The configuration of an airway(or production drift)in panel cave mines is different from the typical(straight)mine airway designs.The drawpoints are connected to the airway(cross-cuts),which allows airflow from the ca...The configuration of an airway(or production drift)in panel cave mines is different from the typical(straight)mine airway designs.The drawpoints are connected to the airway(cross-cuts),which allows airflow from the cave into the airway or air loss from the airway into the cave due to the ventilation approach and cave porosity.These affect airflow in the production drifts,but it is difficult to investigate these conditions from field or laboratory scaled studies.Therefore,this study develops discrete and continuum computational fluid dynamics(CFD)models to study the effects of the ventilation approach and cave porosity on the airway resistance.Our findings show that:with active undercut ventilation,a unique resistance model is required for the airway in panel cave mines;and an increase in cave porosity decreases the drift’s resistance.These findings provide essential tools for a panel cave ventilation design.展开更多
Because carbonate rocks have a wide range of reservoir forms,a low matrix permeability,and a complicated seam hole formation,using traditional capacity prediction methods to estimate carbonate reservoirs can lead to s...Because carbonate rocks have a wide range of reservoir forms,a low matrix permeability,and a complicated seam hole formation,using traditional capacity prediction methods to estimate carbonate reservoirs can lead to significant errors.We propose a machine learning-based capacity prediction method for carbonate rocks by analyzing the degree of correlation between various factors and three machine learning models:support vector machine,BP neural network,and elastic network.The error rate for these three models are 10%,16%,and 33%,respectively(according to the analysis of 40 training wells and 10 test wells).展开更多
According to the complex differential accumulation history of deep marine oil and gas in superimposed basins,the Lower Paleozoic petroleum system in Tahe Oilfield of Tarim Basin is selected as a typical case,and the p...According to the complex differential accumulation history of deep marine oil and gas in superimposed basins,the Lower Paleozoic petroleum system in Tahe Oilfield of Tarim Basin is selected as a typical case,and the process of hydrocarbon generation and expulsion,migration and accumulation,adjustment and transformation of deep oil and gas is restored by means of reservoine-forming dynamics simulation.The thermal evolution history of the Lower Cambrian source rocks in Tahe Oilfield reflects the obvious differences in hydrocarbon generation and expulsion process and intensity in different tectonic zones,which is the main reason controlling the differences in deep oil and gas phases.The complex transport system composed of strike-slip fault and unconformity,etc.controlled early migration and accumulation and late adjustment of deep oil and gas,while the Middle Cambrian gypsum-salt rock in inner carbonate platform prevented vertical migration and accumulation of deep oil and gas,resulting in an obvious"fault-controlled"feature of deep oil and gas,in which the low potential area superimposed by the NE-strike-slip fault zone and deep oil and gas migration was conducive to accumulation,and it is mainly beaded along the strike-slip fault zone in the northeast direction.The dynamic simulation of reservoir formation reveals that the spatio-temporal configuration of"source-fault-fracture-gypsum-preservation"controls the differential accumulation of deep oil and gas in Tahe Oilfield.The Ordovician has experienced the accumulation history of multiple periods of charging,vertical migration and accumulation,and lateral adjustment and transformation,and deep oil and gas have always been in the dynamic equilibrium of migration,accumulation and escape.The statistics of residual oil and gas show that the deep stratum of Tahe Oilfield still has exploration and development potential in the Ordovician Yingshan Formation and Penglaiba Formation,and the Middle and Upper Cambrian ultra-deep stratum has a certain oil and gas resource prospect.This study provides a reference for the dynamic quantitative evaluation of deep oil and gas in the Tarim Basin,and also provides a reference for the study of reservoir formation and evolution in carbonate reservoir of paleo-craton basin.展开更多
Ventilation is one of the radon control measures in an underground working environment.However,the dynamics related to the cave mining methods particularly in block/panel cave mines,complicate the design of effective ...Ventilation is one of the radon control measures in an underground working environment.However,the dynamics related to the cave mining methods particularly in block/panel cave mines,complicate the design of effective ventilation system,and implementation.Events such as hang ups(in the drawbells),leakage from old workings,and changes in cave porosity lead to differing response of an existing ventilation designs.However,it is difficult to investigate these conditions at the mine or with a laboratory scale study.Therefore,this study develops a discrete model to investigate the impact of different radon control measures in cave mines using computational fluid dynamics techniques.We considered two ventilation conditions for a fully developed cave:with and without the undercut ventilation.For each of the two conditions,we studied four parameters:airflow distribution through the production drifts,radon distribution through the production drifts,the effect of increasing airflow on radon concentration,and the effect of a cave top negative pressure on radon distribution.The results show that:the undercut ventilation significantly increases the radon concentration in the production drift;the growth of radon concentration through the production drift is nonlinear(oscillating pattern);maintaining a negative pressure on top of the cave is more effective at mitigating radon exposure,when the undercut ventilation is active;and increase in air volume flow rate decreases radon concentration in most regions,however,there might be regions with significant radon accumulation due to pressure variation across the drifts.These findings provide vital information for designing an effective ventilation system and for proactive implementation of radon control measures in cave mines.展开更多
基金support from the National Institute for Occupational Safety and Health(NIOSH)(No.200-2014-59613)for conducting this research.
