Experimental Study of Effect of Proppant Concentration, Types, Sizes, Rock Mineralogy and Overburden Stress on Fracture Conductivity

Download Experimental Study of Effect of Proppant Concentration, Types, Sizes, Rock Mineralogy and Overburden Stress on Fracture Conductivity PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 111 pages
Book Rating : 4.:/5 (113 download)

DOWNLOAD NOW!


Book Synopsis Experimental Study of Effect of Proppant Concentration, Types, Sizes, Rock Mineralogy and Overburden Stress on Fracture Conductivity by : Abhishek Kumar Gupta

Download or read book Experimental Study of Effect of Proppant Concentration, Types, Sizes, Rock Mineralogy and Overburden Stress on Fracture Conductivity written by Abhishek Kumar Gupta and published by . This book was released on 2019 with total page 111 pages. Available in PDF, EPUB and Kindle. Book excerpt:

The Effect of Proppant Size and Concentration on Hydraulic Fracture Conductivity in Shale Reservoirs

Download The Effect of Proppant Size and Concentration on Hydraulic Fracture Conductivity in Shale Reservoirs PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (868 download)

DOWNLOAD NOW!


Book Synopsis The Effect of Proppant Size and Concentration on Hydraulic Fracture Conductivity in Shale Reservoirs by : Anton Nikolaev Kamenov

Download or read book The Effect of Proppant Size and Concentration on Hydraulic Fracture Conductivity in Shale Reservoirs written by Anton Nikolaev Kamenov and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydraulic fracture conductivity in ultra-low permeability shale reservoirs is directly related to well productivity. The main goal of hydraulic fracturing in shale formations is to create a network of conductive pathways in the rock which increase the surface area of the formation that is connected to the wellbore. These highly conductive fractures significantly increase the production rates of petroleum fluids. During the process of hydraulic fracturing proppant is pumped and distributed in the fractures to keep them open after closure. Economic considerations have driven the industry to find ways to determine the optimal type, size and concentration of proppant that would enhance fracture conductivity and improve well performance. Therefore, direct laboratory conductivity measurements using real shale samples under realistic experimental conditions are needed for reliable hydraulic fracturing design optimization. A series of laboratory experiments was conducted to measure the conductivity of propped and unpropped fractures of Barnett shale using a modified API conductivity cell at room temperature for both natural fractures and induced fractures. The induced fractures were artificially created along the bedding plane to account for the effect of fracture face roughness on conductivity. The cementing material present on the surface of the natural fractures was preserved only for the initial unpropped conductivity tests. Natural proppants of difference sizes were manually placed and evenly distributed along the fracture face. The effect of proppant monolayer was also studied. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/149386

Proppant Fracture Conductivity with High Proppant Loading and High Closure Stress

Download Proppant Fracture Conductivity with High Proppant Loading and High Closure Stress PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (747 download)

DOWNLOAD NOW!


Book Synopsis Proppant Fracture Conductivity with High Proppant Loading and High Closure Stress by : Matthew Charles Rivers

Download or read book Proppant Fracture Conductivity with High Proppant Loading and High Closure Stress written by Matthew Charles Rivers and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Ultra-deepwater reservoirs are important unconventional reservoirs that hold the potential to produce billions of barrels of hydrocarbons, but also present major challenges. This type of reservoir is usually high pressure and high temperature (HPHT) and has a relatively high permeability. Hydraulic fracturing high permeability reservoirs are different from the hydraulic fracturing technology used in low permeability formations. The main purpose of hydraulic fracturing in low permeability reservoirs is to create a long, highly conductive path, whereas in high permeability formations hydraulic fracturing is used predominantly to bypass near wellbore formation damage, control sand production and reduce near wellbore pressure drop. Hydraulically fracturing these types of wells requires short fractures packed with high proppant concentrations. In addition, fracturing in high permeability reservoirs aims at achieving enough fracture length to increase productivity, especially when the viscosity of the reservoir fluid is high. In order to pump such a job and ensure long term productivity from the fracture, understanding the behavior of the fracture fluid and proppant is critical. A series of laboratory experiments have been conducted to study conductivity and fracture width with high proppant loading, high temperature and high pressure. Proppant was manually placed in the fracture and fracture fluid was pumped through the pack. Conductivity was measured by pumping oil to simulate reservoir conditions. Proppant performance and fracture fluids, which carry the proppant into the fracture, and their subsequent clean-up during production, were studied. High strength proppant is ideal for deep fracture stimulations and in this study different proppant loadings at different stresses were tested to see the impact of crushing and fracture width reduction on fracture conductivity. The preliminary test results indicated that oil at reservoir conditions improves clean-up of fracture fluid left in the proppant pack compared with using water at ambient temperature. Increasing the proppant concentration in the fracture showed higher conductivity values in some cases even at high closure stress. The increase in effective closure stress with high temperature resulted in a significant loss in conductivity. Additionally, the fracture width decreased with time and increased effective closure stress. Tests were also run to study the effect of cyclic loading which is expected to further decrease conductivity.

