Mechanical Performance of a Gravel Pack Prototype Under High Stress Contrast

2010 ◽  
Author(s):  
Flavia Mara Guzman Villarroel ◽  
Mauro Bloch ◽  
Euripedes Vargas
Keyword(s):  
Mechanical Performance ◽  
High Stress ◽  
Stress Contrast ◽  
Gravel Pack

High Stress Contrast between Different Lithologies and its Implications for Drilling and Stimulation in the Northern Cooper Basin

2016 ◽  
Author(s):  
Feng Gui ◽  
Khalil Rahman ◽  
Duncan Lockhart ◽  
Diogo Cunha ◽  
Dylan Meadows
Keyword(s):  
High Stress ◽  
Stress Contrast ◽  
Cooper Basin

Comparison of Hydraulic Fracture Models for Highly Elongated Fractures of Variable Height

1986 ◽  
Vol 108 (2) ◽  
pp. 107-115 ◽  
Author(s):  
I. D. Palmer ◽  
C. T. Luiskutty
Keyword(s):  
Fluid Flow ◽  
Hydraulic Fracture ◽  
Reasonable Agreement ◽  
High Stress ◽  
Vertical Direction ◽  
Critical Examination ◽  
Wellbore Pressure ◽  
Fracture Models ◽  
Fracture Height ◽  
Stress Contrast

There is a pressing need to compare and evaluate hydraulic fracture models which are now being used by industry to predict variable fracture height. The fractures of concern here are vertical fractures which have a pronounced elongation in the direction of the payzone, i.e., there is a dominant one-dimensional fluid flow along the payzone direction. A summary is given of the modeling entailed in the basic ORU fracture model, which calculates fracture height as a function of distance from the wellbore in the case of a continuous sand bounded by zones of higher (but equal) minimum in-situ stress. The elastic parameters are assumed the same in each layer, and injected flow rates and fluid parameters are taken to be constant. Leak-off is included with spurt loss, as well as non-Newtonian flow. An advantage of the model is its small computer run time. Predictions for wellbore height and pressure from the ORU model are compared separately with the AMOCO and MIT pseudo-3D models. In one instance of high stress contrast the ORU wellbore pressure agrees fairly well with the AMOCO model, but the AMOCO wellbore height is greater by 32 percent. Comparison between the ORU and MIT models in two cases (also high stress contrast) indicates height disagreement at the wellbore by factors of 1.5–2.5 with the MIT model giving a lower height. Thus it appears there can be substantial discrepancies between all three models. Next we compare the ORU model results with six cases of elongated fractures from the TERRA-TEK fully-3D model. Although two of these cases are precluded due to anomolous discrepancies, the other four cases show reasonable agreement. We make a critical examination of assumptions that differ in all the models (e.g., the effective modulus-stiffness multiplier approximation in the AMOCO model, the effect of finite fluid flow in the vertical direction in the MIT model, and the effect of 2D flow and limited perforated height in the TERRA-TEK model). Suggestions are made for reconciling some of the discrepancies between the various models. For example, the ORU/AMOCO height discrepancy appears to be resolved; for other discrepancies we have no explanation. Our main conclusion is that the AMOCO, TERRA-TEK and ORU models for fracture height and bottomhole pressure are in reasonable agreement for highly elongated fractures. Despite the difficulties in understanding the different models, the comparisons herein are an encouraging first step towards normalizing these hydraulic fracture models.

