Proppant Transport With Varrying Injection Points And Its Impact On Proppant Development Inside A Fracture

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Proppant Transport in Complex Fracture Networks

Author : Christopher Allen Johnson Blyton
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (987 download)

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Book Synopsis Proppant Transport in Complex Fracture Networks by : Christopher Allen Johnson Blyton

Download or read book Proppant Transport in Complex Fracture Networks written by Christopher Allen Johnson Blyton and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Current hydraulic fracturing practice in unconventional resource development typically involves multiple fracturing stages, each consisting of the simultaneous creation of several fractures from a horizontal well. A large mass of proppant, often millions of pounds per well, is injected with the fluid to provide post-closure conductivity. Despite the large quantity of proppant used and its critical importance to well productivity, simple models are often applied to determine its placement in fractures. Propped or effective fracture lengths indicated by modeling may be 100 to 300% larger than the lengths inferred from production data. A common assumption is that the average proppant velocity due to pressure driven flow is equal to the average carrier fluid velocity, while the settling velocity calculation uses Stokes' law. To more accurately determine the placement of proppant in a fracture, it is necessary to rigorously account for many effects not included in the above assumptions. In this study, the motion of particles flowing with a fluid between fracture walls has been simulated using a coupled computational fluid dynamics and discrete element method (CFD-DEM) that rigorously accounts for the both aspects of the problem. These simulations determine individual particle trajectories as particle to particle and particle to wall collisions occur and include the effect of fluid flow. The results show that the proppant concentration and the ratio of proppant diameter to fracture width govern the relative velocity of proppant and fluid. Proppant settling velocity has been examined for small fracture widths to delineate the effect of several independent variables, including concentration. Simulations demonstrate that larger concentration increases the average settling velocity, in apparent contrast with much of the available literature, which indicates that increased concentration reduces settling velocity. However, this is due to the absence of displacement driven counter current fluid flow. This demonstrates that proppant settling in a hydraulic fracture is more complex than usually considered. A proppant transport model developed from the results of the direct numerical simulations and existing correlations for particle settling velocity has been incorporated into a fully three-dimensional hydraulic fracturing simulator. This simulator couples fracture geomechanics with fluid flow and proppant transport considerations to enable the fracture geometry and proppant distribution to be determined rigorously. Two engineering fracture design parameters, injection rate and proppant diameter, have been varied to show the effect on proppant placement. This allows for an understanding of the relative importance of each and optimization of the treatment to a particular application. The presence of natural fractures in unconventional reservoirs can significantly contribute to well productivity. As proppant is transported along a hydraulic fracture, the presence of a dilated natural fracture forms a fluid accepting branch and may result in proppant entry. The proportion of proppant transported into a branch at steady state has been determined using the CFD-DEM approach and is presented via a dimensionless 'particle transport coefficient' through normalization by the proportion of fluid flowing into the branch. Reynolds number at the inlet, branch aperture and the angle of orientation between the main slot and branch, particle size and concentration each affect the transport coefficient. A very different physical process, which controls particle transport into a branch under certain conditions, is the formation of a stable particle bridge preventing subsequent particle transport into the branch. This phenomenon was observed in several simulation cases. The complete set of equations for a three-dimensional formulation of rectangular displacement discontinuity elements has been used to determine the width distribution of a hydraulic fracture and dilated natural fracture. The widths have been determined for several combinations of stress anisotropy, net pressure, hydraulic fracture height and length. The effect of the length, height and orientation of the natural fracture and the elastic moduli of the rock have also been examined. Of the cases examined, many show that natural fracture dilation does not occur. Further, of those cases where dilation is apparent, the proppant transport efficiency corresponding to the natural fracture width is significantly less than one and in many cases zero due to size exclusion. The location and orientation of the natural fracture do not significantly affect its width, while its length and the elastic moduli of the rock substantially change the width.

Improvement of Fracture Conductivity Through Study of Proppant Transport and Chemical Stimulation

Author : Songyang Tong
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (131 download)

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Book Synopsis Improvement of Fracture Conductivity Through Study of Proppant Transport and Chemical Stimulation by : Songyang Tong

