Collapse of Oil Well Casing With Ovality

1985 ◽  
Vol 107 (1) ◽  
pp. 128-134 ◽  
Author(s):  
P. D. Pattillo ◽  
N. C. Huang
Keyword(s):  
Nonlinear Response ◽  
External Pressure ◽  
Oil Well ◽  
Infinite Length ◽  
Service Environment ◽  
Collapse Resistance ◽  
Eventual Collapse ◽  
Design Calculations ◽  
Model Oil ◽  
Interesting Alternative

The nonlinear response and eventual collapse of an initially imperfect cross section of a cylinder of infinite length is analyzed. The cylinder is loaded by external pressure and axial load and is intended to model oil well casing in a service environment. Results from the analysis agree well with experimental data and provide an interesting alternative to current empirical/statistical methods for determining the minimum collapse resistance of casing for use in design calculations.

Collapse of Imperfect Tubulars

1986 ◽  
Vol 108 (3) ◽  
pp. 214-220
Author(s):  
P. D. Pattillo ◽  
N. C. Huang
Keyword(s):  
Axial Load ◽  
Nonlinear Response ◽  
External Pressure ◽  
Cross Sectional ◽  
Collapse Resistance ◽  
The Cross ◽  
Eventual Collapse

The nonlinear response and eventual collapse of a cylinder loaded by resultant external pressure and axial load is analyzed. The cross-sectional description of the cylinder is sufficiently general to include ovality, eccentricity, and local thickness anomalies. Applications of the model include the prediction of minimum collapse resistance of commercial tubulars.

The Effect of Length: Diameter Ratio on Collapse of Casing

1984 ◽  
Vol 106 (2) ◽  
pp. 160-165 ◽  
Author(s):  
N. C. Huang ◽  
P. D. Pattillo
Keyword(s):  
Axial Load ◽  
External Pressure ◽  
Field Application ◽  
Diameter Ratio ◽  
Finite Cylinder ◽  
Oil Well ◽  
Steel Mill ◽  
Cross Sectional ◽  
Axial Tension ◽  
Collapse Resistance

This paper presents an analysis of the cross-sectional collapse of a cylinder of finite length loaded simultaneously by an axial tension (which may be zero) and external pressure. The calculation is based on Sanders’ nonlinear shell equations with plasticity introduced via the concept of effective stress from a uniaxial tension test. The finite cylinder is an appropriate model of oil well casing as it undergoes quality control testing in the steel mill where the edges of the cylinder are usually fixed in the case of nonzero axial load and free in the case of zero axial load. However, in field application, the length: diameter ratio of casing is such that the cylinder may be considered infinite. Guidelines contained herein permit prediction of the collapse resistance of field casing from the results of mill tests performed on short samples.

Collapse of Oil Well Casing

1982 ◽  
Vol 104 (1) ◽  
pp. 36-41 ◽  
Author(s):  
N. C. Huang ◽  
P. D. Pattillo
Keyword(s):  
External Pressure ◽  
Critical Conditions ◽  
Oil Well ◽  
Infinite Length ◽  
Empirical Formulas ◽  
Plastic Buckling ◽  
Incremental Theory ◽  
Axial Tension ◽  
Strain Formulation ◽  
Theoretical Results

This paper is concerned with the theoretical study of the collapse of oil well casing under various loading conditions. The analysis is based on a model of a cylindrical shell of infinite length subjected to an axial tension and an external pressure. It is found that when the thickness-radius ratio of the casing is sufficiently small, collapse of the casing may take place in a form of plastic buckling. Critical conditions for plastic buckling are derived based on the J2-incremental theory and the J2-deformation theory. Another type of collapse is caused by the realization of the ultimate strength of the material. Critical conditions in the second case of collapse are calculated based on a plane strain formulation associated with the J2-incremental theory. The theoretical results obtained in this paper correspond well with empirical formulas developed earlier by the API for the design of oil well casing.

