C. Thielsen, J. Furtney, M. Pierce, María Elena Valencia, Cristián Orrego, P. Stonestreet, David Tennant
Understanding the spatial variation in intact and defected rock strength is critical to geomechanical mine design. At the Newcrest Cadia East mine, systematic point load testing (PLT) was used to measure the strength of intact rock and individual defects (e.g., veins) at regular closely spaced intervals along several boreholes. The systematic PLT data collection covers only 1.3% of the 590 km of hole logged at Cadia East. A procedure was developed to homogenize the available geotechnical and geological logging data, infill missing values, and encode raw data into engineered features for use in a machine learning model. A random forest classifier was applied to predict point load index (Is50) from core logging data where tests were not performed. The random forest model predicts the rolling average Is50 value within 1 MPa 48% of the time. The model gives insights into which core logging quantities have the strongest controls on rock strength and provides the basis for developing more detailed geospatial models of intact and defected rock strength.
了解完整和缺陷岩石强度的空间变化规律对地质力学矿山设计至关重要。在Newcrest Cadia East矿山，系统点载荷测试(PLT)用于沿几个钻孔在规则的紧密间隔上测量完整岩石和单个缺陷(如矿脉)的强度。系统的PLT数据收集只覆盖了Cadia East 590公里井眼的1.3%。开发了一种程序来均匀化可用的岩土和地质测井数据，填充缺失值，并将原始数据编码为工程特征，以便在机器学习模型中使用。随机森林分类器应用于未进行测试的岩心测井数据预测点负荷指数(Is50)。随机森林模型在48%的时间内预测1 MPa范围内的滚动平均Is50值。该模型揭示了岩心测井量对岩石强度的最强控制，并为开发更详细的完整和缺陷岩石强度地理空间模型提供了基础。
{"title":"Application of Machine Learning to the Estimation of Intact Rock Strength from Core Logging Data: A Case Study at the Newcrest Cadia East Mine","authors":"C. Thielsen, J. Furtney, M. Pierce, María Elena Valencia, Cristián Orrego, P. Stonestreet, David Tennant","doi":"10.56952/arma-2022-0283","DOIUrl":"https://doi.org/10.56952/arma-2022-0283","url":null,"abstract":"Understanding the spatial variation in intact and defected rock strength is critical to geomechanical mine design. At the Newcrest Cadia East mine, systematic point load testing (PLT) was used to measure the strength of intact rock and individual defects (e.g., veins) at regular closely spaced intervals along several boreholes. The systematic PLT data collection covers only 1.3% of the 590 km of hole logged at Cadia East. A procedure was developed to homogenize the available geotechnical and geological logging data, infill missing values, and encode raw data into engineered features for use in a machine learning model. A random forest classifier was applied to predict point load index (Is50) from core logging data where tests were not performed. The random forest model predicts the rolling average Is50 value within 1 MPa 48% of the time. The model gives insights into which core logging quantities have the strongest controls on rock strength and provides the basis for developing more detailed geospatial models of intact and defected rock strength.","PeriodicalId":418045,"journal":{"name":"Proceedings 56th US Rock Mechanics / Geomechanics Symposium","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128237852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Julia A Grasley, M. Rahmani, A. Azzam, G. Nsengiyumva, Yong-Rak Kim, Jongwan Eun, Seunghee Kim
Secure storage of nuclear spent fuel is of great concern for protecting public health and safety. The standard long-term solution for nuclear waste disposal is containment in geological repositories. Nuclear spent fuel, stored in canisters, is placed deep underground with one or more Engineered Barrier Materials (EBM) forming a buffer between the waste containers and the natural rock. Bentonite clay is commonly used as an EBM for its low cost, long-term stability, low hydraulic permeability in a saturated state, high thermal resistance, high radionuclide retardation capacity, high swelling pressure, and “self-healing” capability. However, bentonite clay subjected to heating from nuclear waste decay may undergo desiccation cracking. In this study, inorganic microfiber reinforcement was evaluated as a method of reducing desiccation cracking in EBM. A restrained ring test method for soils coupled with digital image correlation (DIC) was employed to capture free shrinkage and desiccation cracking. Reinforcement of bentonite clay with 1.0 % wt. basalt fibers was shown to be effective in reducing crack propagation and separation.
