Design for Vibrator Field Experiment Based-on Vibrator-earth System

Source-generated energy in seismic vibrator records high frequency harmonic behavior. Conventional vibrator-earth coupling model was set up on the linear system. Some assumptions in the application of linear theory to the vibrator problem play an insignificant role in the overall coupling structure. Obviously, non-linear behaviors can be modeled using a “hard-spring” form of the Duffing equation. Model dedicates that a qualitatively similar harmonic component is present for a broad range of possible mathematical descriptions. After some qualitative analysis about the non-linear system, some conclusion can be drawn. Firstly, The design of the vibrator weight should be abided by two points as followed: In order to avoid decoupling for the vibrator to the earth, the weight should be greater than the peak of the driving force amplitude as to keep the resultant force pointing to the earth’s core. On the other hand, for the limited energy output, the vibrator overweight may damage the system high-frequency ability.Secondly, as the driving force frequency approaching to the ground hard-spring inherent frequency, the energy transmission was found to climb its peak from the system energy absorbed curve. At last, due to the non-linear coupling model system, its load curve would come into unstable frequency range, which might limit the application of the Vibroseis conventional sweeping pattern-linear sweep. A new sweeping pattern was listed: the driving signal was the pseudo-random sequence modulated by a fixed frequency cosine signal satisfying with the exploration precision and absorbing efficiency. The synthesized signal was ready to be realized by the electromagnetic driven system. Even the side-lobes noise of its auto-correlation function was restrained well. The theory coming from the Vibrator-earth coupling model was applied to the design of the Portable High-frequency Vibrator System (PHVS), and the good result was obtained. By the analysis of the vibrator base plate signal, the model was proved to be true. The exploration research on PHVS made a first step on its following optimal design.

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在河北省迁安大石河铁矿进行轻便高频可控源 (PHV)地震反射勘探的试验研究是成功的。可控震源的优点主要在于分辨率高、可以自由选择频率范围 ,对输入到地下能量的频谱有一定的控制作用。通过与夯击震源WACKERBS60Y系统结果的对比 ,证实了它工作稳定 ,效率高 ,优于其它震源。

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轻便高频可控震源系统的研制

轻便高频可控震源系统 (PHVS)是一种用于浅层地震勘探和振动测试与分析的仪器系统。本文讨论了PHVS的软、硬件设计与实现。

电磁式可控震源与大地耦合的研究

目前国内各大油田采用的可控震源 ,主要以车载液压式为主 ,频率低 ,重量大。耦合方式是把整车的重量压在激震器基板上 ,由于整车的重量远大于激振器的输出力 ,所以耦合效果较好。通过物理工程建模 ,研究了激震器所输出的力与底座、弹簧、配重的关系。使得实际工作中可以避免激震器与大地脱耦 ,实现在浅层地震勘探时将激震器产生的力最大限度的传入地下 。

轻便高频可控震源的设计与实验

轻便高频可控震源 (PHV)是一种用于工程探测和浅层地震勘探的非爆炸性震源 ,其工作原理来源于Chirp雷达技术 ,它的主要任务是向地下发射参数得到严格控制的Chirp信号。PHV由 3部分组成 :测控单元、振动单元、数据采集与处理单元。其中测控单元是PHV的核心。文中从系统设计出发 ,重点讨论了测控单元的软硬件设计与实现。PHV在唐山地区的实验结果证明它能够稳定、有效的工作 ,而且优于其它非爆炸性震源。

轻便高频可控震源的计算机测控系统

轻便高频可控震源是一种用于工程探测和浅层地震勘探的激震设备 ,它的主要作用是提供参数得到严格控制的Chirp信号 (LFM )。围绕信号的产生和参数的控制 。

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在浅层地质工程应用中,缺乏一种可控、无损、高分辨率的探测工具。一种新型震源———电磁驱动式轻便高频可控震源,填补了空白。通过简单调制扫描频率,可控震源具有探测深度大、分辨率高、工作稳定、抗干扰、效率高等一系列优点。实际应用表明,该技术对应用于采空区、溶洞探测等浅层工程勘察是可行的,探测效果良好。这拓宽了可控震源的应用领域。

电磁驱动可控震源系统在工程勘察中的应用

在浅层地质工程勘察中,缺乏一种可控、无损、高分辨率的探测工具,一种新型震源电磁驱动式轻便高频可控震源,填补了此项空白。通过调制扫描频率,可控震源具有探测深度大、分辨率高、工作稳定、抗干扰、效率高等优点。实际应用表明,该技术对于采空区、溶洞、隧道探测等浅层工程勘察是可行的,探测效果良好,进而拓宽了可控震源的应用领域。