混频信号数字检波方法在阵列侧向测井中的应用  

Application of Digital Detection Method for Mixed Signal in Array Lateral Logging

作　　者：高怡[1] 李东航 曹景致 张翔宇 罗旋 GAO Yi;LI Donghang;CAO Jingzhi;ZHANG Xiangyu;LUO Xuan(School of Electronic Engineering,Xi’an Shiyou University,Xi’an,Shaanxi 710065,China;Logging Technology Research Institute,CNPC Logging Co.,Ltd,Xi’an,Shaanxi 710077,China;Jilin Branch,CNPC Logging Co.,Ltd.,Songyuan,Jilin 138000,China)

机构地区：[1]西安石油大学电子工程学院,陕西西安710065 [2]中国石油集团测井有限公司测井技术研究院,陕西西安710077 [3]中国石油集团测井有限公司吉林分公司,吉林松原138000

出　　处：《西安石油大学学报（自然科学版）》2023年第5期98-103,91,共7页Journal of Xi’an Shiyou University（Natural Science Edition）

基　　金：国家自然科学基金(51604226);西安石油大学研究生创新与实践能力培养计划项目(YCS22113107)。

摘　　要：阵列侧向测井已经成为目前电法测井领域研究的热点。准确、快速地提取出混频信号中每个频率点处的信号幅值是最终准确计算地层视电阻率的关键。数字相敏检波(DPSD)与快速傅里叶变换(FFT)是侧向仪器常用的两种数字检波方法。传统基-2 FFT采用雷德算法进行倒位序使得整体运行速度较慢,本文针对此问题进行了优化。测试结果表明:DPSD运算速度为传统基-2 FFT的7倍左右,改进算法的运算速度较原来提高了近1倍;精度方面,当待测信号与标准信号无相位差时,DPSD计算精度略高于FFT,但当相移增大时,DPSD误差显著增加,而FFT的计算误差则不受相位差影响。两种方法在阵列侧向仪器的应用实例表明:与DPSD相比,使用FFT所测得的电阻率曲线一致性更好,并且可测出视电阻率值高达45000Ω·m的高阻地层,仪器测量精度更高,为准确识别油气层提供了更加可靠的资料。Array logging has become a hot spot in the field of electrical logging.How to accurately and quickly extract the amplitudes of the signals with different frequencies in mixed signal becomes the key to accurately calculating the apparent resistivity of formation.Digital phase-sensitive detection(DPSD)and fast fourier transform(FFT)are two digital detection methods commonly used for lateral logging instruments.Traditional base-2 FFT uses Reed algorithm to reverse bit sequence,which makes the overall running speed slow.This problem is optimized in this paper.The test results show that the operation speed of DPSD is about 7 times that of the traditional base-2 FFT,and the operation speed of the improved algorithm is nearly doubled.When there is no phase difference between the signal to be measured and the standard signal,the calculation accuracy of DPSD is slightly higher than that of FFT,but when the phase difference increases,the calculation error of DPSD increases significantly,while the calculation error of FFT is not affected by the phase difference.The application examples of two methods in array lateral instruments show that,compared with DPSD,the resistivity curve measured by FFT is more consistent,and the high-resistivity formation with apparent resistivity as high as 45000Ω·m can be measured.So the instrument has higher measurement accuracy and provides more reliable information for accurately identifying oil and gas reservoirs.

关 键 词：阵列侧向测井 混频信号 数字相敏检波 FFT 信号采集与处理 

分 类 号：TE927[石油与天然气工程—石油机械设备]