Fault Reactivation and Induced Seismicity During Multistage Hydraulic Fracturing: Microseismic Analysis and Geomechanical Modeling

SPE Journal ◽  
2019 ◽  
Vol 25 (02) ◽  
pp. 692-711 ◽  
Author(s):  
Fengshou Zhang ◽  
Zirui Yin ◽  
Zhaowei Chen ◽  
Shawn Maxwell ◽  
Lianyang Zhang ◽  
...  
Keyword(s):  
Hydraulic Fracturing ◽  
Seismic Activity ◽  
Induced Seismicity ◽  
Fault Reactivation ◽  
Fluid Injection ◽  
Fluid Viscosity ◽  
Multistage Hydraulic Fracturing ◽  
Budget Analysis ◽  
Casing Deformation ◽  
The Impact

Summary This paper presents a case study of fault reactivation and induced seismicity during multistage hydraulic fracturing in Sichuan Basin, China. The field microseismicity data delineate a fault activated near the toe of the horizontal well. The spatio-temporal characteristics of the microseismicity indicate that the seismic activity on the fault during the first three stages is directly related to the fluid injection, while after Stage 3, the seismic activity is possibly due to the relaxation of the fault. The fault-related events have larger magnitudes and different frequency-magnitude characteristics compared to the fracturing-related events. Three-dimensional (3D) fully coupled distinct element geomechanical modeling for the first two hydraulic fracturing stages and a shut-in stage between them is performed. The modeling result generates features of microseismicity similar to that of the field data. The energy budget analysis indicates that the aseismic deformation consumes a major part of the energy. The simulated fault shear displacement is also consistent with the casing deformation measured in the field. The model is also used to investigate the impact of possible operational changes on expected seismic responses. The results show that lower injection rate and lower fluid viscosity would be helpful in reducing casing deformation but not in mitigating seismicity. Decreasing the total fluid injection volume is an effective way to mitigate the seismicity, but it may hinder the stimulation of the reservoir formation and the production of the well.

Stress perturbation caused by multistage hydraulic fracturing: Implications for deep fault reactivation

2021 ◽  
Vol 141 ◽  
pp. 104704
Author(s):  
Mengke An ◽  
Fengshou Zhang ◽  
Egor Dontsov ◽  
Derek Elsworth ◽  
Hehua Zhu ◽  
...  
Keyword(s):  
Hydraulic Fracturing ◽  
Fault Reactivation ◽  
Deep Fault ◽  
Multistage Hydraulic Fracturing

scholarly journals Induced seismicity in geologic carbon storage

Solid Earth ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 871-892 ◽  
Author(s):  
Víctor Vilarrasa ◽  
Jesus Carrera ◽  
Sebastià Olivella ◽  
Jonny Rutqvist ◽  
Lyesse Laloui
Keyword(s):  
Carbon Storage ◽  
Induced Seismicity ◽  
Public Perception ◽  
Fault Reactivation ◽  
Wellbore Stability ◽  
Rock Properties ◽  
Geologic Carbon Storage ◽  
Stress Changes ◽  
The Impact ◽  
Injection Formation

Abstract. Geologic carbon storage, as well as other geo-energy applications, such as geothermal energy, seasonal natural gas storage and subsurface energy storage imply fluid injection and/or extraction that causes changes in rock stress field and may induce (micro)seismicity. If felt, seismicity has a negative effect on public perception and may jeopardize wellbore stability and damage infrastructure. Thus, induced earthquakes should be minimized to successfully deploy geo-energies. However, numerous processes may trigger induced seismicity, which contribute to making it complex and translates into a limited forecast ability of current predictive models. We review the triggering mechanisms of induced seismicity. Specifically, we analyze (1) the impact of pore pressure evolution and the effect that properties of the injected fluid have on fracture and/or fault stability; (2) non-isothermal effects caused by the fact that the injected fluid usually reaches the injection formation at a lower temperature than that of the rock, inducing rock contraction, thermal stress reduction and stress redistribution around the cooled region; (3) local stress changes induced when low-permeability faults cross the injection formation, which may reduce their stability and eventually cause fault reactivation; (4) stress transfer caused by seismic or aseismic slip; and (5) geochemical effects, which may be especially relevant in carbonate-containing formations. We also review characterization techniques developed by the authors to reduce the uncertainty in rock properties and subsurface heterogeneity both for the screening of injection sites and for the operation of projects. Based on the review, we propose a methodology based on proper site characterization, monitoring and pressure management to minimize induced seismicity.

