共查询到20条相似文献，搜索用时 31 毫秒
1.
天然水体中存在同化二氧化碳(CO2)的光合作用,也存在释放CO2的微生物呼吸过程。地球表层水体与大气之间的CO2交换构成全球碳循环的一个重要环节。水-气之间CO2交换的方向和通量主要受大气圈和水体表层CO2分压(pCO2)的制约。水体pCO2值可以通过对近水面气体成分变化过程的现场仪器检测或者根据测定的水体化学参数运用经验公式计算求得。迄今对陆地水体,尤其河流筑坝形成的"蓄水河流"(下称水库)水体CO2动态研究中,由于水域及其近表层大气成分的时空多变,一般采用水化学参数计算方法求得水体的pCO2值。全球约70.97%的水库表层水体pCO2高于大气pCO2。全球尺度上水库表层水体pCO2自热带向寒温带逐渐递减;单个水库水体的pCO2一般呈现"出库>入库>库中"、pCO2随深度而增加的变化规律。水库表层水体pCO2的时间变化一般表现为"冬季>夏季、消融期>冰冻期、黑夜>白天"。水库水体的pCO2是其水化学平衡的结果,受水温、水体pH、水生生物活动以及外来水体的混合等多种因素影响,变化较为复杂。为精确量化水库水-气界面CO2交换通量,水文学、湖沼学、生态学和地球化学等领域的学者有必要合作,共同努力进行水库流域尺度的实地观测,完善水体溶解无机碳计算模型,深入探讨水库水体碳动力学机制,为全球碳循环研究和气候变化预测提供可靠的基础数据。 相似文献
2.
北京城区地热田某地热井热水地球化学研究 总被引：2，自引：0，他引：2
地热的开采会引起热储压力的降低 ,从而引起热流场的改变。热储压力的降低可能导致温度较低的地下水的流入 ,也可能导致深部更高温度热流体的补充 ,从而引起地热流体化学特征的变化。地热流体中一些组分的浓度依赖于热流体温度的高低。不同温度的水发生混合会破坏地热系统的化学平衡 ,从而改变地热流体的化学成分。因此 ,地热流体的化学监测可以提供许多有关地热系统变化的宝贵信息。由于长期开采 ,北京城区地热田的压力明显下降 ,并引起了地热水化学成分的细微变化。根据 1984年以来一眼地热井的地热水化学监测资料 ,研究了地热水的化学成分、地球化学温标的变化规律以及地热活动的总体强度和水 /岩平衡矿物中的示温矿物的变化趋势 ,说明地热的开采既引起了地热田水补给的加强 ,又导致了地热田热补给的加强 相似文献
3.
山西太原西山汾河二库的泉域归属及其渗漏量计算 总被引：1，自引：1，他引：0
山西省汾河二库是建于汾河中上游的一座大型水库。由于水库处于晋祠兰村泉域交界地带的碳酸盐岩河段,水库蓄水并淹没了天然条件下出流的悬泉寺泉群,造成库区岩溶水文地质条件发生根本性改变,直接影响到泉域岩溶水的水资源评价、开发管理和以泉水复流为目标的生态修复的措施制定。本文针对汾河二库修建后的以下两个问题开展了讨论。第一,利用最新调查与勘探资料分析二库修建对岩溶水文地质条件的影响,并对二库库区的泉域归属问题进行了划定,认为悬泉寺泉水的出流受控于汾河河谷内向西倾斜的下奥陶统区域相对隔水层的阻水作用,汾河二库蓄水水位提高近40 m,天然条件下挟持于晋祠-兰村泉域间相对独立循环的悬泉寺泉域降落漏斗被“充满”,泉水消失,形成对岩溶地下水渗漏反补给,水库渗漏水量通过中奥陶统主要进入晋祠泉域,汾河二库以寺头-下槐间下奥陶统出露的地段为界,下槐泉以上划归晋祠泉域,下槐泉以下则划归兰村泉域;第二,利用二库上游寨上水文站、下游的上兰村水文站资料和二库蓄水水位系列资料,由均衡法建立了二库蓄水水位与渗漏量之间的非线性方程,并据此预测,当二库水位提高至905.7 m时的渗漏量为2.862 m3·s-1,而对兰村泉域岩溶水及山前西张水源地的补给量有限。 相似文献
4.
