The Finite Element Analysis of Coupling Law of Stress Field / Seepage Field in Impermeable Stratum Medium

2011 ◽  
Vol 250-253 ◽  
pp. 298-304
Author(s):  
Jing Yan Li

In order to forecast the mining process of oil and gas field rightly, simulate the flow process of reservoir fluid accurately and reveal the fluid distribution law, it must be considered that multiphase fluid seepage caused by water injection and exploitation, the change of stress state and the coupling between the reservoir deformations. According to the basic theory of rock mechanics, fluid mechanics in porous medium, geologic mechanics, calculated mechanics and fluid-solid coupling seepage, a mathematical and numerical model of seepage field and stress field coupling is developed in porous medium and a computer program is designed with the method of finite element technique. The Coupling Law of depressurizing exploitation Seepage field /Stress field in porous medium is studied. By the method of numerical simulation the variation law of stress-strain with time and space around borehole of impermeable rock medium, variety law of rock physical properties parameters is studied. Results show that the quantity of change nearby oil well and the change gradient is bigger, so it reduces very quickly to the oil deposit boundary,the stress and the strain are also biger in the oil well control area's influence area.

2011 ◽  
Vol 71-78 ◽  
pp. 3067-3070
Author(s):  
Yu Fen Mei

The research of reservoir fluid-solid coupling theory is hot issues in home or foreign recently, In oil, civil, environment and geology, mining and other fields with a wide application. On the basis of summarizing the predecessors' achievements,according to the basic theory of rock mechanics, fluid mechanics in porous medium, geologic mechanics, calculated mechanics and fluid-solid coupling seepage, a mathematical and numerical model of seepage field and stress field coupling is developed in porous medium and the LiuNan blocks of JiDong oilfield wells.based area single phase Stress Field / Seepage Field in solving with the method of finite element software ANSYS, Contrast analysis of LiuNan blocks Coupling around of Field / Seepage Field is the change of average stress and total displacement. As can be seen from Table 3, after coupling the value of average stress and total displacement are greater than before coupling.The results show than it is important meaning for used to solve practical engineering problems.


2013 ◽  
Vol 405-408 ◽  
pp. 1278-1282
Author(s):  
Cheng Li ◽  
Tai Quan Zhou ◽  
Sha Sha Jiang ◽  
Jie Kong

The submarine geology characteristic for Qingdao submarine tunnel is fracture and fragmentation with smash rock mass and unevenly distributed rock mass strength. The submarine tunnel is excavated in a weathered rock mass containing water. Before the tunnel lining is constructed, it is important to assure the stability and safety for the rock tunnel and tunnel lining structure during construction and operational periods. As the submarine tunnel is under severe condition, the rock mass stabilization is to a large extent to be determined by the underwater seepage effect. It is fundamental to investigate how the seawater interacts with the tunnel rock mass stress field. To investigate the interaction between the rock mass seepage field and the secondary stress field, the nonlinear finite element software ABAQUS is used to analyze the interaction behavior between the rock mass seepage effect and the tunnel secondary stress field. The rock mass seepage field, stress field are analyzed in detail using the numerical simulation method. Also, the distribution of the tunnel rock mass plastic region is obtained. The numerical analysis results provide guidance for the submarine tunnel construction.


2011 ◽  
Vol 63-64 ◽  
pp. 597-602
Author(s):  
You Quan Huang

The research of reservoir fluid-solid coupling theory, especially that multiphase fluid seepage caused by water injection and exploitation, the change of stress state and the coupling between the reservoir deformations. In recent years, it caused than the great interest of chinese scholars, one of the hot topics is become the reservoir engineering and related field of research. According to the basic theory of rock mechanics, fluid mechanics in porous medium, geologic mechanics, calculated mechanics and fluid-solid coupling seepage, a mathematical and numerical model of seepage field and stress field coupling is developed in porous medium and a computer program is designed with the method of finite element technique. The Coupling Law of depressurizing exploitation Seepage field /Stress field in porous medium is studied. By the method of numerical simulation the variation law of stress-strain with time and space around borehole of impermeable rock medium, variety law of rock physical properties parameters is studied. Results show that the change of stress and strain is due to the fluid pressure of change by caused, the fluid pressure is greater, and the Stress and strain change is bigger. So from the far field pore pressure can be seen in near bottom-hole formed bigger fluid pressure, to reservoir boundaries, fluid pressure quickly cut. So, from the pore pressure of far field Pp are 15 Mpa, Pp are 21 Mpa, and Pp are 24Mpa,we can see that bigger flow pressure formed at the well bottom nearby. To the boundary of reservoir, the flow pressure decreases very quickly.


