Modeling the Propagation of Waterflood-Induced Hydraulic Fractures

1980 ◽  
Vol 20 (04) ◽  
pp. 293-303 ◽  
Author(s):  
Jacques Hagoort ◽  
Brian D. Weatherill ◽  
Antonin Settari
Keyword(s):  
Physical Model ◽  
Injection Rate ◽  
Symmetry Element ◽  
Hydraulic Fractures ◽  
Production Rates ◽  
Predictive Tool ◽  
Replacement Ratio ◽  
Fluid Properties ◽  
Induced Fractures ◽  
Fracture Growth

Abstract A mathematical reservoir model is presented to simulate the propagation of waterflood-induced hydraulic fractures in a symmetry element of a waterflood pattern. The model consists of a conventional single-phase reservoir simulator coupled with an analytical fracture model.The model is capable of simulating fracture propagation as a function of (1) injection and propagation as a function of (1) injection and production rates or pressures, (2) reservoir and fluid production rates or pressures, (2) reservoir and fluid properties, and (3) formation-fracturing pressures. properties, and (3) formation-fracturing pressures. Examples are given that clearly illustrate the characteristics of hydraulic-fracture growth. The key variables are injection rate and voidage/replacement ratio. Fractures can be contained by restricting the injection rate and by imposing a voidage/ replacement ratio equal to or less than 1.The modeling technique presented here also may be applied to other fracturing problems, particularly in cases where leakoff is significant and, thus, should be taken into account rigorously. Introduction Injection pressures in water-injection wells often exceed the formation-fracturing pressures, either unintentionally or by design. Although this leads to improved injectivity, it might jeopardize the flooding efficiency of waterfloods; induced hydraulic fractures can grow to be very long, thereby adversly affecting areal sweep efficiency.At present, quantitative information on the propagation of waterflood-induced hydraulic propagation of waterflood-induced hydraulic fractures is scarce. Theories of hydraulic fracturing do exist but are geared to controlled fracture-stimulation techniques. In these techniques the induced fractures and propagation times are relatively short and fluid losses are kept low by using additives in the fracture fluids. Waterflood-induced fractures, on the other hand, may grow for many years and are characterized by high fluid losses.In this paper a mathematical model for simulating hydraulic fracture growth under waterflood conditions is presented. The model is capable of calculating fracture propagation in a two-dimensional symmetry element of a unit mobility ratio waterflood containing one injector and one or more producers. With this model, fracture growth can be investigated as a function of (1) injection rates and production rates or pressures, (2) reservoir and fluid properties, and (3) formation-fracturing pressures. pressures. Several examples are given that clearly illustrate the general growth characteristics of waterflood-induced hydraulic fractures.The model presented is relatively simple in scope and is certainly open to improvements. Yet in its present form it is already a valuable diagnostic and present form it is already a valuable diagnostic and predictive tool that can be used to manage fractured predictive tool that can be used to manage fractured waterfloods better. Physical Model Physical Model Fig. 1 depicts the physical model we wish to simulate. It consists of (1) a symmetry element of a waterflood reservoir containing injection and production wells, and (2) a fracture extending from an injection well in a chosen direction.In this model the reservoir has a uniform or slightly varying thickness that is small relative to the areal dimensions. The mobility ratio of the waterflood is M = 1.0. In this system fluid flow in the reservoir can be approximated by the equation for two-dimensional single-phase compressible flow. SPEJ P. 293

scholarly journals Factors affecting reorientation of hydraulically induced fracture during fracturing with oriented perforations in shale gas reservoirs

2021 ◽  
Vol 15 (58) ◽  
pp. 1-20
Author(s):  
Qingchao Li ◽  
Liang Zhou ◽  
Zhi-Min Li ◽  
Zhen-Hua Liu ◽  
Yong Fang ◽  
...  
Keyword(s):  
Shale Gas ◽  
Injection Rate ◽  
Single Fracture ◽  
Fluid Viscosity ◽  
Fracture Conductivity ◽  
Factors Affecting ◽  
Controllable Factors ◽  
Initiation Pressure ◽  
Shale Reservoirs ◽  
Induced Fractures

Hydraulic fracturing with oriented perforations is an effective technology for reservoir stimulation for gas development in shale reservoirs. However, fracture reorientation during fracturing operation can affect the fracture conductivity and hinder the effective production of shale gas. In the present work, a numerical simulation model for investigating fracture reorientation during fracturing with oriented perforations was established, and it was verified to be suitable for all investigations in this paper. Based on this, factors (such as injection rate and fluid viscosity) affecting both of initiation and reorientation of the hydraulically induced fractures were investigated. The investigation results show that the fluid viscosity has little effect on initiation pressure of hydraulically induced fracture during fracturing operation, and the initiation pressure is mainly affected by perforation azimuth, injection rate and the stress difference. Moreover, the investigation results also show that perforation azimuth and difference between two horizontal principle stresses are the two most important factors affecting fracture reorientation. Based on the investigation results, the optimization of fracturing design can be achieved by adjusting some controllable factors. However, the regret is that the research object herein is a single fracture, and the interaction between fractures during fracturing operation needs to be further explored.