Download or read book Improvement of Fracture Conductivity Through Study of Proppant Transport and Chemical Stimulation written by Songyang Tong and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: During hydraulic fracturing treatments, proppants - usually sand - are placed inside fractures to improve fracture conductivity. However, a large portion of the generated hydraulic fractures often remain unpropped after fracturing treatments. There are two primary reasons for this poor proppant placement. First, proppants settle quickly in common fracturing fluids (e.g., slickwater), which results in unpropped sections at the tip or top of the fracture. Second, a large number of the microfractures are too narrow to accommodate any common commercial proppant. Such unpropped fractures hold a large potential flow capacity as they exhibit a large contact area with the reservoir. However, their potential flow capacity is diminished during production due to closing of unpropped fractures because of closure stress. In this study, fractures are categorized as wider fractures, which are accessible to proppant, and narrower fractures, which are inaccessible to proppant. For wider fractures, proppant transport is important as proppant is needed for keeping them open. For narrower fractures, a chemical formulation is proposed as there is less physical restriction for fluids to flow inside across them. The chemical formulation is expected to improve fracture conductivity by generating roughness on fracture surfaces. This dissertation uses experiments and simulations to investigate proppant transport in a complex fracture network with laboratory-scale transparent fracture slots. Proppant size, injection flow rate and bypass fracture angle are varied and their effects are systematically evaluated. Based on experimental results, a straight-line relationship can be used to quantify the fraction of proppant that flows into bypass fractures with the total amount of proppant injected. A Computational Fluid Dynamics (CFD) model is developed to simulate the experiments; both qualitative and quantitative matches are achieved with this model. It is concluded that the fraction of proppant which flows into bypass fractures could be small unless a significant amount of proppant is injected, which indicates the inefficiency of slickwater in transporting proppant. An alternative fracturing fluid - foam - has been proposed to improve proppant placement because of its proppant carrying capacity. Foam is not a single-phase fluid, and it suffers liquid drainage with time due to gravity. Additionally, the existence of foam bubbles and lamellae could alter the movement of proppants. Experiments and simulations are performed to evaluate proppant placement in field-scale foam fracturing application. A liquid drainage model and a proppant settling correlation are developed and incorporated into an in-housing fracturing simulator. Results indicate that liquid drainage could negatively affect proppant placement, while dry foams could lead to negligible proppant settling and consequently uniform proppant placement. For narrower fractures, two chemical stimulation techniques are proposed to improve fracture conductivity by increasing fracture surface roughness. The first is a nanoparticle-microencapsulated acid (MEA) system for shale acidizing applications, and the second is a new technology which can generate mineral crystals on the shale surface to act as in-situ proppants. The MEA could be released as the fracture closes and the released acid could etch the surface of the rock locally, in a non-uniform way, to improve fracture conductivity (up to 40 times). Furthermore, the in-situ proppant generation technology can lead to crystal growth in both fracking water and formation brine conditions, and it also improves fracture conductivity (up to 10 times) based on core flooding experiments

Proppant Transport Down a Three-dimensional Planar Fracture

Author : Zillur Rahim
Publisher :
ISBN 13 :
Total Pages : 402 pages
Book Rating : 4.:/5 (216 download)

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Book Synopsis Proppant Transport Down a Three-dimensional Planar Fracture by : Zillur Rahim

Download or read book Proppant Transport Down a Three-dimensional Planar Fracture written by Zillur Rahim and published by . This book was released on 1988 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Role of Fluid Elasticity and Viscous Instabilities in Proppant Transport in Hydraulic Fractures

Author : Sahil Malhotra
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (87 download)

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Book Synopsis Role of Fluid Elasticity and Viscous Instabilities in Proppant Transport in Hydraulic Fractures by : Sahil Malhotra

