利用稳定反Q滤波技术提高储层预测精度——以川西新场气田上三叠统须家河组气藏为例
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摘要
四川盆地西部上三叠统须家河组埋深超过3 000m,表层低降速带厚度大(几十米至200多米),地震波高频信号衰减很快,地震反射有效频带窄、主频较低(25～30Hz),储层预测特别是薄砂体预测存在精度差的问题。为此,首先在资料常规处理中采用能同时进行振幅补偿和相位畸变校正的稳定反Q滤波方法来提高地震资料的分辨率,随后在储层精细标定及对比追踪的基础上,利用GR地震随机反演进行砂岩储层预测。实际应用结果表明,在保持低频能量相对关系不变的情况下,该方法可有效拓展高频10～15Hz,由此提高了对薄层砂岩的识别能力及储层预测的精度。
The Upper Triassic Xujiahe Formation in the western Sichuan Basin is featured by large burial depths over 300m,large thickness of surface subweathered zones(from tens to over 200m),rapid attenuation of high frequency signals of seismic waves,narrow effective band width,and low predominant frequency(25-30Hz) of seismic reflectance,resulting in a low accuracy of seismic reservoir prediction,especially for those thin sandstone reservoirs.In order to solve these problems,the stable Q-filtering technique that can simultaneously realize amplitude compensation and phase distortion correction is applied in the conventional seismic processing.Moreover,the stochastic seismic inversion by use of the Gamma-ray log is used to predict sandstone reservoirs based on the detailed reservoir calibration and correlation.These methods can effectively widen the amplitude at high frequencies up to 10-15 Hz while those at low frequencies are kept unchanged,in this way the recognition ability of thin sandstone layers and the accuracy of reservoir evaluation are both improved.
The Upper Triassic Xujiahe Formation in the western Sichuan Basin is featured by large burial depths over 300m,large thickness of surface subweathered zones(from tens to over 200m),rapid attenuation of high frequency signals of seismic waves,narrow effective band width,and low predominant frequency(25-30Hz) of seismic reflectance,resulting in a low accuracy of seismic reservoir prediction,especially for those thin sandstone reservoirs.In order to solve these problems,the stable Q-filtering technique that can simultaneously realize amplitude compensation and phase distortion correction is applied in the conventional seismic processing.Moreover,the stochastic seismic inversion by use of the Gamma-ray log is used to predict sandstone reservoirs based on the detailed reservoir calibration and correlation.These methods can effectively widen the amplitude at high frequencies up to 10-15 Hz while those at low frequencies are kept unchanged,in this way the recognition ability of thin sandstone layers and the accuracy of reservoir evaluation are both improved.
引文
[1]李庆忠.走向精确勘探的道路——高分辨率地震勘探系统工程剖析[M].北京:石油工业出版社,1993:31-92.
[2]WANG Y H.A stable and efficient approach to inverse Qfiltering[J].Geophysics,2002,67(2):657-663.
[3]WANG Y H.Quantifying the effectiveness of stabilized in-verse Qfiltering[J].Geophysics,2003,68(1):337-345.
[4]WANG Y H.Qanalysis on reflection seismic data[J].Geo-physical Research Letters,2004,31(17):L17606.
[5]WANG Y H.Inverse Q-filter for seismic resolution en-hancement[J].Geophysics,2006,71(3):51-60.
[2]WANG Y H.A stable and efficient approach to inverse Qfiltering[J].Geophysics,2002,67(2):657-663.
[3]WANG Y H.Quantifying the effectiveness of stabilized in-verse Qfiltering[J].Geophysics,2003,68(1):337-345.
[4]WANG Y H.Qanalysis on reflection seismic data[J].Geo-physical Research Letters,2004,31(17):L17606.
[5]WANG Y H.Inverse Q-filter for seismic resolution en-hancement[J].Geophysics,2006,71(3):51-60.
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