松辽盆地梨树断陷SN167井三维VSP采集参数优化

3D VSP acquisition parameters optimization and its application in Lishu Faulted Depression,Songliao Basin

SN167井是位于松辽盆地梨树断陷中央构造带上的一口大斜度井.针对SN167井区的井-地联合地震资料采集,开展了三维VSP采集参数优化技术应用研究.基于弱各向异性介质假设下计算的入射角与反射系数关系,确定最大井源距;根据不同接收深度时成像范围和覆盖次数的正演结果,分析优选最佳检波器沉放深度;综合考虑目的层成像范围和覆盖次数,选择合适的井下观测点数.应用优化确定的SN167井三维VSP采集方案取得了较好的采集效果,所获三维VSP资料的频宽较地面三维地震资料高出20～30 Hz,井周小断层的分辨能力显著提高.

SN167 is a high-angle deviated well,which is located in the central structural zone of Lishu Faulted Depression,Songliao Basin.Targeted on well-seismic united acquisition of SN167 wellblock,application of 3D VSP acquisition parameters optimization is studied.Based on the assumption of weakly anisotropic medium,the maximum offset can be determined by the calculated relation between incidence angle and reflection coefficient.According to the forward modeling result of imaging range and folds in different depth,the optimization geophone sinking depth was analyzed.Comprehensive consideration of imaging range and folds in target layer identified appropriate number of borehole observation points.Application of optimization and determined 3D VSP acquisition scheme had achieved good effect in SN167 well.The bandwidth of 3D VSP data is 20～30 Hz higher than that of surface 3D seismic data and the resolution of small fault around the well is significantly improved.