Simulation and Field Analysis of Waterflood Induced Fracturing

Settari, A.; Warren, G.M.

doi:10.2118/28081-ms

Cited by 32 publications

(11 citation statements)

References 17 publications

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“…In contrast to conventional fracturing, these unconventional fracturing applications are usually characterized by high fluid leakoff velocity from the fracture into the reservoir, significant changes in stress, pore pressure, permeability, and porosity, all possibly in a large region around the wellbore and fracture (Cottrel and Baker 1983;Settari and Warren 1994). These phenomena are often manifested by interactions among geomechanical aspects of the porous media and reservoir fluid flow (Ji et al 2006).…”

Section: Introductionmentioning

confidence: 99%

A Novel Hydraulic Fracturing Model Fully Coupled With Geomechanics and Reservoir Simulation

Settari

Sullivan³

2009

SPE Journal

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102

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Unconventional fracturing techniques, such as high-rate waterfracs, waterflooding, or steam stimulation, produced water and cuttings reinjection, CO 2 sequestration, and coalbed methane stimulation, are difficult to model because of strong interactions among the fracturing process, geomechanical changes in the porous media, and reservoir fluid flow. The resulting strong poroelastic/thermoelastic effects, permeability and porosity changes, and possible rock failure make current conventional fracturing models inadequate in such circumstances. Therefore, it is necessary to develop new models that include all of these mechanisms and that are capable of conducting integrated data analysis.This paper presents a new fracturing model with all of these mechanisms included. The model fully couples fracture mechanics with reservoir and geomechanics simulation. This methodology allows us to model fracture initiation and propagation, post-frac multiphase cleanup in the reservoir and fracture and pre-frac and post-frac well performance in a changing stress and pressure environment, all within the same system.The model couples a 3D finite element geomechanics model with a conventional 3D finite difference reservoir flow simulator. The geomechanics module implicitly models fracture propagation via displacements on the fracture face. The flow and geomechanics/fracturing are coupled in an iterative manner that is equivalent to full coupling of geomechanical and reservoir flow modeling. The 3D (planar) fracture geometry and the pressures in it are the common dynamic boundary conditions for the flow and stress modules. The new iterative process yields smooth fracture propagation, and the model has been tested on classical fracturing problems.A field example demonstrates the validity and advantages of the approach. To illustrate the model capabilities, we model a waterfrac stimulation performed in Bossier tight-gas sands. The model results show that the model is capable of matching complex injection history and calibrating the stress-dependency of formation permeability.

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Section: Introductionmentioning

confidence: 99%

A Novel Hydraulic Fracturing Model Fully Coupled With Geomechanics and Reservoir Simulation

Settari

Sullivan³

2009

SPE Journal

Self Cite

102

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“…The introduction of particulates or wax precipitation 17 will reduce leak off rates from the fractures which can cause a negative feedback loop, causing the fracture to increase in length and potentially cause earlier breakthrough. Damage due to particulates, waxes, etc, cause a reduction in leak off rate from the fractures to matrix and therefore may lead to longer fracture growth 8,16,19 .…”

Section: Growth Of Waterflood Induced Fracturesmentioning

confidence: 99%

“…WIF will continue to grow if the local voidage replacement ratio is greater than 1.0 16 . This fracture growth profile has important practical implications; often operators will inject at a voidage replacement ratio (VRR) greater than 1 initially in order to quickly re-pressurize the reservoir.…”

Section: Growth Of Waterflood Induced Fracturesmentioning

confidence: 99%

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The Myths of Waterfloods, EOR Floods and How to Optimize Real Injection Schemes

