The most common way to achieve an enormous production rate of a reservoir is to increase drawdown pressure during the production procedure by decreasing the bottom-hole pressure.This process was done by artificial pat...The most common way to achieve an enormous production rate of a reservoir is to increase drawdown pressure during the production procedure by decreasing the bottom-hole pressure.This process was done by artificial patterns like a gas lift.Nowadays,most of the wells worldwide due to years of production and reducing the amount of energy which was supplied by natural drive mechanisms are being placed on artificial lift methodologies.Hence,the number of wells that used this method will continue to increase.The primary purposes in the gas lift design of a wellbore are to determine the proper depths and the location of valve installation,select appropriate flow regime during the pipeline and calibrate the pressures of the operating and unloading valves.The purpose of this research is to design gas lift system in the oil wells of on the south fields of Iran by considering the maximum production connate water volume of 40 percent and average pressure drop(20-25 psia)throughout the year regarding production continuously or increasing the flow rate of the wells.Therefore,20 wells that their number starts A to T with this locations L280N,W115S and W002S are the candidates for gas lift procedures.Furthermore,the appropriate flow regimes through the well are being studied,and the most proper method for gas lifting and required surficial equipment will be designed for this field.Consequently,due to increasing the volume of gas and connate water among the production after gas lifting,fundamental changes on the equipment,flow regimes and gas lift system are being proposed that production will be done by proper engineering method.In the well gas lift design,Beggs&Brill Revised method is being selected for hydraulic calculation of pipeline flow due to low errors.展开更多
The initial motivation of the lifting technique is to solve the H∞control problems. However, the conventional weighted H∞design does not meet the conditions required by lifting, so the result often leads to a misjud...The initial motivation of the lifting technique is to solve the H∞control problems. However, the conventional weighted H∞design does not meet the conditions required by lifting, so the result often leads to a misjudgement of the design. Two conditions required by using the lifting technique are presented based on the basic formulae of the lifting. It is pointed out that only the H∞disturbance attenuation problem with no weighting functions can meet these conditions, hence, the application of the lifting technique is quite limited.展开更多
The individual difference and non-repeatability in acupuncture have not only restricted the devel- opment of acupuncture, but have also affected the specificity of acupoints. The present study used instruments to cont...The individual difference and non-repeatability in acupuncture have not only restricted the devel- opment of acupuncture, but have also affected the specificity of acupoints. The present study used instruments to control needle depth, lifting and thrusting frequency, and the duration of acupuncture. Effects of the quantified acupuncture were observed at Neiguan （PC6） with different stimulation parameters. A frequency of 1, 2, or 3 Hz and duration of 5, 60, or 180 seconds were used to observe cerebral blood flow and ratio of infarct volume recovery. Results showed that stimulation at Neiguan with a frequency of 1 Hz and long duration of 180 seconds or 2/3 Hz and long duration of 5/60 seconds significantly increased cerebral blood flow and decreased the ratio of infarct volume. In- teractions between frequency and duration play a critical role in quantified acupuncture therapy.展开更多
An optimal maneuver strategy is proposed for lifting reentry vehicle to reach the maximum lateral range after reentering the atmosphere. Aiming at problems that too many co-state variables and difficulty in estimating...An optimal maneuver strategy is proposed for lifting reentry vehicle to reach the maximum lateral range after reentering the atmosphere. Aiming at problems that too many co-state variables and difficulty in estimating the initial values of co-state variables,the equilibrium glide condition (EGC) is utilized to reduce the reentry motion equations and then the optimal maneuver strategy satisfied above performance index is derived. This maneuvering strategy is applied to the lifting reentry weapon platform CAV which was designed by America recently to realize both longitudinal and lateral trajectory design by controlling the attack angle and the bank angle respectively. The simulation result indicates that the maneuver strategy proposed enables CAV to reach favorable longitudinal range and lateral range.展开更多
Using the supercavitation phenomenon is necessary to reach high velocities underwater. Supercavitation can be achieved in two ways: natural and artificial. In this article, the simulation of flows around a torpedo was...Using the supercavitation phenomenon is necessary to reach high velocities underwater. Supercavitation can be achieved in two ways: natural and artificial. In this article, the simulation of flows around a torpedo was studied naturally and artificially. The validity of simulation using theoretical and practical data in the natural and artificial phases was evaluated. Results showed that the simulations were consistent with the laboratory results. The results in different injection coefficient rates, injection angles, and cavitation numbers were studied. The obtained results showed the importance of cavitation number, injection rate coefficient, and injection angle in cavity shape. At the final level, determining the performance conditions using the Design of Experiment (DOE) method was emphasized, and the performance of cavitation number, injection rate coefficient, and injection angle in drag and lift coefficient was studied. The increase in injection angle in the low injection rate coefficient resulted in a diminished drag coefficient and that in the high injection rate coefficient resulted in an enhanced drag coefficient.展开更多
