Temperature-dependent stability of deep wells in the Cooper Basin

2010 ◽  
Vol 50 (2) ◽  
pp. 734
Author(s):  
Fermin Fernandez-Ibañez ◽  
David Castillo ◽  
Doone Wyborn ◽  
Dean Hindle ◽  
Adrian White
Keyword(s):  
Thermal Stresses ◽  
High Heat ◽  
In Situ Stress ◽  
Silica Content ◽  
Granitic Rocks ◽  
Drilling Fluids ◽  
Radiogenic Heat ◽  
Collapse Pressure ◽  
Compressive Stresses ◽  
Cooper Basin

The Cooper-Eromanga Basin is characterised by high heat flow that has been related to the presence of high radiogenic heat-producing granites. Several wells have been drilled in the area to exploit the heat from the fractured granitic rocks of the basement. Drilling through the hot formations in the Cooper Basin (max. temperature ca. 250 °C) with relatively cool drilling fluids induces an almost instantaneous cooling of the wellbore wallrock. Cooling of the hole (the usual case) increases the tensile stresses (and decreases the compressive stresses) at the wellbore wall. The magnitude of the thermal stresses is also dependent on the silica content of the formation. Modelling of the in situ stress tensor and mechanical properties of the wellbore rocks has revealed the time-dependent effect that the borehole collapse pressure has on the stability of the wells. Narrow breakouts form at the time of drilling. Afterwards, the temperature difference (ΔT) decays with time, and as the hole warms up compressive stresses increase and breakouts become enhanced. Therefore, if a high ΔT and a short well exposure time are achieved, it would be possible to inhibit breakout development, drill with a lower mud weight (eventually underbalanced), and, thus, minimise the risk of formation damage.

Thermo-Fluid-Stress-Deformation Analysis of Two-Layer Microchannels for Cooling Chips With Hot Spots

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Abas Abdoli ◽  
George S. Dulikravich ◽  
Genesis Vasquez ◽  
Siavash Rastkar
Keyword(s):  
Heat Flux ◽  
Thermal Stresses ◽  
Hot Spot ◽  
Heat Removal ◽  
High Heat ◽  
Heat Transfer Analysis ◽  
Deformation Analysis ◽  
High Heat Flux ◽  
Cooling Design ◽  
Microchannel Cooling

Two-layer single phase flow microchannels were studied for cooling of electronic chips with a hot spot. A chip with 2.45 × 2.45 mm footprint and a hot spot of 0.5 × 0.5 mm in its center was studied in this research. Two different cases were simulated in which heat fluxes of 1500 W cm−2 and 2000 W cm−2 were applied at the hot spot. Heat flux of 1000 W cm−2 was applied on the rest of the chip. Each microchannel layer had 20 channels with an aspect ratio of 4:1. Direction of the second microchannel layer was rotated 90 deg with respect to the first layer. Fully three-dimensional (3D) conjugate heat transfer analysis was performed to study the heat removal capacity of the proposed two-layer microchannel cooling design for high heat flux chips. In the next step, a linear stress analysis was performed to investigate the effects of thermal stresses applied to the microchannel cooling design due to variations of temperature field. Results showed that two-layer microchannel configuration was capable of removing heat from high heat flux chips with a hot spot.

Residual Stress Analysis in Different Thickness TiN Coatings on High-Speed-Steel Substrates

2011 ◽  
Vol 239-242 ◽  
pp. 2331-2335 ◽  
Author(s):  
Fang Mei ◽  
Guang Zhou Sui ◽  
Man Feng Gong
Keyword(s):  
Residual Stresses ◽  
High Speed ◽  
Thermal Stresses ◽  
High Speed Steel ◽  
X Ray Diffraction ◽  
Tin Coatings ◽  
Compressive Stresses ◽  
M2 High Speed Steel ◽  
Steel Substrates ◽  
Different Thickness

