Parameters Affecting Azimuth and Length of a Secondary Fracture During a Refracture Treatment

Siebrits, E.; Elbel, J.L.; Detournay, Emmanuel; Detournay-Piette, C.; Christianson, Mark; Robinson, B.M.; Diyashev, Iskander R.

doi:10.2118/48928-ms

Cited by 63 publications

(11 citation statements)

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“…The extent of the stress-reversal region (L f Ј) is not limited to 0.58 L f , which has been shown numerically by Siebrits et al (1998) to be the highest possible value of L f Ј because of poroelastic effects. It may even extend to a distance larger than the fracture half-length (L f ).…”

Section: δSmentioning

confidence: 90%

“…However, in other cases where signifi cant volumes of fl uids have been produced from a well, poroelastic effects can be dominant. The structure of stress reorientation around a single fracture because of poroelastic effects has been well described in the literature (Siebrits et al 1998;Singh et al 2008;Roussel and Sharma 2010). In the vicinity of the fracture, the direction of maximum horizontal stress is rotated 90° from its in-situ direction (for producing wells).…”

Section: Comparison Of Stress Reorientation Because Of Poroelastic Andmentioning

confidence: 99%

“…Previous studies in the literature on fracture-induced stress interference mostly focus on the effect of a single fracture (Siebrits et al 1998). Using analytical solutions, Soliman and Adams (2004) calculated the effect of multiple fractures on the expected net pressure and the stress contrast.…”

Section: Introductionmentioning

confidence: 99%

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Optimizing Fracture Spacing and Sequencing in Horizontal-Well Fracturing

Roussel

Sharma

2011

SPE Production &Amp; Operations

133

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Horizontal wells with multiple fractures are now commonly used in unconventional (low-permeability) gas reservoirs. The spacing between perforations and the number and orientation of transverse fractures all have a major impact on well production.The opening of propped fractures results in the redistribution of local Earth stresses. In this paper, the extent of stress reversal and reorientation has been calculated for fractured horizontal wells using a 3D numerical model of the stress interference induced by the creation of one or more propped fractures. The results have been analyzed for their impact on simultaneous and sequential fracturing of horizontal wells.Our results demonstrate that a transverse fracture initiated from a horizontal well may deviate away from the previous fracture. The effect of the reservoir's mechanical properties on the spatial extent of stress reorientation caused by an opened crack has been quantified. The paper takes into account the presence of layers that bound the pay zone but have mechanical properties different from those of the pay zone. The fracture vertical growth into the bounding layers is also examined.It is shown that stress interference, or reorientation, increases with the number of fractures created and depends on the sequence of fracturing. Three fracturing sequences are investigated for a typical field case in the Barnett shale: (a) consecutive fracturing, (b) alternative fracturing, and (c) simultaneous fracturing of adjacent wells. The numerical calculation of the fracture spacing required to avoid fracture deviation during propagation, for all three fracturing techniques, demonstrates the potential advantages of alternate fracture sequencing and zipper fracs to improve the performance of stimulation treatments in horizontal wells.

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Section: δSmentioning

confidence: 90%

Section: Comparison Of Stress Reorientation Because Of Poroelastic Andmentioning

confidence: 99%

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Optimizing Fracture Spacing and Sequencing in Horizontal-Well Fracturing

Roussel

Sharma

2011

SPE Production &Amp; Operations

133

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“…In tight gas plays, poroelastic stress interference has been investigated and applied to the refracturing of vertical wells (Roussel 2011;Roussel and Sharma 2010a, 2010b;Siebrits and Elbel 1998;Warpinski and Branagan 1989;Weng and Siebrits 2007). In the case of a previously fractured well, it is possible to create a secondary fracture that is perpendicular to the first.…”

Section: Spe 166503mentioning

confidence: 99%

“…One-way to resolve this complexity is to develop stress reorientation models for specific 6 SPE 166503 geometries and applications, i.e. vertical-well refracturing (Roussel andSharma 2010a, 2010b;Siebrits and Elbel 1998) or in this paper case, the stimulation of infill horizontal wells.…”

