针对实际油气集输过程中一定时间区间内平均产量基本稳定,但瞬时产量在小尺度范围内尚有波动的情形,利用分形理论和时间序列统计分析相结合的方法,提出了基于分形无标度区间的集输过程产量时间跨度分析模型。利用该模型,对辽河油田3个采油小站的产量进行了分析计算。计算结果表明,集输过程产量时间序列变化在无标度区间内具有分形特征,无标度区间在1~10 000 s范围内,以天为标度间距过大,依本研究计算结果分形特征会消失。各小站集输过程产量时间序列Hurst指数均小于0.5,说明油气集输过程产量变化具有反持续性。研究结果表明利用重标度极差分析(即R/S分析)模型分析油气集输过程产量时间跨度变化规律是可行的。图5表2参13
In the oil-gas gathering and transportation process,oil production changes by time.But in small-scale time intervals,average production is normally stable with instantaneous production fluctuating in a certain range.By combining fractal theory with statistical analysis of time series,this paper proposes a time-span production analysis model based on fractal scale-free intervals.Based on this model,the production data of three small oil producing stations of the Liaohe Oilfield were analyzed and calculated.The calculation showed that: time-series changes of production have fractal characteristics within a scale-free interval between 1-10 000 s in the gathering and transportation process;if take day as scale,intervals will be too large and fractal characteristics may disappear.In the gathering and transportation process of oil and gas,the Hurst indexes of time series in the three stations are all less than 0.5,suggesting that oil-gas production change is anti-continuous.The results showed that it is effective and feasible to use Scaling-Range analysis(R/S analysis) model to analyze time-span variation of oil-gas production in gathering and transportation process.