{"title":"Experimental Investigation of Desiccation Behavior in Inorganic Microfiber-Reinforced Engineered Barrier Materials (IMEBM) for Geological Repository of Nuclear Spent Fuel","authors":"Julia A Grasley, M. Rahmani, A. Azzam, G. Nsengiyumva, Yong-Rak Kim, Jongwan Eun, Seunghee Kim","doi":"10.56952/arma-2022-0741","DOIUrl":"https://doi.org/10.56952/arma-2022-0741","url":null,"abstract":"Secure storage of nuclear spent fuel is of great concern for protecting public health and safety. The standard long-term solution for nuclear waste disposal is containment in geological repositories. Nuclear spent fuel, stored in canisters, is placed deep underground with one or more Engineered Barrier Materials (EBM) forming a buffer between the waste containers and the natural rock. Bentonite clay is commonly used as an EBM for its low cost, long-term stability, low hydraulic permeability in a saturated state, high thermal resistance, high radionuclide retardation capacity, high swelling pressure, and “self-healing” capability. However, bentonite clay subjected to heating from nuclear waste decay may undergo desiccation cracking. In this study, inorganic microfiber reinforcement was evaluated as a method of reducing desiccation cracking in EBM. A restrained ring test method for soils coupled with digital image correlation (DIC) was employed to capture free shrinkage and desiccation cracking. Reinforcement of bentonite clay with 1.0 % wt. basalt fibers was shown to be effective in reducing crack propagation and separation.","PeriodicalId":418045,"journal":{"name":"Proceedings 56th US Rock Mechanics / Geomechanics Symposium","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128652846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
There are many applications which require a fracture flow model that accounts for variations in aperture beyond surface roughness. Large-scale models and simulations of fluid flow through fractures are almost exclusively based on the cubic law (Poiseuille flow) for steady-state flow through rigid parallel plates. When the fracture aperture is time and/or spatially varying, flow is transient, and/or flow rates are modest (Re≥1), cubic law predictions can deviate substantially from true fluid behaviour. In this paper, we present a new Reduced Dimension Fracture Flow (RDFF) model which more accurately predicts transient flow for incompressible fluids with modest Reynolds numbers through fractures with time and/or spatially varying aperture. The RDFF model is derived from the two-dimensional Navier-Stokes equations and yields a two-field model (fluid flux and pressure) governed by the conservation of mass and momentum. The RDFF model is shown to conserve energy in spatially varying fractures where the cubic law does not. We demonstrate that the RDFF model captures complex transient and inertial behaviours not previously captured for flows with modest Reynolds numbers (1≤Re≤100) and demonstrates up to 400% improvements in error over the cubic law in steady-state flow conditions through fractures with sinusoidally varying aperture.
{"title":"Inertia Dominant and Transient Flow in Fractures - Beyond the Cubic Law","authors":"R. Gracie, Bruce Gee","doi":"10.56952/arma-2022-0731","DOIUrl":"https://doi.org/10.56952/arma-2022-0731","url":null,"abstract":"There are many applications which require a fracture flow model that accounts for variations in aperture beyond surface roughness. Large-scale models and simulations of fluid flow through fractures are almost exclusively based on the cubic law (Poiseuille flow) for steady-state flow through rigid parallel plates. When the fracture aperture is time and/or spatially varying, flow is transient, and/or flow rates are modest (Re≥1), cubic law predictions can deviate substantially from true fluid behaviour. In this paper, we present a new Reduced Dimension Fracture Flow (RDFF) model which more accurately predicts transient flow for incompressible fluids with modest Reynolds numbers through fractures with time and/or spatially varying aperture. The RDFF model is derived from the two-dimensional Navier-Stokes equations and yields a two-field model (fluid flux and pressure) governed by the conservation of mass and momentum. The RDFF model is shown to conserve energy in spatially varying fractures where the cubic law does not. We demonstrate that the RDFF model captures complex transient and inertial behaviours not previously captured for flows with modest Reynolds numbers (1≤Re≤100) and demonstrates up to 400% improvements in error over the cubic law in steady-state flow conditions through fractures with sinusoidally varying aperture.","PeriodicalId":418045,"journal":{"name":"Proceedings 56th US Rock Mechanics / Geomechanics Symposium","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130351101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In traditional hydraulic fracturing stimulation, the effective conductivity of low permeability rock is increased by generating or activating fractures through injection of pressurized fluid. Methods that use dynamic loading from explosives and propellants potentially extend stimulation to previously unrealized geological resources. In contrast to traditional fracturing methods (e.g. hydraulic fracturing) the stresses in the source region may be significantly larger than the in-situ stress, which helps to create fractures not oriented with the maximum in-situ stress. Fractures initially are generated by the diverging stress wave propagating from the energy release zone. It has been shown in the past that the crack area and final extend depend on the ability of explosive products to flow into the cracks after the wave propagation. This mechanism has been confirmed utilizing high - speed schlieren imaging, and Photon Doppler Velocimety (PDV) in recent explosive fracturing experiments with 0.3-0.7 g of high explosive source detonated in prestressed 1-foot PMMA cubic blocks with and without articial joints. Modeling of these experiments is challenging, as various scales need to be resolved to address this problem. We present first analysis and 3D modelling attempts. The goal of this work is to study the main mechanisms of dynamic fracture in brittle materials validated against recent and ongoing small scale experiments in order to upscale the results to realistic scenarios for the purpose of subsurface dynamic stimulations of geothermal systems.
