We propose a new method for inverting source function of microseismic event induced in mining. The observed data from microseismic monitoring during mining are represented by a wave equation in a spherical coordinate ...We propose a new method for inverting source function of microseismic event induced in mining. The observed data from microseismic monitoring during mining are represented by a wave equation in a spherical coordinate system and then the data are transformed from the time-space domain to the time-slowness domain based on tomographic principle, from whichwe can obtain the signals related to the source in the time-slowness domain. Through analyzing the relationship between the signal located at the maximum energy and the source function, we derive the tomographic equations to compute the source function from the signals and to calculate the effective radiated energy based on the source function. Moreover, we fit the real amplitude spectrum of the source function computed from the observed data into the co-2 model based on the least squares principle and determine the zero-frequency level spectrum and the corner frequency, finally, the source rupture radius of the event is calculated and The synthetic and field examples demonstrate that the proposed tomographic inversion methods are reliable and efficient展开更多
For microseisimic monitoring it is difficult to determine wave modes and their propagation velocity. In this paper, we propose a new method for automatically inverting in real time the source characteristics of micros...For microseisimic monitoring it is difficult to determine wave modes and their propagation velocity. In this paper, we propose a new method for automatically inverting in real time the source characteristics of microseismic events in mine engineering without wave mode identification and velocities. Based on the wave equation in a spherical coordinate system, we derive a tomographic imaging equation and formulate a scanning parameter selection criterion by which the microseisimic event maximum energy and corresponding parameters can be determined. By determining the maximum energy positions inside a given risk district, we can indentify microseismic events inside or outside the risk districts. The synthetic and field examples demonstrate that the proposed tomographic imaging method can automatically position microseismic events by only knowing the risk district dimensions and range of velocities without identifying the wavefield modes and accurate velocities. Therefore, the new method utilizes the full wavefields to automatically monitor microseismic events.展开更多
We present a workflow linking coupled fluid-flow and geomechanical simulation with seismic modelling to predict seismic anisotropy induced by non-hydrostatic stress changes. We generate seismic models from coupled sim...We present a workflow linking coupled fluid-flow and geomechanical simulation with seismic modelling to predict seismic anisotropy induced by non-hydrostatic stress changes. We generate seismic models from coupled simulations to examine the relationship between reservoir geometry, stress path and seismic anisotropy. The results indicate that geometry influences the evolution of stress,which leads to stress-induced seismic anisotropy. Although stress anisotropy is high for the small reservoir, the effect of stress arching and the ability of the side-burden to support the excess load limit the overall change in effective stress and hence seismic anisotropy. For the extensive reservoir, stress anisotropy and induced seismic anisotropy are high. The extensive and elongate reservoirs experience significant compaction, where the inefficiency of the developed stress arching in the side-burden cannot support the excess load.The elongate reservoir displays significant stress asymmetry,with seismic anisotropy developing predominantly along the long-edge of the reservoir. We show that the link betweenstress path parameters and seismic anisotropy is complex,where the anisotropic symmetry is controlled not only by model geometry but also the nonlinear rock physics model used. Nevertheless, a workflow has been developed to model seismic anisotropy induced by non-hydrostatic stress changes, allowing field observations of anisotropy to be linked with geomechanical models.展开更多
Unsupervised neural networks such as the Kohonen Self-Organizing Maps （SOM） have been widely used for searching natural clusters in multidimensional and massive data. One example where the data available for analysi...Unsupervised neural networks such as the Kohonen Self-Organizing Maps （SOM） have been widely used for searching natural clusters in multidimensional and massive data. One example where the data available for analysis can be extremely large is seismic interpretation for hydrocarbon exploration. In order to assist the interpreter in identifying characteristics of interest confined in the seismic data, the authors present a set of data attributes that can be used to train a SOM in such a way that zones of interest can be automatically identified or segmented, reducing time in the interpretation process. The authors show how to associate SOM to 2D color maps to visually identify the clustering structure of the input seismic data, and apply the proposed technique to a 2D synthetic seismic dataset of salt structures.展开更多