scholarly journals Characterization of venturi injector using dimensional analysis

2019 ◽  
Vol 23 (7) ◽  
pp. 484-491 ◽  
Author(s):  
Luiz R. Sobenko ◽  
José A. Frizzone ◽  
Antonio P. de Camargo ◽  
Ezequiel Saretta ◽  
Hermes S. da Rocha
Keyword(s):  
Dimensional Analysis ◽  
Flow Rate ◽  
Injection Rate ◽  
Operating Conditions ◽  
Functional Tests ◽  
Injection Flow Rate ◽  
Injection Flow ◽  
Hydraulic Conditions ◽  
Fluid Properties ◽  
Pi Theorem

ABSTRACT Venturi injectors are commonly employed for fertigation purposes in agriculture, in which they draw fertilizer from a tank into the irrigation pipeline. The knowledge of the amount of liquid injected by this device is used to ensure an adequate fertigation operation and management. The objectives of this research were (1) to carry out functional tests of Venturi injectors following requirements stated by ISO 15873; and (2) to model the injection rate using dimensional analysis by the Buckingham Pi theorem. Four models of Venturi injectors were submitted to functional tests using clean water as motive and injected fluid. A general model for predicting injection flow rate was proposed and validated. In this model, the injection flow rate depends on the fluid properties, operating hydraulic conditions and geometrical characteristics of the Venturi injector. Another model for estimating motive flow rate as a function of inlet pressure and differential pressure was adjusted and validated for each size of Venturi injector. Finally, an example of an application was presented. The Venturi injector size was selected to fulfill the requirements of the application and the operating conditions were estimated using the proposed models.

scholarly journals Symmetric coalescence of two hydraulic fractures

2018 ◽  
Vol 115 (41) ◽  
pp. 10228-10232
Author(s):  
Niall J. O’Keeffe ◽  
Zhong Zheng ◽  
Herbert E. Huppert ◽  
P. F. Linden
Keyword(s):  
Network Formation ◽  
Light Attenuation ◽  
Energy Resource ◽  
Fracture Network ◽  
Injection Rate ◽  
Hydraulic Fractures ◽  
Fracture Aperture ◽  
Initial Contact ◽  
Intermediate Period ◽  
Initial Location

The formation of a fracture network is a key process for many geophysical and industrial practices from energy resource recovery to induced seismic management. We focus on the initial stage of a fracture network formation using experiments on the symmetric coalescence of two equal coplanar, fluid-driven, penny-shaped fractures in a brittle elastic medium. Initially, the fractures propagate independently of each other. The fractures then begin to interact and coalesce, forming a bridge between them. Within an intermediate period after the initial contact, most of the fracture growth is localized along this bridge, perpendicular to the line connecting the injection sources. Using light attenuation and particle image velocimetry to measure both the fracture aperture and velocity field, we characterize the growth of this bridge. We model this behavior using a geometric volume conservation argument dependent on the symmetry of the interaction, with a 2D approximation for the bridge. We also verify experimentally the scaling for the bridge growth and the shape of the thickness profile along the bridge. The influence of elasticity and toughness of the solid, injection rate of the fluid, and initial location of the fractures are captured by our scaling.

Optimizing Recovery for Waterflooding Under Dynamic Induced Fracturing Conditions

2009 ◽  
Vol 12 (05) ◽  
pp. 671-682 ◽  
Author(s):  
Paul J. van den Hoek ◽  
Rashid A. Al-Masfry ◽  
Dirk Zwarts ◽  
Jan-Dirk Jansen ◽  
Bernhard Hustedt ◽  
...  
Keyword(s):  
Oil Recovery ◽  
Water Injection ◽  
Injection Rate ◽  
Reservoir Engineering ◽  
Spot Pattern ◽  
Engineering Parameters ◽  
Induced Fractures ◽  
Modeling Strategy ◽  
Reservoir Simulator ◽  
Fully Coupled