{"title":"Analysis and Modeling of Explosive Fracturing Process in a Transparent Surrogate of Jointed Rock","authors":"O. Vorobiev","doi":"10.56952/arma-2022-0090","DOIUrl":"https://doi.org/10.56952/arma-2022-0090","url":null,"abstract":"In traditional hydraulic fracturing stimulation, the effective conductivity of low permeability rock is increased by generating or activating fractures through injection of pressurized fluid. Methods that use dynamic loading from explosives and propellants potentially extend stimulation to previously unrealized geological resources. In contrast to traditional fracturing methods (e.g. hydraulic fracturing) the stresses in the source region may be significantly larger than the in-situ stress, which helps to create fractures not oriented with the maximum in-situ stress. Fractures initially are generated by the diverging stress wave propagating from the energy release zone. It has been shown in the past that the crack area and final extend depend on the ability of explosive products to flow into the cracks after the wave propagation. This mechanism has been confirmed utilizing high - speed schlieren imaging, and Photon Doppler Velocimety (PDV) in recent explosive fracturing experiments with 0.3-0.7 g of high explosive source detonated in prestressed 1-foot PMMA cubic blocks with and without articial joints. Modeling of these experiments is challenging, as various scales need to be resolved to address this problem. We present first analysis and 3D modelling attempts. The goal of this work is to study the main mechanisms of dynamic fracture in brittle materials validated against recent and ongoing small scale experiments in order to upscale the results to realistic scenarios for the purpose of subsurface dynamic stimulations of geothermal systems.","PeriodicalId":418045,"journal":{"name":"Proceedings 56th US Rock Mechanics / Geomechanics Symposium","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129218216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study investigates the performance of yielding bolt in a weak rock mass tunnel with high in-situ stress conditions. The genetic algorithm and the Komamura-Huang rheological model are combined to perform an inversion analysis of the mechanical parameters of the weak surrounding rock mass before and after implementing the anchoring system. The results based on an actual tunnel project suggest that the mechanical properties all enhanced in the anchoring tunnel section The elastic modulus of the surrounding rock increased by 45.7%, the cohesive force increased by 18.1%, and the friction angle increased by 2.92%. Hence, the yielding cable anchor can effectively prevent the squeezing deformation of the surrounding rock mass and improve the structural integrity of the tunnel lining. The performance of the anchoring system and the inversion process of the mechanical parameters can guide the design and construction of similar tunnel projects in weak rock mass configurationsKEYWORDS: yielding bolt, tunnel engineering, weak rock mass, parameter inversion, rheological model
{"title":"The inversion of mechanical parameters of weak surrounding rock in high-stress tunnel after casting anchor","authors":"宇 江","doi":"10.56952/arma-2022-0695","DOIUrl":"https://doi.org/10.56952/arma-2022-0695","url":null,"abstract":"This study investigates the performance of yielding bolt in a weak rock mass tunnel with high in-situ stress conditions. The genetic algorithm and the Komamura-Huang rheological model are combined to perform an inversion analysis of the mechanical parameters of the weak surrounding rock mass before and after implementing the anchoring system. The results based on an actual tunnel project suggest that the mechanical properties all enhanced in the anchoring tunnel section The elastic modulus of the surrounding rock increased by 45.7%, the cohesive force increased by 18.1%, and the friction angle increased by 2.92%. Hence, the yielding cable anchor can effectively prevent the squeezing deformation of the surrounding rock mass and improve the structural integrity of the tunnel lining. The performance of the anchoring system and the inversion process of the mechanical parameters can guide the design and construction of similar tunnel projects in weak rock mass configurationsKEYWORDS: yielding bolt, tunnel engineering, weak rock mass, parameter inversion, rheological model","PeriodicalId":418045,"journal":{"name":"Proceedings 56th US Rock Mechanics / Geomechanics Symposium","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129228132","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, 3DEC modeling in conjunction with the Discrete Fracture Networks (DFNs) technique