The equivalent monochromatic wavelength(EMW)approximation allowed us to predict the photochemical lifetimes of the lipid regulator metabolite clofibric acid(CLO,triplet sensitization)and of the non-steroidal antiinfla...The equivalent monochromatic wavelength(EMW)approximation allowed us to predict the photochemical lifetimes of the lipid regulator metabolite clofibric acid(CLO,triplet sensitization)and of the non-steroidal antiinflammatory drug diclofenac(DIC,direct photolysis t triplet sensitization)in lakes worldwide.To do so,we used large lake databases that collect photochemically significant parameters such as water depth and dissolved organic carbon,which allow for a preliminary assessment of some photoreactions.Extension to other photoreactions is currently prevented by the lack of important parameters such as water absorption spectrum,suspended solids,nitrate,nitrite,pH,and inorganic carbon on a global scale.It appears that triplet-sensitized CLO photodegradation would be strongly affected by the dissolved organic carbon values of the lake water and,for this reason,it would be fastest in Nordic environments.By contrast,direct photolysis(DIC)would be highly affected by sunlight irradiance and would proceed at the highest rates in the tropical belt.Interestingly,the predicted lifetimes of CLO and DIC are shorter than the residence time of water in the majority of global lake basins,which suggests a high potential for photoreactions to attenuate the two contaminants on a global scale.Photodegradation of DIC and CLO would also be important in waste stabilization ponds,except for elevated latitudes during winter,which makes these basins potentially cost-effective systems for the partial removal of these emerging contaminants from wastewater.展开更多
Flow assurance has been a major challenge in petroleum production systems especially in offshore operations where severe slugging is a dominant aching issue.This is characterized by pulsating flow behavior which impac...Flow assurance has been a major challenge in petroleum production systems especially in offshore operations where severe slugging is a dominant aching issue.This is characterized by pulsating flow behavior which impacts the reservoir productivity,pipeline-riser systems,and surface facilities(separator).The only means so far,of delivering reservoir fluids from offshore wells to the separator at the surface is by pipeline-riser systems where slugging is most prominent and oftentimes unavoidable.Though passive and active measures have been deployed over time to mitigate the associated problem,there is the need to develop a predictive tool for mitigating offshore slugging in the riser system.This study involves the use of a model and analysis approach to eliminate severe slugging based on the balance of forces acting on the pipeline-riser system.Modified stability criteria which consider accumulation and frictional pressure drops have been developed.The current approach is solely physicsdriven,to predict the corresponding liquid and gas velocities at which the fluctuations would be severe when producing multiphase fluids through pipeline-riser systems.By balancing the forces acting on a riser-pipeline system and accounting for frictional and accumulation effects,two hydraulic flow modeling approaches have been used in this study to improve the criteria for predicting the condition of severe slugging.The developed criteria were computed using MATLAB/Simulink and a severe slugging flow map was generated.The“new study 1”and“new study 2”showed a 16%and 13%increase respectively in predicted unstable cases than the Malekzadeh criteria.The criteria were tested at different separator pressures.The Taitel and Jansen criteria could not predict severe slugging at elevated separator pressure.Notwithstanding,the developed flow maps using the“new study 1”are more reliable than the“new study 2”.This is because the“new study 2”approach over defines the physics of severe slugging.The criteria were also tested at varying accumulation times.This was done by step increments in the order of magnitude of time.The separator pressure affects the optimal time for modeling the accumulation at the riser-base.The criteria are therefore useful for predicting optimal operating conditions for flow assurance for the pipeline-riser system in consideration.展开更多
