考虑多因素衰减的陆域大容量气枪震源子波模拟及其影响要素分析

The Simulation of Large Volume Air-Gun Excited in Land Area and Analysis of Its Influence Factors

建立针对大容量气枪震源的气泡振荡方程及压力子波方程,引入多个对模拟结果具有重要影响的修正因子,包括基于开口的热力学模型、枪口节流作用、蒸发冷凝、枪体影响、气体释放率等来改善传统的单枪压力子波计算方法。利用模型及与水库实测的子波比对结果,分析各修正因素对子波模拟的影响,通过改进的单枪信号进一步计算大容量枪阵的压力子波。对比改进的模拟方法预测的子波波形与实测信号,结果显示,改进的模型比原有模型能更好地模拟单枪和枪阵的震源子波。最后,分析了模型产生模拟误差的原因。

The bubble oscillation equations and pressure wavelet equations for large-capacity air-gun source are established,and several correction factors that have important influence on the simulation results are introduced,including open thermodynamic model,muzzle throttling,evaporation and condensation,gun body’s influence and air release rate to improve the traditional method of single air-gun pressure wavelet calculation.By comparing the simulation and the measured wavelets of reservoir experiment,influences of each correction factor on the wavelet simulation is analyzed,and the pressure wavelet of the large-capacity air-guns array is further calculated by the improved single-airgun signal.Comparing the wavelet waveform predicted by the improved simulation method with the measured signal,It shows that the improved model can simulate the source wavelet of single gun and gun array well.Finally,the reason why the model produces simulation error is analyzed.