陆9井区近地表结构及静校正方法

Near-Surface Structure and Static Correction Method for Lu-9 Well Area in Junggar Basin

地表及近地表结构的纵横向变化是产生不同波长静校正问题的重要因素之一。陆9井区地表为沙漠所覆盖,地形起伏较大,具有典型的风成沉积特征;未胶结的沙丘之下是早期出露于地表的古湖底,分布着胶结或半胶结的砂泥岩互层,具有水成特征。以往该区采用传统的表层结构调查方法,无法获取准确的地表及近地表结构深度、速度参数,以致地震数据存在严重的长波长静校正问题。据此,就陆9井区地震数据不同静校正处理的方法进行分析、对比,其结果表明,表层模型层析反演静校正技术不仅可以用于静校正数据的求取,而且可以建立近地表深度-速度模型,以便连续观测测线下高速层顶界以上介质的纵横向速度变化,为表层结构研究提供依据。

The vertical and lateral variation of surfae or near-surface structnres is one important factos ofausing difereni wave lengths static correction problem. The surface of Lu-9 well area in Junggar basin is covered by desert and characterized by varied reliefs and typical aeolian sediments. Under the uncemented dune ix Ihe early exposed ancient lakebed where cemented or semi-ceniented sandshale interhed is distributed and characterized hy aqueous origin. In the past the traditional surface structure investigation method could not lie used to get accurate depth and veloity parameters of the surface and/or near-surface structures, resulting in thai the long wavelength static＇ correction shouhl be made for the seismic data available. This paper presents the method for such correction of seismic data from this well area. The analysis, comparison and result show thai such a correction can not only be used in obtain the data as required, but also develop the model for near-surface depth vs. velocity, so as to continuously determine the vertical and lateral velocity variations of strata above the lop of high velocity layers and provide basis for the near-surface structural researches.