Uncertainty analysis of impact indicators for the integrity of combined caprock during CO2 geosequestration

Wei, Xiao; Li, Qi; Li, Xiaying; Sun, Yan Quan; Liu, Xue Hao

doi:10.1016/j.enggeo.2015.06.023

Cited by 36 publications

(12 citation statements)

References 40 publications

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“…In addition, CO 2 injection changes the pore pressure and consequently the stress state within the coal seam, which results in mechanical deformations in the reservoir and consequently the rock mass above. [12][13][14][15][16][17][18][19][20] Studies have used powerful reservoir simulators, or mechanical analysis tools, or their combinations, such as FLAC-TOUGH, 17 FLAC-SIMED, 14 and ABAQUS-ECLIPSE. 7 Th e injection-induced mechanical deformations can change the aperture of the fractures and hence the permeability of the coal seam.…”

Section: Introductionmentioning

confidence: 99%

“…[9][10][11] Th e need for coupled modeling of geological sequestration of CO 2 has been addressed and investigated in many studies. [12][13][14][15][16][17][18][19][20] Studies have used powerful reservoir simulators, or mechanical analysis tools, or their combinations, such as FLAC-TOUGH, 17 FLAC-SIMED, 14 and ABAQUS-ECLIPSE. 21 While some of these studies have considered coalbed sequestration, they use mainly conventional dual porosity models implemented in commercial reservoir simulators.…”

Section: Introductionmentioning

confidence: 99%

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The role of coal seam properties on coupled processes during CO₂sequestration: A parametric study

2015

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It has been proposed that a considerable amount of CO2 can be safely sequestered from the atmosphere in geological formations such as coalbeds. In spite of promising evidence of the economic and technical viability of CO2 sequestration in coal seams, many of its hydro‐geomechanical aspects are not fully understood. This paper presents a coupled hydro‐mechanical model that is used to assess the reservoir performance of a coalbed and the induced surface and subsurface deformations. A series of numerical simulations has been performed to study the effects of different parameters on the reservoir and geomechanical behaviors associated with CO2 injection. A single‐phase dual‐porosity model is coupled to a one‐dimensional poroelastic model and an analytical model for the ground surface movements. Through these simulations, the role of three sets of parameters at different scales is investigated: fracture characteristics, matrix characteristics, and geomechanical/geometrical characteristics. The comparative impacts of these parameters on reservoir permeability, volume of the stored CO2, and deformations of the coalbed and the ground surface, are quantitatively assessed, in order to identify the most important parameters influencing the hydro‐mechanical response of the ground.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The role of coal seam properties on coupled processes during CO₂sequestration: A parametric study

2015

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“…According to the mechanisms of how elevating the pore pressure can bring the fault to slippage illustrated by (Ellsworth, 2013), a fault remains locked as long as the applied shear stress is less than the strength of the contact. During the stimulation injection, the shear stress evolves simultaneously with tensile failure; the activation of the fault is usually initiated by the increase in the shear stress and the decrease in the normal stress that can bring the fault to failure and trigger the nucleation of microseismic events (Wei et al, 2015(Wei et al, , 2016. The variations in the contact stress and shear stress along the fault plane at the ends of the "Pump" stage (green line), the "Hold" stage (blue line) and the "Extraction" stage (black line) are shown in Figure 7.…”

Section: Fault Slippage and Induced Microseismicitymentioning

confidence: 99%

Fault slippage and its permeability evolution during supercritical CO₂ fracturing in layered formation