水位骤降时的非饱和坝坡稳定分析 总被引：2，自引：1，他引：2
从非饱和土抗剪强度理论出发,应用极限平衡法和以有限元应力计算为基础的极限平衡法,分别对库水位骤降时的坝坡稳定进行了计算。分析中采用非饱和-非稳定渗流理论,模拟了孔隙水压力的消散过程,并考虑基质吸力对土体抗剪强度的影响,将每个渗流分析结果调入稳定分析模块计算其稳定性。最后将两类极限平衡法稳定分析结果进行了比较,结果表明,库水位的骤降,易引起坝坡的滑动,随着超静孔隙水压力的消散,坝坡稳定性逐渐提高;随着孔压消散,基质吸力对抗剪强度的贡献增大。 相似文献
5.
The Bouillante geothermal field provides about 8% of the annual electricity needs of the French West Indies island of Guadeloupe. It has been the subject of several studies covering various disciplines. A hydrogeological conceptual model of the field is proposed. The reservoir consists of two perpendicular sets of fractures and faults, related to major regional tectonic structures, which have been clogged near surface by self sealing. The heat exchanges of the reservoir with the outside are reduced, through thermal and hydraulic blanketing, to conductive transfers. Convection cells are active within the reservoir, ensuring its thermal and geochemical homogeneity. Heat exchange with the magmatic chamber is only conductive. The Na–Cl geothermal fluid in the reservoir is composed of 60% seawater and 40% freshwater and has reached a chemical equilibrium with a mineralogical assemblage at 250–260°C. Many arguments (equilibrium state, absence of tritium, low in/out fluxes, large reservoir volume) suggest a long residence time (>100 years) of the geothermal fluid. Three factors explain the existence and location of the geothermal field: a heat source (cooling hypovolcanic intrusion), a network of permeable fractures at the origin of the geothermal aquifer, and an impermeable surface cover, limiting the loss of energy and ensuring the durability of the field. 相似文献
6.
The availability of fluids and drill cuttings from the active hydrothermal system at Roosevelt Hot Springs allows a quantitative comparison between the observed and predicted alteration mineralogy, calculated from fluid-mineral equilibria relationships. Comparison of all wells and springs in the thermal area indicates a common reservoir source, and geothermometer calculations predict its temperature to be higher () than the maximum measured temperature of 268°C.The composition of the deep reservoir fluid was estimated from surface well samples, allowing for steam loss, gas release, mineral precipitation and ground-water mixing in the well bore. This deep fluid is sodium chloride in character, with approximately 9700 ppm dissolved solids, a pH of 6.0, and gas partial pressures of O2 ranging from 10?32 to 10?35 atm, CO2 of 11 atm, H2S of 0.020 atm and CH4 of 0.001 atm.Comparison of the alteration mineralogy from producing and nonproducing wells allowed delineation of an alteration pattern characteristic of the reservoir rock. Theoretical alteration mineral assemblages in equilibrium with the deep reservoir fluid, between 150° and 300°C, in the system Na2O-K2O-CaO-MgO-FeO-Fe2O3-Al2O3-H4SiO4-H2O-H2S-CO2-HCl, were calculated. Minerals theoretically in equilibrium with the calculated reservoir fluid at include sericite, K-feldspar, quartz, chalcedony, hematite, magnetite and pyrite. This assemblage corresponds with observed higher-temperature () alteration assemblage in the deeper parts of the producing wells. The presence of montmorillonite and mixed-layer clays with the above assemblage observed at temperatures <210°C corresponds with minerals predicted to be in equilibrium with the fluid below 240°C.Alteration minerals present in the reservoir rock that do not exhibit equilibrium with respect to the reservoir fluid include epidote, anhydrite, calcite and chlorite. These may be products of an earlier hydrothermal event, or processes such as boiling and mixing, or a result of errors in the equilibrium calculations as a result of inadequate thermochemical data. 相似文献
7.
Hydrochemistry and geothermometry of thermal groundwater of southeastern Tunisia (Gabes region) 总被引：1，自引：0，他引：1
Given the vital importance of water and energy in desert regions, we undertook a study dealing with the deep reservoirs in Gabes area, which is located in the southeastern part of Tunisia. Geothermal resources are taken from the Intercalary Continental [or Continental Intercalaire (CI)], known as the largest deep aquifer in Tunisia and are used in a number of applications, mainly in agriculture. Previous investigations performed on the thermal waters of this area focused on the genesis of the deep waters with regard to the thermal features of geothermal reservoirs. A more detailed investigation has been carried out, considering both deep and shallow waters. In order to estimate the potential temperatures of deep reservoir in the Gabes area, we developed a synthetic study including chemical geothermometers, multiple mineral equilibrium approach, and other approaches. Chemical types of the thermal waters and effects of mixing between shallow cold waters with deep thermal waters were also discussed. In fact, the application of Na–K–Mg diagram relative to deep geothermal reservoir capitulate estimated temperatures (about 90°C). In addition, the multiple mineral equilibrium approach submits a similar estimated temperature ranging between 65 and 70°C, showing a disequilibrium status which indicates a possibly mixing with surface water. Indeed, wells exploiting the CI aquifer in the south part of the studied area showed the same characteristics, corroborating the reliability of the applied methods. 相似文献
8.
