脉冲氧活化测井水流速度计算方法研究

脉冲氧活化水流速度测井解释的关键是准确求解时间谱上水流信号的峰位.由于时间谱计数存在放射性统计涨落,传统上采用统计方法求解峰位.针对对称谱形和非对称谱形峰形,提出用函数拟合的方法求解峰位,计算被活化水流流经源距的时间.对称谱形用Gaussian分布密度函数,非对称谱形用对数时间坐标上的Gaussian分布密度函数.模拟井实验数据检验表明,峰形拟合的算法计算精度更高.统计算法具有时效高的优点,适宜于现场快速直观解释;函数拟合法适用于对精度要求更高的室内回放解释.

Calculation Method of Water Flow Velocity in Impulse Oxygen Activation Log

The one of important steps concerning data process of impulse oxygen activation water flow log is to accurately locate the peak position in the time spectrum, and its current algorithm is a weighted average time method. Now a function fitting method is used by this paper, in which the objective function selected for background spectrum is a linear function, that for symmetrical spectrum shape is Gaussian distribution density function, and for unsymmetrical spectrum shape is Gaussian distribution density function on logarithmic time axis. Test in well model shows that the weighted average time method is preferred in wellsite interpretation for its better efficiency in time; while function fitting method is preferred in station reprocess interpretation for its better accuracy.