Severe Casing Failure in Multistage Hydraulic Fracturing Using Dual-Scale Modelling Approach

2021 ◽  
Author(s):  
Hao Yu ◽  
Arash Dahi Taleghani ◽  
Zhanghua Lian ◽  
Yisheng Mou
Keyword(s):  
Hydraulic Fracturing ◽  
Positive Impact ◽  
Horizontal Stress ◽  
Fracture Network ◽  
Scale Model ◽  
Fracture Geometry ◽  
Multistage Hydraulic Fracturing ◽  
Field Evidence ◽  
Casing Deformation ◽  
Casing Failure

Abstract Field evidence of production logs after fracturing have documented the existence of abundant natural fractures in Weiyuan shale plays, which is widely acknowledged to have a positive impact on fracture network complexity. On the other hand, cases of severe casing failures have been frequently reported in this field during multistage fracturing jobs. Stress interference between two adjacent stages may intensify non-uniform loading on the casing string and accommodate failure. To better understand this problem, we establish a coupled 3D reservoir-scale model with complex well trajectory and tie it to a single well-scale model consisting of casing and the surrounding cement sheath. Using this model, we investigate the potential impacts of cement deficiency, clustered perforations, fracture geometry as well as spacing strategy on casing integrity. Our simulation results indicate that cement deficiency could intensify the load nonuniformity around the borehole which escalates the potential threats for casing failure. When cement deficiency reaches 45° along the minimum horizontal stress, it has the largest influence on the stress level in the casing. In addition, perforations could lower the casing strength, but the reduction may not change furthermore when the perforation diameter reaches a certain value. Moreover, impacts of fracture geometry and spacing on casing deformation are investigated. We conclude that the lower ratio of fracture length to its width and reasonable spacing strategy could help reduce the load non-uniformity on casing which avoid the casing deformation. The described workflow may be adopted in other areas to predict the possible casing failure problems induced by multistage hydraulic fracturing with cheap computational costs, to anticipate the challenges and avoid them by revisiting pumping schedule or spacing strategy.

scholarly journals Real‐Time Imaging, Forecasting, and Management of Human‐Induced Seismicity at Preston New Road, Lancashire, England

2019 ◽  
Author(s):  
Huw Clarke ◽  
James P. Verdon ◽  
Tom Kettlety ◽  
Alan F. Baird ◽  
J‐Michael Kendall
Keyword(s):  
Hydraulic Fracturing ◽  
Real Time ◽  
Shale Gas ◽  
Statistical Models ◽  
Induced Seismicity ◽  
Red Light ◽  
Fracture Network ◽  
Fluid Injection ◽  
Traffic Light ◽  
Subsurface Fluid

ABSTRACTEarthquakes induced by subsurface fluid injection pose a significant issue across a range of industries. Debate continues as to the most effective methods to mitigate the resulting seismic hazard. Observations of induced seismicity indicate that the rate of seismicity scales with the injection volume and that events follow the Gutenberg–Richter distribution. These two inferences permit us to populate statistical models of the seismicity and extrapolate them to make forecasts of the expected event magnitudes as injection continues. Here, we describe a shale gas site where this approach was used in real time to make operational decisions during hydraulic fracturing operations.Microseismic observations revealed the intersection between hydraulic fracturing and a pre‐existing fault or fracture network that became seismically active. Although “red light” events, requiring a pause to the injection program, occurred on several occasions, the observed event magnitudes fell within expected levels based on the extrapolated statistical models, and the levels of seismicity remained within acceptable limits as defined by the regulator. To date, induced seismicity has typically been regulated using retroactive traffic light schemes. This study shows that the use of high‐quality microseismic observations to populate statistical models that forecast expected event magnitudes can provide a more effective approach.

scholarly journals Effects of Different Penetration Patterns on a Fault during Underground Fluid Injection

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Xiaochen Wei ◽  
Qi Li ◽  
Xiaying Li ◽  
Zhiyong Niu ◽  
Xiangjun Liu ◽  
...  
Keyword(s):  
Finite Element ◽  
Site Selection ◽  
Induced Seismicity ◽  
Anthropogenic Activities ◽  
Fault Reactivation ◽  
Fluid Injection ◽  
Barrier Effect ◽  
Hydraulic Connection ◽  
Shengli Oilfield ◽  
Fault Structures

At underground fluid injection sites with natural faults, understanding how to avoid the subsequent fault reactivation and induced seismicity plays a crucial role in the success of subsurface anthropogenic activities. In this work, with the objective of avoiding risky faults in site selection in the Shengli Oilfield, we investigated the faults that are usually encountered in the target demonstration zone; based on the geophysical observations of fault structures, we designed different fault tectonic scenarios to investigate the different penetration patterns of faults. We used the finite element-based numerical method to assess the influence of the effective lateral and vertical reservoir transmissivity in each fault penetration pattern. Our results indicate that when a permeable fault intersects into the target reservoir, it presents both barrier effect to reservoir transmissivity within the target reservoir and hydraulic connection between reservoirs. The effective lateral reservoir transmissivity is dominated by the barrier effect of the fault, and the effective vertical reservoir transmissivity is dominated by the hydraulic connection between reservoirs. Relatively impermeable faults with less contact with the target aquifer make higher effective lateral reservoir transmissivity and lower effective vertical reservoir transmissivity, which would mitigate the risk of caprock failure and the magnitude of the induced seismicity.

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