川东南门场高陡构造的地震成像技术试验研究

TESTING STUDY ON SEISMIC IMAGING TECHNIQUES OF NANMENCHANG HIGH-STEEP STRUCTURE IN EAST SICHUAN

南门场构造是四川盆地东部地区主要的含气构造之一 ,其地震地质条件具有四川盆地东部高陡复杂区的共同特点 ,即地形起伏大、普遍出露石灰岩、地下构造复杂。地震勘探的难点是构造主体部位的清晰成像。为解决成像问题 ,进行了以提高资料信噪比与叠加成像质量为目标的采集处理技术联合攻关。攻关中 ,采用正演技术进行灵活的观测系统设计、充分考虑激发炸药类型、接收检波器与岩层的耦合匹配问题、运用潜行波层析反演解决复杂近地表的静校正、使用叠前部分偏移优选CMP道集等方法来提高采集处理质量。经过攻关 ,该区的地震剖面的成像质量较攻关前有明显的提高 ,基本上解决了该区高陡构造成像难的问题。

Nanmenchang structure is one of the main gas-bearing structure in East Sichuan Basin and its seismic-geological conditions are of the common complicated structural characters in East Sichuan region, i. e. large topographic fluctuation, universally outcropping limestones and complicated underground structures. The difficulty of seismic exploration is to make the imaging at structural main portion clear. A joint testing study on the gathering and processing technique of seismic data, which aim is to raise the signal-to-noise ratio of data and the quality of stack imaging was carried out in order to cause the imaging problem's being well solved. In the process of studying, the following methods were adopted to raise the gathering and processing quality, i. e. the forward model technique was used for flexible layout system design; the coupling matching of explosive geophone find rock was fully regarded; the complicated near-surface static correction was made by applying the tomo-graphic inversion of diving waves: and the common midpoint gather was optimized by use of prestack partial migration Through studying hardly, the imaging quality of the seismic sections is obviously raised, thus solving the problem of the high-steep structure's being difficulty imaged.