Smart Lost Circulation Materials to Seal Large Fractures

2021 ◽  
Author(s):  
Maryam Tabatabaei ◽  
Arash Dahi Taleghani
Keyword(s):  
Three Dimensional ◽  
Shape Memory Polymers ◽  
Control Problems ◽  
Well Control ◽  
Rate Of Penetration ◽  
One Dimensional ◽  
Lost Circulation ◽  
Permanent Shape ◽  
Lost Circulation Materials ◽  
Fractured Carbonates

Abstract Lost circulation problems may result in a significant downtime, a considerable reduction of the rate of penetration, or even well control problems. Despite advances in manufacturing lost circulation materials (LCMs), some formations, like heavily fractured carbonates, have complete losses during drilling. We develop smart LCMs using shape memory polymers (SMPs), and program them thermo-mechanically to satisfy size limitations imposed by bottomhole assemblies (BHA). Elevated downhole temperatures act as an external trigger to recover the permanent shape of LCMs, which could expand ten times larger than the temporary (programmed) dimensions for deployment. Smart LCMs are a combination of various material categories such as granular, fibrous (one-dimensional or 1-D) and planar (two-dimensional or 2-D) configurations that resume to the original shape after exposure to high temperatures. The LCMs form different structures such as flatted pellet, disc-shaped, spider-shaped, and spindled, which, respectively, presents grains, 1-D fibers, 2-D stars, and 2-D lattices after recovery. A combination of the above categories attempt to build three-dimensional (3-D) plugging capabilities across various sized fractures.

Shape Memory Polymers as Lost Circulation Materials for Sealing Wide-Opened Natural Fractures

2021 ◽  
pp. 1-12
Author(s):  
Maryam Tabatabaei ◽  
Arash Dahi Taleghani ◽  
Guoqiang Li ◽  
Tianyi Zhang
Keyword(s):  
Shape Memory ◽  
Oil And Gas ◽  
Shape Memory Polymers ◽  
Reservoir Temperature ◽  
Lost Circulation ◽  
Drilling Equipment ◽  
Order Of Magnitude ◽  
X Ray Computed ◽  
Large Width ◽  
Lost Circulation Materials

Summary While there have been various lost circulation materials (LCMs) available in the market for treating fractures during the drilling of oil and gas wells, there is still a demand for a technology to seal large fractures. Considering limitations on the size of the particles that can be circulated through the drilling equipment, especially the bottomhole assembly, simply enlarging conventional LCM particles becomes ineffective for sealing large vugs and fractures. In this study, we use shape memory polymers (SMPs) to prepare programmed LCMs with various temporary shapes, which can transform to their permanent shapes with much larger dimensions as compared to their temporary shapes. A series of steps for thermomechanical programming of SMP is designed to trigger their expansion at the reservoir temperature. The dimensions of the programmed shapes can be an order of magnitude smaller than the ones for the original shapes, making their transport through the flowlines feasible, and bridging wide-opened fractures possible. The basic idea is that, after recovery, the SMP-based LCMs form an entangled network across a large width of fracture, and SMP particles recovered within the network, filling in the pores to form an effective sealing. We seek the capability of entangled ladders and interwoven fibers in forming a network across the fracture. A permeability plugging apparatus (PPA) is used to examine the efficiency of developed LCMs. The technique of 3D X-ray computed tomography (CT) is used to visualize the internal structure of formed plugs, enabling us to understand the mechanisms of bridging, plugging, and sealing.

Three-Dimensional Numerical Simulation of Thermomechanical Constitutive Model for Shape Memory Polymers With Application to Morphing Wing Skin

2013 ◽  
Author(s):  
Olaniyi A. Balogun ◽  
Changki Mo ◽  
A. K. Mazher ◽  
John C. Brigham
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Constitutive Model ◽  
Shape Memory ◽  
Three Dimensional ◽  
Shape Memory Polymers ◽  
Thermomechanical Behavior ◽  
One Dimensional ◽  
Simulation Results ◽  
Wing Skin

This paper presents three-dimensional numerical simulation of thermomechanical constitutive model for shape memory polymers. Shape memory polymers (SMPs) are a class of smart materials with high potential for application to automotive, aerostructures, and medical devices, which can benefit from its intrinsic shape changing properties. In particular, looking at its application to aerospace substructure such as morphing wings, thermomechanical behavior of the SMPs needs to be well established and predicted. In order to predict the thermomechanical behavior of SMPs structures, a one-dimensional rheological thermomechanical constitutive model was adopted and a numerical simulation of this model was developed using a commercial finite element analysis package ABAQUS. The particular one-dimensional model was selected due to its potential to represent the key material behaviors of SMP with a relatively low number of required material constants, which is practical for engineering industrial applications. The model was expanded to a three-dimensional isotropic model and then incorporated into the finite element method by means of an ABAQUS user-defined subroutine (UMAT). The methods of three-dimensional expansion and numerical implementation are presented in this work. A time evolution of the analysis was conducted by making use of the backward difference method, which was applied to all quantities within the model including the material properties. A comparison of the numerical simulation results was carried out with the available experimental data. Numerical simulation results clearly exhibit the thermomechanical properties of the material, which include shape fixity, shape recovery, and recovery stress. Finally, a preliminary set of predictions for an unmanned aerial vehicle (UAV) morphing wing skin are also presented.