Download or read book Role of Fluid Elasticity and Viscous Instabilities in Proppant Transport in Hydraulic Fractures written by Sahil Malhotra and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation presents an experimental investigation of fluid flow, proppant settling and horizontal proppant transport in hydraulic fractures. The work is divided into two major sections: investigation of proppant settling in polymer-free surfactant-based viscoelastic (VES) fluids and development of a new method of proppant injection, referred to as Alternate-Slug fracturing. VES fluid systems have been used to eliminate polymer-based damage and to efficiently transport proppant into the fracture. Current models and correlations neglect the important influence of fracture walls and fluid elasticity on proppant settling. Experimental data is presented to show that elastic effects can increase or decrease the settling velocity of particles, even in the creeping flow regime. Experimental data shows that significant drag reduction occurs at low Weissenberg number, followed by a transition to drag enhancement at higher Weissenberg numbers. A new correlation is presented for the sphere settling velocity in unbounded viscoelastic fluids as a function of the fluid rheology and the proppant properties. The wall factors for sphere settling velocities in viscoelastic fluids confined between solid parallel plates (fracture walls) are calculated from experimental measurements made on these fluids over a range of Weissenberg numbers. Results indicate that elasticity reduces the retardation effect of the confining walls and this reduction is more pronounced at higher ratios of the particle diameter to spacing between the walls. Shear thinning behavior of fluids is also observed to reduce the retardation effect of the confining walls. A new empirical correlation for wall factors for spheres settling in a viscoelastic fluid confined between two parallel walls is presented. An experimental study on proppant placement using a new method of fracturing referred to as Alternate-Slug fracturing is presented. This method involves alternate injection of low viscosity and high viscosity fluids into the fracture, with proppant pumped in the low viscosity fluid. Experiments are conducted in Hele-Shaw cells to study the growth of viscous fingers over a wide range of viscosity ratios. Data is presented to show that the viscous finger velocities and mixing zone velocities increase with viscosity ratio up to viscosity ratios of about 350 and the trend is consistent with Koval's theory. However, at higher viscosity ratios the mixing zone velocity values plateau signifying no further effect of viscosity contrast on the growth of fingers and mixing zone. The plateau in the velocities at high viscosity ratios is caused by an increase in the thickness of the displacing fluid and a reduction in the thin film of the displaced fluid on the walls of the Hele-Shaw cell. Fluid elasticity is observed to retard the growth of fingers and leads to growth of multiple thin fingers as compared to a single thick dominant finger in less elastic fluids. Observations show the shielding effect is reduced by fluid elasticity. Elastic effects are observed to reduce the thickness of thin film of displaced fluid on the walls of Hele-Shaw cell. The dominant wave number for the growth of instabilities is observed to be higher in more elastic fluids. At the onset of instability, the interface breaks down into a greater number of fingers in more elastic fluids. Experiments are performed in simulated fractures (slot cells) to show the proppant distribution using alternate-slug fracturing. Observations show alternate-slug fracturing ensures deeper placement of proppant through two primary mechanisms: (a) proppant transport in viscous fingers formed by the low viscosity fluid and (b) an increase in drag force in the polymer slug leading to better entrainment and displacement of any proppant banks that may have formed. The method offers advantages of lower polymer costs, lower pumping horsepower, smaller fracture widths, better control of fluid leak-off and less gel damage compared to conventional gel fracs.

Effect of Fracture Heterogeneity on Proppant Transport and Settling Mechanism

Author : Dhurgham Abdulameer Kadhim
Publisher :
ISBN 13 :
Total Pages : 104 pages
Book Rating : 4.:/5 (1 download)

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Book Synopsis Effect of Fracture Heterogeneity on Proppant Transport and Settling Mechanism by : Dhurgham Abdulameer Kadhim

Download or read book Effect of Fracture Heterogeneity on Proppant Transport and Settling Mechanism written by Dhurgham Abdulameer Kadhim and published by . This book was released on 2017 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Proppant transport modeling through fractures with slickwater fluid systems assumes uniform and homogeneous fracture widths by implying constant fluid behavior at wall boundaries. Hydraulic fracturing mineback operations have demonstrated that induced fractures are heterogeneous and varying in width. This work investigates the impact of fracture width heterogeneity, roughness, and leak-off on ceramic proppant transport and settling, using proppant distribution concepts of Equilibrium Dune Level (EDL) and equilibrium Dune Length (EDX). Experimental work was conducted to investigate the impact of fracture width heterogeneity by varying fracture width along two plexiglass sheets. To mimic actual hydraulic fractures, the injection side was designed as the largest width, and the width of the opposite end was reduced. The ratio between the injection and tip side widths was varied to study the effect of changing fracture width. One ratio was used as a base to study the effect of varying wall roughness and leak-off on the proppant placement. Results of this work demonstrate the impacts of reservoir heterogeneity, wall roughness, and leak off on proppant conveyance and distribution. Fracture width and wall roughness have a significant effect on proppant distribution along a fracture. Increasing width heterogeneity and roughness provide a better proppant distribution and thus better fracture propped conductivity. The effect of leak-off on proppant distribution was monitored, and it showed that proppant followed water movement. Consequently, average water volume that left the slot was affected by proppant distribution"--Abstract, page iii.

Quantifying Ceramic Proppant Transport in Complex Fracture Networks

Author : Vivekvardhan Reddy Kesireddy
Publisher :
ISBN 13 :
Total Pages : 91 pages
Book Rating : 4.:/5 (12 download)

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Book Synopsis Quantifying Ceramic Proppant Transport in Complex Fracture Networks by : Vivekvardhan Reddy Kesireddy

