Effect of Expansion Ratio and Wall Thickness on Large-Diameter Solid Expandable Tubular after Expansion

Author(s):  
Changshuai Shi ◽  
Kailin Chen ◽  
Xiaohua Zhu ◽  
Feilong Cheng ◽  
Yuekui Qi ◽  
...  

Abstract The large-diameter solid expandable tubular with a smaller wall thickness faces the risk of internal pressure burst and external squeeze collapse in repairing damaged casing well. The internal pressure and external squeezing resistance calculation of the tubes using the analytical method require many expansion experiments and post-expansion tensile experiments, resulting in high costs and low efficiency. This paper gives a set of laboratory expansion and post-expansion performance test, which is based on the laboratory experiment and mechanical properties of material expansion. Two materials are studied: 316L and 20G. Then it analyses the error and causes of the error in the traditional analytical algorithm. Besides, it establishes an accurate finite element (FE) model to study the quantitative influence of expansion ratio and wall thickness on the burst strengths and collapse strengths of the tube. The results show that the toughness and hardening ratio of 316L is better than 20G at the same expansion ratio. The numerical simulation results of the model can effectively simulate the expansion process and the mechanical properties of SET in good agreement with the laboratory test results. The expansion ratio and wall thickness affect the mechanical properties after expansion. Thus the quantitative laws of the expansion driving force, internal pressure resistance, and external squeezing resistance under different variables are summarized. To ensure the integrity of the reinforced wellbore, the expansion ratio should not exceed 12.7%. In the current study lays a theoretical basis and technical support for optimizing SET and preventing downhole accidents.

Author(s):  
L. M. Gurevich ◽  
V. F. Danenko ◽  
A. A. Istrati ◽  
V. A. Sonnova

Finite element simulates of changing stresses and strains under loading by gradually increasing internal pressure of cylindrical welded vessels was carried out. The vessels had an annular mechanically inhomogeneous welded joint with different mechanical properties of the joint, heat-affected zone, and base metal. Maximum stresses developed in the caps of the vessels, and the annular joint are lightly loaded. The distribution of stresses and strains in joint at various design parameters of the vessels is investigated.


2019 ◽  
Vol 142 (3) ◽  
Author(s):  
Le Zhao ◽  
Hong Zhang ◽  
Qingquan Duan ◽  
Guoping Tang

Abstract Fatigue tests were conducted to analyze the fatigue behavior and diameter growth of large-diameter coiled tubing (CT) under the combined loads of bending and internal pressure. The experimental results reveal that mechanical limitations on the allowable diameter growth mean that the effective working life of CT at high pressures is only a fraction of the available fatigue life. The finite element software abaqus is used to further research the changes in diameter growth and to analyze the sensitivity of CT diameter growth to the main influencing factors, including internal pressure, tubing outside diameter (OD), wall thickness, yield strength, and bending radius. For CT with a diameter larger than 2 in., the diameter growth is sensitive to the above factors. As the bending and straightening cycles increase, the OD of the CT increases in association with obvious ovalization deformation, and the increase in the OD is closely related to the internal pressure load. The redistribution of material causes the wall thickness of the CT to become universally thinner. The ovality of the CT and the uneven decrease in wall thickness reduce the resistance to external extrusion. Therefore, it is becoming increasingly necessary to account for diameter growth as one of the key elements when predicting CT life or determining when to retire a string from service.


2021 ◽  
Author(s):  
Ruud Selker ◽  
Joost Brugmans ◽  
Ping Liu ◽  
Carlos Sicilia

Abstract Internally pressurised pipe behaves differently than externally pressurised pipe. DNVGL-ST-F101 [4], a prevailing standard for the design of submarine pipelines, provides limit-state equations for combined loading that are valid only if the diameter-to-wall-thickness ratio (D/t) is between 15 and 45. A recent study has shown that the results are increasingly conservative for lower values of this ratio if the nett pressure is acting on the pipe’s outside [8], especially if it is below 20. In this paper, the applicability of the limit-state equations for thick-walled pipe with D/t less than 15 and loaded by a nett internal pressure has been investigated. The first step was a fundamental review of the formulations. Next, the predicted capacities were compared with those estimated using a finite-element (FE) model. The results greatly coincided, which indicates that the conservatism underlying the formulations does not depend on D/t. Hence they can be used for design against local buckling under internal overpressure, too, when the ratio is below 15.


