FIR滤波器海上试井压力数据预处理方法

Preprocessing method of offshore well test pressure data based on FIR filtering method

试井压力恢复测试与解释可以获取储层参数,但海上油气井底压力数据受到潮汐、噪声等因素影响时,会影响试井解释模型的判断和参数解释。因此,需要在数据解释分析之前对原始数据进行预处理。针对海上油气井测试中压力数据出现的异常特征,利用FFT变换方法将原始数据从时间域变换到频率域,判断异常特征的幅值响应及对应的频率范围;根据特定的频率范围指标设计FIR滤波器,把包含储层有用信息的频率响应范围设置为通带,潮汐、高频噪声所在的频率响应范围则设置为阻带,抑制其幅值。通过模拟数据及现场实测数据的处理过程显示,FFT变换和FIR滤波组合方法能够有效识别和去除压力数据中的异常特征,并保留有用的储层物性信息,从而减少对模型判断以及对储层参数解释的影响。

Reservoir parameters can be obtained from well test pressure build-up test and interpretation,but when the bottom hole pressure data is affected by tide,noise and other factors,it will affect the judgment and parameter interpretation of well test interpretation model.Therefore,it is necessary to preprocess the original data before data interpretation and analysis.Aiming at the problem of abnormal characteristics in pressure data in offshore oil and gas well test,FFT transformation method is used to transform the original data from time domain to frequency domain to determine the amplitude response and corresponding frequency range of abnormal characteristics.The FIR filter is designed according to the specific frequency range index.The frequency response range containing useful information of reservoir is set as passband,and the frequency response range of tide and high-frequency noise is set as stopband to suppress its amplitude response.The processing results of simulated data and field measured data show that the combination of FFT transform and FIR filter can effectively identify and remove the abnormal characteristics in pressure data,and retain useful reservoir physical property information,so as to realize the judgment of interpretation model and reservoir parameter interpretation.