丹巴县莫洛村滑坡的地质成因与稳定评价 总被引：1，自引：0，他引：1
莫洛村滑坡位于大渡河左岸猴子岩水库库尾的梭坡堆积体前缘,是丹巴县古碉的集中分布区之一。由于古碉群独特的历史、人文和旅游价值,其稳定性不论是对古碉群保护,还是对水库蓄水位选择均十分重要。在简介滑坡区域地质环境的基础上,基于地质勘察和现场调查资料,分析了堆积体与滑坡地质成因与稳定现状,同时采用三维强度折减法和二维极限平衡法预测了不同蓄水位与水库运行方案对其稳定性的影响。结果表明：梭坡堆积体是冰川作用形成的;莫洛村滑坡是堆积体前缘近3 300年来蠕变和局部解体形成的,总方量约为4 000×104 m3;导致滑坡变形的原因是1983年后向坡体引水,坡体地下水位抬升;现状下滑坡的二维极限平衡法和三维强度折减法安全系数分别为1.048和1.07,处于临界稳定状态;不论是1 842 m还是1 852 m水位方案,水库蓄水与运行对滑坡稳定的影响均很小;排水是维持滑坡稳定和保护古碉的最有效措施。 相似文献
9.
鄂尔多斯盆地姬塬油田长6储层原油储量丰富,储层致密制约着油气的勘探开发潜力和评价精度.通过开展物性、粒度、铸体薄片、X衍射、扫描电镜、压汞等测试研究储层特征,以时间为主轴,综合成岩史、埋藏史、地热史、构造等因素,采用“成岩作用模拟”和“地质效应模拟”构建孔隙度演化模型及计算方法探讨致密储层成因机理.结果表明:储层经过较强的演化改造发育微-纳米孔喉系统,形成低孔特低孔-超低渗的致密砂岩储层.H53井长6段孔隙度演化史揭示了增孔和减孔因素对孔隙度及油气充注的影响;通过对比最大粒间孔面孔率、最大溶蚀面孔率、最大压实率、最大胶结率样品孔隙度演化路径和含油饱和度,查明了致密储层成因的差异及品质. 相似文献
10.
准噶尔盆地南缘中段紫泥泉子组三段(E1-2z3)储集性能好,是本区油气勘探的重要层段。储层的分布与物源有密切的成生联系,物源体系分析是油气勘探的一项重要工作。本文基于研究区内钻井和野外露头剖面的重矿物资料,对重矿物含量变化及平面分布特征进行分析,划分出不同的重矿物分区,同时对工区内钻井的砂砾岩厚度进行统计,并分析其在平面上的展布特征,确定了准噶尔盆地南缘紫泥泉子组三段物源体系,为下一步沉积体系的精细研究和储层预测奠定了基础。 相似文献
11.
HAO Fang GUO Tonglou DU Chunguo ZOU Huayao CAI Xunyu ZHU Yangming LI Pingping WANG Chunwu ZHANG Yuanchun 《《地质学报》英文版》2009,83(1)
Solid bitumens were found throughout the carbonate reservoirs in the Puguang gas field,the largest gas field SO far found in marine carbonates in China,confirming that the Puguang gas field evolved from a paleo-oil reservoir.The fluid conduit system at the time of intensive oil accumulation in the field Was reconstructed,and petroleum migration pathways were modeled using a 3-D model and traced by geochemical parameters.The forward modeling and inversion tracing coincided with each other and both indicated that oils accumulated in the Puguang-Dongyuezhai structure originated from a generative kitchen to the northwest of the Puguang gas field.The deposition of organic-rich Upper Permian source rocks dominated by sapropelic organic matter in the Northeast Sichuan Basin, the development of fluid conduit system that was vertically near-source rock and laterally near-generative kitchen,and the focusing of oils originated from a large area of the generative kitchen,were the three requirements for the formation of the giant paleo-oil reservoir from which the giant Puguang gas field evolved.The Puguang gas field had experienced a three-stage evolution.The post-accumulation processes,especially the organic-inorganic interaction in the hydrocarbon-water-rock system,had not only profoundly altered the composition and characteristics of the petroleum fluids,but also obviously changed the physicochemical conditions in the reservoir and resulted in complicated precipitation and solution of carbonate minerals. 相似文献
12.
