摘要
In this paper, we theoretically and numerically study a combined monopole–dipole measurement mode to show its capability to overcome the issues encountered in conventional single-well imaging, i.e., the low signal-to-noise ratio of the reflections and azimuth ambiguity. First, the azimuth ambiguity, which exists extensively in conventional single-well imaging, is solved with an improved imaging procedure using combined monopole–dipole logging data in addition to conventional logging data. Furthermore, we demonstrate that the direct waves propagating along the boreholes with strong energy, can be effectively eliminated with the proposed combined monopole–dipole measurement mode. The reflections are therefore predominant in the combined monopole–dipole data even before the signals are filtered; thus, the reflections' arrival times in each receiver are identified, which may help minimize the difficulties in filtering conventional logging data. The optimized processing flow of the combined measurement mode logging image is given in this paper. The proposed combined monopole–dipole measurement mode may improve the accuracy of single-well imaging.
高质量的观测系统是获得高质量地震数据的关键,并能影响到数据处理成像的精度。本文在分析观测系统质量与四个采集参数(接收道数,跑线距,接收线距和接收线数)关系的基础上,提出了基于综合质量因子的观测系统质量评价方法,给出了观测系统质量随四参数变化的关系式。根据野外采集实际资料,利用综合质量因子评价方法,计算并给出了观测系统随四参数变化的关系曲线,分析结果显示,炮线距对观测系统质量影响最大,接收线距的增大可以适当的提高观测系统质量,接收道数增加可以提高观测系统质量,不同的采集参数对浅层和深层同相轴成像质量有不同的影响。并利用模型正演和叠前深度偏移方法生成不同采集参数的叠前深度偏移剖面,成像结果显示与上述计算分析结果一致。在实际生产中根据目的层深度,应用本文质量因子评价方法指导观测系统的设计,优选采集参数,达到提高地震数据成像精度的目的。
基金
supported by the National Natural Science Foundation of China(Nos.11574347,11374322,11134011,11734017,and 91630309)
PetroChina Innovation Foundation(No.2016D-5007-0304)
