全方位局部角度域叠前深度偏移成像技术及其应用——以准噶尔盆地车排子逆掩断裂带为例

Application of omnidirectional local angle domain prestack depth migration in overthrust fault zone--Take Chepaizi overthrust fault zone in Junggar basin as an example

准噶尔盆地经过多期建造和改造,逆掩断裂发育、构造复杂,地层速度横向变化非均质性强的特点,使得地震数据的信噪比较低,很难获得准确的地下构造成像。针对复杂逆掩断裂带构造成像困难的问题,从全方位局部角度域叠前深度偏移成像的原理入手,应用了偏移孔径内所有的地震波场数据以及各方向波场的方位信息,在角度域对成像道集进行构建,通过镜像加权得到高质量的地下构造成像资料。常规Kirchhoff叠前深度偏移与全方位局部角度域叠前深度偏移资料的对比结果表明,全方位局部角度域叠前深度偏移技术能够满足构造精细解释和勘探生产的地质需求。

The Junggar basin is characterized by multiple periods of construction and reconstruction,overthrust fault development,complex structure,and strong heterogeneity of lateral variation of formation velocity.This makes the signal-to-noise ratio of seismic data low and it is difficult to obtain accurate underground structural imaging.For complex overthrust fault structure imaging and difficult problems,from the perspective of comprehensive local domain prestack depth migration imaging principle,this paper applied the migration aperture within the whole seismic wave field data and the location information of each direction of wave field in angle domain to build imaging gathers,and then high quality of underground structure is obtained by image weighted imaging data.The comparison of conventional Kirchhoff prestack depth migration data with omnidirectional local angle domain data shows that the omnidirectional local angle domain prestack depth migration technology can meet the geological needs of fine structural interpretation and exploration and production.