复杂近地表区走时射线层析的应用及效果  

Application of travel-time ray tomography in complicated near surface areas and its effect

作　　者：周翼[1] 杨洪波 黄有晖[1] 吕景峰[2] 张立超 陈建国[2] 

机构地区：[1]中国石油塔里木油田公司 [2]中国石油集团东方地球物理勘探有限责任公司

出　　处：《天然气勘探与开发》2017年第4期52-58,共7页Natural Gas Exploration and Development

基　　金：国家科技重大专项"库东坳陷深层-超深层天然气开发示范工程"(编号:2016ZX05051-001)

摘　　要：塔里木盆地油气资源蕴含量丰富,勘探前景良好,是我国西气东输的主力气源地。该盆地地表类型主要为沙漠、山地山前带及黄土塬等,表层结构复杂多样,纵、横向上变化剧烈,其地震波静校正问题较为严重。多年攻关经验表明,与模型静校正方法相比,初至层析反演静校正技术是解决复杂近地表区静校正问题的有效途径。但是随着高密度、宽方位采集技术的推广应用,地震初至数据剧增,严重影响了层析反演的计算周期。为此,提出了一种提高层析反演效率的方法 :(1)确定合理的层析反演网格面元及偏移距范围;(2)按照一定方式抽稀初至数据;(3)采用抽稀后的初至数据层析反演,获得近地表速度场;(4)根据给定的基准面及替换速度计算静校正量。结果表明:该方法经过理论模型数据及实际资料对比验证后能够保证静校正精度,并在2016年度的实际三维地震勘探中,取得了良好的效果。The Tarim Basin, as the main gas source of West-to-East Gas Pipeline Project in China, has abundant oil and gas resources and presents promising exploration prospect. In the Tarim Basin, the surface is mainly in the forms of desert, mountain front belt and loess tableland. The surface structures are complicated and diverse and they change violently in vertical and lateral directions, so their static correction of seismic wave is difficult. Years＇ research experience shows that compared with the model static correction method, the first-arrival tomographic inversion static correction is more effective to solve the static correction problems of complicated near surface areas. With the popularization and application of high-density, wide-azimuth acquisition technology, however, the number of first-arrival seismic data is increased sharply, so the calculation cycle of tomographic inversion is impacted seriously. In this paper, a method for increasing the efficiency of tomographic inversion was proposed. First, determine the rational surface element and offset range of tomographic inversion grid. Second, thin the first-arrival data by means of a certain method. Third, conduct tomographic in- version using the thinned first-arrival data to calculate the velocity field near the surface. And fourth, calculate the static correction on the basis of the given datum and replacement velocity. It is verified by comparing the theoretical model data and the actual data that this method can guarantee the accuracy of static correction. It was practically applied to the 3D seismic exploration in 2016 and the application effect is satisfactory.

关 键 词：塔里木盆地 复杂近地表区 表层结构 静校正 层析反演 海量数据 

分 类 号：P618.13[天文地球—矿床学] P631.4[天文地球—地质学]