叠前时间偏移技术及其在三江盆地的应用

Prestack time migration technology and its application in Sanjiang basin

（1.吉林大学地球科学学院，吉林长春130061；2.中国石油化工股份有限公司河南油田分公司石油勘探开发研究院，河南南阳473132）

College of Geosciences, Jilin University, Changchun 130061, China

三江盆地前进坳陷XDLZ地区构造较复杂，以往开展的二维叠后时间偏移成像精度低且空间位置不够准确，为此进行了二维叠前时间偏移处理研究。首先分析了Krchhoff积分法叠前时间偏移处理中关键技术和参数（如叠前去噪、振幅补偿、反褶积、静校正、均方根速度建模和偏移孔径选取）对研究区复杂构造成像的影响及处理技巧；然后对叠前时间偏移和叠后时间偏移在该区的应用效果进行了对比分析，表明Kirchhoff积分法叠前时间偏移处理结果包含的地震信息更加丰富，深层复杂构造成像得到改善，同相轴的连续性和断层及断点空间位置更趋合理， 成像相位和振幅误差较小，构造成图精度较高（约提高了4％）；最后，指出了该技术在实际应用中应注意的问题。

XDLZ area of Qianjin sag in Sanjiang basin has complex structure. In the past, the precision of 2D poststack time migration imaging was low, and the space location was not accurate. Therefore, the 2D prestack time migration imaging was carried out in this area. Firstly, the key technical parameters in prestack time migration by Kirchhoff integral method were analyzed, including prestack de-noise, amplitude compensation, de-convolution, statics, root-mean-square velocity model building and migration aperture selecting. The influence on the imaging of the complex structure in the area and the handling techniques were studied. Then, the comparative analysis of prestack and poststack time migration shows that the results of prestack time migration processing by Kirchhoff integral method contain more seismic information. Meanwhile, the event consistency and the spatial position of faults and breakpoints in deep complex structure imaging are more reasonable, the error of imaging phase and amplitude are smaller, and the accuracy of structure mapping raises about 4%. Finally, the aspects should be cared in actual application were pointed out.