was performed to better understand the behavior of shearing faults in a relatively large-scale direct shear test model. The DFNs explicitly generated two different geometries of the fault plane surface indicating the stepped or smooth waviness of the surface using probability distribution functions to generate orientation, fracture density (or frequency), and size of the discrete fractures. A 3-dimensional block model of hundreds of meters was constructed for the direct shear test using 3DEC modeling software. After the completion of the direct shear test simulations, a shear strength of the fault plane was estimated by back calculation. The DFNs with subhorizontal/vertical dip angles created an imbricate structure that resulted in a stepped geometry and strong shear response in the fault plane. Under direct shear, the fault plane needed to break the asperities or block before any frictional behavior was allowed or the fault plane would dilate significantly. This resulted in higher shear strength of the fault plane. On the other hand, the DFNs with oblique dip angles generated a relatively smooth surface of the fault plane. The smooth surface of the fault plane allowed deformation principally parallel to the fault plane, and only a few failures developed across the rock blocks in the model. Consequently, the 3DEC model explicitly replicated the complicated geometries of the fault plane using the two very contrasting DFNs and allowed researchers to investigate different shear behaviors of fault planes as a function of surface conditions.
{"title":"Approaches to Determine Fault Shear Strength in Large-scale Direct Shear Test Simulations using Discrete Fracture Networks","authors":"Bona Kim","doi":"10.56952/arma-2022-0019","DOIUrl":"https://doi.org/10.56952/arma-2022-0019","url":null,"abstract":"In this study, 3DEC modeling in conjunction with the Discrete Fracture Networks (DFNs) technique was performed to better understand the behavior of shearing faults in a relatively large-scale direct shear test model. The DFNs explicitly generated two different geometries of the fault plane surface indicating the stepped or smooth waviness of the surface using probability distribution functions to generate orientation, fracture density (or frequency), and size of the discrete fractures. A 3-dimensional block model of hundreds of meters was constructed for the direct shear test using 3DEC modeling software. After the completion of the direct shear test simulations, a shear strength of the fault plane was estimated by back calculation. The DFNs with subhorizontal/vertical dip angles created an imbricate structure that resulted in a stepped geometry and strong shear response in the fault plane. Under direct shear, the fault plane needed to break the asperities or block before any frictional behavior was allowed or the fault plane would dilate significantly. This resulted in higher shear strength of the fault plane. On the other hand, the DFNs with oblique dip angles generated a relatively smooth surface of the fault plane. The smooth surface of the fault plane allowed deformation principally parallel to the fault plane, and only a few failures developed across the rock blocks in the model. Consequently, the 3DEC model explicitly replicated the complicated geometries of the fault plane using the two very contrasting DFNs and allowed researchers to investigate different shear behaviors of fault planes as a function of surface conditions.","PeriodicalId":418045,"journal":{"name":"Proceedings 56th US Rock Mechanics / Geomechanics Symposium","volume":"292 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116245165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In order to analyze the interference risk of shale gas horizontal wells, a model is established to analyze the interference domain in shale gas horizontal wells. With this model, the borehole uncertainty and the fracturing interference domain can be coupled reasonably. To reduce borehole uncertainty and further reduce the interference domain, the multi-station analysis (MSA) is employed to correct the magnetic azimuth of the shale gas horizontal wells. The interference domain of a shale gas horizontal well was studied. With magnetic azimuth correction, the semimajor axis of ellipse of borehole uncertainty (EOU) decreases from 23.10 m to 19.48 m (lateral) at the measure depth of 5671.60 m. And the edge length of the interference domain decreases from 206.20 m to 198.96 m. The results show that, magnetic azimuth correction based on MSA can reduce the interference domain and interference risk. And this analysis method can provide a theoretical reference for avoiding interference in shale gas horizontal wells.
