共和盆地干热岩地震勘探技术研究  

Research on seismic exploration technology of hot dry rock in Gonghe Basin

作　　者：王瑞贞[1] 王金宽 晏丰 李海东[1] 韩力 武佩佩 WANG Ruizhen;WANG Jinkuan;YAN Feng;LI Haidong;HAN Li;WU Peipei(Bureau of Geophysical Prospecting , China National Petroleum Corporation, Hebei Renqiu 062552, China)

机构地区：[1]中国石油集团东方地球物理勘探有限责任公司,河北任丘062552

出　　处：《非常规油气》2022年第4期9-15,共7页Unconventional Oil & Gas

基　　金：国家重点研发计划项目“深部热储地球物理探测技术联合研究”(2020YFE0201300-02)。

摘　　要：共和盆地干热岩热储层是印支期花岗岩,成层性差,反射系数小,反射能量弱,对地震波的下传具有很强的屏蔽作用,造成资料信噪比低、成像困难。针对上述问题,该文从地震采集和资料处理两方面进行了研究。研究结果表明1)可控震源低频3 Hz激发获得的花岗岩地层能量最强,15 Hz次之,30 Hz最弱;2)采用6000 m长排列,使中、近偏移距花岗岩内地层反射能量较弱,约4000 m产生的广角反射可使反射能量明显增强;3)覆盖次数提高200~600次,目的层的照明效果越来越好;4)在检波点域抑制线性干扰可使信噪比提高到1.2以上,常速扫描网格为20 m×20 m、速度间隔为100 m/s时能使信噪比提高到1.4以上;5)偏移距大于3000 m的道集成像采用高阶动校正后才能拉平,以100 m/s的间隔速度扫描不会丢失弱信号层位,常规地区采用11道、低信噪比区采用21道兼顾斜层成像,生成的叠加段信噪比明显提升,信噪比较高的中偏移距(800~3500 m)速度谱可抑制干扰。以上成果认识,可使剖面信噪比提高50%,满足干热岩的勘探开发需要。The hot dry rock reservoir in the Gonghe Basin is Indosinian granite,with poor stratification,low reflection coefficient,weak reflection energy,and a strong shielding effect on the transmission of seismic waves,resulting in low data signal-to-noise ratio and imaging difficulties.In view of the above problems,research has been done from two aspects of seismic acquisition and data processing.The research result shows that:1)The energy of the granite strata obtained by the low-frequency excitation of the controllable seismic source at 3 Hz is the strongest,followed by 15 Hz,and the weakest at 30 Hz;2)The use of a 6000 m long arrangement can make the reflection of the granite in the middle and near offset range weaker.Wide-angle reflection around 4000 m can significantly increase the reflected energy;3)200~600 coverage times are increased,and the lighting effect of the target layer is getting better and better;4)Suppression of linear interference in the detection point domain can increase the signal-to-noise ratio to 1.2 above,the normal speed scanning grid of 20 m×20 m and the speed interval of 100 m/s can increase the signal-to-noise ratio to more than 1.4;5)The integrated image of the channel with an offset greater than 3000 m can be leveled after high-level dynamic correction,100 m/s interval speed scan does not lose the weak signal horizon,the conventional area uses eleven channels,the low signal-to-noise ratio area takes into account the twenty-one channels of the oblique layer imaging,the signal-to-noise ratio is significantly improved,and the mid-offset with high signal-to-noise ratio(800~3500 m)speed spectrum can suppress interference.The recognition of the above results can increase the signal-to-noise ratio of the profile by 50%and meet the needs of hot dry rock exploration and development.

关 键 词：干热岩 地震勘探 可控震源 低频 高覆盖 综合静校正 多域去噪 精细速度建场 

分 类 号：P31[天文地球—固体地球物理学]