Seismic characterization of fault facies models

2017 ◽  
Vol 5 (4) ◽  
pp. SP9-SP26 ◽  
Author(s):  
Charlotte Botter ◽  
Nestor Cardozo ◽  
Dongfang Qu ◽  
Jan Tveranger ◽  
Dmitriy Kolyukhin
Keyword(s):  
Internal Structure ◽  
Fault Zone ◽  
Damage Zone ◽  
Seismic Attributes ◽  
Wave Frequency ◽  
Seismic Facies ◽  
Zone Model ◽  
Deformation Bands ◽  
Reservoir Models ◽  
Seismic Image

Faults play a key role in reservoirs by enhancing or restricting fluid flow. A fault zone can be divided into a fault core that accommodates most of the displacement and a surrounding damage zone. Interpretation of seismic data is a key method for studying subsurface features, but the internal structure and properties of fault zones are often at the limit of seismic resolution. We have investigated the seismic response of a vertical fault zone model in sandstone, populated with fault facies based on deformation band distributions. Deformation bands reduce the porosity of the sandstone, and they condition its elastic properties. We generate synthetic seismic cubes of the fault facies model for several wave frequencies and under realistic conditions of reservoir burial and seismic acquisition. Seismic image quality and fault zone definition are highly dependent on wave frequency. At a low wave frequency (e.g., 10 Hz), the fault zone is broader and no information about its fault facies distribution can be extracted. At higher wave frequencies (e.g., 30 and 60 Hz), seismic attributes, such as tensor and envelope, can be used to characterize the fault volume and its internal structure. Based on these attributes, we can subdivide the fault zone into several seismic facies from the core to the damage zone. Statistical analyses indicate a correlation between the seismic attributes and the fault internal structure, although seismic facies, due to their coarser resolution, cannot be matched to individual fault facies. The seismic facies can be used as input for reservoir models as spatial conditioning parameters for fault facies distributions inside the fault zone. However, relying only on the information provided by seismic analyses might not be enough to create high-resolution fault reservoir models.

scholarly journals Influence of deformation-band fault damage zone on reservoir performance

2017 ◽  
Vol 5 (4) ◽  
pp. SP41-SP56 ◽  
Author(s):  
Dongfang Qu ◽  
Jan Tveranger ◽  
Muhammad Fachri
Keyword(s):  
Fault Zone ◽  
Deformation Band ◽  
Damage Zone ◽  
Flow Simulation ◽  
Deformation Bands ◽  
Reservoir Performance ◽  
Reservoir Models ◽  
Model Domain ◽  
Fault Damage Zone ◽  
The Impact

Access to 3D descriptions of fault zone architectures and recent development of modeling techniques allowing explicit rendering of these features in reservoir models, provide a new tool for detailed implementation of fault zone properties. Our aim is to assess how explicit rendering of fault zone architecture and properties affects performance of fluid flow simulation models. The test models use a fault with a maximum 100 m displacement and a fault damage zone with petrophysical heterogeneity caused by the presence of deformation bands. The distribution pattern of deformation bands in fault damage zones is well-documented, which allows generation of realistic models. A multiscale modeling workflow is applied to incorporate these features into reservoir models. Model input parameters were modulated to provide a range of property distributions, and the interplay between the modeling parameters and reservoir performance was analyzed. The influence of deformation-band damage zone on reservoir performance in the presence of different fault core transmissibility-multipliers was investigated. Two configurations are considered: one in which the fault terminates inside the model domain, representing a case in which the fluid can flow around the fault, and one in which the fault dissects the entire model domain, representing a case in which the fluid is forced to cross the fault. We observed that the impact of deformation-band fault damage zone on reservoir performance changes when the fault core transmissibility multiplier is changed. Reservoir performance is insensitive to changing damage zone heterogeneity in a configuration in which flow can move around the fault. Where flow cannot bypass the fault, the influence of fault damage zone heterogeneity on reservoir performance is significant even when the fault core transmissibility multiplier is low.

Physical and chemical strain-hardening during faulting in poorly lithified sandstone: The role of kinematic stress field and selective cementation

2019 ◽  
Vol 132 (5-6) ◽  
pp. 1183-1200 ◽  
Author(s):  
Mattia Pizzati ◽  
Fabrizio Balsamo ◽  
Fabrizio Storti ◽  
Paola Iacumin
Keyword(s):  
Stress Field ◽  
Strain Hardening ◽  
Fault Zone ◽  
Deformation Band ◽  
Early Stage ◽  
Damage Zone ◽  
Isotope Analysis ◽  
Deformation Bands ◽  
Multidisciplinary Study ◽  
Diagenetic Evolution

