地下水封储气洞库原理及数值模拟分析

 结合我国第一座地下水封储气洞库工程, 对水封式地下储气洞库的原理及设计作了简单的论述。通过数值模拟方法对地下水封储气洞库从理论上进行了分析探讨。为我国地下储气洞库工程的发展、设计和施工提供了理论依据。     

盐岩地下储气库群间距数值计算分析

 为确保储气库群的安全性及使用功能，各储存库之间应该保证有足够的距离。盐岩储库群地质条件及运行工况复杂，材料参数变异性强，随机特性对结构安全性影响较大。从稳定性和密闭性两方面出发，以莫尔–库仑准则和损伤扩容准则作为主要失效准则，建立两腔储库群数值计算模型，计算不同储库间距和运行内压下塑性区及损伤扩容区分布。采用响应面法，结合蒙特卡罗方法计算储库群腔周矿柱单元失效概率。结果表明，正常运行状态下，随储库间距减小，损伤扩容区范围明显增大，塑性区范围及腔周矿柱单元失效概率计算结果均明显增大，尤其在低压时更可能产生损伤连通区。对于运行过程中存在的注、采气不同步情况，随着储库间距的增大，压力差对腔周矿柱单元失效概率的影响逐渐减弱。根据稳定性和密闭性分析结果，建议储气库最小间距为2D。     

水封油库地下水位动态变化特性数值研究

为认识水封石油洞库区地下水位的动态变化过程,以黄岛地下水封石油洞库的基本地质条件为依据,采用饱和非饱和非恒定流数值分析方法,对水封油库在施工期和运行期可能出现工况下的地下水位变化情况进行了全过程数值仿真计算,分析了不同时期洞库区附近岩体的地下水位分布特点及变化过程。研究表明水封油库区内的地下水位变化过程主要受岩体渗透系数、洞库开挖方式和运行方式的影响;当洞库区岩体渗透系数大于 m/s 时,洞顶上方岩体中的地下水将被疏干,必须设置水幕系统来保证洞库的水封效果。     

盐穴储气库腔体收缩风险影响因素的敏感性分析

 如何有效减少盐穴储气库在运营过程中的有效体积损失以延长储气库的使用寿命是运营和管理部门非常关心的问题。从宏观角度分析腔体的地层、设计和运行各参数对我国盐穴储气库腔体收缩风险的影响,归纳出7个可能影响因素并分别对其影响趋势进行预测,然后采用单因素敏感性分析方法,通过数值模拟计算结果的对比分析得到这7个可能影响因素对腔体体积收缩率的敏感度系数,并基于运行工况因素的敏感性系数值,提出盐穴储气库在运营过程中运行工况发生变化时腔体年体积收缩率的预测方法。结果表明除了盐岩本身的蠕变特性参数,从宏观角度分析,相邻腔体运行模式、单周期内低压运行时间比例和腔体高径比是盐穴储气库腔体收缩风险的敏感因素。因此,在腔体的建设和运营过程中,采用邻近腔体同采同注的运行模式,尽量减少低压运行时间,同时合理控制腔体的成腔形状,可以有效控制腔体的体积收缩变形。     

Design and operation problems related to water curtain system for underground water-sealed oil storage caverns

The underground water-sealed storage technique is critically important and generally accepted for the national energy strategy in China.Although several small underground water-sealed oil storage caverns have been built in China since the 1970 s,there is still a lack of experience for large-volume underground storage in complicated geological conditions.The current design concept of water curtain system and the technical instruction for system operation have limitations in maintaining the stability of surrounding rock mass during the construction of the main storage caverns,as well as the long-term stability.Although several large-scale underground oil storage projects are under construction at present in China,the design concepts and construction methods,especially for the water curtain system,are mainly based on the ideal porosity medium flow theory and the experiences gained from the similar projects overseas.The storage projects currently constructed in China have the specific features such as huge scale,large depth,multiple-level arrangement,high seepage pressure,complicated geological conditions,and high in situ stresses,which are the challenging issues for the stability of the storage caverns.Based on years' experiences obtained from the first large-scale(millions of cubic meters) underground water-sealed oil storage project in China,some design and operation problems related to water curtain system during project construction are discussed.The drawbacks and merits of the water curtain system are also presented.As an example,the conventional concept of "filling joints with water" is widely used in many cases,as a basic concept for the design of the water curtain system,but it is immature.In this paper,the advantages and disadvantages of the conventional concept are pointed out,with respect to the long-term stability as well as the safety of construction of storage caverns.Finally,new concepts and principles for design and construction of the underground water-sealed oil storage caverns are proposed.     

