为了探索低渗透油田适用的平衡判定方法,合理调整抽油机平衡,进一步降低机采举升能耗,开展了抽油机平衡与能耗关系研究。通过对比现场应用的不同平衡判定方法调整效果的准确性和能耗情况得出:在低渗透油田开展平衡调整,应用平均功率法...为了探索低渗透油田适用的平衡判定方法,合理调整抽油机平衡,进一步降低机采举升能耗,开展了抽油机平衡与能耗关系研究。通过对比现场应用的不同平衡判定方法调整效果的准确性和能耗情况得出:在低渗透油田开展平衡调整,应用平均功率法要比峰值电流法判定抽油机平衡的准确性高,能够使抽油机达到最低能耗的运行状态,最大限度节约能源;平均功率法判定抽油机平衡的标准宽泛,应用平均功率法判定抽油机平衡的平衡度区间在70%~120%内时,抽油机能耗变化不大,抽油机运行处于最佳平衡状态,能够实现最佳能耗运行状态;抽油机由峰值电流平衡状态调整到最佳平衡状态时,一般可以实现单井日节电11.2 k Wh的效果。因此,平均功率平衡判定方法更适用于指导低渗透油田抽油机平衡调整,能够实现抽油机最低能耗运行,对油田节能降耗工作具有一定的指导意义。展开更多
The monthly mean temperature for October in the Fenglin National Natural Reserve of Wuying, in Heilongjiang province, was reconstructed for the period running from 1796 to 2004 using RES tree ring chronology. The expl...The monthly mean temperature for October in the Fenglin National Natural Reserve of Wuying, in Heilongjiang province, was reconstructed for the period running from 1796 to 2004 using RES tree ring chronology. The explained variance of the reconstruction is 34.8%. In the past 209 years, there are 4 colder and 4 warmer periods according to the reconstructed series. A period of 3.33-year is found significant based on the power spectrum method. Abrupt changes are also detected in the reconstructed series with 30-year time scale based on the smoothing t-test, smoothing F-test and Le Page test methods. Significant abrupt changes in mean value are observed for around 1871 and 1900, and a significant abrupt change in standard deviation is observed for around 1851.展开更多
Wind energy is one of the most promising electricity generating sources as a clean and free alternate compared with the conventional power plants and due to the volatility feature in the wind speeds it will reflect so...Wind energy is one of the most promising electricity generating sources as a clean and free alternate compared with the conventional power plants and due to the volatility feature in the wind speeds it will reflect some problems in power systems reliability particularly if the system is deeply penetrated by wind farms. Therefore, wind power forecasting issue become and is still an important scope that will help in ED （economic dispatch）, UC （unit commitment） purposes to get more reliable and economic systems. This paper introduces short term wind power forecasting model, based on ARIMA （autoregressive integrated moving average） which will be applied to hourly wind data from Zaafarana 5 project in Egypt. The proposed model successfully outperforms the persistence model with significant improvement up to 6 h ahead.展开更多
文摘为了探索低渗透油田适用的平衡判定方法,合理调整抽油机平衡,进一步降低机采举升能耗,开展了抽油机平衡与能耗关系研究。通过对比现场应用的不同平衡判定方法调整效果的准确性和能耗情况得出:在低渗透油田开展平衡调整,应用平均功率法要比峰值电流法判定抽油机平衡的准确性高,能够使抽油机达到最低能耗的运行状态,最大限度节约能源;平均功率法判定抽油机平衡的标准宽泛,应用平均功率法判定抽油机平衡的平衡度区间在70%~120%内时,抽油机能耗变化不大,抽油机运行处于最佳平衡状态,能够实现最佳能耗运行状态;抽油机由峰值电流平衡状态调整到最佳平衡状态时,一般可以实现单井日节电11.2 k Wh的效果。因此,平均功率平衡判定方法更适用于指导低渗透油田抽油机平衡调整,能够实现抽油机最低能耗运行,对油田节能降耗工作具有一定的指导意义。
基金supported by the Special Research Program for Public-welfare Forestry(No. 200804001)National Science and Technology Support Program(No.2007BAC29B01)the Natural Science Foundation of China(No.40705032)
文摘The monthly mean temperature for October in the Fenglin National Natural Reserve of Wuying, in Heilongjiang province, was reconstructed for the period running from 1796 to 2004 using RES tree ring chronology. The explained variance of the reconstruction is 34.8%. In the past 209 years, there are 4 colder and 4 warmer periods according to the reconstructed series. A period of 3.33-year is found significant based on the power spectrum method. Abrupt changes are also detected in the reconstructed series with 30-year time scale based on the smoothing t-test, smoothing F-test and Le Page test methods. Significant abrupt changes in mean value are observed for around 1871 and 1900, and a significant abrupt change in standard deviation is observed for around 1851.
文摘Wind energy is one of the most promising electricity generating sources as a clean and free alternate compared with the conventional power plants and due to the volatility feature in the wind speeds it will reflect some problems in power systems reliability particularly if the system is deeply penetrated by wind farms. Therefore, wind power forecasting issue become and is still an important scope that will help in ED （economic dispatch）, UC （unit commitment） purposes to get more reliable and economic systems. This paper introduces short term wind power forecasting model, based on ARIMA （autoregressive integrated moving average） which will be applied to hourly wind data from Zaafarana 5 project in Egypt. The proposed model successfully outperforms the persistence model with significant improvement up to 6 h ahead.