Download or read book Quantifying Ceramic Proppant Transport in Complex Fracture Networks written by Vivekvardhan Reddy Kesireddy and published by . This book was released on 2017 with total page 91 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Water fracs have become an essential part of unconventional reservoirs to create deeper fracture networks. Proppant transport in water fracs is challenging in terms of fluids ability to carry the proppant deeper into these fracture networks. This experimental study investigates the impact of the flow rates, fracture widths and complexity controlling the ability of proppant to flow into complex fracture networks. This research attempts to nullify the knowledge gap in understanding width heterogeneity in primary and secondary fractures. This study speaks for settling pattern and proppant transport through a slot flow model with a unique approach to understand stage wise distribution of proppant. The slurry was injected in multiple fracture pore volumes at required flow rates to monitor the stage-wise development of proppant bed. Study illustrates proppant transport in terms of proppant bed heights, equilibrium dune levels and proppant area fractions. Results represents proppant transport for fracture widths, which are comparable to proppant diameter. Two different configurations of apparatus were used to investigate heterogeneity in width in complex fracture networks. Results describe stepwise distribution of ceramic proppant under the influence of flow rates, fracture width and complexity. The bed height gradually builds up in the slot with each injection to achieve an equilibrium bed height. Injection slurry velocities primarily affect proppant transport affecting its distribution in fractures. The fracture width showed a significant impact on proppant transport. Width heterogeneity in complex fracture systems provide better proppant distribution in complex fracture networks. Heterogeneity of width in the fracture caused increased settling and more proppant surface area fractions. The results help in optimizing the proppant flow patterns into complex fracture networks"--Abstract, page iii.

Modeling of Solid Particle Transport in Fractures and Its Applications to Proppant Placement During Hydraulic Fracturing Operations

Download Modeling of Solid Particle Transport in Fractures and Its Applications to Proppant Placement During Hydraulic Fracturing Operations PDF Online Free

Author : Yanan Ding
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (137 download)

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Book Synopsis Modeling of Solid Particle Transport in Fractures and Its Applications to Proppant Placement During Hydraulic Fracturing Operations by : Yanan Ding

Download or read book Modeling of Solid Particle Transport in Fractures and Its Applications to Proppant Placement During Hydraulic Fracturing Operations written by Yanan Ding and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In addition to conventional enhanced oil recovery (EOR) technologies, extensive efforts have been made to explore new approaches to sustain the increasing global oil and gas consumption while lowering the operational costs. In recent decades, nanoparticles (NPs) have seen their promising potentials in recovering hydrocarbons from numerous laboratory experiments and field pilots. Also, hydraulic fracturing techniques have unlocked a significant quantity of hydrocarbon resources from unconventional reservoirs. Solid particle transport including NP transport, dispersion, and distribution in hydrocarbon reservoirs, proppant placement within hydraulic fractures, and sand production is critical to the efficient and effective hydrocarbon exploitation. Considering the petrophysical complexity as well as the intricate interactions among particles, fluids, and rock matrix, it is, therefore, an extremely challenging task to accurately predict the associated transport and placement behaviour of solid particles in a hydrocarbon reservoir. Theoretically, a robust and pragmatic method has been developed and validated to analytically determine the dynamic dispersion coefficients for particles flowing in a parallel-plate fracture with instantaneous point source as well as uniform and volumetric line sourcess, in which particle gravity settling effect has been considered. It is found that the point source and the uniform line source are respectively the most and least sensitive to the gravity effect. An increase of particle size larger than its critical value decreases the asymptotical dispersion coefficient for all the source conditions, while gravity settling promotes the dispersion phenomenon during the early-stage of point source condition. Particle-tracking simulations have been performed and validated on polydisperse dense particle transport in a randomly-orientated fracture with spatially variable apertures. The simulated results indicate that the mass breakthrough efficiency of particles and particle plume distribution in a randomly-orientated rough fracture are significantly influenced by different factors when particle gravity settling occurs. In addition, particle attachment consisting of reversible and irreversible adsorptions on an aperture surface is quantified applying the Derjaguin-Landau-Verwey-Overbeek (DLVO) kinetics. With sensitivity analysis performed, the impacts of different factors on particle attachment are found to vary with each other through non-unique patterns. By integrating the Perkins-Kern-Nordgren-Carter (PKN-C) fracture propagation model and the particle tracking algorithm, a novel Eulerian-Lagrangian (E-L) model has been developed and validated to simulate field-scale proppant transport during hydraulic fracturing operations. Such an E-L model incorporates pertinent empirical correlations determined from regressing experimental measurements regarding the proppant settling velocity and the drag/lift forces, which is applicable to both the Newtonian and non- Newtonian fluid conditions. The non-Newtonian fluid is usually found to yield a less "heel-biased" pattern of proppant distribution in a hydraulic fracture, e.g., a larger slurry coverage together with a longer proppant dune, while distinct patterns of the dominant factors are observed and evaluated.