海岛地下水封洞库围岩稳定性及水封可靠性研究

为提高我国的石油储备量及海岛资源利用率,在海岛环境建造地下水封油库成为了一种新的思路。海岛环境相比于内陆具有更好的水力条件,且可作为港口,便于油品运输。以某海岛地下水封油库为依托,基于流固耦合理论,采用有限元数值模拟方法对海岛环境建造地下水封洞库的围岩稳定性和水封可靠性进行研究。结果表明:在海岛环境建造地下水封洞库围岩的应力和位移均较小,可以满足围岩稳定性要求;在不设置水幕系统情况下,开挖地下洞库会在洞库上方形成明显的降落漏斗,部分洞库顶部甚至发生疏干现象,无法满足水封可靠性要求;在设置水幕系统后,地下洞库上方可形成较大厚度的地下水覆盖层,可以满足水封可靠性要求。该成果对在海岛环境下建造地下水封洞库的研究具有借鉴意义。     

大型地下石油洞库自然水封性应力-渗流耦合分析

根据地质条件,地下水封石油洞库可以选择自然水封或人工水封方式。以中国首个大型地下水封石油洞库为背景,开展了岩石三轴压缩试验和现场水文试验,获得了洞库围岩变形特征和渗透特性,采用应力-渗流耦合理论,分析了该地下石油洞库的自然水封性与稳定性。岩石三轴实验表明,岩体受剪作用下体积变化情况与剪胀性密不可分。现场水文试验表明,洞库渗透系数存在一定的不确定性。通过数值分析得出如下结论：自然水封条件下,洞库水位将不满足水封要求;地下水封洞库实现水封条件的水头受水力梯度和岩体渗透性影响;洞库施工期涌水量与渗透系数存在着分形关系;施工期各洞室拱顶沉降为19～32 mm,水平收敛为16～35 mm。研究成果为中国首个大型地下水封石油洞库工程建设提供了科学依据。     

地下盐穴处理核废料的方法

核废料对环境和人类安全具有较大危害,如何安全高效处理常常是困扰人类的棘手问题,目前认为有效的处理方式是深部埋藏处理,利用盐穴进行核废料的深埋处理是一种较为安全的方法。盐穴就是在地下盐层中通过钻井,利用水循环的方法,将盐层溶解,最终形成一个体积较大的空洞。利用地下盐穴可以进行各种工业废料的埋藏处理,特别是对具有放射性污染的核废料。建设埋藏放射性核废料的盐穴需要选择地质条件好,具有良好封闭性的盐层中,造穴方式主要是通过水溶洗盐形成地下溶洞。埋藏核废料需要通过一系列的特定工艺才能完成,放射性核废料埋藏处理后需要进行监测以防止产生污染事故。一般来说,由于地下盐穴埋深大、盐穴封闭性好,具有较高的安全性。利用盐穴进行核废料的埋藏具有费用低、容量大、占地少、安全性高等优点,是一种可以推广应用的核废料处理新方法。     

地下水封洞库岩体渗透系数估算研究

 在分析现有主要岩体渗透系数估算模型适宜性的基础上,根据地下水封洞库区岩体渗透性特征,依据烟台LPG洞库岩体渗透系数测试数据,以岩石质量指标(RQD)、岩体完整性指标(RID)、裂隙宽度指标(AD)、岩石渗透性指标(LPD)为建模指标,建立地下水封洞库岩体渗透系数估算模型--RMP模型,并采用该RMP模型估算青岛地下水封洞库区14个钻孔277段岩体的渗透系数。研究结果表明,青岛地下水封洞库岩体渗透系数空间分布随机性较大,其中57.04%的渗透系数集中于10－4 m/d≤K＜10－3 m/d的区间内。研究成果对地下水封洞库工程的水幕系统设计和水封效果评价具有一定理论意义和工程参考价值。     