2007 ◽  
Vol 539-543 ◽  
pp. 2651-2656 ◽  
Author(s):  
C.J. Huang ◽  
E. Ghassemieh

A 3-D coupled temperature-displacement finite element analysis is performed to study an ultrasonic consolidation process. Results show that ultrasonic wave is effective in causing deformation in aluminum foils. Ultrasonic vibration leads to an oscillating stress field. The oscillation of stress in substrate lags behind the ultrasonic vibration by about 0.1 cycle of ultrasonic wave. The upper foil, which is in contact with the substrate, has the most severe deformation. The substrate undergoes little deformation. Apparent material softening by ultrasonic wave, which is of great concern for decades, is successfully simulated. The higher the friction coefficient, the more obvious the apparent material softening effect.


2011 ◽  
Vol 399-401 ◽  
pp. 1806-1811
Author(s):  
Yong Hong Chen ◽  
Peng Chen ◽  
Ai Qin Tian

The finite element model of the roof of aluminum high-speed train was established, double ellipsoid heat source was employed, and heat elastic-plastic theory was used to simulate welding residual stress of the component under different welding sequence based on the finite element analysis software SYSWELD. The distribution law of welding residual stress was obtained. And the effects of the welding sequence on the value and distribution of residual stress was analyzed. The numerical results showed that the simulation data agree well with experimental test data. The maximum residual stress appears in the weld seam and nearby. The residual stress value decreases far away from the welding center. Welding sequence has a significant impact on the final welding residual stress when welding the roof of aluminum body. The side whose residual stress needs to be controlled should be welded first.


Author(s):  
M. Perl

The equivalent thermal load was previously shown to be the only feasible method by which the residual stresses due to autofrettage and its redistribution, as a result of cracking, can be implemented in a finite element analysis, of a fully or partially autofrettaged thick-walled cylindrical pressure vessel. The present analysis involves developing a similar methodology for treating an autofrettaged thick-walled spherical pressure vessel. A general procedure for evaluating the equivalent temperature loading for simulating an arbitrary, analytical or numerical, spherosymmetric autofrettage residual stress field in a spherical pressure vessel is developed. Once presented, the algorithm is applied to two distinct cases. In the first case, an analytical expression for the equivalent thermal loading is obtained for the ideal autofrettage stress field in a spherical shell. In the second case, the algorithm is applied to the discrete numerical values of a realistic autofrettage residual stress field incorporating the Bauschinger effect. As a result, a discrete equivalent temperature field is obtained. Furthermore, a finite element analysis is performed for each of the above cases, applying the respective temperature field to the spherical vessel. The induced stress fields are evaluated for each case and then compared to the original stress. The finite element results prove that the proposed procedure yields equivalent temperature fields that in turn simulate very accurately the residual stress fields for both the ideal and the realistic autofrettage cases.


2013 ◽  
Vol 683 ◽  
pp. 556-559
Author(s):  
Bin Bin Jiao ◽  
Fu Sheng Yu ◽  
Yun Jiang Li ◽  
Rong Lu Zhang ◽  
Gui Lin Du ◽  
...  

In order to study the distribution of the stress field in the high-speed intermittent cutting process, finite element model of high-speed intermittent cutting is established. Exponential material model of the constitutive equation and adaptive grid technology are applied in the finite element analysis software AdvantEdge. The material processing is simulated under certain cutting conditions with FEM ( Finite Element Method ) and the distribution of cutting force, stress field, and temperature field are received. A periodic variation to the cutting force and temperature is showed in the simulation of high-speed intermittent cutting. Highest value of the milling temperature appears in front contacting area of the knife -the chip.and maximum stress occurs at the tip of tool or the vicinity of the main cutting edge. The analysis of stress and strain fields in-depth is of great significance to improve tool design and durability of tool.


2011 ◽  
Vol 264-265 ◽  
pp. 1654-1659 ◽  
Author(s):  
Tasneem Pervez ◽  
Sayyad Zahid Qamar

This paper presents the finite element analysis of tubular expansion in oval bore holes such as those frequently observed in Upper Natih reservoirs. The minimum inner diameter of the expanded tubular must be larger than the drift diameter set by American Petroleum Institute (API) standards. If the minimum inner diameter is smaller than drift diameter, completion equipments can not be run successfully, which is necessary to complete an oil-well for production. The phenomenon of tubular ovality has been previously unknown to petroleum industry. Finite element model of tubular expansion in oval bore-holes is developed to determine the tubular ovality and compared with measured ovality. It was found that ovality increases linearly with tubular expansion ratio. With increase in expansion ratio, the tubular contact length with formation and developed contact pressure increases. Tubular ovality, if not considered in well design, may lead to premature tubular failure due to lower collapse rating and higher stresses.


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