How cementation and fluid flow influence slip behavior at the subduction interface

Geology ◽  
2021 ◽  
Author(s):  
J.N. Hooker ◽  
D.M. Fisher
Keyword(s):  
Fluid Flow ◽  
Fluid Pressure ◽  
Plate Boundary ◽  
Earthquake Simulator ◽  
Earthquake Size ◽  
Porosity And Permeability ◽  
Positive And Negative Feedbacks ◽  
Subduction Zone Earthquake ◽  
Fault Healing ◽  
Large Earthquakes

Much of the complexity of subduction-zone earthquake size and temporal patterns owes to linkages among fluid flow, stress, and fault healing. To investigate these linkages, we introduce a novel numerical model that tracks cementation and fluid flow within the framework of an earthquake simulator. In the model, there are interseismic increases in cohesion across the plate boundary and decreases in porosity and permeability caused by cementation along the interface. Seismogenic slip is sensitive to the effective stress and therefore fluid pressure; in turn, slip events increase porosity by fracturing. The model therefore accounts for positive and negative feedbacks that modify slip behavior through the seismic cycle. The model produces temporal clustering of earthquakes in the seismic record of the Aleutian margin, which has well-documented along-strike variations in locking characteristics. Model results illustrate how physical, geochemical, and hydraulic linkages can affect natural slip behavior. Specifically, coseismic drops in fluid pressure steal energy from large ruptures, suppress slip, moderate the magnitudes of large earthquakes, and lead to aftershocks.

scholarly journals Insights from the geological record of deformation along the subduction interface at depths of seismogenesis

Geosphere ◽  
2021 ◽  
Author(s):  
Donald M. Fisher ◽  
John N. Hooker ◽  
Andrew J. Smye ◽  
Tsai-Wei Chen
Keyword(s):  
Fluid Flow ◽  
Fluid Pressure ◽  
Seismogenic Zone ◽  
Chemical Components ◽  
Low Grade ◽  
Coseismic Slip ◽  
Seismic Slip ◽  
Earthquake Simulator ◽  
Interseismic Deformation ◽  
Fluid Production

Subduction interfaces are loci of interdependent seismic slip behavior, fluid flow, and mineral redistribution. Mineral redistribution leads to coupling between fluid flow and slip behavior through decreases in porosity/permeability and increases in cohesion during the interseismic period. We investigate this system from the perspective of ancient accretionary complexes with regional zones of mélange that record noncoaxial strain during underthrusting adjacent to the subduction interface. Deformation of weak mudstones is accompanied by low-grade metamorphic reactions, dissolution along scaly microfaults, and the removal of fluid-mobile chemical components, whereas stronger sandstone blocks preserve veins that contain chemical components depleted in mudstones. These observations support local diffusive mass transport from scaly fabrics to veins during interseismic viscous coupling. Underthrusting sediments record a crack porosity that fluctuates due to the interplay of cracking and precipitation. Permanent interseismic deformation involves pressure solution slip, strain hardening, and the development of new shears in undeformed material. In contrast, coseismic slip may be accommodated within observed narrow zones of cataclastic deformation at the top of many mélange terranes. A kinetic model implies interseismic changes in physical properties in less than hundreds of years, and a numerical model that couples an earthquake simulator with a fluid flow system depicts a subduction zone interface governed by feedbacks between fluid production, permeability, hydrofracturing, and aging via mineral precipitation. During an earthquake, interseismic permeability reduction is followed by coseismic rupture of low permeability seals and fluid pressure drop in the seismogenic zone. Updip of the seismogenic zone, there is a post-seismic wave of higher fluid pressure that propagates trenchward.

scholarly journals Fluid pressure evolution during the earthquake cycle controlled by fluid flow and pressure solution crack sealing

2002 ◽  
Vol 54 (11) ◽  
pp. 1139-1146 ◽  
Author(s):  
Jean-Pierre Gratier ◽  
Pascal Favreau ◽  
François Renard ◽  
Eric Pili
Keyword(s):  
Fluid Flow ◽  
Fluid Pressure ◽  
Pressure Solution ◽  
Earthquake Cycle ◽  
Crack Sealing ◽  
Pressure Evolution

Time Constraints on Seepage Through Fractured Regions on the Vestnesa Ridge off the W-Svalbard Coast