Durability and reliability have been studied for decades through intensive trial-error experimentation.However,there are numerous fields of application where the costs associated with this approach are not acceptable....Durability and reliability have been studied for decades through intensive trial-error experimentation.However,there are numerous fields of application where the costs associated with this approach are not acceptable.In lubricated machines with severe dynamic loads,such as high-power-density engines,simulation tools offer clear advantages over intensive testing.Prototypes and multiple scenarios can be cost-effectively simulated to assess different lubricants and engine configurations.The work presented here details the study of wear based on a validated elastohydrodynamic(EHD)simulation model of the connecting rod journal bearing.This model accounts for elastic deformation through a connecting rod finite element model(FEM).In addition,multiple lubricant rheological and tribological dependences,determined by specific experimental tests,are applied in the model through their interaction with the simulation software.Correspondingly,a novel wear algorithm is proposed to predict wear depth over time evolution along a proposed wear cycle based on the typical working ranges of high-performance engines.A final assessment is presented to compare 4 different ultralow-viscosity lubricants in their protective performance under severe conditions.The results show the evolution of the wear load and wear depth over the wear cycle.This evaluation is key to describing a lubricant selection procedure for high-power-density engines.展开更多
The contribution of geomechanics to provide a rigorous quantification of porosity changes and associated permeability changes is often neglected when considering hydrocarbon production.However,it often has significant...The contribution of geomechanics to provide a rigorous quantification of porosity changes and associated permeability changes is often neglected when considering hydrocarbon production.However,it often has significant effects on production rates and ultimate recovery.For the cold heavy oil production with sand(CHOPS)technique,geomechanics is the key for reservoir simulations and promoting successful operations.In fact,the technique employed in CHOPS significantly affects the stress state within the reservoir by inducing“on-purpose”formation damage.It is not only vital to comprehend the behaviour of the reservoir during production,but it is crucial to identify how to harness that behaviour to improve productivity.In order to simulate the mechanical behaviour of unconsolidated sand material,an elastoplastic damage model was formulated.Fluid-flow-geomechanical modelling was then performed for predicting individual well behaviour and overall field performance.The combined effect of fluid-flow and geomechanics improved predictions with respect to oil,water,and gas production rates at key wells.Fluid rates matched satisfactorily most of the wells.In addition,the onset and propagation of equivalent wormhole networks were quantified throughout the production history.This enabled quantification of the volume of produced sand at individual wells.The comparisons between the measured and simulated sand volume rate at well locations showed reasonable agreement.Such calibrated models can then be used for the placement of new wells to optimize production.展开更多
基金supported jointly by projects of the National Natural Science Fund Project(No.51174016)the National Key Basic Research and Development Plan 973(No.2010CB226803)
文摘We propose a new method for inverting source function of microseismic event induced in mining. The observed data from microseismic monitoring during mining are represented by a wave equation in a spherical coordinate system and then the data are transformed from the time-space domain to the time-slowness domain based on tomographic principle, from whichwe can obtain the signals related to the source in the time-slowness domain. Through analyzing the relationship between the signal located at the maximum energy and the source function, we derive the tomographic equations to compute the source function from the signals and to calculate the effective radiated energy based on the source function. Moreover, we fit the real amplitude spectrum of the source function computed from the observed data into the co-2 model based on the least squares principle and determine the zero-frequency level spectrum and the corner frequency, finally, the source rupture radius of the event is calculated and The synthetic and field examples demonstrate that the proposed tomographic inversion methods are reliable and efficient
基金support jointly by projects of the National Natural Science Fund Project (40674017 and 50774012)the National Key Basic Research and Development Plan 973 (2010CB226803)
文摘For microseisimic monitoring it is difficult to determine wave modes and their propagation velocity. In this paper, we propose a new method for automatically inverting in real time the source characteristics of microseismic events in mine engineering without wave mode identification and velocities. Based on the wave equation in a spherical coordinate system, we derive a tomographic imaging equation and formulate a scanning parameter selection criterion by which the microseisimic event maximum energy and corresponding parameters can be determined. By determining the maximum energy positions inside a given risk district, we can indentify microseismic events inside or outside the risk districts. The synthetic and field examples demonstrate that the proposed tomographic imaging method can automatically position microseismic events by only knowing the risk district dimensions and range of velocities without identifying the wavefield modes and accurate velocities. Therefore, the new method utilizes the full wavefields to automatically monitor microseismic events.
