Thermal stresses analysis of casing string used in enhanced geothermal systems wells

IF 16.4 1区化学 Q1 CHEMISTRY, MULTIDISCIPLINARY

Accounts of Chemical Research Pub Date : 2016-12-01 DOI:10.26599/jgse.2016.9280033

P. Zhang

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引用次数: 1

Abstract

: In the enhanced geothermal systems wells, casing temperature variation produces casing thermal stresses, resulting in casing uplift or bucking. When the induced thermal stresses exceed casing material ’ s yield strength, the casing deforms and collapses. The traditional casing design standard only considers the influence of temperature variation on casing material ’ s yield strength. Actually, for commonly used grades of steel pipe, casing ’ s material properties-such as yield strength, coefficient of thermal expansion, and modulus of elasticity change with temperature variation. In this paper, the modified thermal stress equation is given. Examples show that the allowable temperature of the material grade N80 ’ s casing is only 164 ℃ , which is much lower than that of the traditional design standard. The effective method to improve the casing pipe ’ s allowable temperature is pre-stressed cementing technology. Pre-stressed cementing includes pre-tension stress cementing and pre-pressure stress cementing. This paper focuses on the design method of full casing pre-tension stress cementing and the ground anchor full casing string pre-tension cementing construction process.

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增强型地热系统井套管柱热应力分析

在增强型地热系统井中，套管温度变化会产生套管热应力，导致套管隆起或屈曲。当诱导热应力超过套管材料的屈服强度时，套管就会发生变形和坍塌。传统的套管设计标准只考虑了温度变化对套管材料屈服强度的影响。实际上，对于常用牌号的钢管，套管的材料性能，如屈服强度、热膨胀系数、弹性模量等都是随温度的变化而变化的。本文给出了修正后的热应力方程。实例表明，N80材料等级外壳的允许温度仅为164℃，远低于传统设计标准。提高套管许用温度的有效方法是预应力固井技术。预应力固井包括预张应力固井和预压应力固井。本文重点介绍了全套管预张应力固井的设计方法和地锚全套管管柱预张应力固井施工过程。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Accounts of Chemical Research 化学-化学综合

CiteScore

31.40

自引率

1.10%

发文量

312

审稿时长

2 months

期刊介绍： Accounts of Chemical Research presents short, concise and critical articles offering easy-to-read overviews of basic research and applications in all areas of chemistry and biochemistry. These short reviews focus on research from the author’s own laboratory and are designed to teach the reader about a research project. In addition, Accounts of Chemical Research publishes commentaries that give an informed opinion on a current research problem. Special Issues online are devoted to a single topic of unusual activity and significance. Accounts of Chemical Research replaces the traditional article abstract with an article "Conspectus." These entries synopsize the research affording the reader a closer look at the content and significance of an article. Through this provision of a more detailed description of the article contents, the Conspectus enhances the article's discoverability by search engines and the exposure for the research.