砂岩热储地热尾水回灌悬浮物堵塞研究

砂岩热储人工回灌过程中介质堵塞问题严重影响到回灌效率,为查明回灌过程中悬浮物堵塞对回灌效率的影响。试验依据德城区鲁北院内回灌井现场尾水中悬浮物粒径分布特征,并以市政自来水为水源,粘性土颗粒为入渗介质,配制0.038 mm和0.050 mm的不同悬浮物粒径和0 mg/L、20 mg/L、50 mg/L、60 mg/L、100 mg/L的不同悬浮物浓度开展一维砂柱模拟回灌试验。试验结果表明:悬浮物堵塞会引起整柱相对渗透系数呈现"快速下降-趋于稳定"的趋势,且堵塞主要发生在表层,可能在一定程度上抑制了悬浮物颗粒向下迁移;悬浮物粒径的大小和浓度均可以影响热储介质堵塞发生时间,悬浮物粒径越大堵塞发生时间越早,浓度越高,堵塞时间越短。试验针对悬浮物堵塞试验研究成果及现实情况,提出了一些针对性的治理措施:(1)设计一级除砂器,除砂器不仅可以沉降颗粒较大的悬浮物,降低悬浮物浓度,也能对尾水进行降温,有益于缓解物理悬浮物堵塞。(2)经过除砂器后,尾水进入二级过滤器,设计粗过滤器的过滤级为50μm,而精过滤器的过滤级为10μm,过滤器的个数可以根据尾水回灌量确定。     

砂岩热储回灌对储层影响评价——以鲁西北坳陷地热区为例

地热流体经供暖利用后尾水温度降低,经过滤、排气处理后的尾水中仍含有不同粒径的悬浮物、气体,因此回灌不可避免的会对储层造成负面影响,如堵塞储层导致回灌量衰减、热储温度降低甚至产生热突破等,这严重阻碍了地热回灌的长期可持续运行。评价回灌对储层的影响,对下一步全面推进、科学回灌及合理可持续开发利用、保护地热资源具有重要意义。本文以近几年鲁西北坳陷区开展的馆陶组热储回灌试验为基础,设立了一套评价指标,即用回灌前、后水质的变化率评价回灌对热储流体的影响,温度的变化率评价回灌对热储温度的影响,单位涌水量变化率、渗透系数的比值和单位回灌量比值评价回灌堵塞程度并确定了分级标准。评价结果表明,回灌不会改变储层流体的化学类型;回灌堵塞主要发生在回灌井周围,相比回灌前,回灌后回灌井的单位涌水量降低14.3%～59.0%、渗透系数为原来的41%～86%,末期单位回灌量为初期回灌量的51%～92%,回灌堵塞程度为轻度到严重。采灌井距180～500m,历经一个供暖季回灌对热储温度的影响较小,但回灌导致回灌井周边热储温度明显降低,历经一个非回灌期224d,从35. 7℃恢复到40. 53℃,恢复速率为0. 036～0. 022℃/d,还需658d才能恢复到原热储温度(55℃)。本区热储水位仍呈下降趋势,但回灌可延缓热储水位的下降速度。     

深层地热水开采与地面沉降的关系研究

本文根据天津塘沽区深层地沉观测标观测到的地面沉降数据,分析了深层地下热水开采对地面沉降的影响比例.在分析地热水开采引起地面沉降机理的基础上,通过统计回归方法建立了深层孔隙型地热水开采量与地面沉降量的相关模型;提出了进行地热尾水回灌和建立深层沉降监测网以加强综合研究的防治对策.     

地热对井运行系统中回灌井堵塞原因浅析及预防措施

人工回灌做为提高地热资源利用率、防止地面沉降、减少尾水排放、实现地热资源的可持续利用的最有效手段,已在地学界达成共识。基岩岩溶裂隙型热储对井回灌取得的良好效果使人们看到了回灌技术的广阔应用前景,但有些热储尤其是孔隙型热储回灌量的衰减问题一直未能得到彻底解决,各种因素引起的堵塞是主要原因。本文根据天津市历年的回灌试验,就造成地热回灌堵塞的多种原因进行了分析,并提出了可能的解决办法。     