Abstract In this work, we report the results of a multidisciplinary study describing the structural architecture and diagenetic evolution of the Rocca di Neto extensional fault zone developed in poorly lithified sandstones of the Crotone Basin, Southern Italy. The studied fault zone has an estimated displacement of ∼90 m and consists of: (1) a low-deformation zone with subsidiary faults and widely spaced deformation bands; (2) an ∼10-m-wide damage zone, characterized by a dense network of conjugate deformation bands; (3) an ∼3-m-wide mixed zone produced by tectonic mixing of sediments with different grain size; (4) an ∼1-m-wide fault core with bedding transposed into foliation and ultra-comminute black gouge layers. Microstructural investigations indicate that particulate flow was the dominant early-stage deformation mechanism, while cataclasis became predominant after porosity loss, shallow burial, and selective calcite cementation. The combination of tectonic compaction and preferential cementation led to a strain-hardening behavior inducing the formation of “inclined conjugate deformation band sets” inside the damage zone, caused by the kinematic stress field associated with fault activity. Conversely, conjugate deformation band sets with a vertical bisector formed outside the damage zone in response to the regional extensional stress field. Stable isotope analysis helped in constraining the diagenetic environment of deformation, which is characterized by mixed marine-meteoric signature for cements hosted inside the damage zone, while it progressively becomes more meteoric moving outside the fault zone. This evidence supports the outward propagation of fault-related deformation structures in the footwall damage zone.

Discrete and continuous conceptual models of fault zones.

2021 ◽  
Author(s):  
Tom Manzocchi
Keyword(s):  
Numerical Model ◽  
Conceptual Model ◽  
Fault Zone ◽  
Large Scale ◽  
Damage Zone ◽  
Fault Zones ◽  
Zone Model ◽  
Multiple Model ◽  
Modelling Studies ◽  
Scale Properties

<p>Faults can control the large-scale properties of rock volumes through their behaviour as flow conduits and/or barriers or by localising geomechanical effects. Hence, often the fidelity of a numerical model of faulted site relies on the accuracy with which the fault zone is represented.  There are two distinct factors that must be considered in a modelling study: first, does the model contain the most relevant characteristics of the fault that influence the behaviour of interest; and second, are these characteristics assigned realistic and representative values that capture both their natural variability and the uncertainty with which they can be determined for the specific case of interest. These two factors are contained in the conceptual fault model and choice of modelling proxy-properties, respectively.</p><p>In recent years, two classes of conceptual fault zone model have dominated the description of fault zones, broadly characterised by either a continuous or a discrete approach. Continuous fault zone properties (e.g. fault core and damage zone thickness, displacement partitioning statistics) often show high variability which many modelling studies attempt to capture by running multiple model containing property values sampled from the distribution. Discrete descriptions focus on the presence of individual fault zone elements (e.g. shale smears, relay zones), and models guided by a discrete conceptual model attempt to place representative frequencies of elements. A single discrete model might contain the same property distributions as an ensemble of continuous models yet, because it contains a representative frequency of different elements, its behaviour might lie beyond the extreme behaviour of the continuous ensemble. Hence, the manner in which a geologist’s conceptual model is represented in a modeller’s numerical model can be hugely important for the outcome of the study, and it is in the interest of both modellers and geologists to ensure that they have a correct understanding of the other’s part of the process.</p>

Internal structure of the San Jacinto fault zone at the Ramona Reservation, north of Anza, California, from dense array seismic data

2020 ◽  
Vol 224 (2) ◽  
pp. 1225-1241
Author(s):  
Lei Qin ◽  
Pieter-Ewald Share ◽  
Hongrui Qiu ◽  
Amir A Allam ◽  
Frank L Vernon ◽  
...  
Keyword(s):  
Internal Structure ◽  
Fault Zone ◽  
Seismic Data ◽  
Damage Zone ◽  
Normal Direction ◽  
Bimaterial Interface ◽  
Trapped Waves ◽  
San Jacinto Fault ◽  
Core Damage ◽  
San Jacinto Fault Zone