Author(s):  
Hossein Ghaednia ◽  
Sreekanta Das ◽  
Jamshid Zohrehheydariha ◽  
Rick Wang ◽  
Richard Kania

External interferences cause various defects, which significantly affect the transportation of oil and gas in pipelines. Corrosion, crack, puncture, dent, gouge, and combination of such damages from a variety of external interferences are some common examples of surface damage in pipelines. Gouges, dents, cracks, and punctures that form in the pipe wall as a result of contact and/or impact from foreign objects are often referred to as mechanical damage. Structural integrity of oil and gas transmission pipelines is often threatened by these mechanical damages and as a result, a failure of the pipeline may occur. A defect that contains both dent and crack, often known as dent-crack defect, may lead to a rupture or leak in the pipe wall. This kind of defect is a matter of serious concern for the pipeline operator since a rupture or a leak may occur. Hence, an experimental study was completed at the Centre for Engineering Research in Pipelines (CERP), University of Windsor on 30 inch (762 mm) diameter and X70 grade pipes with D/t of 90. This project was undertaken through laboratory based experimental work and numerical study using non-linear finite element analysis (FEA) method. The purpose of full-scale test was to collect test data to be able to validate finite element (FE) model. The validated FE model was then used to undertake parametric study for determining the effect of the crack depth and operating (internal) pressure on the burst strength of NPS30 X70 grade oil and gas pipe. The parameters chosen in the FE based parametric study are: (1) crack depth which was varied from 0.25 to 0.75 of pipe wall thickness and (2) internal pressure applied during denting process (operating pressure of linepipe) was varied from no internal pressure to 0.75py. This study found that the dent-crack defect with crack depth of 75% of wall thickness could reduce the pressure capacity by 54%.


Vibration ◽  
2021 ◽  
Vol 4 (1) ◽  
pp. 151-174
Author(s):  
André F. S. Rodrigues ◽  
Zuzana Dimitrovová

In this paper, the three-layer model of ballasted railway track with discrete supports is analyzed to access its applicability. The model is referred as the discrete support model and abbreviated by DSM. For calibration, a 3D finite element (FE) model is created and validated by experiments. Formulas available in the literature are analyzed and new formulas for identifying parameters of the DSM are derived and validated over the range of typical track properties. These formulas are determined by fitting the results of the DSM to the 3D FE model using metaheuristic optimization. In addition, the range of applicability of the DSM is established. The new formulas are presented as a simple computational engineering tool, allowing one to calculate all the data needed for the DSM by adopting the geometrical and basic mechanical properties of the track. It is demonstrated that the currently available formulas have to be adapted to include inertial effects of the dynamically activated part of the foundation and that the contribution of the shear stiffness, being determined by ballast and foundation properties, is essential. Based on this conclusion, all similar models that neglect the shear resistance of the model and inertial properties of the foundation are unable to reproduce the deflection shape of the rail in a general way.


2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Tuo Shi ◽  
Nianchun Deng ◽  
Xiao Guo ◽  
Wen Xu ◽  
Shi Wang

Taking the construction of a concrete-filled steel tube (CFST) arch bridge (part of the Sichuan-Tibet Railway) in low temperatures as the test site, firstly the deformation performance test of concrete was carried out. Following this initial testing, measurement of compressive strength and shrinkage performance was conducted in large-diameter CFSTs under a variety of curing conditions. Experimental results showed that the expansion effect of Ca-Mg composite expansive agent in concrete was better than that of other expansive agents at any stage. Under low-temperature curing (0°C), the sampling strength of the large-diameter CFSTs reached 73.5% of the design strength at 28 d in the presence of a nonthermal curing system. The design strength itself was reached, when a curing system involving a thermal insulation film was applied, and use of this film also led to improvements in concrete shrinkage. The results suggested that a Ca-Mg composite expansive agent, combined with an insulation film curing system, should be the technique selected for concrete pumping construction of CFST arch bridges in Tibet.


2006 ◽  
Vol 321-323 ◽  
pp. 1070-1073
Author(s):  
Ye Yeon Won ◽  
Myong Hyun Baek ◽  
Wen Quan Cui ◽  
Kwang Kyun Kim

This study investigates micro-structural and mechanical properties of trabecular bone in human femoral head with and without osteoporosis using a micro-CT and a finite element model. 15 cored trabecular bone specimens with 20 of diameter were obtained from femoral heads with osteoporosis resected for total hip arthroplasty, and 5 specimens were removed from femoral head of cadavers, which has no history of musculoskeletal diseases. A high-resolution micro-CT system was used to scan each specimen to obtain histomorphometry indexes. Based on the micro-images, a FE-model was created to determine mechanical property indexes. While the non-osteoporosis group had increases the trabecular thickness, the bone volume, the bone volume fraction, the degree of anisotropy and the trabecular number compared with those of osteoporotic group, the non-osteoporotic group showed decreases in trabecular separation and structure model index. Regarding the mechanical property indexes, the reaction force and the Young's modulus were lower in the osteoporotic group than in non-osteoporotic group. Our data shows salient deteriorations in trabecular micro-structural and mechanical properties in human femoral head with osteoporosis.


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