Section: Where Do Fracs Grow (In Depleted/waterflooded Reservoirs)?mentioning

confidence: 99%

Hydraulic Fracture Propagation from Infill Horizontal Wells

Roussel

Florez

Rodríguez

2013

Day 3 Wed, October 02, 2013

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As pressure increases or decreases non-uniformly as a result of well injection/production, stresses vary anisotropically in the reservoir. The principal stresses, which govern the propagation direction of hydraulic fractures, are thus modified not only in magnitude but also in direction. Previous modeling efforts and field observations have demonstrated the impact of stress reorientation on the refracturing of vertical wells and the multi-stage fracturing of horizontal wells.Using a state-of-the-art coupled symmetric Galerkin boundary-element method (SGBEM) and finite-element method (FEM) model, we simulate the impact of prior production from offset wells on the propagation direction of fractures initiated from an infill horizontal well. Geomechanical calculations demonstrate the occurrence of stress reversal in the infill region following a period of production from the offset wells in the order of years. The numerically simulated hydraulic fracture network in the infill well is shown to contact a smaller reservoir area past the onset time of stress reversal, as the induced fractures gradually turn to orient parallel to the infill well. The risk is to see the performance of the infill well drop compared to the offset wells. On the other hand, a window of opportunity exists when the horizontal stress contrast is reduced compared to in-situ, thus favoring the interaction with natural fractures and enhancing fracture complexity.These new observations have significant implications for field development strategies, hydraulic fracturing design, well placement and spacing, as well as the timing of infill-well stimulation, especially in shale plays where poroelastic stress reorientation is sustained over the life of the reservoir. SPE 166503bigger role than fluid flow interference depends largely on the value of the in situ stress contrast. In cases featuring large in situ horizontal anisotropy, stress reversal is unlikely to occur and fluid flow interference is then likely to dominate.Studying of the impact of pressure-induced stress changes on fracture propagation direction is by no means of recent interest (Berchenko and Detournay 1997). In tight gas plays, poroelastic stress interference has been investigated and applied to the refracturing of vertical wells (Roussel 2011;Roussel and Sharma 2010a, 2010b;Siebrits and Elbel 1998;Warpinski and Branagan 1989;Weng and Siebrits 2007). In the case of a previously fractured well, it is possible to create a secondary fracture that is perpendicular to the first. Thus, refracturing makes it possible to access zones of the reservoirs that were previously unstimulated or understimulated. Initially, the direction of maximum horizontal stress is aligned with the initial vertical fracture. During production, the maximum horizontal stress decreases faster than the minimum horizontal stress, causing principal stresses to be reversed in the vicinity of the fracture. As a result, the second fracture may propagate orthogonal to the initial fracture. Past the isotropic point (L f '), the...

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Study on the mechanisms of refracturing technology featuring temporary plug for fracturing fluid diversion in tight sandstone reservoirs

Zhao

et al. 2018

Energy Science & Engineering

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Well production rates in unconventional plays usually decline dramatically in the first year. Refracturing, which is a remedial production operation, is often done because original hydraulic fracturing failed to contribute any significant amount of flow or significant unfractured pay exists in the well. In order to maximize the fracturing fluid contact with the intact rock and to stimulate more reservoir volume in previously stimulated wells, a refracturing technology featuring a novel temporary plugging for fluid diversion is developed to enable the fracturing fluid to reach the untouched areas and to create reoriented fractures. In this paper, laboratory physical simulation tests of refracturing using fiber for effective temporary plugging is carried out to study the refracture morphology and the influencing factors of refractures. Results show that the refracture morphology is affected by the horizontal stress difference, the injection rate of initial fracturing fluid, and the natural fractures. Under condition of the different horizontal stress differences, the fracture initiation and orientation angle are different. When the horizontal stress difference is small, it is easy to form large angle fractures. The injection rate of initial fracturing fluid affects the length of initial fractures and refractures. The smaller the initial fracturing fluid injection rate is, the better the effect of temporary plugging in refracturing. The presence of natural fractures will lead to reorientation of refractures to form a complex fracture network. This study provides a theoretical guidance and technology support for refracturing operations.

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Parameters Affecting Azimuth and Length of a Secondary Fracture During a Refracture Treatment

Cited by 63 publications

References 0 publications

Optimizing Fracture Spacing and Sequencing in Horizontal-Well Fracturing

Optimizing Fracture Spacing and Sequencing in Horizontal-Well Fracturing

Hydraulic Fracture Propagation from Infill Horizontal Wells

Study on the mechanisms of refracturing technology featuring temporary plug for fracturing fluid diversion in tight sandstone reservoirs

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