基金the sponsors of the IPEGG project, BG, BP, Statoilthe Research Council UK (EP/K035878/1+1 种基金 EP/K021869/1 NE/L000423/1) for financial support
文摘We present a workflow linking coupled fluid-flow and geomechanical simulation with seismic modelling to predict seismic anisotropy induced by non-hydrostatic stress changes. We generate seismic models from coupled simulations to examine the relationship between reservoir geometry, stress path and seismic anisotropy. The results indicate that geometry influences the evolution of stress,which leads to stress-induced seismic anisotropy. Although stress anisotropy is high for the small reservoir, the effect of stress arching and the ability of the side-burden to support the excess load limit the overall change in effective stress and hence seismic anisotropy. For the extensive reservoir, stress anisotropy and induced seismic anisotropy are high. The extensive and elongate reservoirs experience significant compaction, where the inefficiency of the developed stress arching in the side-burden cannot support the excess load.The elongate reservoir displays significant stress asymmetry,with seismic anisotropy developing predominantly along the long-edge of the reservoir. We show that the link betweenstress path parameters and seismic anisotropy is complex,where the anisotropic symmetry is controlled not only by model geometry but also the nonlinear rock physics model used. Nevertheless, a workflow has been developed to model seismic anisotropy induced by non-hydrostatic stress changes, allowing field observations of anisotropy to be linked with geomechanical models.
文摘Unsupervised neural networks such as the Kohonen Self-Organizing Maps （SOM） have been widely used for searching natural clusters in multidimensional and massive data. One example where the data available for analysis can be extremely large is seismic interpretation for hydrocarbon exploration. In order to assist the interpreter in identifying characteristics of interest confined in the seismic data, the authors present a set of data attributes that can be used to train a SOM in such a way that zones of interest can be automatically identified or segmented, reducing time in the interpretation process. The authors show how to associate SOM to 2D color maps to visually identify the clustering structure of the input seismic data, and apply the proposed technique to a 2D synthetic seismic dataset of salt structures.
基金the financial support of the Spanish State Research Agency(AEI)the Spanish Ministry of Science and Innovation through the project AQUAENAGRI(PID2021-126400OB-C32)+1 种基金support from the Project CH4.0 under the MUR program“Dipartimenti di Eccellenza 2023-2027”(CUP:D13C22003520001)financial support by European Union,Next Generation EU,Mission 4,Component 2,in the framework of the project GRINS,Growing Resilient,INclusive,and Sustainable(GRINS PE00000018,CUP D13C22002160001).
文摘The equivalent monochromatic wavelength(EMW)approximation allowed us to predict the photochemical lifetimes of the lipid regulator metabolite clofibric acid(CLO,triplet sensitization)and of the non-steroidal antiinflammatory drug diclofenac(DIC,direct photolysis t triplet sensitization)in lakes worldwide.To do so,we used large lake databases that collect photochemically significant parameters such as water depth and dissolved organic carbon,which allow for a preliminary assessment of some photoreactions.Extension to other photoreactions is currently prevented by the lack of important parameters such as water absorption spectrum,suspended solids,nitrate,nitrite,pH,and inorganic carbon on a global scale.It appears that triplet-sensitized CLO photodegradation would be strongly affected by the dissolved organic carbon values of the lake water and,for this reason,it would be fastest in Nordic environments.By contrast,direct photolysis(DIC)would be highly affected by sunlight irradiance and would proceed at the highest rates in the tropical belt.Interestingly,the predicted lifetimes of CLO and DIC are shorter than the residence time of water in the majority of global lake basins,which suggests a high potential for photoreactions to attenuate the two contaminants on a global scale.Photodegradation of DIC and CLO would also be important in waste stabilization ponds,except for elevated latitudes during winter,which makes these basins potentially cost-effective systems for the partial removal of these emerging contaminants from wastewater.
