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为了对横向范围不大的地下浅层特征进行层析成象研究,非常需要一种高频廉价的井中震源,对经费预算有限的研究者来说,这一点尤为重要。作者根据现成的元件制成了一种简单的电弧发射震源。这种震源由注有盐水的一个瓶子及瓶内有裸露的同轴电缆导体组成,通过导体可发射出100至300焦耳的电能。这种震源能产生主频在1.5千赫左右的地震脉冲其半功率带宽超过千赫。在水平井距为100米的情况下,用该震源能产生足够的能量,观测的地震信号的信噪比至少为35dB。当井距为33.2米时在垂直面至68°角范围内观测到的地震信号至少为35dB。作者已测定,该震源的流体静压头大致为430米。
In order to study the tomographic imaging of shallow horizontal subsurface features, there is a great need for a high-frequency, low-cost source in the well, which is particularly important for researchers with limited funding. The author has made a simple arc-firing source based on off-the-shelf components. The source consists of a bottle of saline water and a bare coax conductor in the bottle that emits 100 to 300 joules of electrical energy through the conductor. This source produces a half-power bandwidth of more than kilohertz at a seismic pulse of about 1.5 kHz. With a horizontal well spacing of 100 meters, enough energy is generated from this source, and the observed signal-to-noise ratio for seismic signals is at least 35 dB. Seismic signals observed at a vertical plane to a 68 ° angle of at least 35 dB at a well spacing of 33.2 meters. The authors have determined that the hydrostatic head of the source is approximately 430 meters.