Summary It is well established within the industry that water injection mostly takes place under induced fracturing conditions. Particularly in low-mobility reservoirs, large fractures may be induced during the field life. This paper presents a new modeling strategy that combines fluid flow and fracture growth (fully coupled) within the framework of an existing "standard" reservoir simulator. We demonstrate the coupled simulator by applications to repeated five-spot pattern flood models, addressing various aspects that often play an important role in waterfloods: shortcut of injector and producer, fracture containment to the reservoir layer, and areal and vertical reservoir sweep. We also demonstrate how induced fracture dimensions (length, height) can be very sensitive to typical reservoir engineering parameters, such as fluid mobility, mobility ratio, 3D saturation distribution (in particular, shockfront position), 3D temperature distribution, positions of wells (producers, injectors), and geological details (e.g., layering and faulting). In particular, it is shown that lower overall (time-dependent) reservoir transmissibility will result in larger induced fractures. Finally, it is demonstrated how induced fractures can be taken into account to determine an optimum life-cycle injection rate strategy. The results presented in this paper are expected to also apply to (part of) enhanced-oil-recovery operations (e.g., polymer flooding).

A Case Study of Vertical Hydraulic Fracture Growth, Stress Variations with Depth and Shear Stimulation in the Niobrara Shale and Codell Sand, DJ Basin, Colorado

2021 ◽  
pp. 1-34
Author(s):  
Kevin L. McCormack ◽  
Mark D. Zoback ◽  
Wenhuan Kuang
Keyword(s):  
Principal Stress ◽  
Hydraulic Fracture ◽  
Oil And Gas ◽  
Velocity Model ◽  
Growth Stress ◽  
Hydraulic Fractures ◽  
Stress Profile ◽  
Microseismic Events ◽  
Stress Variations ◽  
Fracture Growth

We carried out a geomechanical study of three wells, one each in the Niobrara A, Niobrara C and Codell sandstone to investigate how the state of stress and stress variations with depth affect vertical hydraulic fracture growth and shear stimulation of pre-existing fractures. We demonstrate that the higher magnitudes of measured least principal stress values in the Niobrara A and C shales are the result of viscoplastic stress relaxation. Using a density log and a VTI velocity model developed to accurately locate the microseismic events, we theoretically calculated a continuous profile of the magnitude of the least principal stress with depth. This stress profile explains the apparent vertical hydraulic fracture growth as inferred from the well-constrained depths of associated microseismic events. Finally, we demonstrate that because of the upward propagation of hydraulic fractures from the Niobrara C to the Niobrara A, the latter formation experienced considerably more shear stimulation, which may contribute to the greater production of oil and gas from that formation.

Hybrid Analytical/Numerical Computation of Heat Transfer in a Gas-Driven Fracture

1986 ◽  
Vol 108 (3) ◽  
pp. 585-590 ◽  
Author(s):  
S. K. Griffiths ◽  
R. H. Nilson ◽  
F. A. Morrison
Keyword(s):  
Heat Transfer ◽  
Surrounding Medium ◽  
Numerical Procedure ◽  
Early Time ◽  
Similarity Solutions ◽  
Fixed Number ◽  
Coupled Processes ◽  
Hydraulic Fractures ◽  
Rock Blasting ◽  
Fracture Growth

In gas-driven hydraulic fractures, as occur in rock blasting and underground nuclear testing, the high-temperature gases (1000 to 30,000 K) are radically cooled by heat transfer to the host material. This significantly reduces both the maximum extent and rate of fracture growth. The coupled processes of fluid flow, heat transfer, and rock deformation governing fracture growth are calculated here by a hybrid analytical/numerical procedure. The gas motion along a fracture of increasing length and aperture is described by a finite-difference form of the one-dimensional transport equations; fluid friction, advective heat transfer, and heat loss to the walls of the fracture are considered. Lateral heat losses are evaluated in a quasi-analytical fashion, based on an integral method that accounts for the convective film resistance between the fluid and fracture wall, as well as the conductive resistance within the surrounding medium. The calculations are performed on a difference grid that expands to maintain a fixed number of points uniformly distributed along the fracture. The present numerical results agree, within appropriate limits, with known similarity solutions. Beyond this, new nonsimilar solutions for early-time fracture growth are presented.

Combined Proppant Placement and Early Production Modeling Achieve Increased Fracture Performance in Ecuador's Oriente Basin

2021 ◽  
Author(s):  
Maxim Chertov ◽  
Franck Ivan Salazar Suarez ◽  
Mikhail Kaznacheev ◽  
Ludmila Belyakova
Keyword(s):  
Continuous Improvement ◽  
Hydraulic Fractures ◽  
Well Performance ◽  
Fracture Conductivity ◽  
The Past ◽  
First Results ◽  
Early Production ◽  
Fracture Performance ◽  
Production Modeling ◽  
Fracture Growth

Abstract In the paper, we document one iteration of the continuous improvement of well performance undertaken in the Oriente Basin in Ecuador. In the past, it had been observed that well economics was sometimes degraded by the issues related to proppant flowback from hydraulic fractures. Proppant flowback resulted in extra costs from well cleanouts, pump replacement, and damage to fracture conductivity. After evaluation of proppant flowback cases using the combined modeling workflow that simulates fracture growth, proppant placement, and early production of solids and fluids, it had been proposed to modify fracture designs and well startup strategy. In this paper, we review the first results of implementation of these modifications in the field and evaluate the significance of improvements.