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

Download Improvement of Fracture Conductivity Through Study of Proppant Transport and Chemical Stimulation PDF Online Free

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

DOWNLOAD NOW!


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

Experimental Investigation of Propped Fracture Conductivity in Tight Gas Reservoirs Using The Dynamic Conductivity Test

Download Experimental Investigation of Propped Fracture Conductivity in Tight Gas Reservoirs Using The Dynamic Conductivity Test PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (865 download)

DOWNLOAD NOW!


Book Synopsis Experimental Investigation of Propped Fracture Conductivity in Tight Gas Reservoirs Using The Dynamic Conductivity Test by : Jose Domingo Romero Lugo

Download or read book Experimental Investigation of Propped Fracture Conductivity in Tight Gas Reservoirs Using The Dynamic Conductivity Test written by Jose Domingo Romero Lugo and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydraulic Fracturing stimulation technology is used to increase the amount of oil and gas produced from low permeability reservoirs. The primary objective of the process is to increase the conductivity of the reservoir by the creation of fractures deep into the formation, changing the flow pattern from radial to linear flow. The dynamic conductivity test was used for this research to evaluate the effect of closure stress, temperature, proppant concentration, and flow back rates on fracture conductivity. The objective of performing a dynamic conductivity test is to be able to mimic actual field conditions by pumping fracturing fluid/proppant slurry fluid into a conductivity cell, and applying closure stress afterwards. In addition, a factorial design was implemented in order to determine the main effect of each of the investigated factors and to minimize the number of experimental runs. Due to the stochastic nature of the dynamic conductivity test, each experiment was repeated several times to evaluate the consistency of the results. Experimental results indicate that the increase in closure stress has a detrimental effect on fracture conductivity. This effect can be attributed to the reduction in fracture width as closure stress was increased. Moreover, the formation of channels at low proppant concentration plays a significant role in determining the final conductivity of a fracture. The presence of these channels created an additional flow path for nitrogen, resulting in a significant increase in the conductivity of the fracture. In addition, experiments performed at high temperatures and stresses exhibited a reduction in fracture conductivity. The formation of a polymer cake due to unbroken gel dried up at high temperatures further impeded the propped conductivity. The effect of nitrogen rate was observed to be inversely proportional to fracture conductivity. The significant reduction in fracture conductivity could possibly be due to the effect of polymer dehydration at higher flow rates and temperatures. However, there is no certainty from experimental results that this conductivity reduction is an effect that occurs in real fractures or whether it is an effect that is only significant in laboratory conditions. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/148364

Hydraulic Proppant Fracturing and Gravel Packing

Download Hydraulic Proppant Fracturing and Gravel Packing PDF Online Free

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

DOWNLOAD NOW!


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.

A Study of the Effect of Stress and Fluid Sensitivity on Propped Fracture Conductivity in Preserved Reservoir Shales

Download A Study of the Effect of Stress and Fluid Sensitivity on Propped Fracture Conductivity in Preserved Reservoir Shales PDF Online Free

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

DOWNLOAD NOW!


Book Synopsis A Study of the Effect of Stress and Fluid Sensitivity on Propped Fracture Conductivity in Preserved Reservoir Shales by : John Wesley Pedlow

Download or read book A Study of the Effect of Stress and Fluid Sensitivity on Propped Fracture Conductivity in Preserved Reservoir Shales written by John Wesley Pedlow and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A sizable amount of literature exists analyzing the effect of confining stress on fracture conductivity in sandstones. This thesis attempts to answer similar questions with regard to shale formations. The low Young's Moduli and Brinell hardness values characteristic of many prospective shale formations may lead to a great deal of embedment and fines production which can drastically reduce fracture conductivity. Furthermore, shales exhibit sensitivity to aqueous fluids which may cause them to be weakened in the presence of certain fracturing fluids. Previous work analyzing shale fluid sensitivity has failed to preserve the shales' formation properties by allowing the shale to dry out. This paper presents a study of propped fracture conductivity experiments at reservoir temperature and pressure using various North American shale reservoir cores. Exposure to the atmosphere can alter the mechanical properties of the shale by either drying or hydrating the samples, so care was taken to preserve these shales in their native state by maintaining constant water activity (relative humidity). Variations in applied closure stress and aqueous fluid exposure were analyzed and in certain cases altered the propped fracture conductivity by crushing proppant, embedding the proppant into the fracture face, and producing fines. The damage to fracture conductivity is correlated to mineralogy for the various shale samples. These findings show that a one-size-fits-all frac design will not work in every shale formation, rather a tailored approach to each shale is necessary. In the future, the results of this work will be analyzed alongside easier to perform Brinell hardness tests, swelling tests, and other characterization techniques incorporated into the UT Shale Characterization Protocol. Correlations were developed to relate the simpler tests to the fracture conductivity experiments which yield a straight forward method to determine the role embedment and fluid sensitivity have on post treatment fracture conductivity in shales. The UT Shale characterization Protocol can then be used to optimize the design and execution of fracing treatments.

