Optimum Mandrel Configuration for Efficient Down-Hole Tube Expansion

Author(s):  
Tasneem Pervez ◽  
Omar S. Al-Abri ◽  
Sayyad Z. Qamar ◽  
Asiya M. Al-Busaidi

In the last decade, traditional tube expansion process has found an innovative application in oil and gas well drilling and remediation. The ultimate goal is to replace the conventional telescopic wells to mono-diameter wells with minimum cost, which is still a distant reality. Further to this, large diameters are needed at terminal depths for enhanced production from a single well while keeping the power required for expansion and related costs to a minimum. Progress has been made to realize slim wells by driving a rigid mandrel of a suitable diameter through the tube either mechanically or hydraulically to attain a desirable expansion ratio. This paper presents a finite element model which predicts the drawing force for expansion, the stress field in expanded and pre/post expanded zones, and the energy required for expansion. Through minimization of energy required for expansion, an optimum mandrel configuration i.e. shape, size and angle was obtained which can be used to achieve larger in-situ expansion. It is found that mandrel with elliptical, hemispherical and curved conical shapes have minimum resistance during expansion as compared to the widely used circular cross section mandrel with a cone angle of 10°. However, further manipulation of shape parameters of the circular cross section mandrel revealed an improved efficiency. The drawing force required for expansion reduces by 7% to 10% having minimum dissipated energy during expansion. It is also found that these cones yield less reduction in tube thickness after expansion, which results in higher post-expansion collapse strength. In addition, rotating a mandrel further reduces the energy required for expansion by 7%.

Author(s):  
Omar S. Al-Abri ◽  
Tasneem Pervez ◽  
Sayyad Z. Qamar ◽  
Asiya M. Al-Busaidi

In the last decade, traditional tube expansion process has found an innovative application in oil and gas wells drilling and remediation. The ultimate goal is to replace the conventional telescopic wells to monodiameter wells with minimum cost, which is still a distant reality. Further to this, large diameters are needed at terminal depths for enhanced production from a single well while keeping the power required for expansion and related costs to a minimum. Progress has been made to realize slim wells by driving a rigid mandrel of a suitable diameter through the tube either mechanically or hydraulically to attain a desirable expansion ratio. This paper presents a finite element model, which predicts the drawing force for expansion, the stress field in expanded and pre-/postexpanded zones, and the energy required for expansion. Through minimization of energy required for expansion, an optimum mandrel configuration, i.e., shape, size, and angle, was obtained, which can be used to achieve larger in situ expansion. It is found that mandrel with elliptical, hemispherical, and curved conical shapes has minimum resistance during expansion as compared to the widely used circular cross section mandrel with a cone angle of 10 deg. However, further manipulation of shape parameters of the circular cross section mandrel yielded an improved efficiency. The drawing force required for expansion reduces by 7–10% having minimum dissipated energy during expansion. It is also found that these mandrels yield less reduction in tube thickness after expansion, which results in higher postexpansion collapse strength. In addition, rotating a mandrel further reduces the energy required for expansion by another 7%.


Author(s):  
Fethi Abbassi ◽  
Furqan Ahmad ◽  
Ali Karrech ◽  
Md. Saiful Islam

Abstract Solid Expandable Tubular Technology (SETT) finds its extensive applications in the oil and gas industries where it is used for well completion and remediation. The purpose of his work is to investigate the material behavior upon expansion and to optimize the parameters that are relevant to the expansion process. Tube expansion tests have been performed using a newly designed experimental setup. Seamless stainless steel (AISI 304) tubes have been deformed and monitored using a Digital Image Correlation (DIC) system to measure the full field displacement. A parametric study has been performed in order to study the effect of key expansion parameters such us mandrel geometry (angle), expansion ratio, mandrel-tube friction on the tube expansion and its buckling. The commercial code VIC-3D has been used to process the strain and displacement data obtained by the charge-coupled device (CCD) cameras. Moreover, the tests have been modeled numerically using the Finite Element Method (FEM) to gain further insight into the stress and strain distributions during metal forming. A good correlation has been observed between the numerical and experimental results.


2018 ◽  
Vol 763 ◽  
pp. 908-915
Author(s):  
Jian Cui ◽  
Chin Long Lee ◽  
Gregory A. MacRae

During earthquakes, buckling restrained braces (BRBs) are likely subjected to both in-plane (INP) and out-of-plane (OOP) loadings simultaneously, therefore, BRBs are required to act robustly under combined INP and OOP loading. It is believed that the OOP loading will reduce the energy dissipation ability of BRBs. The intent of this study is to numerically investigate the performance of BRBs under combined INP and OOP loading with a finite element model of BRB with circular cross-section. Restraining concrete within the BRB is modeled as connector elements in the model and is proven to be an effective way. Simulation results show that the performance of BRBs under combined INP and OOP loading is not as good as that under the INP loading only and the energy dissipation ability is decreased by about 15% when the magnitude of OOP loading is equal to that of INP loading. Furthermore, the results give a deeper insight into the behaviour of BRBs under different combined OOP and INP loading histories.


1994 ◽  
Vol 116 (1) ◽  
pp. 14-20 ◽  
Author(s):  
T. T. Le ◽  
R. H. Knapp

A new two-dimensional finite element model is proposed for the deformation analysis of cable cross sections. The deformations of the cable cross section are of considerable design interest because of their effect on the induced torque or rotation of the cable. This model accounts for material orthotropy and nonsymmetrical geometry and loads. Each component of the cable is assumed to possess a circular cross section and is modeled as a macro-element having nodal degrees-of-freedom at all contact points with adjoining components. Usual finite element procedures are applied to solve for the unknown displacements at contact nodal points. The model is implemented in a computer code and is verified by test results obtained for an as-built cable.


2018 ◽  
Vol 14 (1) ◽  
pp. 1
Author(s):  
Prof. Dr. Jamal Aziz Mehdi

The biological objectives of root canal treatment have not changed over the recentdecades, but the methods to attain these goals have been greatly modified. Theintroduction of NiTi rotary files represents a major leap in the development ofendodontic instruments, with a wide variety of sophisticated instruments presentlyavailable (1, 2).Whatever their modification or improvement, all of these instruments have onething in common: they consist of a metal core with some type of rotating blade thatmachines the canal with a circular motion using flutes to carry the dentin chips anddebris coronally. Consequently, all rotary NiTi files will machine the root canal to acylindrical bore with a circular cross-section if the clinician applies them in a strictboring manner


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