Simulation-Based Unitary Fracking Condition and Multiscale Self-Consistent Fracture Network Formation in Shale

2017 ◽  
Vol 84 (5) ◽  
Author(s):  
Qinglei Zeng ◽  
Tao Wang ◽  
Zhanli Liu ◽  
Zhuo Zhuang
Keyword(s):  
Oil Shale ◽  
Network Formation ◽  
Numerical Models ◽  
Fracture Network ◽  
Extended Finite Element ◽  
Fluid Flux ◽  
Simulation Based ◽  
Self Consistent ◽  
Horizontal Wellbore ◽  
Multiple Clusters

Hydraulic fracturing (fracking) technology in gas or oil shale engineering is highly developed last decades, but the knowledge of the actual fracking process is mostly empirical and makes mechanicians and petroleum engineers wonder: why fracking works? (Bažant et al., 2014, “Why Fracking Works,” ASME J. Appl. Mech., 81(10), p. 101010) Two crucial issues should be considered in order to answer this question, which are fracture propagation condition and multiscale fracture network formation in shale. Multiple clusters of fractures initiate from the horizontal wellbore and several major fractures propagate simultaneously during one fracking stage. The simulation-based unitary fracking condition is proposed in this paper by extended finite element method (XFEM) to drive fracture clusters growing or arresting dominated by inlet fluid flux and stress intensity factors. However, there are millions of smeared fractures in the formation, which compose a multiscale fracture network beyond the computation capacity by XFEM. So, another simulation-based multiscale self-consistent fracture network model is proposed bridging the multiscale smeared fractures. The purpose of this work is to predict pressure on mouth of well or fluid flux in the wellbore based on the required minimum fracture spacing scale, reservoir pressure, and proppant size, as well as other given conditions. Examples are provided to verify the theoretic and numerical models.

3-D fracture network dynamic simulation based on error analysis in rock mass of dam foundation

2018 ◽  
Vol 25 (4) ◽  
pp. 919-935 ◽  
Author(s):  
Deng-hua Zhong ◽  
Han Wu ◽  
Bin-ping Wu ◽  
Yi-chi Zhang ◽  
Pan Yue
Keyword(s):  
Rock Mass ◽  
Error Analysis ◽  
Dynamic Simulation ◽  
Fracture Network ◽  
Network Dynamic ◽  
Dam Foundation ◽  
Simulation Based

On the multiscale quantification of fracture network geometry from lineament maps of crystalline basement units

2021 ◽  
Author(s):  
Alberto Ceccato ◽  
Giulia Tartaglia ◽  
Giulio Viola ◽  
Marco Antonellini
Keyword(s):  
Statistical Analysis ◽  
Scaling Laws ◽  
Numerical Models ◽  
Regional Scale ◽  
Fracture Network ◽  
Crystalline Basement ◽  
Fracture Networks ◽  
Spatial Organisation ◽  
Robust Analysis ◽  
Network Properties

