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 stre...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.展开更多
A new kinematical shakedown theorem is presented under the consideration thatexternal load and temperature change slowly . A incremental collapse criterion, whichis simple and applicable, is also derived based on the ...A new kinematical shakedown theorem is presented under the consideration thatexternal load and temperature change slowly . A incremental collapse criterion, whichis simple and applicable, is also derived based on the theorem. In the end of this paper,its application is illustrated by an example.展开更多
A new flexible 3D porous metal-organic framework （MOF） with 1D open nanotube, [Co2（/zs-CTAl）（dpe）（H20）2]n-6n（H20） （1） （CTA = cyclohexane-1,2,4,5-tetracarboxylic acid, dpe = 1,2-di（4-pyridyl） ethylene） ...A new flexible 3D porous metal-organic framework （MOF） with 1D open nanotube, [Co2（/zs-CTAl）（dpe）（H20）2]n-6n（H20） （1） （CTA = cyclohexane-1,2,4,5-tetracarboxylic acid, dpe = 1,2-di（4-pyridyl） ethylene） has been prepared and structurally character- ized. Meanwhile, each 1D nanotubes filled with 1D water chain with dimension of 13.711 ~ 12.275/~2. Compound 1 represents a new example that collapse/deform upon dehydration/hydration and shows adsorb 1-120 selectively over organic solvents.展开更多
基金supported by the Hydrogeology Survey And Comprehensive Evaluation of Large Basin and Deep Typical Southeast Coastal Region(No.12120114025101)
文摘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.
文摘A new kinematical shakedown theorem is presented under the consideration thatexternal load and temperature change slowly . A incremental collapse criterion, whichis simple and applicable, is also derived based on the theorem. In the end of this paper,its application is illustrated by an example.
基金supported by the National Natural Science Foundation of China (20771090)State Key Program of National Natural Science Foundation of China (20931005)+1 种基金Major Research Plan of National Natural Science Foundation of China (91022004)Specialized Research Found for the Doctoral Program of Higher Education (20096101110005)
文摘A new flexible 3D porous metal-organic framework （MOF） with 1D open nanotube, [Co2（/zs-CTAl）（dpe）（H20）2]n-6n（H20） （1） （CTA = cyclohexane-1,2,4,5-tetracarboxylic acid, dpe = 1,2-di（4-pyridyl） ethylene） has been prepared and structurally character- ized. Meanwhile, each 1D nanotubes filled with 1D water chain with dimension of 13.711 ~ 12.275/~2. Compound 1 represents a new example that collapse/deform upon dehydration/hydration and shows adsorb 1-120 selectively over organic solvents.
