小波分析在水淹层定性评价中的应用

小波分析具有多分辨率的特点，在时频两域都具有表征信号局部特征的能力，是一种窗口大小不变但其形状可以改变的时频局部分析方法。由于小波系数与储层有着很好的相关性，对于岩相变化较小的复杂碳酸盐岩储层，小波分解后的高频小尺度信号就是岩石中流体性质情况的反映。水淹层评价中最重要的就是弄清楚地层中流体性质的变化情况，故利用Daubechies小波函数对测井资料中的电阻率曲线进行离散小波变换和小波单支重构，然后计算小波系数能量和单支重构高频信号能量，作出平均能量随分解层数（尺度）变化的关系图，从而定性地评价水淹层。通过在让那若尔油气田2口井的实际应用，证明该方法在水淹层定性识别中不受岩性、孔隙结构等因素的影响，具有广泛的应用价值。

APPLICATION OF WAVELET TO QUALITATIVE EVALUATION ON WATER FLOODED LAYER

Wavelet analysis, characterized by multi resolution and capability to signify signal’s partial property both in time and frequency, is a partly analytical method of time frequency that can maintain window’s size but change its shape. Since wavelet coefficient is related to reservoir well, high resolution small scale signal after wavelet decomposition is reflection of fluid property in rocks for carbonate reservoir with little facies change. The most important for evaluation is to make the change of fluid property in rocks clear, so discrete wavelet transformation and wavelet single scale reconstruction are done to RT logging data by Daubechies wavelet function, then relationship map between average energy and variance of wavelet level is drawn after calculating energy of wavelet coefficient and high frequency signal energy of single scale reconstruction to quantitatively evaluate water flooded layer. It is proven by its application in 2 wells in the Zhalaroer oil and gas field that this method can be applied in field widely since it will not be influenced by lithology and pore texture etc.