Experimental study of water curtain performance for gas storage in an underground cavern

An artificial water curtain system is composed of a network of underground galleries and horizontal boreholes drilled from these galleries.Pre-grouting measures are introduced to keep the bedrock saturated all the time.This system is deployed over an artificial or natural underground cavern used for the storage of gas（or some other fluids） to prevent the gas from escaping through leakage paths in the rock mass.An experimental physical modeling system has been constructed to evaluate the performance of artificial water curtain systems under various conditions.These conditions include different spacings of caverns and cavern radii located below the natural groundwater level.The principles of the experiment,devices,design of the physical model,calculation of gas leakage,and evaluation of the critical gas pressure are presented in this paper.Experimental result shows that gas leakage is strongly affected by the spacing of water curtain boreholes,the critical gas pressure,and the number and proximity of storage caverns.The hydraulic connection between boreholes is observed to vary with depth or location,which suggests that the distribution of water-conducting joint sets along the boreholes is also variable.When designing the drainage system for a cavern,drainage holes should be orientated to maximize the frequency at which they encounter major joint sets and permeable intervals studying in order to maintain the seal on the cavern through water pressure.Our experimental results provide a significant contribution to the theoretical controls on water curtains,and they can be used to guide the design and construction of practical storage caverns.     

Latest technology of underground rock cavern excavation in Japan

Four major projects with large-scale rock underground caverns are discussed in this report; two hydropower stations, one underground oil storage facility and one underground museum in Japan. The technology applied to the construction of these caverns have some unique characteristics and can be applied to various other underground uses for different purposes and applied to larger-scale underground rock caverns with different geological and in situ stress conditions. Generally, construction of an underground cavern is comprised of five major activities: geological investigation; cavern stability analysis; initial rock support design; excavation works; and redesign of rock support according to the observational construction method. Weighted factors allocated among these factors should be established based on the rock properties and the purpose of the underground cavern use, which would define the major characteristics of the construction project. This report discusses some of major characteristics of these projects in Japan.     

水封式地下储气洞库的应用及研究

通过对水封式地下储气洞库应用及发展的描述 ,指出利用地下洞室储存石油液化气LPG(LiquefiedPetroleumGas)是当前乃至将来的大趋势。并对水封式地下储库的基本原理及设计作了较为详细的论述。对我国地下储气工程的修建及理论研究有一定的参考价值。     

Hydrocarbon storage in unlined rock caverns: Norway's use and experience

In Norway, approximately 10 large unlined cavern storage plants for crude and refined oil products currently are in operation, and two are under construction. A large number of small underground storage plants for refined oil products, consisting of steel tanks in rock caverns, also are in operation. The caverns are constructed in mostly good quality rock of the Precambrian or Cambro-Silurian age, and few stability problems have occured. Cavern spans up to 22 m and heights up to 40 m have been used. Bolting and shotcrete are partly used to increase rock mass stability. Norwegian experience indicates that for installations larger than roughly 50,000 m³, unlined rock caverns would be the most cost advantageous alternative. Other advantages are better environmental protection, better security with regard to fire and explosion hazard and sabotage, and lesser land requirements.     

天然气盐岩洞室群长期存储能力

对某天然气存储场盐岩洞室群的长期变形进行了三维有限元法流变分析。盐岩洞室周边附近区域内围岩的应力较低,其分布呈现出抽水井附近的水压力特征。当达到设计使用年限(80a)时,该天然气存储场内单一洞室的剩余存储能力保有初始存储能力的29.1%。进一步研究表明,当洞室间距较大时,单一洞室的剩余存储能力较大。间距400m的洞室群中单一洞室的剩余存储能力比间距280m的大5%～10%。     

Storage in lined hard-rock cavens: results of a pilot study

Spiraling natural gas consumption has increased the demand for high-pressure underground gas storage facilities. The proven methods of gas storage in porous geological formations and salt caverns are limited to locations with suitable geological conditions. At present, innovative techniques for high-pressure underground gas storage in lined hard rock caverns are being investigated in order to increase the number of potential sites and raise supply security. Because of the permeability of the generally jointed hard rock masses, these caverns have to be sealed by a lining system. This paper reports the results of a feasibility study of high-pressure gas storage in lined hard rock caverns. The paper commences with a look at the potential uses of hard rock caverns for gas storage, and pertinent design requirements. A preliminary concept for the caverns and the gas plant is discussed, with specific emphasis on geological boundary conditions, rock mechanics and construction. The paper concludes with a discussion of technical and economic feasibility considerations for this storage concept.     