Finite Element Analysis of Fixed Medial Malleolar Fractures

2013 ◽  
Author(s):  
Ruchi D. Chande ◽  
John R. Owen ◽  
Robert S. Adelaar ◽  
Jennifer S. Wayne
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Mechanical Performance ◽  
External Rotation ◽  
Weight Bearing ◽  
High Stress ◽  
Ankle Injuries ◽  
Deltoid Ligament ◽  
Medial Malleolus ◽  
Element Analysis

The ankle joint, comprised of the distal ends of the tibia and fibula as well as talus, is key in permitting movement of the foot and restricting excessive motion during weight-bearing activities. Medial ankle injury occurs as a result of pronation-abduction or pronation-external rotation loading scenarios in which avulsion of the medial malleolus or rupture of the deltoid ligament can result if the force is sufficient [1]. If left untreated, the joint may experience more severe conditions like osteoarthritis [2]. To avoid such consequences, medial ankle injuries — specifically bony injuries — are treated with open reduction and internal fixation via the use of plates, screws, wires, or some combination thereof [1, 3–4]. In this investigation, the mechanical performance of two such devices was compared by creating a 3-dimensional model of an earlier cadaveric study [5], validating the model against the cadaveric data via finite element analysis (FEA), and comparing regions of high stress to regions of experimental failure.

scholarly journals Carbon Nanotubes-Filled Siloxane Composite Foams for Oil Recovery Application: Compression Properties

Fibers ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 45
Author(s):  
Elpida Piperopoulos ◽  
Luigi Calabrese ◽  
Emanuela Mastronardo ◽  
Edoardo Proverbio ◽  
Candida Milone
Keyword(s):  
Carbon Nanotubes ◽  
Elastic Modulus ◽  
Mechanical Behavior ◽  
Oil Recovery ◽  
Mechanical Performance ◽  
Mechanical Stability ◽  
High Stress ◽  
Absorption Capacity ◽  
Simplified Approach ◽  
Composite Foams

This paper studies the correlation between oil recovery usability and mechanical behavior under compression loads of an innovative oil recovery material. The examined composites are silicone foams filled with carbon nanotubes (CNT). Here, the reutilization of oil recovery processes of the newly developed composite foams is evaluated. In this regard, static and cyclic compressive tests are carried out. Samples filled with pristine and functionalized CNT are tested to evaluate the influence of the filler’s characteristics on the composite foam’s mechanical behavior. The results show that the presence of CNT (CNT-0) increases the elastic modulus (0.030 MPa) and collapse stress (0.010 MPa) of the siloxane matrix. On the contrary, as the CNT functionalization degree increases, a worsening of the composite’s mechanical performance is observed. CNT-0 foam evidences, also, the optimal mechanical stability to cyclic compressive loads, maintaining high stress values until 30 cycles. Furthermore, a correlation between the absorption capacity, elastic modulus, and cyclability is reported, highlighting a simplified approach to tailor the high absorption durability performance of filled CNT silicone foams. The promising results confirm the possible reuse of these new composite foams as absorbent materials for oil spill recovery applications.

A Comparative Study of the Strength of Si, SiN and SiC used at Nanoscales

2007 ◽  
Vol 1052 ◽  
Author(s):  
Tuncay Alan ◽  
Pasqualina M. Sarro
Keyword(s):  
Mechanical Properties ◽  
Microelectromechanical Systems ◽  
Mechanical Performance ◽  
High Stress ◽  
Force Microscopy ◽  
Atomic Force ◽  
Sample Shape ◽  
Si Nanostructures ◽  
Very High ◽  
Similar Sample

AbstractMicroelectromechanical systems (MEMS) are being used in many critical applications that require very high stress levels. To properly design MEMS components, mechanical properties should be characterized testing relevant sized samples that are fabricated with the same procedures as the final structure. In this paper we use atomic force microscopy (AFM) experiments to study the fracture strength statistics of polycrystalline SiC and SiN nanobeams, and compare their mechanical performance with the performance of previously tested Si nanostructures. Using the same AFM method and similar sample shape and sizes, allows a direct comparison to be made, which will be useful in determining the best material for different mechanical applications and also to validate the theoretical limits.