An Experimental Investigation on the Transport Characteristics of Rough Fractures in the Presence of Proppants

Author : Raimbay Aigerim
Publisher :
ISBN 13 :
Total Pages : 111 pages
Book Rating : 4.:/5 (959 download)

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Book Synopsis An Experimental Investigation on the Transport Characteristics of Rough Fractures in the Presence of Proppants by : Raimbay Aigerim

Download or read book An Experimental Investigation on the Transport Characteristics of Rough Fractures in the Presence of Proppants written by Raimbay Aigerim and published by . This book was released on 2015 with total page 111 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the introduction of hydraulic fracturing technique, industry has been attempted to enhance production of hydrocarbon from tight reservoirs by selecting optimum design of hydraulic fracturing treatment. One of the essential parameters in hydraulic fracturing design is the proper selection and injection of proppants. They not only provide fracture permeability but also prevent "healing" of fractures. Hence, the quantification of proppant transport characteristics is highly critical in a sustainable production from hydraulically fractured wells. Previous studies in this regard were limited to smooth (parallel) fracture surfaces to a great extent ignoring the effect of roughness of fractures, which may have significant impact in controlling the permeability of hydraulic fractures in the presences of proppants. In this thesis, effect of surface roughness to fluid flow and transportation/distribution of propping agents were investigated through experimental work. Water and polymer solutions representing typical rheological properties of hydraulic fracturing fluids were injected through transparent models of the fractures of different origin rocks (granite, marble, and limestone) with and without propping agents. The permeability changes due to proppant distribution caused by the roughness of fracture surfaces were quantified and correlated to different fractal characteristics of surface roughness. Qualitative and quantitative analyses were supported by visualization of experiments.

Integrated 3-dimensional Modeling of Proppant Transport Through Hydraulic Fracture Network in Shale Gas Reservoir

Author : Oliver Chang
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (959 download)

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Book Synopsis Integrated 3-dimensional Modeling of Proppant Transport Through Hydraulic Fracture Network in Shale Gas Reservoir by : Oliver Chang

Download or read book Integrated 3-dimensional Modeling of Proppant Transport Through Hydraulic Fracture Network in Shale Gas Reservoir written by Oliver Chang and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydraulic fracturing is one of the most successful and widely applied techniques that ensure economic recovery from unconventional reservoirs. Oil and gas bearing formation has pre-existing natural fractures and possesses a large proportion in hydrocarbon resources. Distinct fracture propagational behavior and operational variation both affect the entire hydraulic fracturing treatment. Proppant transport and fracture network conductivity are the most significant factors determining the effectiveness of a treatment. The concept of stimulated reservoir volume (SRV) is used to characterize the efficiency of hydraulic fracturing treatment. However, the unpropped fracture will close after the well starts to produce without contributing hydrocarbon recovery. Only the propped open section of fracture contributes to the hydrocarbon recovery. Therefore, the concept of propped open stimulated reservoir volume (PSRV) is proposed to characterize the effectiveness of the treatment. Physics of proppant transport in a complex fracture network is unclear to the engineers. Most of the model simulates using simplified physics. In this work, we first identified the patterns of proppant transport and we developed equations to quantify the governing physics in each pattern, in order to capture the proppant transport process accurately. To quantify the PSRV, a dynamic 3-D, finite-difference, proppant transport model is developed and linked to a hydraulic fracture propagation model to simulate the process of proppant transport through the hydraulic fracture network. The actual propped open stimulated reservoir volume (PSRV) and fracture network conductivity can be quantified by utilizing the model. The goal of this study is to generate guidelines to maximize the effectiveness of the hydraulic fracturing treatment. Hence, a systematic parametric study was conducted to investigate the relation among engineering factors, geomechanical and reservoir properties. The effect of each parameter on PSRV, PSRV/SRV efficiency ratio, and average fracture conductivity during pressure pumping, flowback and shut-in is evaluate and quantified. Guidelines to optimize the effectiveness of hydraulic fracturing treatment for different scenarios are established based on the systematic parametric study.

A Model for Hydraulic Fracturing and Proppant Placement in Unconsolidated Sands

Author : Dongkeun Lee
Publisher :
ISBN 13 :
Total Pages : 390 pages
Book Rating : 4.:/5 (13 download)

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Book Synopsis A Model for Hydraulic Fracturing and Proppant Placement in Unconsolidated Sands by : Dongkeun Lee

