- 記錄人類文明的那些美文（環球時代美文讀本）
- 吳中東 宮玉波
- 1531字
- 2020-08-20 09:57:23
12 Geothermal
Resources
地質學：介紹地熱的開發利用
導讀
地熱是來自地球內部的一種能量資源。地球上火山噴出的熔巖溫度高達1200℃～1300℃，天然溫泉的溫度大多在60℃以上，有的甚至高達100℃～140℃。這說明地球是一個龐大的熱庫，蘊藏著巨大的熱能。這種熱量滲出地表，于是就有了地熱。地熱能是一種清潔能源，是可再生能源，其開發前景十分廣闊。本文主要介紹了地熱的開發利用。
The energy contained in rock within the Earth's crust represents a nearly unlimited energy source, but until recently commercial retrieval has been limited to underground hot water and/or steam recovery systems. These systems have been developed in areas of recent volcanic activity, where high rates of heat flow cause visible eruption of water in the form of geysers and hot springs. In other areas, however, hot rock also exists near the surface but there is insufficient water present to produce eruptive phenomena. Thus a potential hot dry rock (HDR) reservoir exists whenever the amount of spontaneously produced geothermal fluid has been judged inadequate for existing commercial systems.
As a result of the recent energy crisis, new concepts for creating HDR recovery systems—which involve drilling holes and connecting them to artificial reservoirs placed deep within the crust—are being developed. In all attempts to retrieve energy from HDR's, artificial stimulation will be required to create either sufficient permeability or bounded flow paths to facilitate the removal of heat by circulation of a fluid over the surface of the rock.
The HDR resource base is generally defined to include crustal rock that is hotter than 150℃, is at depths less than ten kilometers, and can be drilled with presently available equipment. Although wells deeper than ten kilometers are technically feasible, prevailing economic factors will obviously determine the commercial feasibility of wells at such depths. Rock temperatures as low as 100℃ may be useful for space heating; however, for producing electricity, temperatures greater than 200℃ are desirable.
The geothermal gradient, which specifically determines the depth of drilling required to reach a desired temperature, is a major factor in the recoverability of geothermal resources. Temperature gradient maps generated from oil and gas well temperature-depth records kept by the American Association of Petroleum Geologists suggest that tappable high-temperature gradients are distributed all across the United States. (There are many areas, however, for which no temperature gradient records exist.)
Indications are that the HDR resource-base is very large. If an average geothermal temperature gradient of 22℃ per kilometer of depth is used, a staggering 13,000,000 quadrillion B.T.U.'s of total energy are calculated to be contained in crustal rock to a ten-kilometer depth in the United States. If we conservatively estimate that only about 0.2 percent is recoverable, we find a total that is comparable to the estimated resource base of all the coal remaining in the United States. The remaining problem is to balance the economics of deeper, hotter, more costly wells and shallower, cooler, less expensive wells against the value of the final product, electricity and/or heat.
地球地殼巖石中的能量代表一種幾乎是無盡的能源，但是直至最近，商業回收工作一直局限于開發地下熱水或者地下蒸汽的回收系統。這些系統是在新近火山活動區開發出來的。在這些地區，高速度的熱流以間歇噴泉和溫泉的可見形式噴發出來。可是，在其他地區，接近地面也存在有熱巖，但缺乏足夠的水以產生噴發現象。這樣，每當自發產生的地熱流量被鑒定為不足以為現行商業系統所利用時，就存在一個可能的干熱巖庫。
由于最近的能源危機，關于建立干熱巖庫回收系統的新概念正在形成。這個回收系統必須包括鉆洞，并把所鉆的洞跟置于地殼深處的人造蓄熱庫聯結起來。在所有試圖從干熱庫回收能源的努力中，人工的刺激是必要的，為的是創造充分的滲透度，或建造封閉的流道，以推進通過巖石表面的流體環流來回收熱能。
干熱巖源區一般規定為包括熱度超過150℃、深度小于10千米、能用現在可以得到的設備來鉆探的地殼巖石。雖然深度大于10千米的井孔在技術上是行得通的，但是流行的經濟因素顯然會決定鉆井深度的商業上的可行性。巖石溫度低于100℃可用于空間加熱；可是為了發電，合乎需要的溫度要高于200℃。
具體決定達到預定溫度所需鉆探深度的地熱梯度是回收地熱能源的主要依據。根據美國石油地質學家協會所保存的根據油氣井溫度記錄繪制出來的溫度梯度變化曲線圖表明：可開發的高溫梯度區分布在美國全國各地（不過，有許多地區還沒有溫度梯度記錄）。
有開采價值的礦苗表明，干熱巖源區是很大的。假如用平均地熱溫度梯度每千米深度22℃來估算，那么美國10千米深度的地殼巖石所含的總能量為13000000億億英國熱量單位，這是一個令人驚愕的數字。假如按保守的估算，只可回收大約0.2%的話，那么其總量相當于美國現存估算的全部煤炭資源。剩下的問題是如何權衡更深更熱而費用更大的熱源井與較淺較冷而費用較小的熱源井同最終產品（電力和熱能，或者是電力或熱能）的價值之間的利害得失關系。
Sentence Translation
句子翻譯
1. These systems have been developed in areas of recent volcanic activity, where high rates of heat flow cause visible eruption of water in the form of geysers and hot springs.
2. The geothermal gradient, which specifically determines the depth of drilling required to reach a desired temperature, is a major factor in the recoverability of geothermal resources.
Key
1．這些系統是在新近火山活動區開發出來的。在這些地區，高速度的熱流以間歇噴泉和溫泉的可見形式噴發出來。
2．具體決定達到預定溫度所需鉆探深度的地熱梯度是回收地熱能源的主要依據。