加强地热回灌 小汤山热田水位显著回升

为有效保护地热资源，促进北京市地热资源的可持续利用。近年来，北京市地热管理处不断加强地热采暖回灌的管理，拟定并发布了《关于加强地热回灌保护地热资源的通知》，对本市地热采暖单位明确提出了限期进行地热采暖尾水回灌的要求。用地热水供暖单位中的大多数均采用了“对井”回灌技术，供暖尾水实时回灌到同一热储层中，全市年回灌量近100万m^3。     

地热资源的可持续开发利用

通过对西安工程技术学院地热资源开发利用的实例分析,证明了采用梯级地热供暖的方法可以扩大供暖面积,并且地热梯级供热技术已经取得显著的经济效益和社会效益.采用打回灌井的方法,通过向回灌井回灌地热尾水可以解决地热井水位下降过快的难题,回灌试验和经济分析的结果表明,回灌方案在技术上是可行的,经济上是合理的.     

U型井取热不取水地热开采潜力及影响因素分析

取热不取水井筒闭循环采热工艺是开采地热水低产区、地热尾水回灌难地区地热资源的有效方式。为了研究U型井式闭循环地热系统对中低温砂岩地热资源的可持续开采能力,文章以河北任县已有的地热地质数据和短期供暖数据为基础,使用井-储耦合模拟程序T2WELL对U型井采热能力进行数值分析,探究U型井式闭循环地热系统对该研究区地热供暖的可持续潜力。此外,定量分析了不同关键工程参数对U型井提热能力的影响,以指导设计合理的U型井取热不取水地热开采方案。结果表明：U型井地热开采系统的产流温度和提热功率在同一个供暖季内随时间降低,在连续多个供暖季内也随时间降低,其变化趋势为先快后慢。基于文章模型研究,确定U型井式闭循环地热系统最适合的注采流量、回灌温度、水平井长度分别为60 m3/h,10℃和400 m。     

供热规划区热储模型研究

地热尾水回灌作为一种处理手段和维持热储压力的一种方法，已在很多地热田有过实践，它对于开采第三系以上的热储层，控制地面沉降和环境保护有着重要的意义。本文针对低焓热储地热田研究了回灌的影响、回灌率、热储渗透率的分布，针对对井回灌开采供热系统做了理论分析，研究了回灌对维持热储压力的水平范围和冷峰面的作用，对井的合理井间距等，将对井模拟研究应用于天津地热田。     

持续开发利用地热资源的实例分析

通过对西安工程技术学院地热资源开发利用的实例分析，证明通过采用梯级地热供暖的方法可以扩大原供暖面积，并取得显著的经济和社会效益。开采回灌井，通过回灌地热尾水，不但增加地热供暖面积，还有效控制地热井水位下降过快。     

地热供暖项目热储工程评价方法研究

地热资源以其清洁环保、可再生、能量大、开发利用设备相对简单的特点,近年来发展较快;但目前对地热资源的开发缺乏相关开发流程和评价方法。该文总结了1套地热供暖项目热储工程评价方法和流程,利用数值模拟和理论计算等方法对合理稳定涌水量、合理回灌量、采灌井数、井网部署、合理井距等技术参数进行优化,最后以H区为例进行了热储评价,验证了方法的可行性。该方法对于优化热储工程设计,指导合理有效的开发地热资源具有借鉴意义。     

地热水回灌井内换热新技术

当前地热水开采使用中浪费水资源与热能的现象不容忽视。文章介绍使用回灌井和井内换热器的新型地热不供热系统,对解决地热水浪和地热供热事业可持续发展具有现实意义。     

地热单井回灌渗流场理论研究

在地热开发过程中经常遇到如下问题：热储压力随开采量和时间的增加而降低，地热尾水排放造成热污染和资源浪费等。回灌是解决上述问题的有效方法。针对回灌过程中渗流场的动态变化，建立地热回灌渗流场数学模型，推导了渗透系数恒定与变化时不同条件下的单井回灌公式。实例分析表明：所得公式能够表征回灌渗流场中各变量之间的相互关系，可以解释和预测回灌过程中水头与流量的变化趋势。     