SUMMARY We image the internal structure of the San Jacinto fault zone (SJFZ) near Anza, California, with seismic data recorded by two dense arrays (RA and RR) from ∼42 000 local and ∼180 teleseismic events occurring between 2012 and 2017. The RA linear array has short aperture (∼470 m long with 12 strong motion sensors) and recorded for the entire analysed time window, whereas the RR is a large three-component nodal array (97 geophones across a ∼2.4 km × 1.4 km area) that operated for about a month in September–October 2016. The SJFZ at the site contains three near-parallel surface traces F1, F2 and F3 from SW to NE that have accommodated several Mw > 6 earthquakes in the past 15 000 yr. Waveform changes in the fault normal direction indicate structural discontinuities that are consistent with the three fault surface traces. Relative slowness from local events and delay time analysis of teleseismic arrivals in the fault normal direction suggest a slower SW side than the NE with a core damage zone between F1 and F2. This core damage zone causes ∼0.05 s delay at stations RR26–31 in the teleseismic P arrivals compared with the SW-most station, and generates both P- and S-type fault zone trapped waves. Inversion of S trapped waves indicates the core damaged structure is ∼100 m wide, ∼4 km deep with a Q value of ∼20 and 40 per cent S-wave velocity reduction compared with bounding rocks. Fault zone head waves observed at stations SW of F3 indicate a local bimaterial interface that separates the locally faster NE block from the broad damage zone in the SW at shallow depth and merges with a deep interface that separates the regionally faster NE block from rocks to the SW with slower velocities at greater depth. The multiscale structural components observed at the site are related to the geological and earthquake rupture history at the site, and provide important information on the preferred NW propagation of earthquake ruptures on the San Jacinto fault.

scholarly journals Geomorphological Geometries and High-Resolution Seismic Sequence Stratigraphy of Malay Basin’s Fluvial Succession

2021 ◽  
Vol 11 (11) ◽  
pp. 5156
Author(s):  
Abd Al-Salam Al-Masgari ◽  
Mohamed Elsaadany ◽  
Numair A. Siddiqui ◽  
Abdul Halim Abdul Latiff ◽  
Azli Abu Bakar ◽  
...  
Keyword(s):  
High Resolution ◽  
Sequence Stratigraphy ◽  
Three Dimensional ◽  
Seismic Attributes ◽  
Seismic Facies ◽  
Seismic Sequence ◽  
3D Seismic ◽  
Seismic Sequences ◽  
Seismic Sequence Stratigraphy ◽  
Point Bars

This study identified the Pleistocene depositional succession of the group (A) (marine, estuarine, and fluvial depositional systems) of the Melor and Inas fields in the central Malay Basin from the seafloor to approximately −507 ms (522 m). During the last few years, hydrocarbon exploration in Malay Basin has moved to focus on stratigraphic traps, specifically those that existed with channel sands. These traps motivate carrying out this research to image and locate these kinds of traps. It can be difficult to determine if closely spaced-out channels and channel belts exist within several seismic sequences in map-view with proper seismic sequence geomorphic elements and stratigraphic surfaces seismic cross lines, or probably reinforce the auto-cyclic aggregational stacking of the avulsing rivers precisely. This analysis overcomes this challenge by combining well-log with three-dimensional (3D) seismic data to resolve the deposition stratigraphic discontinuities’ considerable resolution. Three-dimensional (3D) seismic volume and high-resolution two-dimensional (2D) seismic sections with several wells were utilized. A high-resolution seismic sequence stratigraphy framework of three main seismic sequences (3rd order), four Parasequences sets (4th order), and seven Parasequences (5th order) have been established. The time slice images at consecutive two-way times display single meandering channels ranging in width from 170 to 900 m. Moreover, other geomorphological elements have been perfectly imaged, elements such as interfluves, incised valleys, chute cutoff, point bars, and extinction surfaces, providing proof of rapid growth and transformation of deposits. The high-resolution 2D sections with Cosine of Phase seismic attributes have facilitated identifying the reflection terminations against the stratigraphic amplitude. Several continuous and discontinuous channels, fluvial point bars, and marine sediments through the sequence stratigraphic framework have been addressed. The whole series reveals that almost all fluvial systems lay in the valleys at each depositional sequence’s bottom bars. The degradational stacking patterns are characterized by the fluvial channels with no evidence of fluvial aggradation. Moreover, the aggradation stage is restricted to marine sedimentation incursions. The 3D description of these deposits permits distinguishing seismic facies of the abandoned mud channel and the sand point bar deposits. The continuous meandering channel, which is filled by muddy deposits, may function as horizontal muddy barriers or baffles that might isolate the reservoir body into separate storage containers. The 3rd, 4th, and 5th orders of the seismic sequences were established for the studied succession. The essential geomorphological elements have been imaged utilizing several seismic attributes.

scholarly journals Integrated petrographic – rock mechanic borecore study from the metamorphic basement of the Pannonian Basin, Hungary

2015 ◽  
Vol 7 (1) ◽  
Author(s):  
László Molnár ◽  
Balázs Vásárhelyi ◽  
Tivadar M. Tóth ◽  
Félix Schubert
Keyword(s):  
Compressive Strength ◽  
Fault Zone ◽  
Uniaxial Compressive Strength ◽  
Pannonian Basin ◽  
Damage Zone ◽  
Rock Mechanic ◽  
Fault Rock ◽  
Hydrocarbon Reservoir ◽  
Migration Pathway ◽  
Metamorphic Basement

