油藏电缆地层测试压力信号的小波分析

Wavelet analysis for reservoir pressure signal of wireline formation test

为了抑制非地层压力等噪声信号,有效地提取与产能评价密切相关的油藏压力信息,详细地探讨了电缆地层测试的流动方式及物理方程之后,基于小波分析基本原理,深入剖析了电缆地层测试压力信号的小波分析方法。利用小波分析高分辨率的特点,采用小波变换分析法从不同尺度上提取了电缆地层测试压力的小波系数。结果表明,经小波变换处理后的电缆地层压力测试曲线能够有效地反映地层中的流体信息;不同尺度上提取的电缆地层压力的小波系数中,高频小波系数d1和d2包含的产能及渗透率等信息更强;采用小波变换后降低了干扰信号的影响,突出了油藏产能信号,进而提高了采样数据的可靠性。这也充分说明利用小波分析方法对油藏电缆测试压力信号处理后,油藏产能信息更为明晰,进而提高了油藏电缆地层测试压力有用信号的提取精度,且该法处理方式更为简单,为今后油藏电缆地层测试压力数据处理方法提供了一种新手段。

In order to restrain noise such as the formation pressure,and effectively abstract pressure information which is closely related to the production evaluation,the flow pattern and the physical equations of the wireline formation testing are derived. The wavelet analysis method for wireline formation test pressure is analyzed using the method of wavelet transform. In accordance with high-resolution features of wavelet analysis,the wavelet coefficients of the wireline formation pressure are extracted from different scales. The results show that the test curve of wireline formation pressure reflects the information flow of formation. The wavelet coefficients of high frequency wavelet coefficients of d1 and d2 in different scales from wireline formation pressure contains information such as the capacity and permeability stronger; The effects of interfering signal is reduced using wavelet transform,and the reservoir capacity signal is highlighted,thus the reliability of the sampling data is improved. Through wavelet decomposition for reservoir wireline formation test pressure data,the reservoir capacity information are more clear. Thereby the extraction accuracy of useful signal for reservoir wireline formation pressure test is improved,and the method is simple,it provides a new means for the data processing of wireline test pressure of the reservoir.