防塌堵漏技术不能满足复杂构造带钻探施工原因,提出优选钻井液、优化钻具组合以及改进堵漏工艺等现场可操作的具体改进措施。总结的施工经验可为今后复杂构造带绳索取心钻探施工提供宝贵经验。     

基于现场试验的岩体变形模量尺寸效应研究

岩体力学参数具有随机性和不确定性,合理确定岩体力学参数是岩土工程稳定性分析的基础和关键。以某水电站前期研究的110个钻孔弹模测试数据为研究样本,对其进行了统计特征分析,确定变形模量的概率分布特征更符合Weibull分布。以钻孔弹模仪承压板尺寸为岩体变形模量研究的样本尺度,岩体由该尺度的岩样叠加而成,建立了不同尺寸的立方体岩体数值分析模型,按照Weibull分布随机给出各岩样的变形模量,在此基础上对不同尺寸的岩体分别进行5 000次单轴压缩试验的数值模拟,得到了不同尺度岩体等效变形模量的变化特征,确定了岩体等效变形模量的REV。基于现场实测岩体变形模量与概率统计理论相结合研究岩体变形模量是一个新的尝试,可为该水电站工程岩体力学参数的合理取值提供依据。     

Lithospheric Thermal Isostasy of North Continental Margin of the South China Sea

Accompanied with rifting and detaching of the north continental margin of the South China Sea,the ernst and the lithosphere become thinner away from the continental margin resulting from the tectonic activities,such as tensile deformation,thermal uplift,and cooling subsidence,etc..Integrated with thermal,gravimetric,and isostatic analysis techniques,based on the seismic interpretation of the deep penetration seismic soundings across the northern margin of the South China Sea,we reconstructed the lithospheric thermal structure and derived the variation of the crust boundary in the east and west parts of the seismic profde by using gravity anomaly data.We mainly studied the thermal isostasy problems using the bathymetry of the profiles and calculated the crust thinning effect due to the thermal variety in the rifting process.The results Indicate that the thermal isostasy may reach 2.5 kin,and the compositional variations in the ilthospheric density and thickness may produce a variation of 4.0 kin.Therefore,the compositional isostatic correction is very important to recover the relationship between surface heat flow and topography.Moreover,because of the high heat flow characteristic of the continental margin,building the model of lithospheric geotherm in this region is of great importan for studying the Cenozoic tectonic thermal evolution of the north passive continental margin of the South China Sea.     

广东河源市黄村地热田地热地质特征及地热流体化学特征

广东河源市黄村地热田是该区域一个典型的开启水热型地热系统。黄村地热田具有明显的控热导水构造,地温场受导水导热断裂控制,温度从断裂带向外逐渐降低。通过一系列的地热流体化学特征分析,研究区地热流体为碱性淡水,水化学类型为HCO3-Na型,具有强循环特点,SiO2含量达到理疗矿泉水标准,但F元素含量严重超标。通过各样点的Na-K-Mg组和Cl-SO4-HCO3组离子分析,得出地热流体处于水-岩作用的初级阶段,且混入了大比例冷水,利用硅-焓混和模型计算出了冷水混入比例为72%~75%。使用SiO2温标和硅-焓混合模型对热储温度进行了估算,综合分析认为石英温标估算值（T 石英=141.9~146.2℃）作为热储温度最为合适,进一步计算出热流的循环深度2759~2856 m。综合研究认为黄村地热田地热能开发前景广阔。     

The present-day stress field of New South Wales,Australia

The Australian continent displays the most complex pattern of present-day tectonic stress observed in any major continental area. Although plate boundary forces provide a well-established control on the large-scale (>500 km) orientation of maximum horizontal stress (S_Hmax), smaller-scale variations, caused by local forces, are poorly understood in Australia. Prior to this study, the World Stress Map database contained 101 S_Hmax orientation measurements for New South Wales (NSW), Australia, with the bulk of the data coming from shallow engineering tests in the Sydney Basin. In this study we interpret present-day stress indicators analysed from 58.6 km of borehole image logs in 135 coal-seam gas and petroleum wells in different sedimentary basins of NSW, including the Gunnedah, Clarence-Moreton, Sydney, Gloucester, Darling and Bowen–Surat basins. This study provides a refined stress map of NSW, with a total of 340 (A–E quality) S_Hmax orientations consisting of 186 stress indicators from borehole breakouts, 69 stress measurements from shallow engineering methods, 48 stress indicators from drilling-induced fractures, and 37 stress indicators from earthquake focal mechanism solutions. We define seven stress provinces throughout NSW and determine the mean orientation of the S_Hmax for each stress province. The results show that the S_Hmax is variable across the state, but broadly ranges from NE–SW to ESE–WNW. The S_Hmax is approximately E–W to ESE–WNW in the Darling Basin and Southeastern Seismogenic Zone that covers the west and south of NSW, respectively. However, the present-day S_Hmax rotates across the northeastern part of NSW, from approximately NE–SW in the South Sydney and Gloucester basins to ENE–WSW in the North Sydney, Clarence-Moreton and Gunnedah basins. Comparisons between the observed S_Hmax orientations and Australian stress models in the available literature reveal that previous numerical models were unable to satisfactorily predict the state of stress in NSW. Although clear regional present-day stress trends exist in NSW, there are also large perturbations observed locally within most stress provinces that demonstrate the significant control on local intraplate sources of stress. Local S_Hmax perturbations are interpreted to be due to basement topography, basin geometry, lithological contrasts, igneous intrusions, faults and fractures. Understanding and predicting local stress perturbations has major implications for determining the most productive fractures in petroleum systems, and for modelling the propagation direction and vertical height growth of induced hydraulic fractures in simulation of unconventional reservoirs.     