<p>Fractured crystalline basement units are attracting increasing attention as potential unconventional reservoirs for natural (oil, heat and water) resources and as potential waste (nuclear, CO<sub>2</sub>) disposal sites. The focus of the current efforts is the characterisation of the structural permeability of fractured crystalline basement units, which is primarily related to the geology, geometry, and spatial characteristics of fracture networks. Fracture network properties may be scale–dependent or independent. Thus, a multi–scale characterisation of fracture networks is usually recommended to quantify the scale–variability of properties and, eventually, the related predictive scaling laws. Fracture lineament maps are schematic representations of fracture distributions obtained from either manual or automated interpretation of 2D digital models of the earth surface at different scales. From the quantitative analysis on fracture lineament maps, we can retrieve invaluable information on the scale–dependence of fracture network properties.</p><p>Here we present the results of the quantification of fracture network and fracture set properties (orientation, length, spacing, spatial organisation) from multi– (outcrop to regional) scale 2D lineament maps of two crystalline basement study areas of Western Norway (Bømlo island and Kråkenes). Lineament maps were obtained from the manual interpretation of orthophotos and 2D digital terrain models retrieved from UAV–drone and LiDAR surveys.</p><p>Analyses aimed at the quantification of: (i) scaling laws for fracture length cumulative distributions, defined through a statistically–robust fitting method (Maximum Likelihood Estimations coupled with Kolmogorov–Smirnov tests); (ii) variability of orientation sets as a function of scale; (iii) spatial organisation of fracture sets among scales; (iv) fractal characteristics of fracture networks (fractal exponent). Results suggest that: (i) a statistical analysis considering variable censoring and truncation effects allows to confidently define the best–fitting scaling laws; (ii) the analysis of orientation variability of fracture sets among different scales may provide important constraints about the geometrical complexity of fracture and fault zones; (iii) the statistical analysis of 2D spacing variability and fracture intensity can be adopted to quantify fracture spatial organisation at different scales.</p><p>A statistically robust analysis of the scaling laws, length distributions, spacing, and spatial organisation of lineaments on 2D maps provides reliable results also where only partial or incomplete dataset/lineament maps are available. Such properties are the fundamental input parameters for conceptual (geologic) and numerical (discrete fracture network, DFN) models of fractured crystalline basement reservoirs. Therefore, a statistically robust analysis of fracture lineament maps may help to improve the accuracy of conceptual and numerical models.</p>

scholarly journals Kinematics of Planetary Nebulae in M51's Tidal Tail

2003 ◽  
Vol 209 ◽  
pp. 633-634
Author(s):  
John J. Feldmeier ◽  
J. Christopher Mihos ◽  
Patrick R. Durrell ◽  
Robin Ciardullo ◽  
George H. Jacoby
Keyword(s):  
Surface Brightness ◽  
Numerical Models ◽  
Planetary Nebulae ◽  
Tidal Tail ◽  
Low Surface Brightness ◽  
Galaxy Interaction ◽  
Self Consistent ◽  
The Galaxy ◽  
Interacting Systems ◽  
Kinematic Properties

The galaxy pair NGC 5194/95 (M51) is one of the closest and best known interacting systems. Despite its notoriety, however, many of its features are not well studied. Extending westward from NGC 5195 is a low surface brightness tidal tail, which can only be seen in deep broadband exposures. Our previous [O III] λ5007 planetary nebulae (PN) survey of M51 recovered this tidal tail, and presented us with a opportunity to study the kinematics of a galaxy interaction in progress. We report the results of a spectroscopy survey of the PN, aimed at determining their kinematic properties. We then use these data to constrain new self-consistent numerical models of the system.

scholarly journals A Case Study on the Optimal Design of the Horizontal Wellbore Trajectory for Hydraulic Fracturing in Nong’an Oil Shale

Energies ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 286
Author(s):  
Ying Zhu ◽  
Han Zhang ◽  
Dongbin Pan ◽  
Lianghao Zhai ◽  
Shuai Gao ◽  
...  
Keyword(s):  
Oil Shale ◽  
Fracture Initiation ◽  
Intact Rock ◽  
Hydraulic Fractures ◽  
Trajectory Design ◽  
Rock Matrix ◽  
Preferred Direction ◽  
Bedding Planes ◽  
Horizontal Wellbore

A horizontal well with hydraulic fractures is key to forming a fracture network in oil shale for the generated hydrocarbon flows. By considering the influence of anisotropic strength, a prediction model is proposed for fracture initiation by studying different fracture initiation modes (FIMs) in oil shale: failure of the intact rock matrix and of the bedding planes. Through a case study on Nong’an oil shale, the influences of wellbore trajectory and bedding planes on the fracture initiation pressure (FIP), location (FIL), and FIM were analyzed and the induced changes in wellbore trajectory design were concluded. The preferred angle between the wellbore axis and the minimum horizontal principal stress was the same of 90° or 270°, when the lowest required FIP corresponded to the failure of the intact rock matrix. However, when the angle corresponded to the failure of the bedding planes, the preferred direction of the wellbore axis was away from the fixed direction and not corresponding to the lowest required FIP due to the fracture morphology. The error between the theoretical and experimental results ranges from 7% to 9%. This research provides a framework for the design of horizontal wellbore trajectories in oil shale, for easier fracture initiation and more complex fracture networks.

