基于自然伽马测井信号的维纳滤波法求取泥质含量

A Method for Obtaining Shaliness Using Wiener Filtering Based on Logging Data Natural Gamma Ray

泥质含量是定性、定量评价储层属性的一个重要参数.研究经济、适用、高精度的储层泥质含量求取方法,对储层的评价、预测含油气远景和计算储层油气储量意义明确.提出了测井自然伽马求取泥质含量的新原理,认为测井自然伽马信号是地层自然伽马真值通过一个系统的卷积滤波输出.利用测井自然伽马信号和提取的自然伽马真值子波,采用维纳滤波法求取测井系统逆因子函数,根据逆因子函数,用自然伽马测井信号做卷积直接计算泥质含量.本研究在中国西北某油气勘探区有岩心分析资料的K13井进行了试验,求取的泥质含量精度比测井常规解释方法大幅提高,在同一勘探区K11、S44、S4等井试验性应用,效果良好.

The research on approaches to calculate shaliness accurately and efficiently is of great significance for reservoir capacity estimation, as shaliness is an important parameter to evaluate the reservoir qualitatively and quantitatively. Considering logging data GR （natural gamma ray） is the measured output from its real value which passes through a convolution filter, this paper proposes a new approach to calculate the value of shaliness according to GR values directly. The inversion filter factors can be acquired from a certain sequence of the measured logging data GR and the real value of GR, by taking advantage of Wiener filtering. Then, shaliness can be expressed as a convolution between GR sequence and the inversion filter factors. Experiments on core-analysis-data supported oil well K13, Northwest China show that shaliness values obtained with the above method are much more accurate than those obtained with conventional methods. It＇s trial application in oil well K11, S44, S4 of the same exploration area has proved to be very effective.