2021 ◽  
Author(s):  
Hariharan Ramachandran ◽  
Andreia Plaza-Faverola ◽  
Hugh Daigle ◽  
Stefan Buenz
Keyword(s):  
Fluid Flow ◽  
Effective Stress ◽  
Gas Hydrate ◽  
Fluid Pressure ◽  
Fracture Network ◽  
The Arctic ◽  
Stability Zone ◽  
Methane Seepage ◽  
Carbonate Formation ◽  
Hydrate Stability

<p>Evidences of subsurface fluid flow-driven fractures (from seismic interpretation) are quite common at Vestnesa Ridge (around 79ºN in the Arctic Ocean), W-Svalbard margin. Ultimately, the fractured systems have led to the formation of pockmarks on the seafloor. At present day, the eastern segment of the ridge has active pockmarks with continuous methane seep observations in sonar data. The pockmarks in the western segment are considered inactive or to seep at a rate that is harder to identify. The ridge is at ~1200m water depth with the base of the gas hydrate stability zone (GHSZ) at ~200m below the seafloor. Considerable free gas zone is present below the hydrates. Besides the obvious concern of amount and rates of historic methane seeping into the ocean biosphere and its associated effects, significant gaps exist in the ability to model the processes of flow of methane through this faulted and fractured region. Our aim is to highlight the interactions between physical flow, geomechanics and geological control processes that govern the rates and timing of methane seepage.</p><p>For this purpose, we performed numerical fluid flow simulations. We integrate fundamental mass and component conservation equations with a phase equilibrium approach accounting for hydrate phase boundary effects to simulate the transport of gas from the base of the GHSZ through rock matrix and interconnected fractures until the seafloor. The relation between effective stress and fluid pressure is considered and fractures are activated once the effective stress exceeds the tensile limit. We use field data (seismic, oedometer tests on calypso cores, pore fluid pressure and temperature) to constrain the range of validity of various flow and geomechanical parameters in the simulation (such as vertical stress, porosity, permeability, saturations).</p><p>Preliminary results indicate fluid overpressure greater than 1.5 MPa is required to initiate fractures at the base of the gas hydrate stability zone for the investigated system. Focused fluid flow occurs through the narrow fracture networks and the gas reaches the seafloor within 1 day. The surrounding regions near the fracture network exhibit slower seepage towards the seafloor, but over a wider area. Advective flux through the less fractured surrounding regions, reaches the seafloor within 15 years and a diffusive flux reaches within 1200 years. These times are controlled by the permeability of the sediments and are retarded further due to considerable hydrate/carbonate formation during vertical migration. Next course of action includes constraining the methane availability at the base of the GHSZ and estimating its impact on seepage behavior.</p>

scholarly journals Geostatistical Model for the Arab-D Reservoir, North ’Ain Dar Pilot, Ghawar Field, Saudi Arabia: An Improved Reservoir Simulation Model

GeoArabia ◽  
1996 ◽  
Vol 1 (2) ◽  
pp. 267-284
Author(s):  
John L. Douglas ◽  
Keyword(s):  
Saudi Arabia ◽  
Fluid Flow ◽  
Reservoir Rock ◽  
Well Test ◽  
Geostatistical Model ◽  
Deterministic Models ◽  
Modeling Approach ◽  
The North ◽  
Porosity And Permeability ◽  
Ghawar Field

ABSTRACT The North ‘Ain Dar 3-D geocellular model consists of geostatistical models for electrofacies, porosity and permeability for a portion of the Jurassic Arab-D reservoir of Ghawar field, Saudi Arabia. The reservoir consists of a series of shallow water carbonate shelf sediments and is subdivided into 10 time-stratigraphic slices on the basis of core descriptions and gamma/porosity log correlations. The North ‘Ain Dar model includes an electrofacies model and electrofacies-dependent porosity and permeability models. Sequential Indicator Simulations were used to create the electrofacies and porosity models. Cloud Transform Simulations were used to generate permeability models. Advantages of the geostatistical modeling approach used here include: (1) porosity and permeability models are constrained by the electrofacies model, i.e. by the distribution of reservoir rock types; (2) patterns of spatial correlation and variability present in well log and core data are built into the models; (3) data extremes are preserved and are incorporated into the model. These are critical when it comes to determining fluid flow patterns in the reservoir. Comparison of model Kh with production data Kh indicates that the stratigraphic boundaries used in the model generally coincide with shifts in fluid flow as indicated by flowmeter data, and therefore represent reasonable flow unit boundaries. Further, model permeability and production estimated permeability are correlated on a Kh basis, in terms of vertical patterns of distribution and cumulative Kh values at well locations. This agreement between model and well test Kh improves on previous, deterministic models of the Arab-D reservoir and indicates that the modeling approach used in North ‘Ain Dar should be applicable to other portions of the Ghawar reservoir.

