Flexible net barriers are a new type of effective mitigation measure against debris flows in valleys and can affect the kinematic energy and mass of debris flows. Here, ten flume tests were performed to study the dyna...Flexible net barriers are a new type of effective mitigation measure against debris flows in valleys and can affect the kinematic energy and mass of debris flows. Here, ten flume tests were performed to study the dynamic behaviours of debris flows with differences in volumes, concentrations(solid volume fraction), and travel distances after interception by a uniform flexible net barrier. A high-speed camera was used to monitor the whole test process, and their dynamic behaviours were recorded. A preliminary computational framework on energy conversion is proposed according to the deposition mechanisms and outflow of debris flow under the effects of the flexible net barrier. The experimental results show that the dynamic interaction process between a debris flow and the flexible net barrier can be divided into two stages:(a) the two-phase impact of the leading edge of the debris flow with the net and(b) collision and friction between the body of the debris flow and intercepted debris material. The approach velocity of a debris flow decreases sharply(a maximum of 63%) after the interception by the net barrier, and the mass ratio of the debris material being intercepted and the kinetic energy ratio of the debris material being absorbed by the net barrier are close due to the limited interception efficiency of the flexible net barrier, which is believed to be related to the flexibility. The energy ratio of outflow is relative small despite the large permeability of the flexible net barrier.展开更多
In recent years, most of the drilling engineering accidents are caused by human error of judgment, which has much to do with the fact that technical experts and leaders can't get to know the site situation immedia...In recent years, most of the drilling engineering accidents are caused by human error of judgment, which has much to do with the fact that technical experts and leaders can't get to know the site situation immediately and miss the best time to deal with downhole anomalies. Along the general direction of information-based drilling, relying on the continuous improvement of information construction and the maturing of engineering automatic warning software, in August 2016, our company was the first pilot unit of Great Wall Drilling to establish a remote technical support center. The remote real-time monitoring of drilling parameters, data entry and analysis of EISS system, engineering simulation calculation and analysis software and other modules were applied to construct a remote technical support system for drilling engineering, which achieved the control objectives of "pre-prediction", "in-process control" and "post-analysis", promoted the continuous improvement of ROP, steadily reduced the accident complexity rate, and promoted the overall speed-up and efficiency improvement of all well teams of the Company. At the same time, combining with my own work practice, the author puts forward optimization and expansion methods for the problems and development direction in the operation of the remote support system, hoping to provide reference and reference for more people in the industry.展开更多
基金supported by the National Natural Science Foundation of China (51639007)the Youth Science and Technology Fund of Sichuan Province (2016JQ0011)the Science and Technology Fund of Chengdu Water Authority (14H1055).
文摘Flexible net barriers are a new type of effective mitigation measure against debris flows in valleys and can affect the kinematic energy and mass of debris flows. Here, ten flume tests were performed to study the dynamic behaviours of debris flows with differences in volumes, concentrations(solid volume fraction), and travel distances after interception by a uniform flexible net barrier. A high-speed camera was used to monitor the whole test process, and their dynamic behaviours were recorded. A preliminary computational framework on energy conversion is proposed according to the deposition mechanisms and outflow of debris flow under the effects of the flexible net barrier. The experimental results show that the dynamic interaction process between a debris flow and the flexible net barrier can be divided into two stages:(a) the two-phase impact of the leading edge of the debris flow with the net and(b) collision and friction between the body of the debris flow and intercepted debris material. The approach velocity of a debris flow decreases sharply(a maximum of 63%) after the interception by the net barrier, and the mass ratio of the debris material being intercepted and the kinetic energy ratio of the debris material being absorbed by the net barrier are close due to the limited interception efficiency of the flexible net barrier, which is believed to be related to the flexibility. The energy ratio of outflow is relative small despite the large permeability of the flexible net barrier.
文摘In recent years, most of the drilling engineering accidents are caused by human error of judgment, which has much to do with the fact that technical experts and leaders can't get to know the site situation immediately and miss the best time to deal with downhole anomalies. Along the general direction of information-based drilling, relying on the continuous improvement of information construction and the maturing of engineering automatic warning software, in August 2016, our company was the first pilot unit of Great Wall Drilling to establish a remote technical support center. The remote real-time monitoring of drilling parameters, data entry and analysis of EISS system, engineering simulation calculation and analysis software and other modules were applied to construct a remote technical support system for drilling engineering, which achieved the control objectives of "pre-prediction", "in-process control" and "post-analysis", promoted the continuous improvement of ROP, steadily reduced the accident complexity rate, and promoted the overall speed-up and efficiency improvement of all well teams of the Company. At the same time, combining with my own work practice, the author puts forward optimization and expansion methods for the problems and development direction in the operation of the remote support system, hoping to provide reference and reference for more people in the industry.