Constitutive Modeling of Shape Memory Effects in Semicrystalline Polymers With Stretch Induced Crystallization

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Kristofer K. Westbrook ◽  
Vikas Parakh ◽  
Taekwoong Chung ◽  
Patrick T. Mather ◽  
Logan C. Wan ◽  
...  
Keyword(s):  
Shape Memory ◽  
Constitutive Modeling ◽  
Three Dimensional ◽  
Constitutive Models ◽  
Shape Memory Polymers ◽  
One Dimensional ◽  
Chain Mobility ◽  
Shape Memory Effects ◽  
External Stimuli ◽  
Induced Crystallization

Polymers can demonstrate shape memory (SM) effects by being temporarily fixed in a nonequilibrium shape and then recover their permanent shape when exposed to heat, light, or other external stimuli. Many previously developed shape memory polymers (SMPs) use the dramatic molecular chain mobility change around the glass transition temperature Tg to realize the SM effect. In these materials, the temporary shape cannot be repeated unless it is reprogramed, and therefore the SM effect is one way. Recently, a semicrystalline SMP, which can demonstrate both one- and two-way SM effects, was developed by one of our groups (Chung, T., Rorno-Uribe, A., and Mather, P. T., 2008, “Two-Way Reversible Shape Memory in a Semicrystalline Network,” Macromolecules, 41(1), pp. 184–192). The main mechanism of the observed SM effects is due to stretch induced crystallization. This paper develops a one-dimensional constitutive model to describe the SM effect due to stretch induced crystallization. The model accurately describes the complex thermomechanical SM effect and can be used for the future development of three-dimensional constitutive models.

Structure and function of neural networks in the retina

1988 ◽  
Vol 46 ◽  
pp. 26-27
Author(s):  
Peter Sterling
Keyword(s):  
Ganglion Cells ◽  
Three Dimensional ◽  
Structure And Function ◽  
Synaptic Connections ◽  
Visual Axis ◽  
One Dimensional ◽  
Cat Retina ◽  
Ultrathin Sections ◽  
And Function ◽  
Insight Into

The synaptic connections in cat retina that link photoreceptors to ganglion cells have been analyzed quantitatively. Our approach has been to prepare serial, ultrathin sections and photograph en montage at low magnification (˜2000X) in the electron microscope. Six series, 100-300 sections long, have been prepared over the last decade. They derive from different cats but always from the same region of retina, about one degree from the center of the visual axis. The material has been analyzed by reconstructing adjacent neurons in each array and then identifying systematically the synaptic connections between arrays. Most reconstructions were done manually by tracing the outlines of processes in successive sections onto acetate sheets aligned on a cartoonist's jig. The tracings were then digitized, stacked by computer, and printed with the hidden lines removed. The results have provided rather than the usual one-dimensional account of pathways, a three-dimensional account of circuits. From this has emerged insight into the functional architecture.

Exploring the Multidimensional Facets of Authoritarianism: Authoritarian Aggression and Social Dominance Orientation

2008 ◽  
Vol 67 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Stefano Passini
Keyword(s):  
Social Dominance ◽  
Factor Model ◽  
Three Dimensional ◽  
Social Dominance Orientation ◽  
Model Fit ◽  
Regression Analyses ◽  
One Dimensional ◽  
Confirmatory Factor ◽  
The One ◽  
Better Than

The relation between authoritarianism and social dominance orientation was analyzed, with authoritarianism measured using a three-dimensional scale. The implicit multidimensional structure (authoritarian submission, conventionalism, authoritarian aggression) of Altemeyer’s (1981, 1988) conceptualization of authoritarianism is inconsistent with its one-dimensional methodological operationalization. The dimensionality of authoritarianism was investigated using confirmatory factor analysis in a sample of 713 university students. As hypothesized, the three-factor model fit the data significantly better than the one-factor model. Regression analyses revealed that only authoritarian aggression was related to social dominance orientation. That is, only intolerance of deviance was related to high social dominance, whereas submissiveness was not.

scholarly journals Ergodic control of diffusions with random intervention times

2021 ◽  
Vol 58 (1) ◽  
pp. 1-21
Author(s):  
Harto Saarinen ◽  
Jukka Lempa
Keyword(s):  
Optimal Solution ◽  
Singular Control ◽  
Control Policy ◽  
Control Problems ◽  
Ergodic Control ◽  
Linear Diffusion ◽  
One Dimensional ◽  
And Diffusion ◽  
Independent Poisson Process ◽  
Exact Amount

AbstractWe study an ergodic singular control problem with constraint of a regular one-dimensional linear diffusion. The constraint allows the agent to control the diffusion only at the jump times of an independent Poisson process. Under relatively weak assumptions, we characterize the optimal solution as an impulse-type control policy, where it is optimal to exert the exact amount of control needed to push the process to a unique threshold. Moreover, we discuss the connection of the present problem to ergodic singular control problems, and illustrate the results with different well-known cost and diffusion structures.

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