{"title":"Interference Analysis of Shale Gas Horizontal Wells Considering Magnetic Azimuth Correction","authors":"Yujun Feng, B. Diao, D. Gao","doi":"10.56952/arma-2022-0616","DOIUrl":"https://doi.org/10.56952/arma-2022-0616","url":null,"abstract":"In order to analyze the interference risk of shale gas horizontal wells, a model is established to analyze the interference domain in shale gas horizontal wells. With this model, the borehole uncertainty and the fracturing interference domain can be coupled reasonably. To reduce borehole uncertainty and further reduce the interference domain, the multi-station analysis (MSA) is employed to correct the magnetic azimuth of the shale gas horizontal wells. The interference domain of a shale gas horizontal well was studied. With magnetic azimuth correction, the semimajor axis of ellipse of borehole uncertainty (EOU) decreases from 23.10 m to 19.48 m (lateral) at the measure depth of 5671.60 m. And the edge length of the interference domain decreases from 206.20 m to 198.96 m. The results show that, magnetic azimuth correction based on MSA can reduce the interference domain and interference risk. And this analysis method can provide a theoretical reference for avoiding interference in shale gas horizontal wells.","PeriodicalId":418045,"journal":{"name":"Proceedings 56th US Rock Mechanics / Geomechanics Symposium","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121581440","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Angel Sanchez barra, N. Deisman, F. Guerrero, J. Brandl, R. Chalaturnyk
Hydrocarbon production induces reservoir depletion changing the in-situ stress state. This process alters the effective stress and deforms the reservoir rock, changing the multiphase flow properties. An integrated laboratory testing facility was developed to investigate the effects of triaxial stress on the governing mechanisms of multiphase fluid flow. The paper describes the experimental facility for testing unconventional reservoirs and the system performance. The multiphase triaxial system is composed of a high-pressure triaxial cell, an axial loading system, a multiphase pore pressure circuit, a fluid phase separation system, and a logging system. The setup is installed inside an oven to maintain isothermal conditions. This study presents the initial results of testing on sandpack and Berea sandstone specimens. The experimental procedures and testing facility design can be applied across many disciplines which require two phase flow assessment until changing effective stress conditions including: geothermal processes, radioactive waste repositories, and carbon capture and storage operations.
{"title":"Experimental Facility for Testing Unconventional Reservoirs: Effect of Geomechanics on Multiphase Flow Properties","authors":"Angel Sanchez barra, N. Deisman, F. Guerrero, J. Brandl, R. Chalaturnyk","doi":"10.56952/arma-2022-0543","DOIUrl":"https://doi.org/10.56952/arma-2022-0543","url":null,"abstract":"Hydrocarbon production induces reservoir depletion changing the in-situ stress state. This process alters the effective stress and deforms the reservoir rock, changing the multiphase flow properties. An integrated laboratory testing facility was developed to investigate the effects of triaxial stress on the governing mechanisms of multiphase fluid flow. The paper describes the experimental facility for testing unconventional reservoirs and the system performance. The multiphase triaxial system is composed of a high-pressure triaxial cell, an axial loading system, a multiphase pore pressure circuit, a fluid phase separation system, and a logging system. The setup is installed inside an oven to maintain isothermal conditions. This study presents the initial results of testing on sandpack and Berea sandstone specimens. The experimental procedures and testing facility design can be applied across many disciplines which require two phase flow assessment until changing effective stress conditions including: geothermal processes, radioactive waste repositories, and carbon capture and storage operations.","PeriodicalId":418045,"journal":{"name":"Proceedings 56th US Rock Mechanics / Geomechanics Symposium","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121754513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Hosseinzadehsadati, F. Amour, M. R. Hajiabadi, H. M. Nick
Water weakening effect in the chalk reservoir causes additional compaction due to the interaction between the rock and injected water. To consider the impact of the coupled interactions on the fluid transport (e.g., production) and reservoir deformation due to the seawater injection into the chalk reservoirs, in this study, a wrapper is developed in Matlab that combines Eclipse 100 reservoir simulator and Visage geomechanics simulator to capture the induced alteration of mechanical and petrophysical properties of chalk. Here, we utilize the history-matched reservoir model of the Halfdan sector model to investigate the impact of the temperature-dependent fluid-rock interactions induced by sulfate adsorption on the surface of calcite grains on the deformation behavior of the reservoir during waterflooding. Our sector-scale simulation results show that while considering the geomechanics model has a considerable impact on calculated reservoir pressure and recovery, the impact on history matched data due to water weakening is not significant when yield stress and bulk modulus are expressed as functions of temperature and sulfate concentration for the Halfdan model. We argue that the minor contribution of the water weakening effect at in situ conditions is due to 1) the relatively high initial water saturation in the water flooded section of the reservoir and 2) the low initial temperature (70 ˚C) of Halfdan reservoir, especially towards the northern part of the Danish North Sea.