盐岩中能源(石油和天然气)地下储存库稳定性评价标准研究

由于盐岩属于一类特殊的岩体，储存库的稳定性分析的评价标准与其他岩体有差别，在各国并没有统一的标准和设计规范，多数是用数值计算的方法来评价储存库的稳定性。主要做法是根据具体的储存库及其岩体力学特性，预先设置储存库稳定性的一些标准，然后对盐岩及其相关的岩石进行大量的试验研究，得到所需要的计算参数，最后通过数值计算来确定储存库的稳定性。系统地提出了盐岩中能源储存库的稳定性研究的内容和评判标准，这些标准归纳起来有3个方面，即：(1)储存库稳定性标准如不允许出现片邦，不允许出现蠕变破坏、安全矿柱和地面沉降控制准则；(2)储存库密封性标准如最大内压控制准则；(3)储存库可使用性标准如储存库体积收敛性。同时给出一个算例，以说明如何评价储存库的稳定性，并说明对储存库稳定性评判标准可以根据具体的情况做必要的修改。     

杨房沟水电站地下厂房围岩稳定分析

杨房沟水电站地下厂房是典型的大跨度、高边墙地下洞室群,工程区地质条件较复杂,高边墙及洞室间岩柱的稳定性是洞室设计的关键。根据地应力测试数据,采用边界位移条件回归方法,构造出厂区初始地应力场。采用FLAC3D软件对洞室群围岩稳定进行计算分析,获得洞周围岩变形与应力特征、塑性区分布及支护结构的受力状态,对地下厂房洞室群围岩稳定性做出评价,为洞室设计提供了科学依据与技术指导。     

Application of heat transfer analysis for frozen food storage caverns

Supply of high quality preserved food products has always been very important. Storage of food in underground caverns is superior over food storage tanks constructed at surface from an energy conservation point of view. There are a lot of underground openings excavated in tuff used for the storage of fruits and vegetables at the Cappadocia Region of Turkey. However, there has not been any attempt to use these underground openings for deep frozen food storage and related heat transfer details. The main purpose of this work was to investigate underground food storage openings in the Cappadocia Region and their potential use for frozen food storage. Details of heat transfer around openings for various geometrics in three-dimensional have been modelled by using a finite element software package called MARC. For the sake of comparison, heat transfer details around a similar opening excavated in granite were also determined. A comparison of underground caverns excavated in tuff and granite with a surface deep freeze storage tank was also made by both taking construction and operational costs into account. Construction of an underground deep freeze storage cavern excavated in tuff would cost one half of a same size surface tank whereas, energy loss due to heat transfer is three times lower in the favour of underground storage cavern opened in tuff.     

地下水封石油洞库渗水量预测与统计

渗水量规模与空间分布特征是地下水封石油洞库建设中的关键问题。以中国首个大型地下水封石油洞库项目为背景,采用经验公式、有限元法计算和现场实测等方法研究了该洞库渗水量规模和空间分布特征。在大量现场岩体渗透性试验基础上,获得了可靠的岩体渗透系数,采用经验公式和数值计算等方法对洞库渗水量规模和空间分布特征进行了预测。根据现场揭露的渗水形态,统计了洞库渗水量规模,获得了渗水量空间分布特征,调查了渗水部位地质特征,据此提出了渗水量控制标准和有针对性的工程注浆防渗对策。通过对比预测与统计结果,讨论了渗水量规模预测方法适用性和渗水量空间分布特征离散性等问题。研究成果为提高中国地下水封石油洞库建设水平提供了理论支持,并为复杂条件下地下工程渗流特性研究提供了工程实例。