洞庭盆地两护村孔孢粉组合及其气候与地层意义

两护村ZKC1孔位于洞庭盆地安乡凹陷的东南部,孔内第四系(底部跨上新世)厚达294 m,为河流和湖泊沉积,自下而上依次为上新世—早更新世华田组、早更新世汨罗组、中更新世洞庭湖组、晚更新世坡头组以及全新统等。对ZKC1孔第四系进行了详细的孢粉分析,自下而上划分出16个孢粉组合带。ESR年龄和孢粉组合及其反映的气候特征指示华田组下段形成于上新世末。根据孢粉组合特征,结合构造—沉积演化和区域气候背景,重塑洞庭盆地上新世末以来的气候演化过程:上新世末期由孢粉带Ⅰ和Ⅱ指示具暖干气候。早更新世经历了凉干(孢粉带Ⅲ、Ⅳ)→暖湿间凉干(孢粉带Ⅴ～Ⅶ)→冷干间温湿(孢粉带Ⅷ～Ⅹ)→暖较湿(孢粉带Ⅺ,Ⅻ)的气候演变过程。中更新世早期无孢粉样品(洞庭湖组下部砾石层),其沉积环境暗示冷干气候条件;中期由孢粉带ⅩⅢ反映出暖稍湿的气候特征;晚期因构造抬升缺失沉积,同期湿热化事件指示暖湿气候。晚更新世早期缺乏沉积,据区域对比应为寒冷气候;中期由孢粉带ⅩⅣ指示温较湿的气候特征;晚期缺失沉积,系寒冷气候下区域海平面下降所致。全新世经历了暖稍湿(孢粉带ⅩⅤ)→暖稍干(孢粉带ⅩⅥ)的演变。上述气候演变过程与ZKC1孔化学蚀变指数曲线反映的气候演变过程以及中国东部第四纪气候演化基本吻合。以孔深140 m为界,上部孢粉数量显著高于下部,种属也更为丰富。这一变化很可能对应于一次重要的地质事件,其成因有待今后深入研究。     

世界干热岩地热资源开发进展与地质背景分析

干热岩资源指内部不存在或仅存在少量流体,温度高于180℃的异常高温岩体,是一种极具潜力的地热资源类型。自20世纪70年代美国Fenton Hill项目实施以来,已在全球14个国家实施了41个干热岩开发项目,以干热岩储层建造和连通的目标地层周围或上部是否存在水热型储层为标准,25个属于传统意义的干热岩开发项目,16个属于增强型地热系统(Enhanced Geothermal System或Engineered Geothermal System,缩写为EGS)。从板块构造角度分析,这些干热岩开发项目主要分布在欧亚板块板内地热域、印澳板块板内地热域、东太平洋离散—汇聚板缘型地热域、西太平洋汇聚板缘型地热域和加勒比海火山活动岛弧区。按照盆地类型划分,全球干热岩开发项目所处的大地构造背景包括克拉通盆地、前陆盆地、裂谷盆地、弧前盆地、弧后盆地、近现代火山(火山带)和褶皱带地区,其中以欧洲阿尔卑斯褶皱带磨拉石盆地为代表的前陆盆地,和以欧洲阿尔卑斯褶皱带上莱茵地堑、北美新生代科迪勒拉造山带内华达盆地为代表的裂谷盆地是全球干热岩开发项目最为集中的两种盆地类型。考虑我国干热岩资源分布情况,上莱茵地堑、内华达盆地的干热岩开发历程对我国干热岩资源的勘探和开发具有一定的借鉴作用。     

聊城西部地热田地热资源赋存特征研究

山东省聊城西部地热田位于临清拗陷内的莘县凹陷的南部,面积约1280km^2。通过已有钻探资料及近年的勘查项目研究成果,对聊城市西部地热田的地热资源的地质背景、水文地质特征、地球物理化学特征等进行了综合研究分析,认为聊城西部地热田属于层控型低温地热田,热储层主要为新近纪明化镇组下部、馆陶组、古近纪东营组地层,该区的地温梯度主要受构造控制,断裂导热是形成本区的一个重要因素,地下热水矿化度较小,成因主要为大气降水。     

钻孔充填压浆法在采空区治理中的应用——以湖南省邵东某石膏矿采空区为例

矿山开采形成的采空区往往会给地表建筑物带来破坏，对采空区的治理方法也有多种，针对湖南某石膏矿采空区的分布与埋藏特征及其工程地质条件，采用了钻孔充填压浆法进行了治理。实践证明钻孔充填压浆法对采空区的治理具有成本低，设备简单，技术可靠，效果明显，有进一步推广的意义。