Baker¹,

Dieva

Jobling

et al. 2016

SPE Improved Oil Recovery Conference

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Waterflood implementation accounts for more than half of the oil production worldwide. Despite the observations and extensive research from a large number of floods and thousands of simulation studies, managing waterfloods and Enhanced Oil Recovery (EOR) floods is still a technical challenge. A major contributor to this challenge are waterflood induced fractures (WIF). Managing waterfloods is a multivariable problem although WIF are one aspect, it is by no means the only controlling factor.The best evidence that WIF are one of the main factors controlling flow in reservoirs is the insensitivity of injection pressure to injection rates. With our experience, in hundreds of waterfloods, we have frequently observed this phenomenon in the field data. If fluid flow depended on diffusive Darcy flow alone, we would expect higher injection rates with higher injection pressures. However, it is common to observed relatively constant injection pressures over a wide range of water injection rates. Rapid well communication and changes in water cuts that vary with injection rates also support an interpretation of high permeability induced fractures between injector and producer. In some reservoirs, interwell tracer data can be used to determine the influence of induced fracture features. The interwell tracers usually show very fast water movement.Induced fractures in waterfloods and EOR projects can be caused by a number of mechanisms such as but not limited to, pressure depletion, changing pressure regimes, thermal effects, or plugging effects. These fractures can either be beneficial to the reservoir performance or effect performance negatively. Benefits include improved injectivity and increased throughput of the displacing fluid. Negative effects can come in the form of reduced volumetric sweep efficiency, impaired ultimate recovery or injected fluid losses out of zone.Case studies, theory, and available literature from Western Canada will be reviewed in order to suggest and improve reservoir management strategies for waterfloods. We have completed hundreds of waterflood feasibility, waterflood management and EOR flood studies worldwide and continue to be amazed and humbled by the complexity that many waterfloods and EOR floods exhibit due to induced fracturing. WIF and EOR induced fractures (EIF) are common and should be analysed to optimize production. Growth of the WIF, response to waterflood with the presence of WIF, implication of WIF and reservoir management are the main areas which will be addressed.

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“…The problem of injection of a low-viscosity fluid into a pre-existing fracture may arise in several rock engineering areas, such as, injection of liquid waste (e.g., supercritical CO2) into deep geological formations for storage [3,4,5], waterflooding process to increase recovery from an oil reservoir [6], and control of possible leaks from pre-existing fractures around radioactive and nuclear wastes storage sites [7]. These fractures could be either of natural origin or man-made (e.g., hydraulic fractures used to stimulate production from a now depleted reservoir chosen for waste storage).…”

Section: Introductionmentioning

confidence: 99%

Pressurization of a PKN Fracture in a Permeable Rock During Injection of a Low Viscosity Fluid

Sarvaramini¹,

Garagash²

2013

Effective and Sustainable Hydraulic Fracturing

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The aim of the present work is to investigate injection of a low-viscosity fluid into a pre-existing fracture within a linear elastic, permeable rock, as may occur in waterflooding and supercritical CO2 injection. In conventional hydraulic fracturing, high viscosity and cake building properties of injected fluid limit diffusion to a 1-D boundary layer incasing the crack. In the case of injection of low viscosity fluid into a fracture, diffusion will take place over wider range of scales, from 1-D to 2-D, thus, necessitating a new approach. In addition, the dissipation of energy associated with fracturing of the rock dominates the energy expended to flow a low viscosity fluid into the crack channel. As a result, the rock fracture toughness is an important parameter in evaluating the propagation driven by a low-viscosity fluid. We consider a pre-existing, un-propped, stationary Perkins, Kern and Nordgren's (PKN) fracture into which a low viscosity fluid is injected under a constant flow rate. The fundamental solution to the auxiliary problem of a step pressure increase in a fracture [1] is used to formulate and solve the convolution integral equation governing the transient crack pressurization under the assumption of negligible viscous dissipation. The propagation criterion for a PKN crack [2] is then used to evaluate the onset of propagation. The obtained solution for transient pressurization of a stationary crack provides initial conditions to the fracture propagation problem.

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Simulation and Field Analysis of Waterflood Induced Fracturing

Cited by 32 publications

References 17 publications

A Novel Hydraulic Fracturing Model Fully Coupled With Geomechanics and Reservoir Simulation

A Novel Hydraulic Fracturing Model Fully Coupled With Geomechanics and Reservoir Simulation

The Myths of Waterfloods, EOR Floods and How to Optimize Real Injection Schemes

Pressurization of a PKN Fracture in a Permeable Rock During Injection of a Low Viscosity Fluid

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