单点数字检波器地震资料中弱信号特征分析及识别方法

弱信号的检测和识别是当今地球物理学界非常关注的一个技术问题.对于高密度单点资料究竟多弱的信号才是弱信号,如何检测和识别,以往学术界很少有这样的文献报道.本文以理论研究为主,结合胜利油田某高密度实际资料,对此做了分析和讨论,得出以下初步结论:①就视觉分辨率而言,当弱信号的信噪比S/N＞2时,较易识别；S/N=1时,有可能...

Weak signal characteristics and its identification in high-density single sensor data

The detection and identification of weak signal is a well known technical issue in todayrsquo;s geophysical industry. For high-density single sensor data, there is little information on how weak the signal will be called weak signal and how to detect and identify it in existing academic literatures. Based on theoretical study and combined with analyzing LJ high density data from Shengli Oilfield these questions were touched with and discussed in this paper.We draw the following conclusions: ①In terms of visual resolution, the weak signal is more easily identified when signal to noise ratio S/N2, it may be wrongly identified when S/N=1,and it is basically impossible by visual recognition and interpretation when S/N0.5. 20= 170= 210= for= thin= n= is= the= lower= limit= estimating= its= background= noise= will= significantly= affect= weak= signals= in= deep= part= and= death= value= of= high-density= data= signal= just= amplitude= environmental= noise.= a= single= shares= less= frequency= spectrum.= random= mainly= affects= high= low= spectrum= response= remarkably= altered= even= if= comes= up= to= 5.= has= wide= band= hz.= target= layer= faster= high-frequency= attenuation= at= above= hz= shows= similar= variation= with= difficult= be= horizontal= co-phase= mixed=1) can still be effectively detected after processed with singular value decomposition (SVD), and the S/N=0.5 is the cut-off point determining whether SVD can be used to process the common midpoint (CMP) data after normal moveout (NMO) or not. Even if N/S reaches to 3, it can still be restored by curvelet transform. This gives us an enlightenment that, for high-density single-point data, there is still large potential of identifying more weak signals as long as we use a proper processing technique.