资源评价与数值模拟在对井回灌系统中的应用

主要针对低焓热水型地热热储，分析了对井系统种类参数依赖的因素，关系以及相关程度，回灌率的选取，渗透率在含水层中三维分布情况对开采区域的影响，回灌对维持热储压力的水平范围和回灌冷水的影响程度，对井的合理井间距等，并针对兰庄地热田地热地质的非均质，各向异性特点，研究了该区的地热地质构造特性，地下资源储量，水资源补给可能性，评价了该地区地热资源的开发潜力。     

浅议孔隙型热储的回灌能力

河北平原的地热资源多数储存在第三系孔隙型热储层中,是目前我国地热资源开发的主要热储层之一。由于河北省对该热储层的开采规模扩大、开发利用水平偏低、资源浪费较严重,致使多个地热田的地热水位下降速率惊人。目前,有的地热田已面临资源枯竭的危险。因此,对孔隙型热储层实施地热尾水的回灌已势在必行。本文以第三系孔隙型热储层的回灌试验数据为基础,对孔隙型热储层的回灌能力及回灌的可行性进行初步的研究。     

Modeling studies for production potential of Chingshui geothermal reservoir

The Chingshui geothermal power plant was decommissioned in 1993 due to a continued decline in production. Although some geothermal exploration and field investigation had been exercised, the production potential of the reservoir is still not well understood. In this paper, numerical modeling approaches for characterization of the geothermal reservoir, investigation of reservoir production performance, and evaluation of exploitation scheme design are presented. At first, a site-scale refined grid numerical model was developed for simulating the natural state of Chingshui geothermal reservoir. Through the model, the production potential of the geothermal reservoir was estimated and the availability of water resources was assessed. We further built production model to simulate the production history during 1981–1993. From the production model, we can conclude that the abnormal drop of the reservoir production capacity is mainly caused by carbonate scaling. Potential production schemes with different reinjection designs were evaluated through the model. Simulation results indicated that a sustainable hot water production capacity of Chingshui geothermal reservoir is about 200 t/h without reinjection, and 300 t/h or even higher with reinjection which is enough for a 3 MWe power plant. The simulation results indicate that reinjection provides an effective approach for maintaining reservoir pressure during hot water/steam production.     

考虑热储特征的地热梯级供暖系统经济性及环境效益

地热梯级供暖系统在建筑供暖方面具有广阔的应用前景,但投资费用较高,且当前对地热梯级供暖系统的环境效益影响研究尚存在欠缺。建立了考虑热储特征的地热梯级供暖系统数学模型,以河北省雄县的雾迷山组碳酸盐岩热储为例,分析了井距、井深、回灌温度和地热水流量对地热梯级供暖系统平准化供热成本（LCOH）与污染物减排量（AOER）的影响。结果表明,地热梯级供暖系统存在临界井距和经济回灌温度,且在一定工况范围内,增加地热井深度及提高地热水流量有利于提高系统的经济性及环境效益,但改善幅度逐渐减弱。此外,以LCOH最小与AOER最大为目标函数,利用遗传算法对地热梯级供暖系统开展多目标优化,并通过模糊集决策方法确定了给定工况下的最优解决方案。     

滨海新区东营组地热热储回灌开采优化方案的研究

建立了天津滨海新区东营组热储层的物理和数学模型,分析了不同采灌模式对热储层压力场和温度场的变化特征和影响程度,提出了优化方案.结果表明:回灌能有效缓解热储层压力下降速率,延长热田寿命,并合理利用有限的热储资源.研究结果可为滨海新区地热资源的科学开发提供理论依据.     