Based on the theory of double-porosity, a novel mathematical model for multiphase fluid flow in a deforming fractured reservoir is developed. The present formulation, consisting of both the equilibrium and continuity equations, accounts for the significant influence of coupling between fluid flow and solid deformation, usually ignored in the reservoir simulation literature. A Galerkin-based finite element method is applied to discretize the governing equations both in the space and time domain. Throughout the derived set of equations the solid displacements as well as the fluid pressure values are considered as the primary unknowns and may be used to determine other reservoir parameters such as stresses, saturations, etc. The final set of equations represents a highly non-linear system as the elements of the coefficient matrices are updated during each iteration in terms of the independent variables. The model is employed to solve a field scale example where the results are compared to those of ten other uncoupled models. The results illustrate a significantly different behaviour for the case of a reservoir where the impact of coupling is also considered. © 1997 by John Wiley & Sons, Ltd. 相似文献
13.
Thermal recovery from a hot dry rock (HDR) reservoir viewed as a deformable fractured medium is investigated with a focus on the assumption of local thermal non‐equilibrium (LTNE). Hydraulic diffusion, thermal diffusion, forced convection and deformation are considered in a two‐phase framework, the solid phase being made by impermeable solid blocks separated by saturated fractures. The finite element approximation of the constitutive and field equations is formulated and applied to obtain the response of a generic HDR reservoir to circulation tests. A change of time profile of the outlet fluid temperature is observed as the fracture spacing increases, switching from a single‐step pattern to a double‐step pattern, a feature which is viewed as characteristic of established LTNE. A dimensionless number is proposed to delineate between local thermal equilibrium (LTE) and non‐equilibrium. This number embodies local physical properties of the mixture, elements of the geometry of the reservoir and the production flow rate. All the above properties being fixed, the resulting fracture spacing threshold between LTNE and LTE is found to decrease with increasing porosity or fluid velocity. The thermally induced effective stress is tensile near the injection well, illustrating the thermal contraction of the rock, while the pressure contribution of the fracture fluid is negligible during the late period. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
14.
Accumulation Mechanisms and Evolution History of the Giant Puguang Gas Field,Sichuan Basin,China 总被引：3，自引：2，他引：1
HAO Fang GUO Tonglou DU Chunguo ZOU Huayao CAI Xunyu ZHU Yangming LI Pingping WANG Chunwu ZHANG Yuanchun 《《地质学报》英文版》2009,83(1):136-145
Solid bitumens were found throughout the carbonate reservoirs in the Puguang gas field, the largest gas field so far found in marine carbonates in China, confirming that the Puguang gas field evolved from a paleo-oil reservoir. The fluid conduit system at the time of intensive oil accumulation in the field was reconstructed, and petroleum migration pathways were modeled using a 3-D model and traced by geochemical parameters. The forward modeling and inversion tracing coincided with each other and both indicated that oils accumulated in the Puguang-Dongyuezhai structure originated from a generative kitchen to the northwest of the Puguang gas field. The deposition of organic-rich Upper Permian source rocks dominated by sapropelic organic matter in the Northeast Sichuan Basin, the development of fluid conduit system that was vertically near-source rock and laterally near-generative kitchen, and the focusing of oils originated from a large area of the generative kitchen, were the three requirements for the formation of the giant paleo-oil reservoir from which the giant Puguang gas field evolved. The Puguang gas field had experienced a three-stage evolution. The post-accumulation processes, especially the organic-inorganic interaction in the hydrocarbon-water-rock system, had not only profoundly altered the composition and characteristics of the petroleum fluids, but also obviously changed the physicochemical conditions in the reservoir and resulted in complicated precipitation and solution of carbonate minerals. 相似文献
15.