scholarly journals Oil-in-water microemulsion droplets of TDMAO/decane interconnected by the telechelic C18-EO150-C18: clustering and network formation

Soft Matter ◽  
2014 ◽  
Vol 10 (28) ◽  
pp. 5072-5084 ◽  
Author(s):  
Paula Malo de Molina ◽  
Marie-Sousai Appavou ◽  
Michael Gradzielski
Keyword(s):  
Network Formation ◽  
Mixed System ◽  
Polymer Content ◽  
Structure And Dynamics ◽  
Oil In Water ◽  
Self Consistent ◽  
Consistent Picture ◽  
Evolution Of Structure ◽  
Telechelic Polymer

The combination of SANS, DLS, and FCS allows to derive a self-consistent picture of the evolution of structure and dynamics of the mixed system microemulsion/telechelic polymer as a function of the polymer content.

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.

scholarly journals Comparison of Hydraulic and Tracer Tomography for Discrete Fracture Network Inversion

Geosciences ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 274 ◽  
Author(s):  
Ringel ◽  
Somogyvári ◽  
Jalali ◽  
Bayer
Keyword(s):  
Preferential Flow ◽  
Numerical Models ◽  
Fracture Network ◽  
Discrete Fracture Network ◽  
Simultaneous Estimation ◽  
Well Testing ◽  
Hydraulic Tomography ◽  
Preferential Flow Paths ◽  
Discrete Fracture ◽  
Inversion Procedure

Fractures serve as highly conductive preferential flow paths for fluids in rocks, which are difficult to exactly reconstruct in numerical models. Especially, in low-conductive rocks, fractures are often the only pathways for advection of solutes and heat. The presented study compares the results from hydraulic and tracer tomography applied to invert a theoretical discrete fracture network (DFN) that is based on data from synthetic cross-well testing. For hydraulic tomography, pressure pulses in various injection intervals are induced and the pressure responses in the monitoring intervals of a nearby observation well are recorded. For tracer tomography, a conservative tracer is injected in different well levels and the depth-dependent breakthrough of the tracer is monitored. A recently introduced transdimensional Bayesian inversion procedure is applied for both tomographical methods, which adjusts the fracture positions, orientations, and numbers based on given geometrical fracture statistics. The used Metropolis-Hastings-Green algorithm is refined by the simultaneous estimation of the measurement error´s variance, that is, the measurement noise. Based on the presented application to invert the two-dimensional cross-section between source and the receiver well, the hydraulic tomography reveals itself to be more suitable for reconstructing the original DFN. This is based on a probabilistic representation of the inverted results by means of fracture probabilities.

A Self-Consistent Non-Quasi Static MOSFET Model for Circuit Simulation Based on Transient Carrier Response

2002 ◽  
Author(s):  
Noriaki Nakayama ◽  
Hiroaki Ueno ◽  
Takashi Isa ◽  
Masayasu Tanaka ◽  
Mitiko Miura-Mattausch
Keyword(s):  
Circuit Simulation ◽  
Simulation Based ◽  
Self Consistent

Towards a self-consistent thermodynamic magmatic model for conduit transport processes

2020 ◽  
Author(s):  
Jost von der Lieth ◽  
Matthias Hort
Keyword(s):  
Numerical Study ◽  
Numerical Models ◽  
Fluid Dynamic ◽  
Dynamic Modelling ◽  
Explosive Volcanism ◽  
Transport Processes ◽  
The Other ◽  
Full Potential ◽  
Holistic View ◽  
Self Consistent