TiN coatings were deposited on AISI M2 high-speed-steel (HSS) substrates by multi-arc ion plating technique. The thickness of substrate was 1.0 mm and five thicknesses of TiN coatings were 3.0, 5.0, 7.0, 9.0 and 11.0 μm, respectively. X-ray diffraction (XRD) has been used for measuring residual stresses. The stresses along five different directions (Ψ=0°, 20.7°, 30°, 37.8° and 45°) have been measured by recording the peak positions of TiN (220) reflection for each 2θ at different tilt angles Ψ. Residual compressive stresses present in the TiN coatings. Furthermore, the results revealed that the value of the residual stresses in TiN coatings was high. While the coatings thickness changed from 3 to 11 μm, the residual stresses varied from -3.22 to -2.04 GPa, the intrinsic stresses -1.32 to -0.14 GPa, the thermal stresses -1.86 to -1.75 GPa. The residual stresses in TiN coatings showed a nonlinear change. When the coatings thickness was about 8 μm, the residual stresses in TiN coatings reached to the maximum value.

scholarly journals Chemical Effect on Wellbore Instability of Nahr Umr Shale

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Baohua Yu ◽  
Chuanliang Yan ◽  
Zhen Nie
Keyword(s):  
Drilling Fluid ◽  
Ionic Concentration ◽  
Chemical Effect ◽  
Drilling Fluids ◽  
Collapse Pressure ◽  
Wellbore Instability ◽  
Sealing Capacity ◽  
Engineering Data ◽  
Forward Engineering ◽  
Rock Mechanical Properties

Wellbore instability is one of the major problems that hamper the drilling speed in Halfaya Oilfield. Comprehensive analysis of geological and engineering data indicates that Halfaya Oilfield features fractured shale in the Nahr Umr Formation. Complex accidents such as wellbore collapse and sticking emerged frequently in this formation. Tests and theoretical analysis revealed that wellbore instability in the Halfaya Oilfield was influenced by chemical effect of fractured shale and the formation water with high ionic concentration. The influence of three types of drilling fluids on the rock mechanical properties of Nahr Umr Shale is tested, and time-dependent collapse pressure is calculated. Finally, we put forward engineering countermeasures for safety drilling in Halfaya Oilfield and point out that increasing the ionic concentration and improving the sealing capacity of the drilling fluid are the way to keep the wellbore stable.

Effect of Including the Bauschinger Phenomenon in the Formula for Collapse Pressure of Thin-Walled Pipes

2020 ◽  
Author(s):  
Alastair Walker ◽  
Ruud Selker ◽  
Ping Liu ◽  
Erich Jurdik
Keyword(s):  
Hydrostatic Pressure ◽  
Wall Thickness ◽  
Bauschinger Effect ◽  
Pipe Wall ◽  
Large Diameter ◽  
Pipe Material ◽  
Pipe Wall Thickness ◽  
Collapse Pressure ◽  
Compressive Stresses ◽  
Thin Walled

Abstract The method presented by DNVGL in DNVGL-ST-F101 [1], “Submarine pipeline systems”, 2017, for calculating the collapse pressure of submerged pipelines is well-known for design of pipes intended to operate in very deep water. Such pipes are regarded as quite thick-walled with diameter to wall thickness ratio in the range of 15 to 30. There is now substantial experience in the practical manufacture, installation and operation of such pipes. Recently there has been a growing use of large diameter pipelines to transport high volumes of gas over great lengths at moderate water depths. The pipes are considered to be thin-walled with ratios of diameter to wall thickness in the range of 30 to 45. This paper assesses the validity of the DNVGL design method when applied to the design of such thin-walled pipes. A particular aspect of the buckling pressure of large diameter pipes is the effect of the Bauschinger phenomenon. The phenomenon occurs when pipes made using the UOE method are subjected to internal pressure, to provide expansion of the pipe during manufacture, thus reducing the out-of-roundness of the pipe wall, and subsequently subjected to external hydrostatic pressure during pipeline operation. To date the Bauschinger phenomenon has been recognised as resulting in a reduction of the circumferential compressive yield of the pipe material. This reduction is accommodated in the DNVGL design formula. Recent research into material properties has shown that the Bauschinger effect also has the effect of reducing the modulus of steel materials over a range of values of applied circumferential compressive stresses. The paper reviews the basis of the Bauschinger phenomenon and presents results from very detailed accurate testing of UOE pipe material. The tests determine the levels of modulus for pipes subject to circumferential compressive stresses. Although results for compressive stress-strain values have previously been available for pipes subject to high levels of hydrostatic pressure it has been considered that the Bauschinger effect is not generally significant for thick-walled pipes. The tests reported here consider the calculation of material modulus levels for low levels of stress that correspond to the buckling stress of thin-walled pipes. The calculated collapse pressure for such pipes is examined in this paper and compared to corresponding results from the DNVGL design formula to provide guidance on the effect of design levels of pipe wall thickness due to inclusion of the Bauschinger effect. The comparisons are for example pipe wall thickness and material conditions. Conclusions are drawn that including the Bauschinger effect in the calculated pipe wall thickness can have a beneficial effect with regard to pipe manufacturing and installation costs for pipe subjected to mild heat treatment.