On Some Factors Affecting Casing Collapse Resistance under External Pressure

2020 ◽  
Author(s):  
Bisen Lin ◽  
David Coe ◽  
Richard Harris ◽  
Timothy Thomas
Keyword(s):  
External Pressure ◽  
Factors Affecting ◽  
Collapse Resistance ◽  
Casing Collapse

scholarly journals On Perturbation Solutions for Axisymmetric Bending Boundary Values of a Deep Thin Spherical Shell

2014 ◽  
Vol 2014 ◽  
pp. 1-12
Author(s):  
Rong Xiao ◽  
Danhui Dan ◽  
Wei Cheng
Keyword(s):  
Spherical Shell ◽  
Nonlinear Response ◽  
Fundamental Equation ◽  
Expansion Method ◽  
External Pressure ◽  
Displacement Component ◽  
Moment Theory ◽  
Axisymmetric Bending ◽  
Thin Spherical Shell ◽  
The Moment

On the basis of the general theory of elastic thin shells and the Kirchhoff-Love hypothesis, a fundamental equation for a thin shell under the moment theory is established. In this study, the author derives Reissner’s equation with a transverse shear forceQ1and the displacement componentw. These basic unknown quantities are derived considering the axisymmetry of the deep, thin spherical shell and manage to constitute a boundary value question of axisymmetric bending of the deep thin spherical shell under boundary conditions. The asymptotic solution is obtained by the composite expansion method. At the end of this paper, to prove the correctness and accuracy of the derivation, an example is given to compare the numerical solution by ANSYS and the perturbation solution. Meanwhile, the effects of material and geometric parameters on the nonlinear response of axisymmetric deep thin spherical shell under uniform external pressure are also analyzed in this paper.

scholarly journals Nonlinear response of doubly curved sandwich panels with CNT-reinforced composite core and elastically restrained edges subjected to external pressure in thermal environments

2021 ◽  
Author(s):  
Hoang Van Tung ◽  
Dao Nhu Mai ◽  
Vu Thanh Long
Keyword(s):  
Nonlinear Response ◽  
Effective Properties ◽  
Sandwich Panels ◽  
Shear Deformation Theory ◽  
External Pressure ◽  
Functionally Graded ◽  
Thermal Environments ◽  
Reinforced Composite ◽  
Approximate Analytical Solutions ◽  
Doubly Curved

An analytical investigation on the nonlinear response of doubly curved panels constructed from homogeneous face sheets and carbon nanotube reinforced composite (CNTRC) core and subjected to external pressure in thermal environments is presented in this paper. Carbon nanotubes (CNTs) are reinforced into the core layer through uniform or functionally graded distributions. The properties of constituents are assumed to be temperature dependent and effective properties of CNTRC are determined using an extended rule of mixture. Governing equations are established within the framework of first order shear deformation theory taking into account geometrical imperfection, von Kármán–Donnell nonlinearity, panel-foundation interaction and elasticity of tangential edge restraints. These equations are solved using approximate analytical solutions and Galerkin method for simply supported panels. The results reveal that load carrying capacity of sandwich panels is stronger when boundary edges are more rigorously restrained and face sheets are thicker. Furthermore, elevated temperature has deteriorative and beneficial influences on the load bearing capability of sandwich panels with movable and restrained edges, respectively.

Enhanced Collapse Resistance of Compressed Steel Pipes

2014 ◽  
Author(s):  
Venkat R. Krishnan ◽  
David A. Baker
Keyword(s):  
Experimental Testing ◽  
Three Dimensional ◽  
External Pressure ◽  
Combined Loading ◽  
Finite Element Analyses ◽  
Forming Process ◽  
3D Finite Element ◽  
Steel Pipes ◽  
Collapse Resistance ◽  
Sensitivity Studies

Pipe collapse is a primary design consideration for deep water locations and offshore areas with sharp seabed curvatures or spans, where bending reduces collapse resistance due to ovalization. Previous numerical and experimental work has shown that collapse resistance of steel pipes can be enhanced significantly by using compression instead of expansion during the final stage of the pipe forming process. ExxonMobil has recently undertaken a rigorous numerical modeling and experimental testing program to investigate the collapse resistance of compressed (JCOC) steel pipes under combined loading of external pressure and bending, and this paper presents the main results from the program. The first part of the paper presents results of sensitivity studies from three dimensional (3D) finite element analyses (FEA) of the pipe forming process, and the second part focuses on the collapse modeling under combined loading as well as a comparison of the numerical results with the experiments. The results indicate that the collapse envelope for steel pipes under combined external pressure and bending can be enhanced by up to 35% by adopting pipe compression rather than expansion as the final step of the forming process.

