检波点位置偏移原则在准噶尔盆地沙漠区地震采集中的应用

“避高就低”的检波点位置偏移原则在塔里木盆地大沙漠区提高地震资料分辨率方面取得了效果,但是在准噶尔盆地沙漠区并不完全适用。利用基于实际资料的大数据统计方法对共检波点道集有效频带的能量和信噪比变化关系进行了分析,结合不同地表地貌的湿度、压实度、地表植被发育等地表物性的抽样验证,发现沙漠地表物性空间上的差异性与检波器接收响应相关,是造成接收道之间地震反射能量、相位差异的主要因素之一,在局部范围内其影响程度要强于地表高差。为此,提出了“先避虚就实,后避高就低”的检波点位置偏移原则,并应用理论模型模拟的方法论证了不同的检波点位置偏移距离对波场均匀性的影响,分析了检波点位置偏移距离的约束范围。依据地表植被发育程度(颜色)坡度高程的检波点位置选择优先顺序,以地表面元为约束范围在准噶尔盆地沙漠区完成了一条二维宽线采集的检波点位置偏移对比试验,选点偏移的优选检波点后的道集资料和成像剖面目的层反射的高频端均有不同程度的拓宽,验证了该沙漠区检波点位置优选方法对提高有效地震信号分辨率的有效性。

The principle of deviating detection positions to “avoid high and choose low surfaces” has achieved the desired result in improving the resolution of seismic data in a large desert in the Tarim Basin.However,it is not applicable in the Junggar Basin.This study analyzed the energy and signal-to-noise ratio of the effective frequency band of common receiver gathers via statistical analysis of actual big data and then analyzed surface physical properties,such as the humidity,compactness,and surface vegetation development,of different surface topographies.We then verified that the spatial differences in the deserts surface physical properties are closely related to the detector receiving response,are another major factor causing the difference in seismic reflection energy and phases between receiving channels,and have a stronger influence than the difference in surface height locally.This study proposes the principle of choosing the detection position by “first avoiding a loose surface and choosing a compacted one,then avoiding high surface and finding a low one,” demonstrates the influence of deviations in the detection point on seismic wave field uniformity using theoretical model simulation,and proposes the constraint distance of the detection point deviation.Based on the preferred order of selecting the detection point position using surface color-slope-elevation,with the surface bin as the constraint range,the detection point deviation comparison test was completed using a two-dimensional wide line of acquisition in a desert in the Junggar Basin.The high frequency of common receiver point gather and the target layer reflection of imaging section were broadened.The proposed method for determining the position of the detection point in the desert could improve the resolution of effective seismic signals.

基金项目：中国石油天然气股份有限公司重大科技专项“新疆油田和吐哈油田勘探开发关键技术研究与应用(2017E-04-11)”资助。