膏质白云岩是鄂尔多斯盆地中东部下古生界马家沟组M51最有利储层,影响膏质白云岩储层性质的最大因素在于溶蚀作用。本文在已有的研究基础上,应用岩心资料及阴极发光、地球化学等方法,测定M51膏质白云岩及其特殊的示底构造的化学成分,并分析其成因模式。岩心、薄片以及物性资料显示:石膏溶蚀形成的大量膏模孔及伴生的次生孔是储层的主要储集空间,示底构造规模性出现于膏质云岩中。阴极发光、常微量元素分析结果显示:示底构造上部充填埋藏期方解石;下部充填碎屑白云石,与示底构造外围的准同生期泥-粉晶白云石具有相近的地球化学特征,与深部埋藏期形成的细-中晶白云石差异明显。示底构造的演化是膏质白云岩有利储层形成的重要依据,本文依据化学离子平衡原理,对不同成岩阶段发生的溶蚀作用、填充作用进行离子间相互置换的重演,分析得知不稳定的化学组成是石膏易被溶蚀的内在原因,石膏的规模性溶蚀是膏质云岩有利储层形成的关键。 相似文献
16.
水库的修建给防洪、发电、灌溉、供水等带来巨大经济效益的同时,也对环境产生一定的影响,尤其是水库泄流对下游河道水温的改变,扰乱下游动、植物繁殖与生长的自然节律,而梯级水库无疑将这一影响进行了放大。为研究水库梯级修建对水温的极限影响,构建了虚拟水库Alpha,并使Alpha水库首尾相连无限叠加,采用宽度平均的立面二维数学模型CE-QUAL-W2对梯级水库水温进行模拟。结果表明:河流梯级开发带来的水温累积影响存在极限,梯级开发使水温分层现象极大地弱化,但库区分层结构不会消失;经过22个梯级调节,水库下泄水温相对来流水温不再变化,在同一时刻、同一位置无论是表层水温还是库底水温均与上游梯级相同,库区流场也与上游流场相同;水库水温累积影响达到极限表明入流热量、出流热量完全达到平衡。 相似文献
17.
18.
梁正中 《沉积与特提斯地质》2009,29(4):42-46
针对临盘油区沙三段-沙二下段主力含油层系开发中存在的问题,开展储层精细划分与对比工作。讨论了储层精细对比的原则和方法,强调了高分辨率层序地层学的等时对比。通过精细对比,建立了工区4种砂体对比模式。研究结果对于储层精细描述、高精度油藏地质模型的建立以及提高油田的开发效果和最终采收率具有重要意义。 相似文献
19.
为研究上部气层（⑥~⑨小层）与下部气层（①~⑤小层）气井开发效果存在明显差异的原因,结合压裂数据、现场生产动态、可采储量预测和地质分析等手段,评价上部气层和下部气层在页岩岩性、地化特征和储层物性等方面存在的差异.结合气井生产特征分析,认为上部气层可能存在烃源岩内的一次运移,导致上部气层构造高部位天然气富集程度高,这是造成上部气层评价井开发效果差异以及上部气层、下部气层页岩气井差异的主要原因.焦石坝背斜高部位为上部气层开发有利区,但受技术工艺水平和气价控制,其有效开发范围需要根据页岩气井的可采储量、经济性来圈定,结合上部气层页岩气井稳产能力及可采储量评价,认为上部气层开发应从构造高部位开始,逐步向低部位扩展. 相似文献
20.
Pamancalan is located in Lebak Regency, Province of Banten. This area is located in the western part of Java Island, Indonesia. The geothermal manifestation in this area is in the form of hot spring in Cipamancalan River. But, how the structure of the geothermal system, the reservoir depth, and the thermal source in the Pancamalan area has not been studied much. Therefore, there is a need to conduct a geophysics study by surveying the gravity and magnetic field. A study, which used magnetic and gravity data to discover reservoir, has been conducted in the Pamancalan geothermal area in Lebak, Banten. Topographic map for total magnetic and earth gravity anomaly shows that the anomaly is located in the center and southern part of the presumed reservoir. 2.5-D section model of magnetic anomaly shows that there is a rock formation which shaped the geothermal system in Pamancalan. The thermal source is diorite which is a by-product of Hanjawar Mountain; the reservoir rocks consist of sandstone, limestone, and breccia; and the cap rock is in the form of clay and tuff. It is predicted that there is an intrusive body which functions as thermal source in the depth between 1650 and 4000 m, the reservoir depth is around 700 m, and the depth of clay cap is around 0 to 700 m. The geothermal manifestation in Pamancalan area is controlled by Cigeledug fault from the southwest and Cipamancalan fault from the north and south. 相似文献