Liquid Screen: A Novel Method To Produce an In-Situ Gravel Pack

SPE Journal ◽  
2013 ◽  
Vol 19 (03) ◽  
pp. 437-442 ◽  
Author(s):  
V.O.. O. Ikem ◽  
A.. Menner ◽  
A.. Bismarck ◽  
L.R.. R. Norman
Keyword(s):  
Mechanical Performance ◽  
Gas Permeability ◽  
Pickering Emulsions ◽  
Internal Phase ◽  
Sand Control ◽  
Styrene Divinylbenzene ◽  
Novel Method ◽  
Poly Ethylene ◽  
Gravel Packing ◽  
Gravel Pack

Summary Gravel packs are conventionally used as a permeable solid layer in the annulus between a production screen and the walls of the wellbore in weakly consolidated subterranean formations. Gravel packing is a well-known technique for sand control, whereby unconsolidated fines produced from the soft formation are filtered away from the production fluids. However, gravel packs can be problematic. The bridging of sand particles within the gravel pack can create voids that can result in mechanical failures or significantly reduce the effectiveness of gravel packs to restrain fines from flowing along with the hydrocarbons produced. As an alternative, we present a pioneering method to prepare void-free and mechanically sound permeable barriers in subterranean formations as an alternative to gravel packing. The method of preparation involves the curing of Pickering water-in-oil medium-internal-phase emulsions (MIPEs) or high-internal-phase emulsions (HIPEs) containing monomers in the annular space between a rock formation and pipe. The emulsions were prepared simply by adding low amounts of nonionic surfactant and dispersant to premade Pickering emulsions that were stabilized by oleic-acid (OA) -modified silica particles. The resulting macroporous solid materials, known as “poly(merised)Pickering-M/HIPEs,” have a gas permeability of up to 2.6 darcys and are highly interconnected and permeable to hydrocarbons. This paper shows that it is possible to tailor the gas permeability and mechanical performance of the permeable barrier by altering the emulsion internal-phase volume, the volume of surfactant added to the premade Pickering emulsion, and the composition and constituents of the continuous monomer phase; styrene, divinylbenzene (DVB), and poly(ethylene glycol) dimethacrylate were used in the monomer phase.

Mechanical Performance of Settlement-Reducing Pile Foundation with Cushion

2011 ◽  
Vol 368-373 ◽  
pp. 2545-2549 ◽  
Author(s):  
Hao Zhang ◽  
Ming Lei Shi
Keyword(s):  
Calculation Method ◽  
Pile Foundation ◽  
Mechanical Model ◽  
Optimization Design ◽  
Stress Ratio ◽  
Mechanical Performance ◽  
High Stress ◽  
Work Load ◽  
Pile Penetration ◽  
Soil Stress

The main objective of adding piles to a raft is sometimes for settlement control. In design, the number of piles for reduce settlements under work load to a tolerable limit is usually small. This often results in a high stress in piles that may impede the application of this foundation due to the limits on raft stress or pile stress in practice. An alternative is to install a cushion between piles and raft. In this paper, the performance of disconnected settlement-reducing piles is studied. Based on some simplifications, a mechanical model of pile penetration into cushion and a calculation method of pile-soil interaction are respectively formulated. In consideration of stress-deformation coordination of pile-soil-cushion, a calculation method of pile-soil stress ratio is presented. Optimization design of disconnected settlement-reducing piles can be performed with this method.

SEM/FESEM imaging of lamellar structures in melt extruded polyethylene films

1992 ◽  
Vol 50 (2) ◽  
pp. 1142-1143
Author(s):  
R.T. Chen ◽  
M.G. Jamieson ◽  
R. Callahan
Keyword(s):  
Imaging Techniques ◽  
Membrane Surface ◽  
High Stress ◽  
Extrusion Direction ◽  
Polymeric Membranes ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Crystalline Polymers ◽  
Lamellar Structures ◽  
Resolution Imaging