AbstractThe integrated evaluation of borecores from the Mezősas-Furta fractured metamorphic hydrocarbon reservoir suggests significantly distinct microstructural and rock mechanical features within the analysed fault rock samples. The statistical evaluation of the clast geometries revealed the dominantly cataclastic nature of the samples. Damage zone of the fault can be characterised by an extremely brittle nature and low uniaxial compressive strength, coupled with a predominately coarse fault breccia composition. In contrast, the microstructural manner of the increasing deformation coupled with higher uniaxial compressive strength, strain-hardening nature and low brittleness indicate a transitional interval between the weakly fragmented damage zone and strongly grinded fault core. Moreover, these attributes suggest this unit is mechanically the strongest part of the fault zone. Gougerich cataclasites mark the core zone of the fault, with their widespread plastic nature and locally pseudo-ductile microstructure. Strain localization tends to be strongly linked with the existence of fault gouge ribbons. The fault zone with ∼15 m total thickness can be defined as a significant migration pathway inside the fractured crystalline reservoir. Moreover, as a consequence of the distributed nature of the fault core, it may possibly have a key role in compartmentalisation of the local hydraulic system.

Modelling of interactions between dykes, inclined sheets and faults at Santorini volcano

2021 ◽  
Author(s):  
Kyriaki Drymoni ◽  
John Browning ◽  
Agust Gudmundsson
Keyword(s):  
Tensile Strength ◽  
Fault Zone ◽  
Numerical Models ◽  
Damage Zone ◽  
Sheet Thickness ◽  
Analytical Models ◽  
Energy Conditions ◽  
Dyke Swarm ◽  
Normal Faults ◽  
Santorini Volcano

<p>Dykes and inclined sheets are known occasionally to exploit faults as parts of their paths, but the conditions that allow this to happen are still not fully understood. Here we report field observations from a well-exposed dyke swarm of the Santorini volcano, Greece, that show dykes and inclined sheets deflected into faults and the results of analytical and numerical models to explain the conditions for deflection. The deflected dykes and sheets belong to a local swarm of 91 dyke/sheet segments that was emplaced in a highly heterogeneous and anisotropic host rock and partially cut by some regional faults and a series of historic caldera collapses, the caldera walls providing, excellent exposures of the structures. The numerical models focus on a normal-fault dipping 65° with a damage zone composed of parallel layers or zones of progressively more compliant rocks with increasing distance from the fault rupture plane. We model sheet-intrusions dipping from 0˚ to 90˚ and with overpressures of alternatively 1 MPa and 5 MPa, approaching the fault. We further tested the effects of changing (1) the sheet thickness, (2) the fault-zone thickness, (3) the fault-zone dip-dimension (height), and (4) the loading by, alternatively, regional extension and compression. We find that the stiffness of the fault core, where a compliant core characterises recently active fault zones, has pronounced effects on the orientation and magnitudes of the local stresses and, thereby, on the likelihood of dyke/sheet deflection into the fault zone. Similarly, the analytical models, focusing on the fault-zone tensile strength and energy conditions for dyke/sheet deflection, indicate that dykes/sheets are most likely to be deflected into and use steeply dipping recently active (zero tensile-strength) normal faults as parts of their paths.</p>

scholarly journals COMPUTATION FOR THE DELAMINATION IN THE LAMINATE COMPOSITE MATERIAL USING A COHESIVE ZONE MODEL BY ABAQUS

2020 ◽  
Vol 57 (6A) ◽  
pp. 61
Author(s):  
Hoa Cong Vu
Keyword(s):  
Finite Element ◽  
Cohesive Zone Model ◽  
Constitutive Relations ◽  
Damage Zone ◽  
Damage Model ◽  
Zone Model ◽  
Element Formulation ◽  
Cohesive Elements ◽  
Element Mesh ◽  
Variable Mode

In this paper, a damage model using cohesive damage zone for the simulation of progressive delamination under variable mode is presented. The constitutive relations, based on liner softening law, are using for formulation of the delamination onset and propagation. The implementation of the cohesive elements is described, along with instructions on how to incorporate the elements into a finite element mesh. The model is implemented in a finite element formulation in ABAQUS. The numerical results given by the model are compare with experimental data

scholarly journals Inherent Damage Zone Model for Fatigue Strength Evaluation

1998 ◽  
Vol 1998 (184) ◽  
pp. 311-319
Author(s):  
Yukio Fujimoto ◽  
Won-Beom Kim ◽  
Eiji Shintaku ◽  
Fei Huang
Keyword(s):  
Fatigue Strength ◽  
Damage Zone ◽  
Zone Model ◽  
Strength Evaluation
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