徐家围子断陷致密砂砾岩目标地震处理技术

Seismic processing techniques for tight sandy-conglomerate objective in Xujiaweizi fault depression

地震资料的逆时偏移是基于双程波发展起来的适合复杂波场的高精度成像方法.松辽盆地北部深层的致密砂砾岩是天然气勘探的重点领域,受上覆火山岩地层的屏蔽影响,加之地质构造复杂,使得该地区的地震波场特征复杂.在传统保幅处理的基础上,对研究区进行表层Q的吸收衰减补偿,可有效展宽地震资料的频带;另外,基于网格层析方法和Kirchhoff深度偏移完成深度域的速度模型建立,将预处理后的炮记录和深度域速度模型作为输入,应用GeoEast-Lightning软件的逆时偏移方法完成了研究区三维地震资料的逆时偏移处理,成像效果较以往Kirchhoff积分法叠前深度偏移有较为明显改善,成像数据体可用于后续构造解释和综合地质研究中,所形成的成像处理流程可在大庆探区推广应用.

Seismic data reverse time migration is an algorithm which developed based on two-way wave equation. The tight sandy-conglomerate objective in the deep of north Songliao basin is the major field of gas exploration, which affected by the shield effect of overlying igneous rock formation and the complex geological structure, it makes the seismic wavefield characterization of the researched survey complicated. After we complete the amplitude-preserved preprocessing and velocity modeling of 3-D seismic data in this survey, we apply reverse time migration method of the GeoEast-Lightning software to complete the reverse time migration processing of the researched survey. Compared with the traditional pre-stack depth migration of Kirchhoff integral method, the imaging result has been obviously improved. The imaging data can be used for subsequent structure interpretation, attribute analysis and comprehensive geological study. The imaging processing of this method can be popularized and applied for Daqing exploration area.