Wei

Zhang

et al. 2019

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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Understanding the hydromechanical responses of faults during supercritical CO 2 fracturing is important for reservoir management and the design of energy extraction systems. As small faults are widespread in Chang 7 member of the Yanchang Formation, Ordos Basin, China, supercritical CO 2 fracturing operation has the potential to reactive these undetected small faults and leads to unfavorable fracking fluid migrate. In this work, we examined the role of fault slippage and permeability evolution along a small fault connecting the pay zone and the confining formation during the whole process of fracturing and production. A coupled hydromechanical model conceptualized from actual engineering results was introduced to address the main concerns of this work, including, (1) whether the existence of a undetected small fault would effectively constrain the hydraulic fracture height evolution, (2) what the magnitude of the induced microseismic events would be and (3) whether the permeability change along the fault plane would affect the vertical conductivity of the confining formation and thus increase the risk for the fracturing fluid to leak. Our results have shown that the initial hydrofracture formed at the perforation and propagated upward, once it merged with the fault surface, the existence of an undetected small fault would effectively constrain the hydraulic fracture height evolution. As fracturing continued, further slippage spread from the permeability increase zone of high permeability to shallower levels, and the extent of this zone was dependent on the magnitude of the fault slippage. At the end of extraction, the slip velocity decreases gradually to zero and the fault slippage finally reaches stabilization. In general, undetected small faults in targeted reservoir may not be the source of large earthquakes. The induced microseismic events could be considered as the sources of acoustic emission events detected while monitoring the fracturing fluid front. Due to the limited fault slippage and lower initial permeability, the CO 2 fracturing operation near undetected small faults could not conduct preferential pathway for upward CO 2 leakage or contaminate overlying shallower potable aquifers.

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“…e massive fluid injected into underground formations can often induce fault reactivation and slip. Several studies have explored this effect, and several different mechanisms have been proposed to explain it [17][18][19][20][21]. e pore-pressure increase is considered to be the main mechanism to explain the occurrence of induced seismicity in underground fluidinjection projects.…”

Section: Introductionmentioning

confidence: 99%

A Numerical Investigation of the Hazardous Injection Area of Induced Earthquake during Hydraulic Fracturing

Niu

Wang

et al. 2021

Shock and Vibration

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Hot dry rock (HDR) geothermal energy has many advantages, such as being renewable, clean, widely distributed, and without time and weather limitations. Hydraulic fracturing is usually needed for the exploitation of HDR geothermal energy. It has many hidden faults in the reservoir/caprock sequences. Injecting fluid into underground formations during hydraulic fracturing often induces fault slip and leads to earthquakes. Therefore, to well understand the induced fault slip and earthquakes is important for the applications and development of HDR geothermal exploitation. In this study, we investigated the hazardous injection area of the induced earthquakes during hydraulic fracturing. The study was based on a hydraulic fracturing test in Qiabuqia geothermal field in China. According to the field, a fault-surrounding rock-fracturing region system was developed to study the influences of fluid injection on the stability of the specific fault. A total of 60 hydraulic fracturing regions and 180 numerical experiments were designed. The results revealed that the hazardous injection regions that threaten the fault’s stability were near to the fault and concentrated on the following four areas: (a) above the top of the fault in underlying strata; (b) above the top of the hanging wall of the fault in underlying strata; (c) near to the fault planes in both footwall and hanging wall; (d) at the bottom of the footwall of the fault in underlying strata. The hazardous injection area can be controlled effectively by adjusting the injection pressure.

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Uncertainty analysis of impact indicators for the integrity of combined caprock during CO2 geosequestration

Cited by 36 publications

References 40 publications

The role of coal seam properties on coupled processes during CO₂sequestration: A parametric study

The role of coal seam properties on coupled processes during CO₂sequestration: A parametric study

Fault slippage and its permeability evolution during supercritical CO₂ fracturing in layered formation

A Numerical Investigation of the Hazardous Injection Area of Induced Earthquake during Hydraulic Fracturing

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Uncertainty analysis of impact indicators for the integrity of combined caprock during CO2 geosequestration

Cited by 36 publications

References 40 publications

The role of coal seam properties on coupled processes during CO2sequestration: A parametric study

The role of coal seam properties on coupled processes during CO2sequestration: A parametric study

Fault slippage and its permeability evolution during supercritical CO2 fracturing in layered formation

A Numerical Investigation of the Hazardous Injection Area of Induced Earthquake during Hydraulic Fracturing

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The role of coal seam properties on coupled processes during CO₂sequestration: A parametric study

The role of coal seam properties on coupled processes during CO₂sequestration: A parametric study

Fault slippage and its permeability evolution during supercritical CO₂ fracturing in layered formation