井旁地质界面的反射波模拟及f-k偏移成像

Study of the Sound Field Numerical Simulation and Prestack f-k Migration Imaging of Near-borehole Geological Interface

针对现有阵列声波测井仪器,对井旁不同角度和不同位置井旁地质界面的全波波列进行了物理和数值模拟。结果表明,在现有仪器源距范围内,可以从全波波形中观测到清晰的反射纵波。在此基础之上,针对阵列声波全波数据特点,对Stolt的f-k偏移方法进行了改进,使其更适应于阵列声波测井需要。该方法不受地质界面倾角的限制,而且一次可以有效地处理大量现场数据,可以分别得到上倾和下倾井旁地质界面图像。最后,应用该方法对一个倾斜井的阵列声波数据进行了处理,得到了井旁地层界面成像图,验证了该方法的可靠性。

The full-wave waveform of near-borehole different angles and different locations for near-borehole geological interface in the light of the existing array acoustic-logging tools are simulated.The results show that within the limit of these existing equipment source-receiver spacing range,there is be clearly observed P-P reflected wave in the full-wave waveform.On the basis,to use the common source gathers to the characteristics of full-wave waveform the original Stolt＇s f-k according migration is modified,and then it is made to suit configuration of array acoustic logging.The pre-stack f-k migration has no dip angle limitation and therefore can handle large angle dips（with respect to the borehole axis）quite well.It can also efficiently handle a large volume of data in one processing.At last,the technique has been tested with field data sets from a deviated well acoustic logging data set,and clear structural images away from the borehole are obtained to demonstrate the reliability of the technique.