尼日尔A区块采集方法研究与应用

Acquisition Research and Application of Block A in Niger

A区块主要油气发现位于地堑中,地震成像难度较大,常规三维采集效果不佳。为进一步改善A区块深层地震资料品质,在采集方法设计中引入了基于PSTM的宽方位观测系统设计和基于高覆盖与可控震源拆分技术的高效采集技术。结果表明,本次采集炮密度、道密度、有效覆盖密度分别是以往采集的3倍、1.5倍、4.5倍,提高了空间采样密度,使采样密度更趋均匀,有利于叠前偏移成像。处理后叠前偏移剖面信噪比有大幅提高,浅、中、深层目的层覆盖次数比以往观测系统提高了4~5倍。同时综合投入成本和叠前资料信噪比确定24L观测系统为本区最优"质价比"。未来应以获得更适合叠前偏移处理的地震数据体为标准选择观测系统。

Block A major oil and gas discoveries are located in the graben, seismic imaging is more difficult, the con ventional three-dimensional acquisition of poor results. To further improve the quality of deep seismic data in Block A, the wide azimuth observation system based on PSTM and the high efficiency acquisition technology based on high coverage and controllable vibrator are introduced in the design of acquisition method. The results show that the den sity, channel density and effective coverage density are three times, 1.5 times, 4.5 times,and the spatial sampling density is improved and the sampling density is more uniform, which is favorable for prestack migration imaging. The SNR of pre-stack migration profile is greatly improved, and the coverage of shallow, middle and deep target layers is increased by 4-5 times compared with the previous observation system. While the 24L observation system is the best ＂quality price ratio＂ in this area. The input cost and the pre-stack data SNR are determined. In the future, the observing system should be selected as the standard to obtain the seismic data volume which is more suitable for pre-stack migration.