Download or read book A Model for Hydraulic Fracturing and Proppant Placement in Unconsolidated Sands written by Dongkeun Lee and published by . This book was released on 2017 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydraulic fracturing in unconsolidated or poorly consolidated formations has been used as a technique for well stimulation and for sand control. Although a large number of hydraulic fracturing operations have been performed in soft formations, the exact mechanisms of failure and fracture propagation remain an unresolved issue. Conventional hydraulic fracturing models based on the theory of linear elastic fracture mechanics (LEFM) consistently predict lower net fracturing pressure, smaller fracture widths and longer fracture lengths in soft formations than observed in the field. Operators who want to design and analyze frac-pack treatments routinely use a hard rock model and need to calibrate and often manipulate input parameters beyond a physically reasonable range to match the net fracturing pressure and well performance data. In this dissertation, we have developed a fully-coupled, three-dimensional hydraulic fracture model for poro-elasto-plastic materials and fluid flow coupled with proppant transport. A computational framework for fluid-structure interaction (FSI) based on finite volume method was developed for modeling of hydraulic fracturing and proppant placement in soft formations. Two separate domains, a fracture and a reservoir domain, are discretized individually, separate equations are solved in the two domains, and their interactions are modeled. The model includes the fully coupled process of power-law fluid flow inside the fracture with proppant transport, fluid leak-off from the fracture into the porous reservoir, pore pressure diffusion into the reservoir, inelastic deformation of the poro-elasto-plastic reservoir, and fracture propagation using a cohesive zone model along with a dynamic meshing procedure. Fully-coupled processes between the two domains, and pressure, flow and displacement coupling within each domain are modeled by an iterative and segregated solution procedure, where each component of the field variable is solved separately, consecutively, and iteratively. We verified the essential components of the model by comparing our simulation results with several well-known analytical solutions (elastoplastic deformation and failure problem, KGD model in a 2-D elastic domain, and KGD model in storage-toughness dominated regime). We applied the model to design and analyze frac-pack operations conducted in a Gulf of Mexico oilfield. Our model is capable of capturing the high net fracturing pressure commonly observed during frac-packing operations without adjusting any input parameters. The model shows quantitatively that plasticity causes lower stress concentration around the fracture tip which shields the tip of the propagating fracture from the fracturing pressure, and retards fracture growth. Our model predicts shorter fracture lengths and wider widths compared to a hard rock model. Shear failure around the fracture and ahead of the tip are modeled. Low cohesion sands tend to fail in shear first then in tension if sufficient pore pressure builds up. We investigated the effect of fluid viscosity, injection rate, and proppant diameter on fracture growth and proppant placement using sensitivity studies. Higher apparent fluid viscosity and injection rate results in wider fractures with better proppant placement, when the fracture is expected to be contained within the payzone. Utilizing larger diameter of proppant leads to settling-dominant proppant placement resulting in the formation of a proppant bank at the bottom of the induced fracture. The new frac-pack model for the first time allows operators to design and analyze hydraulic fracturing stimulations in soft, elastoplastic formations when complex fracturing fluids are used. Our results also provide guidelines for the selection of fracturing fluid rheology, proppant size, and injection rates.

Numerical Modeling of Nonlinear Problems in Hydraulic Fracturing

Author : Endrina Rivas
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (126 download)

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Book Synopsis Numerical Modeling of Nonlinear Problems in Hydraulic Fracturing by : Endrina Rivas

Download or read book Numerical Modeling of Nonlinear Problems in Hydraulic Fracturing written by Endrina Rivas and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydraulic fracturing is a stimulation technique in which fluid is injected at high pressure into low-permeability reservoirs to create a fracture network for enhanced production of oil and gas. It is the primary purpose of hydraulic fracturing to enhance well production. The three main mechanisms during hydraulic fracturing for oil and gas production which largely impact the reservoir production are: (1) fracture propagation during initial pad fluid injection, which defines the extent of the fracture; (2) fracture propagation during injection of proppant slurry (fluid mixed with granular material), creating a propped reservoir zone; and (3) shear dilation of natural fractures surrounding the hydraulically fractured zone, creating a broader stimulated zone. The thesis has three objectives that support the simulation of mechanisms that lead to enhanced production of a hydraulically-fractured reservoir. The first objective is to develop a numerical model for the simulation of the mechanical deformation and shear dilation of naturally fractured rock masses. In this work, a two-dimensional model for the simulation of discrete fracture networks (DFN) is developed using the extended finite element method (XFEM), in which the mesh does not conform to the natural fracture network. The model incorporates contact, cohesion, and friction between blocks of rock. Shear dilation is an important mechanism impacting the overall nonlinear response of naturally fractured rock masses and is also included in the model--physics previously not simulated within an XFEM context. Here, shear dilation is modeled through a linear dilation model, capped by a dilation limiting displacement. Highly nonlinear problems involving multiple joint sets are investigated within a quasi-static context. An explicit scheme is used in conjunction with the dynamic relaxation technique to obtain equilibrium solutions in the face of the nonlinear constitutive models from contact, cohesion, friction, and dilation. The numerical implementation is verified and its convergence illustrated using a shear test and a biaxial test. The model is then applied to the practical problem of the stability of a slope of fractured rock. The second objective is to develop a numerical model for the simulation of proppant transport through planar fractures. This work presents the numerical methodology for simulation of proppant transport through a hydraulic fracture using the finite volume method. Proppant models commonly used in the hydraulic fracturing literature solve the linearized advection equation; this work presents solution methods for the nonlinear form of the proppant flux equation. The complexities of solving the nonlinear and heterogeneous hyperbolic advection equation that governs proppant transport are tackled, particularly handling shock waves that are generated due to the nonlinear flux function and the spatially-varying width and pressure gradient along the fracture. A critical time step is derived for the proppant transport problem solved using an explicit solution strategy. Additionally, a predictor-corrector algorithm is developed to constrain the proppant from exceeding the physically admissible range. The model can capture the mechanisms of proppant bridging occurring in sections of narrow fracture width, tip screen-out occurring when fractures become saturated with proppant, and flushing of proppant into new fracture segments. The results are verified by comparison with characteristic solutions and the model is used to simulate proppant transport through a KGD fracture. The final objective is to develop a numerical model for the simulation of proppant transport through propagating non-planar fractures. This work presents the first monolithic coupled numerical model for simulating proppant transport through a propagating hydraulic fracture. A fracture is propagated through a two-dimensional domain, driven by the flow of a proppant-laden slurry. Modeling of the slurry flow includes the effects of proppant bridging and the subsequent flow of fracturing fluid through the packed proppant pack. This allows for the simulation of a tip screen-out, a phenomenon in which there is a high degree of physical interaction between the rock deformation, fluid flow, and proppant transport. Tip screen-out also leads to shock wave formation in the solution. Numerical implementation of the model is verified and the model is then used to simulate a tip screen-out in both planar and non-planar fractures. An analysis of the fracture aperture, fluid pressure, and proppant concentration profiles throughout the simulation is performed for three different coupling schemes: monolithic, sequential, and loose coupling. It is demonstrated that even with time step refinement, the loosely-coupled scheme fails to converge to the same results as the monolithic and sequential schemes. The monolithic and sequential algorithms yield the same solution up to the onset of a tip screen-out, after which the sequential scheme fails to converge. The monolithic scheme is shown to be more efficient than the sequential algorithm (requiring fewer iterations) and has comparable computational cost to the loose coupling algorithm. Thus, the monolithic scheme is shown to be optimal in terms of computational efficiency, robustness, and accuracy. In addition to this finding, a robust and more efficient algorithm for injection-rate controlled hydraulic fracturing simulation based on global mass conservation is presented in the thesis.