文摘Flow assurance has been a major challenge in petroleum production systems especially in offshore operations where severe slugging is a dominant aching issue.This is characterized by pulsating flow behavior which impacts the reservoir productivity,pipeline-riser systems,and surface facilities(separator).The only means so far,of delivering reservoir fluids from offshore wells to the separator at the surface is by pipeline-riser systems where slugging is most prominent and oftentimes unavoidable.Though passive and active measures have been deployed over time to mitigate the associated problem,there is the need to develop a predictive tool for mitigating offshore slugging in the riser system.This study involves the use of a model and analysis approach to eliminate severe slugging based on the balance of forces acting on the pipeline-riser system.Modified stability criteria which consider accumulation and frictional pressure drops have been developed.The current approach is solely physicsdriven,to predict the corresponding liquid and gas velocities at which the fluctuations would be severe when producing multiphase fluids through pipeline-riser systems.By balancing the forces acting on a riser-pipeline system and accounting for frictional and accumulation effects,two hydraulic flow modeling approaches have been used in this study to improve the criteria for predicting the condition of severe slugging.The developed criteria were computed using MATLAB/Simulink and a severe slugging flow map was generated.The“new study 1”and“new study 2”showed a 16%and 13%increase respectively in predicted unstable cases than the Malekzadeh criteria.The criteria were tested at different separator pressures.The Taitel and Jansen criteria could not predict severe slugging at elevated separator pressure.Notwithstanding,the developed flow maps using the“new study 1”are more reliable than the“new study 2”.This is because the“new study 2”approach over defines the physics of severe slugging.The criteria were also tested at varying accumulation times.This was done by step increments in the order of magnitude of time.The separator pressure affects the optimal time for modeling the accumulation at the riser-base.The criteria are therefore useful for predicting optimal operating conditions for flow assurance for the pipeline-riser system in consideration.
文摘Durability and reliability have been studied for decades through intensive trial-error experimentation.However,there are numerous fields of application where the costs associated with this approach are not acceptable.In lubricated machines with severe dynamic loads,such as high-power-density engines,simulation tools offer clear advantages over intensive testing.Prototypes and multiple scenarios can be cost-effectively simulated to assess different lubricants and engine configurations.The work presented here details the study of wear based on a validated elastohydrodynamic(EHD)simulation model of the connecting rod journal bearing.This model accounts for elastic deformation through a connecting rod finite element model(FEM).In addition,multiple lubricant rheological and tribological dependences,determined by specific experimental tests,are applied in the model through their interaction with the simulation software.Correspondingly,a novel wear algorithm is proposed to predict wear depth over time evolution along a proposed wear cycle based on the typical working ranges of high-performance engines.A final assessment is presented to compare 4 different ultralow-viscosity lubricants in their protective performance under severe conditions.The results show the evolution of the wear load and wear depth over the wear cycle.This evaluation is key to describing a lubricant selection procedure for high-power-density engines.
文摘The contribution of geomechanics to provide a rigorous quantification of porosity changes and associated permeability changes is often neglected when considering hydrocarbon production.However,it often has significant effects on production rates and ultimate recovery.For the cold heavy oil production with sand(CHOPS)technique,geomechanics is the key for reservoir simulations and promoting successful operations.In fact,the technique employed in CHOPS significantly affects the stress state within the reservoir by inducing“on-purpose”formation damage.It is not only vital to comprehend the behaviour of the reservoir during production,but it is crucial to identify how to harness that behaviour to improve productivity.In order to simulate the mechanical behaviour of unconsolidated sand material,an elastoplastic damage model was formulated.Fluid-flow-geomechanical modelling was then performed for predicting individual well behaviour and overall field performance.The combined effect of fluid-flow and geomechanics improved predictions with respect to oil,water,and gas production rates at key wells.Fluid rates matched satisfactorily most of the wells.In addition,the onset and propagation of equivalent wormhole networks were quantified throughout the production history.This enabled quantification of the volume of produced sand at individual wells.The comparisons between the measured and simulated sand volume rate at well locations showed reasonable agreement.Such calibrated models can then be used for the placement of new wells to optimize production.