地热外围回灌优化开发方案的研究

根据地质构造特征和地热资源评价,针对目前在资源开采阶段补建回灌井所面临的问题(包括断裂构造对热储层发育、地热流体径流补给通道等因素的影响以及地理位置的限定),提出了在中心采区外围实施回灌的新思路。结合不同采灌模式,对压力场和温度场的变化特征及影响程度分别进行分析。从分析结果可知,外围回灌将会较好的控制中心采区水位下降速率,延长热突破时间,最大限度地挖掘热储潜力,还可解决在中心采区补建回灌井空间位置不足的问题。     

Changes in thermodynamic conditions of the ahuachapán reservoir due to production and injection

Since large-scale exploitation of the Ahuachapán reservoir began in 1975 large changes in the reservoir thermodynamic conditions have occurred. Drawdown of up to 15 bars and significant temperature changes have been observed in the wellfield. Temperatures have declined due to boiling in the reservoir in response to the pressure drawdown; localized and minor cooling due to reinjection of spent geothermal fluids have also been observed. There are indications of cold fluid influx deep into the reservoir from the west and north. Reservoir temperatures show that a significant amount of hot fluid recharge comes to the wellfield from the southeast, and temperatures also indicate that the recharge rate has increased with time as pressure declines in the reservoir. Chemical analyses of the produced fluids show that most wells are fed by a mixture of geothermal fluids and cooler, less-saline waters. The cold water inflow has increased due to exploitation, as demonstrated by decreased salinity of the produced fluids.     

中低温孔隙型地热田回灌试验研究

以天津武清地热田为例,探讨在孔隙介质地热田开展回灌的技术可行性,武清地热田主要开采层为第3系馆陶组砂岩,热储层温度76－86℃,1998年总开采量达到1.18Mn^-3,经过数学模型预测,该热储水位降深将在近期内趋于稳定,在无回灌条件下,如果以最大开采量持续开采,将导致5年内水位下降到105m,如果增加3眼回灌井,水位下降幅度将碱缓15m,此外,计算了在回藻过程中各种不同情况下冷锋面的运移速率,并进一步探讨了示踪剂试验的可行性。     

Simulation of reinjection at Cerro Prieto using an idealized two-reservoir model

Most of the papers published on the hydrodynamic and thermal effects of reinjection in geothermal fields assume a single reservoir with uniform transmissivity and storativity. However, there is evidence that the Cerro Prieto geothermal field is a two-reservoir system and that each reservoir has different hydraulic properties (Abril and Noble, 1979). Because two-reservoir fields have not been adequately studied, we will analyze the thermohydrological response of this kind of geothermal system to various alternative schemes of reinjection. We use parameters relevant to the Cerro Prieto system so that the results will be useful in planning future reinjection operations at this field.     

西藏羊易EGS开发储层温度场与开采寿命影响因素数值模拟研究

西藏羊易地区具有丰富的地热能,单井开发潜力接近10 MW,对其深部热储进行EGS开采,可缓解西部能源紧缺问题。本文建立二维理想EGS开发模型,探讨深层地热开采过程中开采流量、注采方式、注入温度等参数对热储温度场分布及开采寿命的影响。基于羊易温度信息设计了12个数值模型,对比研究发现,开采流量对EGS开采的影响较大,为保证开采50年内的商业利用价值,最大开采流量应控制在0.028 kg/s以下;考虑到钻井成本,注采方式的选择以高注高采和中注高采为最佳;注入温度对热储开采影响较小,可选择40℃ ~ 80℃之间任意温度的地热尾水进行回灌,实现地热资源梯级利用。     

Geothermal reinjection experience

Reinjection into geothermal reservoirs is discussed and the experience gained by reinjection experiments in 44 geothermal fields is reviewed. Reinjection started purely as a disposal method, but has more recently been recognised as an essential and important part of reservoir management. Only a small part of the thermal energy in place in geothermal reservoirs can be recovered if reinjection is not applied. Thermal breakthrough has been observed in few geothermal reservoirs but has in all cases been found to be a manageable part of field operation. Silica scaling in surface equipment and injection wells is a delicate aspect of the reinjection process in most high-temperature geothermal fields, but silica scaling in the reservoir has not been considered a problem. Reinjection of low-enthalpy geothermal fluid into sandstone has not been successful, for reasons that are poorly understood. The location of injection wells in relation to production wells influences the ratio of injected fluid recovered in production wells. For peripheral injection, about one third of the injected fluid is commonly recovered, whereas injection within the production area results in a higher ratio of recovered fluid. Subsidence is in general of small concern in geothermal operations and micro-gravity has proved a valuable tool to estimate the recharge to geothermal reservoirs.