文摘The most common way to achieve an enormous production rate of a reservoir is to increase drawdown pressure during the production procedure by decreasing the bottom-hole pressure.This process was done by artificial patterns like a gas lift.Nowadays,most of the wells worldwide due to years of production and reducing the amount of energy which was supplied by natural drive mechanisms are being placed on artificial lift methodologies.Hence,the number of wells that used this method will continue to increase.The primary purposes in the gas lift design of a wellbore are to determine the proper depths and the location of valve installation,select appropriate flow regime during the pipeline and calibrate the pressures of the operating and unloading valves.The purpose of this research is to design gas lift system in the oil wells of on the south fields of Iran by considering the maximum production connate water volume of 40 percent and average pressure drop(20-25 psia)throughout the year regarding production continuously or increasing the flow rate of the wells.Therefore,20 wells that their number starts A to T with this locations L280N,W115S and W002S are the candidates for gas lift procedures.Furthermore,the appropriate flow regimes through the well are being studied,and the most proper method for gas lifting and required surficial equipment will be designed for this field.Consequently,due to increasing the volume of gas and connate water among the production after gas lifting,fundamental changes on the equipment,flow regimes and gas lift system are being proposed that production will be done by proper engineering method.In the well gas lift design,Beggs&Brill Revised method is being selected for hydraulic calculation of pipeline flow due to low errors.
基金Supported by the Harbin Engineering University Fund for Basic Projects (heuft06041)
文摘The initial motivation of the lifting technique is to solve the H∞control problems. However, the conventional weighted H∞design does not meet the conditions required by lifting, so the result often leads to a misjudgement of the design. Two conditions required by using the lifting technique are presented based on the basic formulae of the lifting. It is pointed out that only the H∞disturbance attenuation problem with no weighting functions can meet these conditions, hence, the application of the lifting technique is quite limited.
基金funded by Development Plan(973 Plan) of National Critical and Basic Research,No.2012CB518505,2010CB530500,2006CB504504
文摘The individual difference and non-repeatability in acupuncture have not only restricted the devel- opment of acupuncture, but have also affected the specificity of acupoints. The present study used instruments to control needle depth, lifting and thrusting frequency, and the duration of acupuncture. Effects of the quantified acupuncture were observed at Neiguan （PC6） with different stimulation parameters. A frequency of 1, 2, or 3 Hz and duration of 5, 60, or 180 seconds were used to observe cerebral blood flow and ratio of infarct volume recovery. Results showed that stimulation at Neiguan with a frequency of 1 Hz and long duration of 180 seconds or 2/3 Hz and long duration of 5/60 seconds significantly increased cerebral blood flow and decreased the ratio of infarct volume. In- teractions between frequency and duration play a critical role in quantified acupuncture therapy.
文摘An optimal maneuver strategy is proposed for lifting reentry vehicle to reach the maximum lateral range after reentering the atmosphere. Aiming at problems that too many co-state variables and difficulty in estimating the initial values of co-state variables,the equilibrium glide condition (EGC) is utilized to reduce the reentry motion equations and then the optimal maneuver strategy satisfied above performance index is derived. This maneuvering strategy is applied to the lifting reentry weapon platform CAV which was designed by America recently to realize both longitudinal and lateral trajectory design by controlling the attack angle and the bank angle respectively. The simulation result indicates that the maneuver strategy proposed enables CAV to reach favorable longitudinal range and lateral range.
文摘Using the supercavitation phenomenon is necessary to reach high velocities underwater. Supercavitation can be achieved in two ways: natural and artificial. In this article, the simulation of flows around a torpedo was studied naturally and artificially. The validity of simulation using theoretical and practical data in the natural and artificial phases was evaluated. Results showed that the simulations were consistent with the laboratory results. The results in different injection coefficient rates, injection angles, and cavitation numbers were studied. The obtained results showed the importance of cavitation number, injection rate coefficient, and injection angle in cavity shape. At the final level, determining the performance conditions using the Design of Experiment (DOE) method was emphasized, and the performance of cavitation number, injection rate coefficient, and injection angle in drag and lift coefficient was studied. The increase in injection angle in the low injection rate coefficient resulted in a diminished drag coefficient and that in the high injection rate coefficient resulted in an enhanced drag coefficient.