“Row lamellar” structures have previously been observed when highly crystalline polymers are melt-extruded and recrystallized under high stress. With annealing to perfect the stacked lamellar superstructure and subsequent stretching in the machine (extrusion) direction, slit-like micropores form between the stacked lamellae. This process has been adopted to produce polymeric membranes on a commercial scale with controlled microporous structures. In order to produce the desired pore morphology, row lamellar structures must be established in the membrane precursors, i.e., as-extruded and annealed polymer films or hollow fibers. Due to the lack of pronounced surface topography, the lamellar structures have typically been investigated by replica-TEM, an indirect and time consuming procedure. Recently, with the availability of high resolution imaging techniques such as scanning tunneling microscopy (STM) and field emission scanning electron microscopy (FESEM), the microporous structures on the membrane surface as well as lamellar structures in the precursors can be directly examined.The materials investigated are Celgard® polyethylene (PE) flat sheet membranes and their film precursors, both as-extruded and annealed, made at different extrusion rates (E.R.).

Crystallization sequence of an A1N-Y2O3-SiO2 glass-ceramic

1986 ◽  
Vol 44 ◽  
pp. 446-447
Author(s):  
T.R. Dinger ◽  
G. Thomas
Keyword(s):  
High Temperature ◽  
Glass Ceramic ◽  
Crystallization Behavior ◽  
High Stress ◽  
Crystallization Sequence ◽  
Sio2 Glass ◽  
Structural Applications ◽  
Ceramic Precursors

The use of Si3N4, alloys for high temperature, high stress structural applications has prompted numerous studies of the oxynitride glasses which exist as intergranular phases in their microstructures. Oxynitride glasses have been investigated recently in their bulk form in order to understand their crystallization behavior for subsequent Si3N4 applications and to investigate their worth as glass-ceramic precursors. This research investigates the crystallization sequence of a glass having a normalized composition of Y26Si30Al11 ON11 and lying in the A1N-Y2O3-SiO2 section of the Y-Si-Al-O-N system. Such glasses exist as intergranular phases in the technologically important Y2O3/Al2O3-fluxed Si3N4 alloys.

Iterative Development of a Home Review Program to Promote Preschoolers' Vocabulary Skills: Social Validity and Learning Outcomes

2020 ◽  
Vol 51 (2) ◽  
pp. 371-389 ◽  
Author(s):  
Xigrid Soto ◽  
Yagmur Seven ◽  
Meaghan McKenna ◽  
Keri Madsen ◽  
Lindsey Peters-Sanders ◽  
...  
Keyword(s):  
High Stress ◽  
Social Validity ◽  
Home Language ◽  
Single Subject ◽  
Considerable Difficulty ◽  
Home Program ◽  
Iterative Development ◽  
Vocabulary Skills ◽  
Validity Measures ◽  
At Home

Purpose This article describes the iterative development of a home review program designed to augment vocabulary instruction for young children (ages 4 and 5 years) occurring at school through the use of a home review component. Method A pilot study followed by two experiments used adapted alternating treatment designs to compare the learning of academic words taught at school to words taught at school and reviewed at home. At school, children in small groups were taught academic words embedded in prerecorded storybooks for 6 weeks. Children were given materials such as stickers with review prompts (e.g., “Tell me what brave means”) to take home for half the words. Across iterations of the home intervention, the home review component was enhanced by promoting parent engagement and buy-in through in-person training, video modeling, and daily text message reminders. Visual analyses of single-subject graphs, multilevel modeling, and social validity measures were used to evaluate the additive effects and feasibility of the home review component. Results Social validity results informed each iteration of the home program. The effects of the home program across sites were mixed, with only one site showing consistently strong effects. Superior learning was evident in the school + home review condition for families that reviewed words frequently at home. Although the home review program was effective in improving the vocabulary skills of many children, some families had considerable difficulty practicing vocabulary words. Conclusion These studies highlight the importance of using social validity measures to inform iterative development of home interventions that promote feasible strategies for enhancing the home language environment. Further research is needed to identify strategies that stimulate facilitators and overcome barriers to implementation, especially in high-stress homes, to enrich the home language environments of more families.

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