Fracture Penetration Through an Interface

Biot, Marco; Medlin, W.L.; Massé, L.

doi:10.2118/10372-pa

Cited by 48 publications

(11 citation statements)

References 20 publications

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“…There are references to the effect of interfacial strength on fracture height containment (e.g., Daneshy [29], Simonson et al [6], Biot et al [30]). While interfacial strength may be an important parameter in some formations, our investigations were limited to the effect of modulus only.…”

Section: This Is Very Important Since "E" Thus Becomes the Only Hydramentioning

confidence: 99%

Layered Modulus Effects on Fracture Propagation, Proppant Placement, and Fracture Modeling

Smith¹,

Bale²,

Britt³

et al. 2001

Proceedings of SPE Annual Technical Conference and Exhibition

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractHydraulic fracture geometry (i.e., critical results of length and proppant placement) is driven by four major in situ parameters: Fracture Height (H), Modulus (E), Fluid Loss (C), and "Apparent" Fracture Toughness (KIc-app). In many (even most) cases, "Height" is the most important of these parametersdue to the need for some height confinement to achieve long fractures, or the need for height growth to insure good pay coverage. Due to this importance, industry research effort and most field measuring techniques concentrate on "Height." In particular, the growing use of seismic imaging is offering a tool to measure height growth away from the wellbore. Results from such diagnostics have often shown, as one expects, that in situ stress variations control height. However, results have also shown situations where this is apparently not the case.This paper examines another in situ parameter, "Layered Modulus," which also affects height. In addition, by controlling the "local" width of a fracture, layered modulus (i.e., layered formations with different layers having significantly different modulus) can have a critical effect on final proppant placement.The importance of layered modulus in directly controlling fracture height is illustrated in this paper, and this is compared with published solutions. In general, it is found that, just as concluded in the past, modulus contrast is probably not an important parameter in terms of direct control of fracture height. The greater importance lies in the effects on local fracture width. These local width changes can have a significant influence on controlling proppant placement -and this can be critical for low net pressure cases such as "water fracs" or fractur-ing in "soft" formations. It is also noted that layered modulus significantly impacts the average width of a fracture, and thus impacts the critical material balance aspects of fracture modeling if not properly accounted for.Finally, some of the theoretical solution problems created by "Layered Modulus" formations for fracture modeling are discussed and compared. This is done by comparing with 3-D Finite Element (static) solutions, and shows how some common industry "approximations" for layered modulus give incorrect results. Based on this, examples with a fracture propagation model using a finite element-generated stiffness matrix are used to define types of cases where a simple "average" modulus is acceptable, versus cases where more complex calculations are needed.

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Section: This Is Very Important Since "E" Thus Becomes the Only Hydramentioning

confidence: 99%

Layered Modulus Effects on Fracture Propagation, Proppant Placement, and Fracture Modeling

Smith¹,

Bale²,

Britt³

et al. 2001

Proceedings of SPE Annual Technical Conference and Exhibition

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“…[15] It is commonly inferred that fractures are not able to propagate across a bedding plane if it is weak and has a high tendency to slip [Biot et al, 1983;Thiercelin et al, 1987;Brenner and Gudmundsson, 2004]. Instead, the fractures tend to divert at the interface, delaminating it in a shear fracture.…”

Section: Introductionmentioning

confidence: 99%

Extension fracture propagation in rocks with veins: Insight into the crack‐seal process using Discrete Element Method modeling

2013

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[1] We investigate how existing veins interact with extension fractures in rocks using 3-D Discrete Element Method models with a geometry inspired by tension tests with notched samples. In a sensitivity study, we varied (a) the angle between the vein and the bulk extension direction and (b) the strength ratio between host rock and vein material. Results show a range of vein-fracture interactions, which fall into different, robust, "structural styles." Veins, which are weaker than the host rock, tend to localize fracturing into the vein, even at high-misorientation angles. Veins, which are stronger than the host rock, cause deflection of the fracture tip along the vein-host rock interface. Fractures are arrested at the interface from weak to stronger material. When propagating from a stronger to a weaker material, macroscopic bifurcation of the fracture is common. Complex interactions are favored by a low angle between the vein and the fracture and by high-strength contrast. The structural styles in the models show good agreement with microstructures and mesostructures of crack-seal veins found in natural systems. We propose that these structural styles form the basis for criteria to recognize strength contrasts and stress of crack-seal systems in nature.Citation: Virgo, S., S. Abe, and J. L. Urai (2013), Extension fracture propagation in rocks with veins: Insight into the crack-seal process using Discrete Element Method modeling,