Conductivity Evolution in Propped Fractures During Reservoir Drawdown

Download Conductivity Evolution in Propped Fractures During Reservoir Drawdown PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (119 download)

DOWNLOAD NOW!


Book Synopsis Conductivity Evolution in Propped Fractures During Reservoir Drawdown by : Jiayi Yu

Download or read book Conductivity Evolution in Propped Fractures During Reservoir Drawdown written by Jiayi Yu and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We investigate the evolution of` fracture conductivity as a function of proppant loading concentration under varying effective stresses as an analog to reservoir drawdown. In particular, we define the relative impacts and interplay between proppant crushing, proppant embedment, compaction and particle rearrangement and their impacts on fluid transport. Proppant of realistic concentrations is sandwiched between split core-plugs of Marcellus shale that accommodates embedment as well as rigid steel that excludes it. Impacts of proppant crushing and embedment and roles of particulate transport in fracturing-fluid clean-up are defined. Experiments are performed under triaxial stresses with independent control on confining stress and pore pressure. Normal loading is incremented to represent reservoir drawdown with conductivity evolution recorded continuously via flow-through of brine (20,000 mg/L KCl). Proppant embedment is characterized pre- and post-test by white light optical profilometry with pre-and post-test particle size distributions of the proppant defining the impact of proppant crushing. The conductivity of propped fractures decreases by up to 95% as effective stress is increased by 50 MPa (7000 psi). This reduction is broadly independent of whether the fracture walls are rigid or deformable. The stress-sensitivity of conductivity is generally muted with increasing proppant loading concentration. We normalize fracture conductivities to equivalent permeabilities of the proppant pack to directly compare pack permeabilities. Low proppant concentrations return higher permeability at low effective stresses but lower permeability at high effective stress, relative to high proppant concentrations. This results since proppant crushing and embedment are both mitigated with increasing proppant loading concentration, as more displacement degree of freedom are added to the system and provide accommodation for interior compaction and rearrangement. Extended effective stress holding times (24h vs

Observations of a Potential Size-effect in Experimental Determination of the Hydraulic Properties of Fractures

Download Observations of a Potential Size-effect in Experimental Determination of the Hydraulic Properties of Fractures PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 26 pages
Book Rating : 4.:/5 (359 download)

DOWNLOAD NOW!


Book Synopsis Observations of a Potential Size-effect in Experimental Determination of the Hydraulic Properties of Fractures by : Lawrence Berkeley Laboratory. Earth Sciences Division

Download or read book Observations of a Potential Size-effect in Experimental Determination of the Hydraulic Properties of Fractures written by Lawrence Berkeley Laboratory. Earth Sciences Division and published by . This book was released on 1979 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt:

The Role of Acidizing in Proppant Fracturing in Carbonate Reservoirs

Download The Role of Acidizing in Proppant Fracturing in Carbonate Reservoirs PDF Online Free

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

DOWNLOAD NOW!


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.

Investigation of Proppant Static Settling Velocity in Hydraulic Fractures Using Viscoelastic Linear Gel

Download Investigation of Proppant Static Settling Velocity in Hydraulic Fractures Using Viscoelastic Linear Gel PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 116 pages
Book Rating : 4.:/5 (18 download)

DOWNLOAD NOW!


Book Synopsis Investigation of Proppant Static Settling Velocity in Hydraulic Fractures Using Viscoelastic Linear Gel by : Vismay Shah

Download or read book Investigation of Proppant Static Settling Velocity in Hydraulic Fractures Using Viscoelastic Linear Gel written by Vismay Shah and published by . This book was released on 2018 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Few studies have quantified proppant transport in static conditions using actual proppant and validated previously established correlation. The objective of this study is to investigate the rheological properties of the linear gel, and determine the effect of size, shape and specific gravity of the proppant, fracture walls and rheological properties of the fluid on the proppant settling velocity in static condition and validate the previously established correlation. Shear viscosity and dynamic frequency sweep tests were performed to investigate the viscous and viscoelastic behaviour of the HPG linear gel with five different concentrations. Proppant settling experiments were conducted with different proppant types and sizes with two different setups, one with a large diameter transparent cylinder and another with a parallel plexiglass plate model which imposes wall effects. Parameters used during the experiments were inserted into previously established correlation and the calculated settling values were compared with the experimental ones to identify the best suitable correlation. HPG linear gel behaved as non-Newtonian shear thinning fluid and showed very little elasticity for the angular frequency from 1 to 100 rad/sec. With increasing shear thinning behaviour of the linear gel it was found that the effect of proppant size, specific gravity and fracture walls got more pronounced. With increasing diameter and specific gravity of the proppant, the effect of viscosity of the unbounded fluid on the settling velocity decreased; however, it remained constant in the case of confined fracturing fluid. The correlation provided by Swanson (1967) and Liu and Sharma (2005) were identified as best suitable correlations based on this study for unbounded fracturing fluid and confined fracturing fluid respectively"--Abstract, page iii.