Hydraulic Proppant Fracturing and Gravel Packing

Author : D. Mader
Publisher : Elsevier
ISBN 13 : 0080868843
Total Pages : 1277 pages
Book Rating : 4.0/5 (88 download)

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Book Synopsis Hydraulic Proppant Fracturing and Gravel Packing by : D. Mader

Download or read book Hydraulic Proppant Fracturing and Gravel Packing written by D. Mader and published by Elsevier. This book was released on 1989-03-01 with total page 1277 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many aspects of hydraulic proppant fracturing have changed since its innovation in 1947. The main significance of this book is its combination of technical and economical aspects to provide an integrated overview of the various applications of proppants in hydraulic fracturing, and gravel in sand control. The monitoring of fractures and gravel packs by well-logging and seismic techniques is also included.The book's extensive coverage of the subject should be of special interest to reservoir geologists and engineers, production engineers and technologists, and well log analysts.

The Role of Acidizing in Proppant Fracturing in Carbonate Reservoirs

Author : Jurairat Densirimongkol
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (689 download)

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Book Synopsis The Role of Acidizing in Proppant Fracturing in Carbonate Reservoirs by : Jurairat Densirimongkol

Download or read book The Role of Acidizing in Proppant Fracturing in Carbonate Reservoirs written by Jurairat Densirimongkol and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Today, optimizing well stimulation techniques to obtain maximum return of investment is still a challenge. Hydraulic fracturing is a typical application to improve ultimate recovery from oil and gas reservoirs. Proppant fracturing has become one of the most widely considered alternatives for application in carbonate reservoirs. Especially in areas that have high closure stress, the non-smoothly etched surface created by acid fracturing may not remain open upon closing, resulting in decrease in fracture conductivity and unsuccessful stimulation treatment. In early years, because of the increase in the success of proppant fracturing, proppant partial monolayer has been put forward as a method that helps generate the maximum fracture conductivity from proppant fracturing treatment. However, this method was not widely successful because of proppant crushing and proppant embedment problems that result in losing conductivity. The ability to transport propping agents in available fracturing fluid was also poor and resulted in difficulties and failures to obtain proppant partial monolayer placement. For carbonate formations, acid fracturing is another effective stimulation method. Simpler operation and lower cost made the technique attractive in the field with plenty of successful experiences. The heterogeneity feature of carbonate formation brings a challenge to create sufficient conductivity. In cases of high closure formation, fracture conductivity is hard to sustain. This factor limited the applications of acid fracturing sometimes. In this study, laboratory tests were carried out using low concentrations of ultralightweight proppant to obtain partial monolayer proppant. Because of low specific gravity property of this proppant, it was claimed to help improve proppant transport inside the fracture. In this experimental study, the partial monolayer technique was examined with particular emphasis upon the impact of acid in possibly improving fracture conductivity of carbonate rocks. The technique is referred as "closed fracture acidizing". After obtaining a partial monolayer distribution on the fracture face, gelled acid was injected through the fracture face. Fracture conductivity before and after acid injection were evaluated. Experimental results showed clearly that acid injection does not enhance fracture conductivity of partial monolayer proppant fracturing. The more the volume of acid injection, the more rapidly fracture conductivity declines.