<p>The geodynamical side of explosive volcanic eruption modelling on the one hand, as well as the petrological one on the other, have reached a high degree of sophistication and maturity independently from each other over the years. Unfortunately, adherents of one discipline often only utilize the other’s tools in a simplified and makeshift way, obscuring the full potential of their synergies. Over the past decade efforts have been made to re-integrate both approaches to the issue into a more holistic view on the sub-surface processes leading to and concurrent with explosive volcanism.<br>One of the difficulties encountered in that effort are conceptual and technical incompatibilities between thermo- and fluid-dynamic modelling toolboxes. While the tools perform well individually, they are often not suitable to work in combination in highly complex numerical models, due to interface problems impeding performance.<br>For an ongoing numerical study on transport processes within a volcanic conduit, it has been deemed necessary to re-implement an established thermodynamic model based on Holland and Powell (2011, and follow-ups) in order to a) attain the required computing performance and b) to gain sufficient petrological insight (starting from a geophysical point of view) to be able to make apt use of the tool then at hand.<br>The path to the intermediate goal of deriving the thermodynamic and transport properties (e.g. density, viscosity, heat capacity and conductivity) in a <em>self-consistent and stable</em> manner suitable for further use in a numerical fluid-dynamics model is illustrated here. The focus is on problems encountered with the petrological modelling, and on the subsequent derivation of the above properties, that are not directly available from the former results. The methods presented are general and applicable to various settings regarding volcanic chemistry and transport processes, however, they will be demonstrated on low-viscosity open-conduit systems typical for strombolian activity.</p>

Depth-dependent analysis of fracture patterns inferred from image logs and cores in crystalline rocks

2020 ◽  
Author(s):  
Mohammad Javad Afshari Moein
Keyword(s):  
Spatial Distribution ◽  
Correlation Dimension ◽  
Numerical Models ◽  
Fracture Network ◽  
Crystalline Rocks ◽  
Geothermal System ◽  
Upper Rhine Graben ◽  
Enhanced Geothermal System ◽  
Fracture Density ◽  
Fracture Patterns

<p>Enhanced Geothermal System (EGS) development requires an accurate fracture network characterization. The knowledge on the fracture network is fundamental for setting up numerical models to simulate the activated processes in hydraulic stimulation experiments. However, direct measurement of fracture network properties at great depth is limited to the data from exploration wells. Geophysical logging techniques and continuous coring, if available, provide the location and orientation of fractures that intersect the wellbore. The statistical parameters derived from borehole datasets (either from image logs or cores) constrain stochastic realizations of the rock mass, known as Discrete Fracture Network (DFN) models. However, accurate parametrization of DFN models requires sufficient knowledge on the depth-dependent spatial distribution of fractures in the earth’s crust.</p><p>This analysis includes a unique collection of fracture datasets from six deep (i.e. 2-5 km depth) boreholes drilled into crystalline basement rocks at the same tectonic settings. All the wells were drilled in the Upper Rhine Graben in Soultz-sous-Forêts Enhanced Geothermal System, France, except the well that was drilled in Basel geothermal project, Switzerland. The datasets included both borehole image logs and core samples, which have a higher resolution. Two-point correlation function was selected to characterize the power-law scaling of fracture patterns. The correlation dimension of spatial patterns showed no systematic variations with depth at one standard deviation level of uncertainty in moving windows of sufficient number of fractures along any of the boreholes. This implies that a single correlation dimension is sufficient to address the global scaling properties of the fractures in crystalline rocks. One could also anticipate the spatial distribution of deeper reservoir conditions from shallower datasets. On the contrary, the fracture density showed some variations with depth that are sometimes consistent with changes in lithology and geological settings at the time of fracture formation.</p>

Sign in / Sign up

Export Citation Format

Share Document