Computational Fluid Dynamics Modeling of Proppant Static Settling Velocity in High Viscosity Friction Reducers

Download Computational Fluid Dynamics Modeling of Proppant Static Settling Velocity in High Viscosity Friction Reducers PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 65 pages
Book Rating : 4.:/5 (11 download)

DOWNLOAD NOW!


Book Synopsis Computational Fluid Dynamics Modeling of Proppant Static Settling Velocity in High Viscosity Friction Reducers by : Chen Yuan

Download or read book Computational Fluid Dynamics Modeling of Proppant Static Settling Velocity in High Viscosity Friction Reducers written by Chen Yuan and published by . This book was released on 2019 with total page 65 pages. Available in PDF, EPUB and Kindle. Book excerpt: "In the current petroleum fracturing industry, it is necessary to understand the downhole migration and settling velocity of the proppant. If we can master this information well, it will be a great help to obtain effective propped fracture conductivity. In order to study the transport of proppants in the well, we used laboratory experiments and computer numerical simulations to compare the results to get a meaningful conclusion. We spent a lot of time building models on a powerful computer and comparing the experimental conclusions. We finally decided to use computational fluid dynamics (CFD) as the simulation platform, discrete phase method (DPM) as the base model, and compare the simulation data with settling velocity experiment data to draw conclusions. Three cases were run and tested including fracture fluid type, proppant size, and fracture orientations. Results show a good integration between experimental results and simulation outputs. This work will help to provide a full understanding of the distinct changes of the mechanical characterization on the High Viscosity Friction Reducers (HVFRs). The findings provide an in-depth understanding of the behavior of HVFRs under confined effect, which could be used as guidance for fracture engineers to design and select better HVFR design"--Abstract, page iii.

Proppant Transport in Complex Fracture Networks

Download Proppant Transport in Complex Fracture Networks PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 320 pages
Book Rating : 4.:/5 (973 download)

DOWNLOAD NOW!


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 320 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.

Rock Fractures and Fluid Flow

Download Rock Fractures and Fluid Flow PDF Online Free

Author :
Publisher : National Academies Press
ISBN 13 : 0309049962
Total Pages : 568 pages
Book Rating : 4.3/5 (9 download)

DOWNLOAD NOW!


Book Synopsis Rock Fractures and Fluid Flow by : National Research Council

Download or read book Rock Fractures and Fluid Flow written by National Research Council and published by National Academies Press. This book was released on 1996-08-27 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt: Scientific understanding of fluid flow in rock fracturesâ€"a process underlying contemporary earth science problems from the search for petroleum to the controversy over nuclear waste storageâ€"has grown significantly in the past 20 years. This volume presents a comprehensive report on the state of the field, with an interdisciplinary viewpoint, case studies of fracture sites, illustrations, conclusions, and research recommendations. The book addresses these questions: How can fractures that are significant hydraulic conductors be identified, located, and characterized? How do flow and transport occur in fracture systems? How can changes in fracture systems be predicted and controlled? Among other topics, the committee provides a geomechanical understanding of fracture formation, reviews methods for detecting subsurface fractures, and looks at the use of hydraulic and tracer tests to investigate fluid flow. The volume examines the state of conceptual and mathematical modeling, and it provides a useful framework for understanding the complexity of fracture changes that occur during fluid pumping and other engineering practices. With a practical and multidisciplinary outlook, this volume will be welcomed by geologists, petroleum geologists, geoengineers, geophysicists, hydrologists, researchers, educators and students in these fields, and public officials involved in geological projects.

Effect of Fracture Heterogeneity on Proppant Transport and Settling Mechanism

Download Effect of Fracture Heterogeneity on Proppant Transport and Settling Mechanism PDF Online Free

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

DOWNLOAD NOW!


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.

Proppant Transport Down a Three-dimensional Planar Fracture

Download Proppant Transport Down a Three-dimensional Planar Fracture PDF Online Free

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

DOWNLOAD NOW!


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:

Unconventional Reservoir Geomechanics

Download Unconventional Reservoir Geomechanics PDF Online Free

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

DOWNLOAD NOW!


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.