【作者】 王鹏；

【导师】 王夫运； 葛洪魁；

【作者基本信息】 中国地震局地球物理研究所 ， 固体地球物理学， 2009， 硕士

【摘要】 随钻地震(Seismic While Drilling)技术是勘探地球物理与石油工程相结合的产物,是一项学科交叉的技术。它以钻头破岩产生的地震波为震源,采集从地层传播上来的振动信号,获得钻头前方地层的反射波信息,用于评价待钻地层、预测超压层、地层界面和地层特性,以降低钻井风险、提高钻井质量。因钻头振动能量弱、井场噪音能量强以及随机连续振动造成的不同时刻、不同震相的波相互叠加,使SWD信噪比很低,波场非常复杂,数据处理难度大。现场实验周期长、费用高、地下结构等未知因素多,不利于开展SWD研究。而数值模拟具有在控制条件下开展研究的优势,是一种高效、廉价的数值实验方法。本文在SEISMOD地震波场模拟软件和MATLAB信号分析软件的基础上,针对随钻地震低信噪比、连续随机震源信号的特点,以粘弹性介质地震波动方程、交错网格高阶有限差分数值解法和互相关信号分析为核心,建立了SWD数值实验平台,算例验证了模拟平台的可靠性。同时利用该平台对SWD波场传播、直达波与反射波时距曲线特征、数据处理方法等进行了数值实验,深化了对SWD波场传播规律和SWD处理方法的认识,为随钻地震技术研究提供了一种高效的研究手段。更多还原

【Abstract】 Seismic while drilling (SWD) is a combination of exploration geophysics and petroleum engineering. It takes the working drill-bit vibration as seismic source, acquiring the reflected wave propagating through the formation. It is useful to evaluate the formation ahead of the drill-bit, predict abnormal pressure and formation interface, and reduce the drilling risk.Because of the low energy of drill-bit vibration and the high energy of rig noise, as well as the superposition of different time and different phasic wave that induce the SWD signal to noise ratio(S/N) much low, make the wave-field much complex, so data processing is very difficult, and that locale experiment present many unknown factors, such as long period, high expenses, unknown geological structure underground, that is disadvantage for developing SWD research .But numerical simulation have the advantage of develop research in control, that is high-efficiency and low-expense numerical experiment technique. This article is based on seismic wave-field simulation software SEISMOD and signal processing software MATLAB, for SWD low signal to noise ratio and continue random seismic-source signal, taking seismic wave equations in sticky and elastic media and the staggered grid high-level finite-difference numerical solution and the signal processing method of the cross-correlation as the central part, makes a SWD numerical simulation experiment solution, the example validate the solution correct. Utilizing this solution to do some numerical experiments, such as SWD wave-field propagation, the time-distance curve character of direct wave and reflect wave, data processing method, deepen the apprehension to SWD wave-field propagation rule and processing method, for SWD technique research offers a efficient research method.更多还原