Buckling of Thin Cylindrical Shell Under Hoop Stresses Varying in Axial Direction

1957 ◽  
Vol 24 (3) ◽  
pp. 405-412
Author(s):  
N. J. Hoff
Keyword(s):  
Cylindrical Shell ◽  
Thermal Stresses ◽  
Axial Direction ◽  
Elastic Buckling ◽  
Thin Cylindrical Shell ◽  
Simply Supported ◽  
Buckling Stress ◽  
Compressive Stresses ◽  
Hoop Stresses ◽  
Approximate Formulas

Abstract The buckling of a thin cylindrical shell simply supported along the perimeter of its end sections is analyzed under hoop compressive stresses varying in the axial direction. The thermal stresses arising from a uniform increase in the temperature of the cylinder are determined. It is found that such thermal stresses are not likely to cause elastic buckling. Simple approximate formulas are developed for buckling stress and thermal stress.

Influence of climate change on thermal stresses in concrete box girders

2021 ◽  
Author(s):  
Saad Saad ◽  
Rashid Bashir ◽  
Stavroula Pantazopoulou
Keyword(s):  
Climate Change ◽  
Temperature Distribution ◽  
Thermal Stresses ◽  
Structural Model ◽  
Meteorological Data ◽  
Structural Response ◽  
Box Girders ◽  
Box Girder ◽  
Compressive Stresses ◽  
The Impact

<p>The purpose of this study is to investigate the impact of climate change on the thermal and structural response of concrete box girders. An advanced finite element platform was used to model a concrete box girder and analyze the additional thermal stresses that result from climate change. Meteorological data for future climate scenarios in Toronto, Canada was used as input in a thermal model to simulate the temperature distribution within the bridge deck. The temperature distribution was then used as input in a structural model of the bridge, to determine the resulting thermal stresses. The results show increases in tensile and compressive stresses as well as increased bridge movements. This study highlights the importance of explicitly considering climate change to achieve more robust bridge codes, particularly when it comes to thermal effects.</p>

Calculation of Thermal Stresses in Mo-Ti FGM with a Continuous Change of Composition

2005 ◽  
Vol 475-479 ◽  
pp. 1529-1532 ◽  
Author(s):  
Lian Meng Zhang ◽  
Qiang Shen ◽  
Zhong Min Yang
Keyword(s):  
Thermal Stresses ◽  
Bending Strength ◽  
Functionally Graded ◽  
Continuous Change ◽  
Hot Press ◽  
Medial Region ◽  
Tensile Stresses ◽  
Compressive Stresses ◽  
Ti Alloys ◽  
Graded Material

In the present paper, a kind of Mo-Ti system functionally graded material with a continuous change of composition was formed via particle settling method at first, and then it was desified by hot-press under 1473K-30MPa-1h. Finally, by using an axisymmetric finite element method, the fabricated thermal stresses in a disk-shaped Mo-Ti FGM were calculated. The results showed that the thermal stresses changed continuously with the smooth variation of graded composition. The residual tensile stresses in the Mo-Ti FGM with a continuously changed composition were located in the medial region of graded layer and the radial compressive stresses distributed in the Mo- and Ti-rich sides. The calculated maximum residual tensile stresses in the Mo-Ti FGM were much lower than the bending strength of Mo-Ti alloys, which demonstrated that during fabrication no damages occurred in the Mo-Ti FGM with continuously graded composition.