近三十年天津市地热大规模开发热储动态特征研究

天津是我国较早大规模开发深层地热的地区之一,经过30多年的持续开采回灌,对深部热储特征有无影响,是否引起了资源枯竭、水质恶化以及热储温度下降等环境问题,一直是社会关注的焦点。本文系统收集了1992年以来天津市地热开发过程中的不同热储层热水开发利用量、回灌量、水位、水质、水温等近30年的时间序列监测资料,通过垂向及横向对比,对地热持续开发30年来天津市不同地区不同热储层的热水动态特征进行了分析。结果表明,天津市各热储层地热流体的主要化学组分基本稳定,多年来无明显变化,地热采灌系统尾水回灌不会从根本上改变地热流体的原始化学特征,但深大断裂作为热流通道引起的顶托补给,会对上层热储水质造成一定的影响;随着近年来天津市回灌工作力度不断加大,大部分热储水位下降幅度减缓或出现回升,热储的温度没有明显的升高或降低的趋势,但回灌井热储段经过非供暖期的恢复无法达到最初的温度,呈逐年下降趋势。未来持续采灌条件下,回灌井筒的“冷堆积”及采灌井的优化调配应是重点关注的问题。     

碳酸盐结垢对中低温地热流体回灌的影响——以咸阳地热田为例

应用水文地球化学模拟和室内模拟耦合方法,对引起地热尾水回灌堵塞的问题进行研究。结果显示,回灌过程中化学结垢的主要类型为碳酸盐。影响碳酸盐堵塞的因素主要为温度、C02脱气、混合程度、pH以及矿化度。随着温度、pH、C02分压的增大CaC03结垢趋势增加;当360％的原水和40％的尾水混合时,CaC03的沉淀量达到最大;而矿化度的影响主要体现在盐效应和同离子效应。运用朗格利尔指数和雷兹诺指数对CaCO3沉淀程度进行计算,结果表明,在研究区内多数井中存在中低程度的CaCO3结垢。     

基于等效渗流通道模型的地热尾水回灌理论模型

深层地热能是一种清洁环保的可再生能源,尾水回灌是深层地热可持续开发利用的重要保证,但目前国内地热尾水回灌还处在起步阶段,地热尾水回灌方案优化设计的理论模型尚不成熟。文章结合示踪试验,提出了基于等效渗流通道模型的热储参数反演与开采井热突破预测的完整理论框架。应用多孔介质溶质运移理论,修正了等效渗流通道中的溶质浓度解析解,并联合移动渐近线法提出了热储参数反演理论模型;推导了等效渗流通道中的对流传热解析模型,可对开采井中的水温变化进行预测。依托山东省德州市平原县魏庄社区地热对井示踪试验,应用该理论框架进行了示踪试验反演及开采井热突破预测,并对影响开采井热突破的主要因素进行了敏感性分析。     

基于Origin的渗透系数衰减方程在地热水回灌中的应用

孔隙型热储层的回灌过程中,由于物理堵塞、生物化学堵塞、悬浮物堵塞和气体堵塞,热储层的渗透性下降,回灌能力变弱.为了定量查明渗透系数的衰减,以辽南地区某回灌试验为例,使用Origin软件计算出研究区渗透系数衰减方程,在此基础上计算了回灌井灌压-时间关系曲线和回扬周期.研究表明,利用Origin软件求取渗透系数衰减方程具有...     

配伍性实验在西安市地热水回灌试验中的应用

西安市地热田储层为砂岩孔隙型储层,孔隙度和渗透率都比较低,很容易发生回灌堵塞现象。对西安市同层回灌水和异层回灌水的配伍性进行研究,配伍性实验结果表明:西安市地热尾水回灌到回灌井后主要的结垢类型为CaCO3,结垢量小于100 mg/L,配伍性较好,不会大量结垢而导致地热储层堵塞。     

地热回灌防腐过滤器及配套技术试验

利用专题立项开凿的地热生产井和地热回灌井,对第三纪孔隙型热储层进行了加压条件下的对井同层回灌试验。通过研发地热回灌防腐过滤器及配套技术,解决了先前在回灌过程中由各种物理、化学和生物因素引起的堵塞,导致回灌量减小、回灌井早期丧失回灌能力这一技术难题。     

The terrestrial fauna of the Late Triassic Pant-y-ffynnon Quarry fissures,South Wales,UK and a new species of Clevosaurus (Lepidosauria: Rhynchocephalia)

Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco.     

