复杂地表二维弯曲测线地震资料处理方法研究

Research on 2-D seismic data processing slalom lines in complex surface condition

(中国石油化工股份有限公司江苏油田物探技术研究院，江苏南京210046)

Geophysical Prospecting Technology Institute, Jiangsu Oilfield, SINOPEC, Nanjing 210046, China

YM地区地表为平台、洼地、冲沟、悬崖等构成，高程变化剧烈，出露地表的岩性复杂。虽然通过采用弯曲测线方式改善了激发接收条件，但在原始地震资料上，干扰类型多，静校正问题突出，信噪比极低；采用常规处理方法处理后的叠加剖面，画弧现象严重，信噪比不高。为此，开展了针对性的处理方法研究。针对弯曲测线剖面位置偏离地下实际反射点位置这一问题，通过利用弯曲测线几何库定义观测系统，并采取一定的措施进行质量控制，确保CMP点的走向与测线走向基本吻合；针对干扰类型多这一问题，联合应用多种去噪方法，在叠前道集上和叠后剖面上进行去噪处理；针对静校正问题复杂这一问题，以野外提供的静校正量为基础，联合应用多种方法解决长波长静校正问题；针对地震资料对叠加速度非常敏感这一问题，采用常规速度扫描和精细速度分析方法来获取准确的叠加速度场；针对剖面的信噪比低这一问题，采用速度分析和剩余静校正多次迭代方法来提高。采取以上措施对老资料进行重新处理后，资料的信噪比得到了大幅度提高，划弧现象较轻。

The surface of YM area is consisted of plains, lowlands, scour channels and cliffs with a big change in elevation and a complex surface lithology. Though the shooting and receiving conditions have been improved by slalom lines, there still exist many problems in original shot records, including many kinds of noises, serious statics problem, and extremely low S/N ratio. The stacked profiles processed by conventional methods are serious in arcs migration and low in S/N ratio. So the responding processing methods have been studied: 1) Aimed at the deviation of slalom linesprofiles position from actualreflectionpoint position, the slalom line geometry definition and quality control are utilized to ensure the trend of CMP points coincide with the slalom lines; 2) Aimed at many types of interference, noise is removed on both prestack gathers and poststack profiles by using several denoise methods; 3) Aimed at the complex statics problem, the longwavelength statics problem is solved by joint application of many methods based on the field statics provided by geophysical crew; 4) Aimed at the sensibility of seismic data on stacking velocity, the conventional velocity scan and detailed velocity analysis are used to extract accurate stacking velocity field; and 5) Aimed at the low S/N ratio, repeated iteration of velocity analysis and residual statics is adopted to increase the ratio. After reprocessing the seismic data by this method, the S/N ratio has been increased greatly, and migration arcs lessened.