低密度三维勘探方法在武隆地区页岩气勘查中的应用

Application of Low-density Three-dimensional Exploration Method in Shale Gas Exploration in Wulong Area

武隆地区为典型常压页岩气区块,区内志留系龙马溪组页岩分布稳定,为常压页岩气有利构造区。为有效勘探开发常压页岩气,需要高精度的三维地震资料进行支撑,但是不同于四川盆地内高压页岩气,常压页岩气单井产量少,经济效益差,常规山地高密度三维勘探方法不适用,因此探索出一套适用于常压页岩气的低密度三维勘探方法。实践证明,通过观测系统优化设计,较好地增加有限炮数下均匀面元能量照明和有效覆盖次数,基于地表岩性激发井深-药量匹配技术提高了激发效率以及针对性处理措施有效地改善成像精度。与前期资料相比,低密度三维剖面信噪比显著提高。结论表明,低密度三维勘探方法作为一种经济、有效的勘探方法,对常压页岩气勘探起到示范作用。

The Wulong area is a typical atmospheric shale gas block.The Silurian Longmaxi formation shale is distributed stably in the area,which is a favorable structural area for atmospheric shale gas.High precision 3D seismic data is required to support effective exploration and development of atmospheric shale gas.However,unlike the high-pressure shale gas in the Sichuan basin,atmospheric shale gas has low single-well production and poor economic benefits.The conventional mountainous high-density 3D exploration method is not applicable,so a set of low-density 3D exploration methods suitable for atmospheric shale gas have been explored.Practice has proved that through the optimization design of the observation system,the uniform panel energy illumination and effective folds under a limited number of shots are better increased.Based on the surface lithology excitation well depth-dose matching technology,the practice has improved the excitation efficiency and the targeted treatment measures effectively improves imaging precision.Compared with the previous data,the data has a significant improvement in the signal-to-noise ratio of the low-density three-dimensional profile.The conclusion shows that the low-density three-dimensional exploration method is more economical and effective in the exploration of atmospheric shale gas.