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“…In the context of hydraulic fracturing, which is performed to enhance the recovery of unconventional hydrocarbons, several indicators are important for defining the effective penetration and propagation inside the source rocks. These factors include the interface property, the vertical compressive stress difference, the mechanical properties of the producing formation and interlayers, and the horizontal stress difference (e.g., Anderson, ; Biot et al, ; Gu et al, ; Huang & Liu, ; Warpinski et al, ; Warpinski & Teufel, ; Zhang et al, ). The mechanical properties of gas‐bearing shales in the Polish part of the BB have not yet been studied with such interdisciplinary magnetic and sedimentary methods.…”

Section: Discussionmentioning

confidence: 99%

Magnetic Anisotropy in Silurian Gas‐Bearing Shale Rocks From the Pomerania Region (Northern Poland)

et al. 2019

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Analysis of anisotropy of magnetic susceptibility (AMS) and anhysteretic remanent magnetization (AARM) was conducted on unconventional gas-bearing Silurian shale rocks from northern Poland. Samples of these rocks were collected from depths greater than 3,500 m from two drill cores. The aim was to investigate magnetic fabrics to verify current models of depositional conditions, current direction, and/or tectonic evolution. To obtain an in-depth interpretation, rock magnetic studies, microscopic analyses, and graptolite orientation measurements were performed. The results indicate that the magnetic susceptibility is mainly governed by paramagnetic minerals (phyllosilicates) with a small contribution of ferromagnetic minerals, mostly magnetite. Typically, in the studied mudstones, the AMS and AARM fabrics are characterized by strong bedding-parallel foliation, resulting mostly from compaction. The foliation is much weaker in the associated early-diagenetic calcareous concretions. Although the mudstones are almost isotropic in the bedding plane, there is a slight tendency for grouping of magnetic lineation axes with an orientation of approximately NNW-SSE. The corresponding orientation of the AMS lineation is preserved in the concretions, and the same trend also prevails in the preferred orientation of graptolites. Thus, we interpret this orientation to be related to paleocurrents. The observed directions show that during the Wenlock (Silurian) in the studied part of the Baltic Basin, the dominant currents had an orientation of circa NNW-SSE along the margin of Baltica. Our results confirm that even in such fine-grained sediments, in which there are no other unequivocal directional sedimentary indicators, paleocurrent directions can be determined by applying AMS and AARM methodology. et al., 2008). Consequently, AMS reflects the preferred orientation of these minerals inherited from sedimentation, compaction, and tectonic processes. AMS analysis is a common and effective method to determine mineral alignment in rocks, even if they do not show any macroscopic signs of sedimentary structures and/or tectonic deformation (e.g. Key Points:• Magnetic foliation in mudstones resides in phyllosilicates and resulted from compaction • In carbonate concretions, the anisotropy is much weaker and originated during early diagenetic formation • The similarity in the orientations of graptolites and the magnetic lineation in concretions suggests an origin related to bottom currentsSupporting Information:• Supporting Information S1

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Fracture Penetration Through an Interface

Cited by 48 publications

References 20 publications

Layered Modulus Effects on Fracture Propagation, Proppant Placement, and Fracture Modeling

Layered Modulus Effects on Fracture Propagation, Proppant Placement, and Fracture Modeling

Extension fracture propagation in rocks with veins: Insight into the crack‐seal process using Discrete Element Method modeling

Magnetic Anisotropy in Silurian Gas‐Bearing Shale Rocks From the Pomerania Region (Northern Poland)

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