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近年来,非炸药震源——气枪(PAR Air Gun),已广泛使用在海洋地震勘探。它用多枪組合法(組合数达30多只)来提高激发能量。但是,当它在浅水沼泽地区使用,由于水底与水面較近,气枪所激发的声脉冲能量輸出急剧下降。用加大枪室容积,增加气枪压力等方法,效果极不理想。本文主要叙述气枪在不改变排气口形状及激发的声脉冲波形特征情况下,增加一个带有同样排气口和加速开門活塞的第二气室,两个气室相互联合,二个活塞相互串联,构成一个串联双活塞气枪,簡称为联合气枪。由于第二气室的减压是受第一气室减压的影响,促使第二气室的开门活塞速度大大提高,贮能的高压气便得到充分有效的释放,从而达到了联合气枪的大能量声脉冲激发。为适用于浅水沼泽地区工作,现将气枪位于水中激发方式变为插入泥层中的激发方式,大大提高了声脉冲能量輸出。测量表明,联合气枪的激发能量大部分集中在10赫～80赫。主频率在35赫附近,基本符合地震勘探。在相同工作压力与容积条件下,联合气枪的激发能量比气枪大6倍以上。其地震剖面記录效果和3公斤炸药井炮相当。
In recent years, the non-explosive source rocker (PAR Air Gun) has been widely used in marine seismic exploration. It uses a combination of multiple guns (combination of more than 30 only) to increase the excitation energy. However, when it is used in shallow-water swamps, the acoustic pulse energy output triggered by the airgun drops sharply as the water bottom is closer to the water surface. Increase gun chamber volume, increase air gun pressure and other methods, the effect is very unsatisfactory. This article mainly describes the air gun without changing the shape of the exhaust port and excited by the characteristics of the acoustic pulse waveform, adding a second exhaust chamber with the same exhaust port and accelerate the opening of the second chamber, the two chambers combined with each other, two pistons In series with each other to form a series of double-piston air gun, referred to as the joint air gun. Because the decompression of the second chamber is influenced by the depressurization of the first chamber, the opening piston speed of the second chamber is greatly increased, and the high-pressure reservoir of energy storage is fully and effectively released, so that the large Energy sound pulse excitation. For the shallow marsh area work, the air gun is now located in the water excitation mode into the mud layer into the excitation mode, greatly improving the sound pulse energy output. The measurements show that most of the combined air-gun excitation energy is concentrated in the range of 10 Hz to 80 Hz. The main frequency near 35 Hz, basically in line with seismic exploration. Under the same working pressure and volume conditions, the combined air gun’s excitation energy is more than 6 times larger than the air gun. The seismic profile recording effect and 3 kg of explosives well guns quite.