INTRODUCTIONThis paper reports the results of work on (i) characterizingflows in wells with perforated casings (as in Figure 1) withAt the present time,over 400 downhole heat exchangers arebeing used in relatively shallow wells for extraction ofgeoth

INTRODUCTIONThis paper reports the results of work on (i) characterizingflows in wells with perforated casings (as in Figure 1) withAt the present time,over 400 downhole heat exchangers arebeing used in relatively shallow wells for extraction ofgeoth
INTRODUCTION
This paper reports the results of work on (i) characterizing
flows in wells with perforated casings (as in Figure 1) with
At the present time,over 400 downhole heat exchangers are
being used in relatively shallow wells for extraction of
geothermal energy at Klamath Fall,OR.Despite the large
number of installations,the exact nature of the flows and
hence,the optimal heat exchanger designs have not been
determined.
Figure 1 shows a typical installation of a downhole heat
exchanger (DHE) as presently used for extracting geothermal
energy from the shallow,low-temperature geothermal
resource at Klamath Falls,OR (Culver,et al.,1974).It
consist of (i) the well bore,generally 15 to 36 cm in diameter
and drilled with a cable rig,(ii) a casing sealed to the well
bore at the top end for a distance of about 6 m and perforated
at two levels,at the hot water strata level (well bottom) and
just below the standing water level,and (iii) an unfinned U-
shaped heat exchanger made from bare steel pipe.
This paper reports the results of work on (i) characterizing
flows in wells with perforated casings (as in Figure 1) with
and without DHEs installed,(ii) determining energy
extraction rates for conventional DHEs in both cased and
uncased wells,and (iii) modeling of DHE systems to predict
effects of heat exchanger and well variable changes.

INTRODUCTIONThis paper reports the results of work on (i) characterizingflows in wells with perforated casings (as in Figure 1) withAt the present time,over 400 downhole heat exchangers arebeing used in relatively shallow wells for extraction ofgeoth
引言
本文报道工作的结果,（我）表征
在与穿孔肠衣井流（如图1）
目前,为了汲取地热,在俄勒冈州的Klamath Falls地区的诸多浅井中大约安装有400多具井下热交换器.尽管装置为数不少,由于水/热流的确切性质还无法掌握,因而在此基础上的热交换器优化设计也无法确定.
图1显示了一个典型的井下热交换器,这种装置在俄勒冈州Klamath Falls地区普遍用于从该地的浅层低温地热源汲取地热能量.它由以下几部分构成：(i)井孔,直径为15到36厘米,通常用钢绳钻井钻成,(ii)一个封闭在井孔上端六米的加固护套,还有两个钻孔护套,一个装在地下热水层(井底)处,另一个紧紧凑在常温地下水层下方,(iii)一具由钢管制的无翼U型热交换器.
本文总结了以下研究的结果,(i)对于装有穿孔护套(见图1)的地热井,在装有及未装井下热交换器两种情况下,就其中的水/热流归纳出其特征.(ii)确定装有护套及未装护套两类井中的井下热交换器的能源提取率,(iii)建立井下热交换器系统的模型,以预测热交换器的效应和地热井变量的变化