{"title":"Application of a coupled thermo-hydro-mechanical-chemical simulation to a North Sea hydrocarbon chalk reservoir","authors":"S. Hosseinzadehsadati, F. Amour, M. R. Hajiabadi, H. M. Nick","doi":"10.56952/arma-2022-0360","DOIUrl":"https://doi.org/10.56952/arma-2022-0360","url":null,"abstract":"Water weakening effect in the chalk reservoir causes additional compaction due to the interaction between the rock and injected water. To consider the impact of the coupled interactions on the fluid transport (e.g., production) and reservoir deformation due to the seawater injection into the chalk reservoirs, in this study, a wrapper is developed in Matlab that combines Eclipse 100 reservoir simulator and Visage geomechanics simulator to capture the induced alteration of mechanical and petrophysical properties of chalk. Here, we utilize the history-matched reservoir model of the Halfdan sector model to investigate the impact of the temperature-dependent fluid-rock interactions induced by sulfate adsorption on the surface of calcite grains on the deformation behavior of the reservoir during waterflooding. Our sector-scale simulation results show that while considering the geomechanics model has a considerable impact on calculated reservoir pressure and recovery, the impact on history matched data due to water weakening is not significant when yield stress and bulk modulus are expressed as functions of temperature and sulfate concentration for the Halfdan model. We argue that the minor contribution of the water weakening effect at in situ conditions is due to 1) the relatively high initial water saturation in the water flooded section of the reservoir and 2) the low initial temperature (70 ˚C) of Halfdan reservoir, especially towards the northern part of the Danish North Sea.","PeriodicalId":418045,"journal":{"name":"Proceedings 56th US Rock Mechanics / Geomechanics Symposium","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127773605","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Merzoug, Hichem A. K. Chellal, R. Brinkerhoff, V. Rasouli, O. Olaoye
Multi-stage hydraulic fracturing technology for enhanced production from unconventional reservoirs has improved significantly during the past decade. However, multi-stage fracturing for multiple closely spaced long horizontal wellbores introduces several technical challenges. One example is Fracture Driven Interaction (FDI). In this study, we document a Fracture Driven Interaction case study where the primary well was drilled into the Three Forks Formation, and an offset well was drilled in the Middle Bakken. The idea of this study was to investigate the possibility of frac-hit as the cause of the low production rate in the offset well. This study estimates the stress in the petroleum system, and combine that with petrophysical analysis to construct a fully coupled hydraulic fracturing, geomechanics and reservoir numerical model. The model matched the production data and the results show the occurrence of a fracture driven interaction was a result of stress decrease due to depletion. Fracture driven interaction effect was severe on the offset well reducing the stimulated reservoir volume, thus jeopardizing the production.
{"title":"Parent-Child Well Interaction in Multi-stage Hydraulic Fracturing: A Bakken Case Study","authors":"A. Merzoug, Hichem A. K. Chellal, R. Brinkerhoff, V. Rasouli, O. Olaoye","doi":"10.56952/arma-2022-0188","DOIUrl":"https://doi.org/10.56952/arma-2022-0188","url":null,"abstract":"Multi-stage hydraulic fracturing technology for enhanced production from unconventional reservoirs has improved significantly during the past decade. However, multi-stage fracturing for multiple closely spaced long horizontal wellbores introduces several technical challenges. One example is Fracture Driven Interaction (FDI). In this study, we document a Fracture Driven Interaction case study where the primary well was drilled into the Three Forks Formation, and an offset well was drilled in the Middle Bakken. The idea of this study was to investigate the possibility of frac-hit as the cause of the low production rate in the offset well. This study estimates the stress in the petroleum system, and combine that with petrophysical analysis to construct a fully coupled hydraulic fracturing, geomechanics and reservoir numerical model. The model matched the production data and the results show the occurrence of a fracture driven interaction was a result of stress decrease due to depletion. Fracture driven interaction effect was severe on the offset well reducing the stimulated reservoir volume, thus jeopardizing the production.","PeriodicalId":418045,"journal":{"name":"Proceedings 56th US Rock Mechanics / Geomechanics Symposium","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125953911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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