The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts

The solubilities of columbite, tantalite, wolframite, rutile, zircon and hafnon were determined as a function of the water contents in peralkaline and subaluminous granite melts. All experiments were conducted at 1035 °C and 2 kbar and the water contents of the melts ranged from nominally dry to approximately 6 wt.% H₂O. Accessory phase solubilities are not affected by the water content of the peralkaline melt. By contrast, solubilities are affected by the water content of the subaluminous melt, where the solubilities of all the accessory phases examined increase with the water content of the melt, up to 2 wt.% H₂O. At higher water contents, solubilities are nearly constant. It can be concluded that water is not an important control of accessory phase solubility, although the water content will affect diffusivities of components in the melt, thus whether or not accessory phases will be present as restite material. The solubility behaviour in the subaluminous and peralkaline melts supports previous spectroscopic studies, which have observed differences in the coordination of high field strength elements in dry vs. wet subaluminous granitic glasses, but not for peralkaline granitic glasses. Lastly, the fact that wolframite solubility increases with increasing water content in the subaluminous melt suggests that tungsten dissolved as a hexavalent species.     

Quaternary stresses revealed by calcite twinning inversion: insights from observations in the Savonnières underground quarry (eastern France)

Calcite samples were extracted both from the rock matrix and the superficial coating of a karstified fault plane of an underground quarry, located in the eastern border of the Paris basin. The karstification is dated as Quaternary. Analysis of mechanical calcite twinning reveals that only the calcite matrix has also undergone a compression trending WNW that can be attributed to the Mio-Pliocene alpine collision. Both coating and matrix have undergone a strike-slip regime with σ₁ roughly trending north–south, that could correspond to the regional present-day state of stress, a strike-slip compression rather trending NNW, modified by local phenomena. To cite this article: M. Rocher et al., C. R. Geoscience 335 (2003).     

HYDROGEOLOGY

正20141756 Chen Ruige(Mathematical College,China University of Geosciences,Beijing100083,China);Zhou Xun Numerical Simulation of Groundwater Level Fluctuation in a Coastal Confined Aquifer with Sloping Initial Groundwater Level Induced by the Tide(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(7),2013,p.1099-1104,6 illus.,16 refs.) Key words:confined water,groundwater level     

METAMORPHIC PETROLOGY

正20141408 Cai Jia(Institute of Geology,Chinese Academy of Geological Sciences,Beijing100037,China);Liu Fulai Petrogenesis and Metamorphic P-T Conditions of Garnet-Spinel-Biotitebearing Paragneiss in Danangou Area,Daqingshan-Wulashan Metamorphic Complex Belt(Acta Petrologica Sinica,ISSN1000-0569,CN11-1922/P,29(7),     

SERIALS

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GEOPHYSICAL EXPLORATION

正20142386An Guoying(China Aero Geophysical Survey and Remote Sensing Center for Land and Resources,Beijing 100083,China)Application of Satellite Remote Sensing in Regional Hydrogeological Investigation:Taking Cenozoic Strata in Wenquan Sheet(1∶250 000)of Karakoram Range as an Example(Geosci-     

QUATERNARY GEOLOGY & GEOMORPHOLOGY

正20141016An Chengbang(Key Laboratory of Western China’s Environmental Systems,Ministry of Education,Lanzhou University,Lanzhou 730000,China);Zhao Yongtao Lake Records during the Last Glacial Maximum from Xinjiang,NW China and Their Climatic Impli-     

PETROLEUM GEOLOGY

正20141538 Cao Qing(School of Earth Sciences and Engineering,Xi’an Petroleum University,Xi’an 710065,China);Zhao Jingzhou Characteristics and Significance of Fluid Inclusions from Majiagou Formation,Yichuan Huangling Area,Ordos Basin(Advances in Earth Science,ISSN1001-8166,CN62-1091/P,28(7),2013,p.819-828,7 illus.,3 tables,43 refs.)     

GEOCHEMISTRY

正20142002 Wei Hualing(Institute of Geophysical and Geochemical Exploration,Chinese Academy of Geological Sciences,Langfang065000,China);Zhou Guohua Element Content and Mineral Compositions in Different Sizes of Soil in Tongling Area,Anhui Province(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(11),2013,p.1861