Q偏移技术在深海地震资料处理中的应用研究

Research of Q migration technology in deep marine seismic data processing

深海探区蕴含着大量的油气资源,高质量的地震资料是识别有利储层的关键,然而,一些探区由于浅层气云、气烟囱、泥浆带、低速异常体等高吸收异常带的存在,造成深层地震波振幅变弱,频率降低,严重影响构造成像精度.Q偏移技术来补偿深海地震资料的吸收衰减,首先采用谱比法建立时间域的等效Q场;其次,基于等效Q场进行深度域Q层析反演建立准确的Q场模型;最后基于高精度Q场进行克希霍夫Q叠前深度偏移.将该技术在某海外深海探区实际资料处理中应用,浅层低速异常造成的能量吸收现象得到了解决,弱能量区的成像质量得到了明显改善.

Deep-marine exploration area contains a large amount of oil and gas resources, the seismic data of high quality is the key to the identification of favorable reservoirs. However, some area because of the existence of high absorption anomaly zones such as shallow gas clouds, gas chimney,mud band or low-velocity anomaly, leads to weakening of seismic wave amplitude, as well as decrease of frequency,and will seriously affect the imaging accuracy of deep formation. Q migration technique is used to compensate for absorption attenuation in seismic propagation. The equivalent Q field firstly established in time domain based Log Spectral Ratio(LSR);secondly, based on the equivalent Q field,carry on depth domain Q tomographic inversion to establish Q field model accurately;finally, carry out kirchhoff Q prestack depth migration based on high precision Q field. The technology is applied to the real seismic data processing in a deep-sea exploration area. The weak energy phenomenon caused by shallow low-velocity anomaly absorption is solved, and the imaging quality of the weak energy area has been improved significantly.