Mechanical Impact Effects of Fluid Hammer Effects on Drag Reduction of Coiled Tubing

2021 ◽  
pp. 1-10
Author(s):  
Yongsheng Liu ◽  
Xing Qin ◽  
Yuchen Sun ◽  
Zijun Dou ◽  
Jiansong Zhang ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Drag Reduction ◽  
Flow Rate ◽  
Fluid Velocity ◽  
Fluid Pressure ◽  
Great Influence ◽  
Radial Force ◽  
Fluid Flow Rate ◽  
Normal Contact ◽  
Coiled Tubing

Abstract Aiming at the oscillation drag reduction tool that improves the extension limit of coiled tubing downhole operations, the fluid hammer equation of the oscillation drag reducer is established based on the fluid hammer effect. The fluid hammer equation is solved by the asymptotic method, and the distribution of fluid pressure and flow velocity in coiled tubing with oscillation drag reducers is obtained. At the same time, the axial force and radial force of the coiled tubing caused by the fluid hammer oscillator are calculated according to the momentum theorem. The radial force will change the normal contact force of the coiled tubing which has a great influence on frictional drag. The results show that the fluid flow rate and pressure decrease stepwise from the oscillator position to the wellhead position, and the fluid flow rate and pressure will change abruptly during each valve opening and closing time. When the fluid passes through the oscillator, the unit mass fluid will generate an instantaneous axial tension due to the change in the fluid velocity, thereby converting the static friction into dynamic friction, which is conducive to the extend limit of coiled tubing.

scholarly journals Study on the biomechanical responses of the loaded bone in macroscale and mesoscale by multiscale poroelastic FE analysis

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
WeiLun Yu ◽  
XiaoGang Wu ◽  
HaiPeng Cen ◽  
Yuan Guo ◽  
ChaoXin Li ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Fluid Velocity ◽  
Fluid Pressure ◽  
Biological Information ◽  
Von Mises Stress ◽  
Fe Model ◽  
Heterogeneous Distribution ◽  
Material Parameters ◽  
Mesoscopic Models ◽  
Von Mises

Abstract Background Bone is a hierarchically structured composite material, and different hierarchical levels exhibit diverse material properties and functions. The stress and strain distribution and fluid flow in bone play an important role in the realization of mechanotransduction and bone remodeling. Methods To investigate the mechanotransduction and fluid behaviors in loaded bone, a multiscale method was developed. Based on poroelastic theory, we established the theoretical and FE model of a segment bone to provide basis for researching more complex bone model. The COMSOL Multiphysics software was used to establish different scales of bone models, and the properties of mechanical and fluid behaviors in each scale were investigated. Results FE results correlated very well with analytical in macroscopic scale, and the results for the mesoscopic models were about less than 2% different compared to that in the macro–mesoscale models, verifying the correctness of the modeling. In macro–mesoscale, results demonstrated that variations in fluid pressure (FP), fluid velocity (FV), von Mises stress (VMS), and maximum principal strain (MPS) in the position of endosteum, periosteum, osteon, and interstitial bone and these variations can be considerable (up to 10, 8, 4 and 3.5 times difference in maximum FP, FV, VMS, and MPS between the highest and the lowest regions, respectively). With the changing of Young’s modulus (E) in each osteon lamella, the strain and stress concentration occurred in different positions and given rise to microscale spatial variations in the fluid pressure field. The heterogeneous distribution of lacunar–canalicular permeability (klcp) in each osteon lamella had various influence on the FP and FV, but had little effect on VMS and MPS. Conclusion Based on the idealized model presented in this article, the presence of endosteum and periosteum has an important influence on the fluid flow in bone. With the hypothetical parameter values in osteon lamellae, the bone material parameters have effect on the propagation of stress and fluid flow in bone. The model can also incorporate alternative material parameters obtained from different individuals. The suggested method is expected to provide dependable biological information for better understanding the bone mechanotransduction and signal transduction.

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