文摘The configuration of an airway(or production drift)in panel cave mines is different from the typical(straight)mine airway designs.The drawpoints are connected to the airway(cross-cuts),which allows airflow from the cave into the airway or air loss from the airway into the cave due to the ventilation approach and cave porosity.These affect airflow in the production drifts,but it is difficult to investigate these conditions from field or laboratory scaled studies.Therefore,this study develops discrete and continuum computational fluid dynamics(CFD)models to study the effects of the ventilation approach and cave porosity on the airway resistance.Our findings show that:with active undercut ventilation,a unique resistance model is required for the airway in panel cave mines;and an increase in cave porosity decreases the drift’s resistance.These findings provide essential tools for a panel cave ventilation design.
文摘Because carbonate rocks have a wide range of reservoir forms,a low matrix permeability,and a complicated seam hole formation,using traditional capacity prediction methods to estimate carbonate reservoirs can lead to significant errors.We propose a machine learning-based capacity prediction method for carbonate rocks by analyzing the degree of correlation between various factors and three machine learning models:support vector machine,BP neural network,and elastic network.The error rate for these three models are 10%,16%,and 33%,respectively(according to the analysis of 40 training wells and 10 test wells).
基金Supported by the Sichuan Province Regional Innovation Cooperation Project(21QYCX0048)Sinopec Science and Technology Department Project(P21048-3)。
文摘According to the complex differential accumulation history of deep marine oil and gas in superimposed basins,the Lower Paleozoic petroleum system in Tahe Oilfield of Tarim Basin is selected as a typical case,and the process of hydrocarbon generation and expulsion,migration and accumulation,adjustment and transformation of deep oil and gas is restored by means of reservoine-forming dynamics simulation.The thermal evolution history of the Lower Cambrian source rocks in Tahe Oilfield reflects the obvious differences in hydrocarbon generation and expulsion process and intensity in different tectonic zones,which is the main reason controlling the differences in deep oil and gas phases.The complex transport system composed of strike-slip fault and unconformity,etc.controlled early migration and accumulation and late adjustment of deep oil and gas,while the Middle Cambrian gypsum-salt rock in inner carbonate platform prevented vertical migration and accumulation of deep oil and gas,resulting in an obvious"fault-controlled"feature of deep oil and gas,in which the low potential area superimposed by the NE-strike-slip fault zone and deep oil and gas migration was conducive to accumulation,and it is mainly beaded along the strike-slip fault zone in the northeast direction.The dynamic simulation of reservoir formation reveals that the spatio-temporal configuration of"source-fault-fracture-gypsum-preservation"controls the differential accumulation of deep oil and gas in Tahe Oilfield.The Ordovician has experienced the accumulation history of multiple periods of charging,vertical migration and accumulation,and lateral adjustment and transformation,and deep oil and gas have always been in the dynamic equilibrium of migration,accumulation and escape.The statistics of residual oil and gas show that the deep stratum of Tahe Oilfield still has exploration and development potential in the Ordovician Yingshan Formation and Penglaiba Formation,and the Middle and Upper Cambrian ultra-deep stratum has a certain oil and gas resource prospect.This study provides a reference for the dynamic quantitative evaluation of deep oil and gas in the Tarim Basin,and also provides a reference for the study of reservoir formation and evolution in carbonate reservoir of paleo-craton basin.
基金financial support from the National Institute for Occupational Safety and Health (NIOSH) (No. 200-2014-59613) for conducting this research
文摘Ventilation is one of the radon control measures in an underground working environment.However,the dynamics related to the cave mining methods particularly in block/panel cave mines,complicate the design of effective ventilation system,and implementation.Events such as hang ups(in the drawbells),leakage from old workings,and changes in cave porosity lead to differing response of an existing ventilation designs.However,it is difficult to investigate these conditions at the mine or with a laboratory scale study.Therefore,this study develops a discrete model to investigate the impact of different radon control measures in cave mines using computational fluid dynamics techniques.We considered two ventilation conditions for a fully developed cave:with and without the undercut ventilation.For each of the two conditions,we studied four parameters:airflow distribution through the production drifts,radon distribution through the production drifts,the effect of increasing airflow on radon concentration,and the effect of a cave top negative pressure on radon distribution.The results show that:the undercut ventilation significantly increases the radon concentration in the production drift;the growth of radon concentration through the production drift is nonlinear(oscillating pattern);maintaining a negative pressure on top of the cave is more effective at mitigating radon exposure,when the undercut ventilation is active;and increase in air volume flow rate decreases radon concentration in most regions,however,there might be regions with significant radon accumulation due to pressure variation across the drifts.These findings provide vital information for designing an effective ventilation system and for proactive implementation of radon control measures in cave mines.