New numerical approaches to model hydraulic fracturing in tight reservoirs with consideration of hydro-mechanical coupling effects

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Author : Lei Zhou
Publisher : Cuvillier Verlag
ISBN 13 : 3736946562
Total Pages : 172 pages
Book Rating : 4.7/5 (369 download)

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Book Synopsis New numerical approaches to model hydraulic fracturing in tight reservoirs with consideration of hydro-mechanical coupling effects by : Lei Zhou

Download or read book New numerical approaches to model hydraulic fracturing in tight reservoirs with consideration of hydro-mechanical coupling effects written by Lei Zhou and published by Cuvillier Verlag. This book was released on 2014-03-20 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation, two new numerical approaches for hydraulic fracturing in tight reservoir were developed. A more physical-based numerical 3D-model was developed for simulating the whole hydraulic fracturing process including fracture propagation, closure and contact as well as proppant transport and settling. In this approach rock formation, pore and fracture systems were assembled together, in which hydro-mechanical coupling effect, proppant transport and settling as well as their influences on fracture closure and contact were fully considered. A combined FDM and FVM schema was used to solve the problem. Three applications by using the new approach were presented. The results illustrated the whole hydraulic fracturing process well and seemed to be logical, which confirmed the ability of the developed approach to model the in-situ hydraulic fracturing operation from injection start till fully closure. In order to investigate the orientation problem of hydraulic fracturing in tight reservoir, a new approach for simulating arbitrary fracture propagation and orientation in 2D was developed. It was solved by a hybrid schema of XFEM and FVM. Three numerical studies were illustrated, which proved the ability of the developed approach to solve the orientation problem in field cases.

Unconventional Reservoir Geomechanics

Author : Mark D. Zoback
Publisher : Cambridge University Press
ISBN 13 : 1107087074
Total Pages : 495 pages
Book Rating : 4.1/5 (7 download)

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Book Synopsis Unconventional Reservoir Geomechanics by : Mark D. Zoback

Download or read book Unconventional Reservoir Geomechanics written by Mark D. Zoback and published by Cambridge University Press. This book was released on 2019-05-16 with total page 495 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive overview of the key geologic, geomechanical and engineering principles that govern the development of unconventional oil and gas reservoirs. Covering hydrocarbon-bearing formations, horizontal drilling, reservoir seismology and environmental impacts, this is an invaluable resource for geologists, geophysicists and reservoir engineers.

Simulating Growth and Proppant Transport in Non-planar Hydraulic Fractures

Author : Stephen Thomas Castonguay
Publisher :
ISBN 13 :
Total Pages : 326 pages
Book Rating : 4.:/5 (15 download)

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Book Synopsis Simulating Growth and Proppant Transport in Non-planar Hydraulic Fractures by : Stephen Thomas Castonguay

Download or read book Simulating Growth and Proppant Transport in Non-planar Hydraulic Fractures written by Stephen Thomas Castonguay and published by . This book was released on 2017 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Hydraulic Fracturing in Unconventional Reservoirs

Author : Hoss Belyadi
Publisher : Gulf Professional Publishing
ISBN 13 : 0128176660
Total Pages : 636 pages
Book Rating : 4.1/5 (281 download)

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Book Synopsis Hydraulic Fracturing in Unconventional Reservoirs by : Hoss Belyadi

Download or read book Hydraulic Fracturing in Unconventional Reservoirs written by Hoss Belyadi and published by Gulf Professional Publishing. This book was released on 2019-06-18 with total page 636 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydraulic Fracturing in Unconventional Reservoirs: Theories, Operations, and Economic Analysis, Second Edition, presents the latest operations and applications in all facets of fracturing. Enhanced to include today's newest technologies, such as machine learning and the monitoring of field performance using pressure and rate transient analysis, this reference gives engineers the full spectrum of information needed to run unconventional field developments. Covering key aspects, including fracture clean-up, expanded material on refracturing, and a discussion on economic analysis in unconventional reservoirs, this book keeps today's petroleum engineers updated on the critical aspects of unconventional activity. - Helps readers understand drilling and production technology and operations in shale gas through real-field examples - Covers various topics on fractured wells and the exploitation of unconventional hydrocarbons in one complete reference - Presents the latest operations and applications in all facets of fracturing