提高碳氧比能谱测井分辨率的反褶积法

THE DECONVOLUTION METHOD FOR RESOLUTION ENHANCEMENT IN C/O SPECTRAL LOGGING

在地层孔隙度比较低的情况下,由于受放射性统计涨落以及地层中其它核反应所产生的伽马射线的影响,传统的碳氧比能谱测井解释的分辨率不高。这些伽马射线形成了碳氧比能谱测井的本底,本底越高,碳氧比值精度越差。因此,必须设法降低本底值来提高谱线的分辨率。本文通过反褶积技术来提高谱线的分辨率,应用修正的高斯函数作为系统响应函数对测井曲线进行反褶积;采用修正的 Blackman 窗函数来消除放射性统计涨落的高频噪声,通过实际资料验证,利用"反褶积-开窗"法对碳氧比能谱测井的谱线进行处理以及用变系数法求取非弹性散射伽马谱,提高了测井资料对油、水储集层的分辨率,对油田的合理开发及油藏管理具有重要的现实意义。

In the case of low formation porosity,because of the influences of radioactive statistical variation and induced Gamma-ray produced by other nuclear reactions in the formation,the resolution of C/O spectral log was poor and its applications was limited.The background of C/O spectral log consists of these Gamma-ray,in which the higher the background,the poorer the resolution of C/O spectral logging.In order to enhance the resolution of C/O spectral logging,the background must be reduced.This paper introduces a deconvolution approach to deal with the spectrum obtained from the C/O spectral log.The amendment Gauss function is used as system response function to deconvolute the spectrum and the amendment Blackman window is used to reduce the high freqeuency noises produced by the radioactive statistical variation.The results show that this approach can effectively enhance the C/ O spectral log resolution.