Mechanical and Thermal Stresses in Clamped, Brazed, and Bonded Carbide Tools

1992 ◽  
Vol 114 (4) ◽  
pp. 377-385 ◽  
Author(s):  
M. A. Younis
Keyword(s):  
Temperature Gradient ◽  
Metal Cutting ◽  
Thermal Stresses ◽  
Rupture Strength ◽  
Shear Stresses ◽  
Flow Strength ◽  
Compressive Stresses ◽  
Bond Layer ◽  
Tool Edge ◽  
Carbide Insert

A model based on the finite element method is presented for determining of thermal and mechanical stresses in a carbide insert due to heat and cutting forces induced during metal cutting with a brazed, clamped, and bonded carbide insert. Analysis revealed a high temperature gradient in the brazed insert, thus causing high thermal stresses. For the bonded insert a low temperature gradient but high temperatures were found, leading to possible tool edge chipping and a significant reduction of the bond layer strength. Finally local maxima of tensile and compressive stresses were identified on the rake face just after the chip had lost contact with the tool face. The estimated tensile stresses were close to the transverse rupture strength of sintered carbide. Shear stresses were at a maximum close to the tool edge at levels nearly equal to the shear flow strength of carbides. High compressive stresses can produce chipping at the tool tip.

scholarly journals Investigations on Thermal Stresses of a Graded Ti(C,N) Coating Deposited on WC-Co Hardmetal

2014 ◽  
Vol 996 ◽  
pp. 848-854 ◽  
Author(s):  
Esteban Ramos-Moore ◽  
Carlos Espinoza ◽  
Rodrigo S. Coelho ◽  
Haroldo Pinto ◽  
Pedro Brito ◽  
...  
Keyword(s):  
Thermal Cycle ◽  
Thermal Stresses ◽  
Rutile Phase ◽  
X Ray Diffraction ◽  
Heating And Cooling ◽  
Coated Tools ◽  
Compressive Stresses ◽  
The Individual ◽  
Stress Behaviour

We investigated the stress behaviour of Ti(C,N) coatings deposited on WC-Co substrates during an individual thermal cycle. The stress analyses were performed in-situ by energy dispersive X-ray diffraction using a white synchrotron beam. The stresses were determined using the sin2ψ method combined with scattering vector measurements at the strain-free ψ-tilt, in order to avoid the effect of the chemical C/N gradient on the strain distributions over sin2ψ. It was found that compressive stresses induced by top blasting on the coating are released after the individual thermal cycle. During heating and cooling, part of the Ti(C,N) coating was oxidized into a TiO2 rutile phase. Stress analysis was also performed in this phase in order to evaluate the influence of oxidation on the residual stress of the coating. The obtained results can support the design of coated tools with improved properties at interrupted cutting operations by understanding the role of thermal cycling on the stresses of Ti(C,N) coatings.

Study on Shale Gas Drilling Fluids Technology

2013 ◽  
Vol 868 ◽  
pp. 651-656
Author(s):  
Gang Xie ◽  
Ming Yi Deng ◽  
Jun Lin Su ◽  
Liang Chun Pu
Keyword(s):  
Shale Gas ◽  
Drilling Fluid ◽  
Blocking Agent ◽  
Drilling Fluids ◽  
Collapse Pressure ◽  
Gas Drilling ◽  
Advantages And Disadvantages ◽  
Water Based ◽  
Column Pressure ◽  
Shale Gas Drilling

Via discussing the advantages and disadvantages of different types of oil-based drilling fluids, the main reason why oil-based drilling fluids are less used in our country is obtained that dont form a complete series of matching technology. The essence of wellbore instability caused by using water-based drilling fluids to drill shale is analyzed that the formation collapse pressure is greater than drilling fluids column pressure. The fundamental way of controlling borehole wall stability that use water-based drilling fluids to drill shale horizontal well was proposed that deeply researched the shale hydration mechanism, developed efficient blocking agent and inhibitors and established shale gas drilling fluid suppression system, which made water-based drilling fluids have excellent performance.

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