Optimizing Fracture Spacing and Sequencing in Horizontal-Well Fracturing

Roussel, Nicolas; Sharma, Mukul M.

doi:10.2118/127986-pa

Cited by 134 publications

(75 citation statements)

References 19 publications

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“…Here, S is the dimensionless crack separation, F is the normalized stress-intensity factor, and a and b are the Dundurs elastic mismatch parameters (Dundurs 1967;Schmauder and Meyer 1992).…”

Section: Governing Integral Equationmentioning

confidence: 99%

Controlling the Height of Multiple Hydraulic Fractures in Layered Media

Khanna

Kotousov

2016

SPE Journal

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Fracture-height containment is desirable in hydraulic-fracturing treatments because it can result in better efficiency of oil or gas recovery and have less impact on the environment. Several mechanisms of the containment of a single hydraulic fracture were investigated in the past, and the outcomes of these studies are now well-documented in the open literature. However, the effectiveness of these mechanisms in the case of multiple closely spaced hydraulic fractures has not received much attention. The latter situation typically arises in the case of multiple transverse fractures emanating from a single horizontal wellbore.In this paper, we develop a mathematical model that one can use to assess the fracture-interaction phenomenon as well as the effect of the modulus contrast between adjacent rock layers. We consider the situation in which one must contain the hydraulic fractures entirely in the pay zone and investigate fracturing-fluidpressure control as a possible mechanism of height containment. It is demonstrated that when the fracture spacing becomes comparable with the fracture height, the interaction between the fractures produces a shielding effect. In this case, the fracturing-fluid pressure that ensures fracture containment is greater in comparison with the case of a single isolated fracture. However, the fracture opening is also smaller in the case of closely spaced fractures. The dependence of the fracturing-fluid pressure and fracture opening on the fracture spacing needs to be taken into consideration during the selection of fracture spacing for a particular treatment.

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Section: Governing Integral Equationmentioning

confidence: 99%

Controlling the Height of Multiple Hydraulic Fractures in Layered Media

Khanna

Kotousov

2016

SPE Journal

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“…The influences of the fracture spacing, rock mechanical properties and in-situ stress ratio were studied. Roussel and Sharma [10] used the same method as that in the work of Nagel and Sanchez-Nagel [9], however, the influence of fracture barriers (cap rock and base rock) was further considered. In that paper, it was found that an alternate fracture sequence (1-3-2-4-5, etc.)…”

Section: Introductionmentioning

confidence: 99%

“…An alternative fracture sequence (1-3-2, etc.) is recommended in Roussel et al [10]. With this sequence, the stress reorientation between the first und the third fracture is minimized as shown in Figure 12.…”

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confidence: 99%

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Numerical Investigation of the Time-Dependent and the Proppant Dominated Stress Shadow Effects in a Transverse Multiple Fracture System and Optimization

et al. 2017

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Abstract:In this paper, a numerical study is conducted to investigate the stress shadow effects (stress reorientation and change) during hydraulic fracturing in a transverse multiple fracture system. A numerical model is used for the numerical study. It is a 3D model and can simulate the fracture operation from injection begin to full closure (fracture contact). Therefore, there is no need to assume the fracture geometry for the investigation of the stress shadow effects (unlike previous studies). In the numerical study, the first and second operations in a fictive transverse multiple fracture system are simulated, meanwhile the stress shadow effects and their influences on the propagation and proppant placement of the second fracture are investigated. According to the results, the following conclusions are discerned: (1) most proppants are located in the lower part of the reservoir, even below the perforation; (2) the stress shadow effects are time-dependent and proppant dominated; (3) the stress shadow effects affect the fracture propagation and the proppant placement of the second fracture, and also the fracture conductivity of the first fracture; (4) the time-dependent stress shadow effects can be divided into four phases, fracture enlargement, closure without proppant contact, closure with proppant contact and full closure; and (5) the superposition effect of the stress shadow in a transverse multiple fracture system exists. According to the conclusions, some optimizations are recommended.

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“…Wright et al (1995) and Weijers et al (1999) reported some field data and observations on hydraulic fracture reorientation of injection wells from field studies (mainly from Belridge and Lost Hills reservoirs). It is noted that if the distance between the multiple injection wells is small such that pronounced stress perturbations exists due to the large volume of injected fluid, the stress interference could influence the fracture geometry and orientation.. Over the years research has been conducted on predicting stress interference effect on hydraulic fracture reorientation (Wright et al 1995, Wright and Conant 1995, Weijers et al 1999, Philip et al 2005, Roussel and Sharma 2011. Recently, Bunger et al (2011) developed a coupled 2D displacement discontinuity method-based numerical simulator to predict parameters effecting the interaction among closely spaced hydraulic factures.…”

Section: Introductionmentioning

confidence: 99%

Computational Analysis of Stress Interference Effect for Hydraulic Fracturing in Waste Injection Wells

et al. 2011

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Hydraulic fracturing is a key mechanism for injection into waste disposal wells. To successfully inject drill cuttings slurry or produced water under fracturing conditions and prevent unwanted migration, it is essential to predict the extent of hydraulic fractures accurately based on understanding the fundamental fracture mechanisms. Popular hydraulic fracture models for injection wells continue to rely on pseudo-3D fracture technology. However, when injection takes place in multiple, closely spaced wells, or under the influence of offset producers, stress interference effect on fracture geometry can hardly be predicted based on simple single-well methods. If the distance between the multiple injection wells is small such that pronounced stress perturbations exist, the stress interference could influence the fracture geometry and orientation. This paper presents a study on the stress interference effects on fracture orientation and spatial extent caused by multiple injection wells using a hybrid computational method incorporating finite element and boundary element fracture models. To investigate the stress interference effects, a pore pressure cohesive zone model was developed to predict hydraulic fracturing for injection wells through finite element analysis and sub-modeling technology. The model was applied to investigate the stress perturbation effect on fracture geometry caused by long-term, high-rate, multi-well waste injection into a heterogeneous geological environment. Boundary element analysis was performed to simulate the possible fracture reorientation and fracture merging caused by the changing of the stress field with the propagation of multiple hydraulic fractures. Injection wells with different well distances and stress boundary conditions were investigated. A 3D analytical tool has been developed to simulate the changes of stress due to the depletion in pore pressure from an offset location. The computational analysis on the stress field was verified with the analytical solution. Based on the finite element and boundary element analyses, revised stresses were incorporated into the tuned pseudo-3D models to update the hydraulic fracturing prediction to account for stress interference effects. Ultimately, the fracture predictions were quantified under the influence of stress interference.

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Optimizing Fracture Spacing and Sequencing in Horizontal-Well Fracturing

Cited by 134 publications

References 19 publications

Controlling the Height of Multiple Hydraulic Fractures in Layered Media

Controlling the Height of Multiple Hydraulic Fractures in Layered Media

Numerical Investigation of the Time-Dependent and the Proppant Dominated Stress Shadow Effects in a Transverse Multiple Fracture System and Optimization

Computational Analysis of Stress Interference Effect for Hydraulic Fracturing in Waste Injection Wells

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