Living-Energy/Water-地热/地冷-:砂岩地层U型管深井闭环地热评估
266. [加拿大:砂岩地层U型管深井闭环地热评估](266. 加拿大砂岩地层U型管深井闭环地热评估 ...) ...
EVALUATION OF CLOSED-LOOP U-TUBE DEEP BOREHOLE HEAT EXCHANGER IN THE BASAL CAMBRIAN SANDSTONE FORMATION, ALBERTA, CANADA
DBHE系统(闭环深井筒换热器)具有将热量从地热源传输至流体回路中的优势。
本研究首次对加拿大阿尔伯塔省一个2330米深的地热储层的U型闭环DBHE评估每单位能源投入所产生的能量。
通过建立精细的从地表到地热源的数值模拟模型，我们可以了解该过程的效率。
结果表明，在U形回路的上升段，流体流动达到最高温度，而不是底部段，这意味着工质的热应从U形回路的上升段开始。
结果显示，闭环系统的能量产出和能量投入比可以达到7 GJ/GJ。
尽管这种效率令人鼓舞，但是通过换热面积的限制，回路在地热储层采集到的热能的绝对量受到限制。
Abstract
Closed-loop deep borehole heat exchanger (DBHE) systems for producing heat from geothermal sources have the advantage that the heat transfer fluid is contained within the loop. In this study, for the first time, a U-configuration closed-loop DBHE was examined to evaluate the energy produced per unit energy invested from a 2330-m-deep geothermal reservoir in central Alberta, Canada. A detailed earth model where the system is modeled from the surface to the geothermal source is used in a numerical simulation model to understand the efficiency of the process. The results reveal that the fluid flow reaches its highest temperature in the ascending section of the U-loop rather than the bottom section which implies that the insulation on the working fluid should start in the ascending section of the U-loop. The results demonstrate that the closed-loop system can achieve ratios of the energy produced and energy invested of 7 GJ/GJ. Although this efficiency is promising, the absolute amount of heat energy harvested is limited by the loop’s heat transfer area in the geothermal reservoir.
中深层U型井供热技术原理与实践
2021-11-22罗娜宁申小龙原博晨
https://m.fx361.cc/news/2021/1122/12462389.html
(1)现阶段国内已开发出多种煤层专用钻井液，现场应用表明其稳定井壁效果显著；
(2)国内已开展钻井筛管完井、充气欠平衡钻井、分段压裂等U型井钻完井新技术研究[27-28]；
(3)远距离连通技术是U型井开发的核心技术，现阶段已取得较好的成绩。专有井眼连通技术可以实时检测控制钻进轨迹，为定向提供距离和方位参数，即时调整工具面，指导钻头向洞穴井钻进，实现水平井与洞穴井较好连通[28]。
(4)组合U型井钻采技术的优化设计，可实现多口U型井共用一口直井进行排采，从而节约地面资源，发挥一井多用的作用。
2 中深层U型井供热技术原理与实践
2.1 技术定义
U型井应用于中深层地热供热系统的技术原理是在U型对接井中泵入循环工质，经水平井段及直井从中深层岩土体中吸收热量，后由直井出水供至热泵供暖系统，降温再返回U型井井下换热系统，从而实现“取热不取水”清洁供热。