Mechanics of Hydraulic-Fracture Growth from a Wellbore Intersecting Natural Fractures

SPE Journal ◽  
2019 ◽  
Vol 25 (02) ◽  
pp. 646-661 ◽  
Author(s):  
Yang Liu ◽  
Ping Chen ◽  
Bisheng Wu ◽  
Tianshou Ma ◽  
Bailin Wu ◽  
...  
Keyword(s):  
Fractured Rock ◽  
Maximum Principal Stress ◽  
Injection Rate ◽  
Reservoir Rock ◽  
Fluid Loss ◽  
Hydraulic Fractures ◽  
Fluid Viscosity ◽  
Natural Fractures ◽  
Principal Stress Direction ◽  
Fully Coupled

Summary The creation and propagation of hydraulic fractures (HFs) emanating from a well in a naturally fractured rock is important not only to the success of fracturing treatments, but also for interpretation of the data from diagnostic fracture injection tests (DFITs). In this paper, we consider the reservoir rock to consist of an impermeable rock matrix and a system of discrete natural fractures (NFs) that are permeable. The well is assumed to intersect two sets of NFs at their midpoints, and injection into the wellbore might open the NFs and/or create new fractures that extend along the maximum-principal-stress direction. Both new fractures and pre-existing NFs can act as either a main HF or a fluid-loss path. In this near-well transient-fracture analysis, the NFs are short segments characterized by size, orientation, and aperture. A fully coupled HF model is used to investigate the interaction between the fractures to determine how the fluid injected is distributed to the fractures for a range of stress, fluid-injection-rate, and NF-geometry conditions. We find that a more-isotropic stress condition and a lower value of the fluid-viscosity/injection-rate product favor propagation of NFs. These conditions cause the NFs to accept more fluid, and, as a result, the growth of new fractures is suppressed. The post-shut-in pressure responses for the cases with propagating new fractures and nonpropagating NFs are studied.

Numerical Investigation Into the Simultaneous Growth of Two Closely Spaced Fluid-Driven Fractures

SPE Journal ◽  
2018 ◽  
Vol 24 (01) ◽  
pp. 274-289 ◽  
Author(s):  
Xiyu Chen ◽  
Jinzhou Zhao ◽  
Wenyi Yan ◽  
Xi Zhang
Keyword(s):  
Fracture Surface ◽  
Viscous Dissipation ◽  
Treatment Success ◽  
Displacement Discontinuity ◽  
Hydraulic Fractures ◽  
Single Fracture ◽  
Fluid Viscosity ◽  
Initial Fracture ◽  
Fracture Growth ◽  
Simultaneous Growth

Summary Multistage, multicluster hydraulic fracturing is a widespread method used in the petroleum industry to enhance the hydrocarbon production of low-permeability unconventional reservoirs. The core for fracturing-treatment success is achieving the simultaneous propagation of multiple closely spaced hydraulic fractures to enlarge the fracture surface. To better understand this coupled elasto-hydrodynamics mechanics, a 2D model comprising a combination of a displacement discontinuity method for elasticity and a finite volume method for lubrication is presented in this paper. Furthermore, a universal tip asymptotic solution, reflecting the unique multiscale tip behavior for fluid-driven fractures, is adopted as a propagation criterion to locate the fracture front. Numerical examples are fully implemented to investigate the competition in the growth of two closely spaced fluid-driven fractures at different initial lengths. Parametric studies reveal that the competition between simultaneous and single fracture growth is governed by dimensionless toughness, which represents the energy ratio of fracture-surface creation to fluid viscous dissipation. The simultaneous growth will be promoted when the fluid viscous dissipation is dominant, while, with increasing rock toughness, the tendency for single-fracture growth will increase correspondingly. Numerical results also demonstrate that initial fracture geometric settings play an important role in this competition. A large initial length offset between two fractures will generate preferential growth for the longer fracture, even in the viscosity-dominated regime. Furthermore, this paper provides dimensionless parameters characterizing fracture deflection caused by fracture interaction. The paper concludes by identifying the controlling parameters and their field applications, emphasizing that high injection rate, high fluid viscosity, and small initial fracture-size offset are beneficial to promoting the simultaneous growth at early time, which is important in enhancing reservoir permeability.

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