Collapse Resistance Under Combined External Pressure and Bending Deformation of Coated Linepipe

2020 ◽  
Author(s):  
Takahiro Sakimoto ◽  
Hisakazu Tajika ◽  
Tsunehisa Handa ◽  
Yoshiaki Murakami ◽  
Satoshi Igi ◽  
...  
Keyword(s):  
Yield Strength ◽  
Deep Water ◽  
Thermal Cycle ◽  
Bauschinger Effect ◽  
Heating Temperature ◽  
External Pressure ◽  
Compressive Yield Strength ◽  
Heat Cycle ◽  
Bending Deformation ◽  
Collapse Resistance

Abstract As offshore pipeline projects have expanded to deeper water regions with depths of more than 2 000 m, higher resistance against collapse by external pressure is now required in linepipe. Collapse resistance is mainly controlled by the pipe geometry and compressive yield strength. In UOE pipe, the compressive yield strength along the circumferential direction changes dramatically due to tensile pre-strain that occurs in pipe forming processes such as the expansion process. In order to improve the compressive yield strength of pipes, it is important to consider the Bauschinger effect caused by pipe expansion. As the mechanism of this effect, it is understood that internal stress is generated by the accumulation of dislocations, and this reduces reverse flow stress. Compressive yield strength is also changed by the thermal cycle associated with application of fusion-bond epoxy in pipe anti-corrosion coating by induction heating. In the typical thermal heat cycle of this coating process, the maximum heating temperature is from 200 °C to 250 °C. In this case, compressive yield strength increases as an effect of the thermal cycle, resulting in increased collapse resistance. Thus, for deep water application of UEO linepipe, it is important to clarify the conflicting effects of the Bauschinger effect and the thermal heat cycle on compressive yield strength. During installation of deep water pipelines by a method such as J-lay, curvature is imposed on the pipe axis, but the circumferential bending that leads to ovalization is determined by the interaction of the curvature of bending deformation. This bending deformation decreases collapse resistance. The interaction of external pressure and bending is also important when evaluating collapse. Against this background, this study discusses the collapse criteria for coated linepipe and their bending interaction against collapse based on a full-scale collapse test under external pressure with and without bending loading. The effect of the thermal heat cycle on linepipe collapse criteria is also discussed based on the results of tensile pre-strain tests with simulation of the thermal cycle and a collapse calculation by FEA.

Optimizing Production and Improving Well Accessibility With Expandable Technology

2021 ◽  
Vol 73 (07) ◽  
pp. 37-38
Author(s):  
Murray Forbes
Keyword(s):  
External Pressure ◽  
Hydraulic Pressure ◽  
Axial Loads ◽  
Squeeze Pressure ◽  
Hydrocarbon Recovery ◽  
Well Location ◽  
Well Design ◽  
Collapse Resistance ◽  
Significant Damage ◽  
Inner Diameter

Collapsed tubing occurs when external pressure outside the casing is greater than the pressure inside. There are several circumstances which can lead to a collapse, including high pressure outside the casing during operations such as cement squeeze, pressure testing in the annulus, and when the mud level inside the casing drops due to a loss of circulation. The well location within the rock formation can also have an impact on the potential for collapsed tubing. Seismic activity can cause significant damage to the casing and tubing so careful well design and strict operating procedures are essential to reduce the risk. When the issue does occur, it can create a significantly restricted area in the wellbore and often results in failure to gain access below the collapsed area in a wellbore. This, in turn, can cause extensive nonproductive time (NPT) to remediate the issue. Planned drilling or intervention work is halted, and production may be deferred. In the most severe instances when the casing collapses the well is completely abandoned. While the industry continues to focus on enhancing hydrocarbon recovery from existing wells, these operations must remain economically viable. Therefore, preventing and resolving well integrity and access issues have never been more important. With advancements in expandable technology, it is now possible to reform the restriction in a tubular, enabling the inner diameter (ID) to be opened. This allows for either reinstatement of production back to surface or access to equipment below, permitting operators to resume operations with minimal NPT.Coretrax recently deployed its ReForm wellbore repair tool when an international oil company experienced collapsed tubing in a remote well off the coast of Papua New Guinea. The solution uses hydraulic pressure applied at surface to reform collapsed, oval, or restricted tubulars. Overcoming Traditional Limitations During drilling and production activity, tubing and casing are exposed to a range of axial loads and temperatures as the operator utilizes various methods to reach, and then extract, hydrocarbons from the well. In drilling activity, mud losses can often be encountered through thief zones which leads to a lower mud level. With the consistent pressure outside the casing, the collapse resistance can be affected, resulting in full collapse in the wellbore. Swaging is a conventional and widely used method of repairing collapsed tubing. The process involves a series of swages run downhole to gradually open the collapsed area. It can be done with specialized swage packers or with a hydraulic expandable swage. Both methods provide a bond to the existing casing once properly prepped. The technique can take a significant amount of time to open the area due to the number of different swages required. Each time a larger size is needed, the operator must use significant rig time to trip out of hole. While it can have successful outcomes for repairing damaged areas of well casing or screens for example, due to the weight required in the pipe to swage, this procedure is not suitable for shallow or lateral wells.

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