川中深层—超深层多次波识别和压制技术——以高石梯—磨溪连片三维区为例
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摘要
川中地区前震旦系勘探程度不高,远远满足不了深层地质研究的需求。现今主要依据地震资料研究前震旦系,但由于地层年代久、地层压力大、波阻抗差异小,导致地震波能量衰减大、有效信号能量弱,中、浅层存在的强反射界面容易掩盖深层有效的弱反射能量,大大降低了深层地震资料的信噪比,影响地震成像的真实性和可靠性,从而造成构造或地层假象,误导地质解释。为此,在详细分析川中深层地震资料特点的基础上,分析了深层的地震反射特征,认为深层寒武系和震旦系地震资料存在强多次波,超深层前震旦系的连续层状反射结构主要源于中、浅层强反射层产生的多次波,致使深层和超深层信噪比很低。基于多次波的认识和压制难点,确定了叠前和叠后联合、组合压制多次波的思路,应用层控速度分析、高分辨率抛物线Radon变换、优势炮检距叠加和叠后F-X域滤波压制残余多次波等关键技术压制多次波。高石梯—磨溪三维地震资料处理结果表明,提高了深层地震数据和测井合成记录相关性,超深层低角度席状多次波强反射能量得到有效压制,地层结构特征更为清楚,地震成像质量显著改善。
The Pre-Sinian in Central Sichuan is under-explored up to now,which is far from meeting the needs of deep geological research.At present,the research on Pre-Sinian is mainly based on seismic data.However,seismic energy attenuation is quite fast and signal energy is rather weak due to ancient strata,high formation pressure,and small impedance difference.Besides,some strong reflections at middle and shallow layers cover up weak deep signals,which greatly reduce the signal-to-noise ratio(SNR)of deep and ultra-deep seismic data.All these will result in structure or formation illusions and mislead the geological interpretation.For this reason,deep seismic reflection characteristics are analyzed on the basis of deep seismic data in Central Sichuan.It is believed that strong multiples exists in Cambrian and Sinian,and multiples at ultradeep Pre-Sinian are originated from shallow strong reflections,which leads very low SNR in deep and ultra-deep seismic data.To remove this kind of multiples,a strategy of multiple suppression combining prestack and poststack is proposed.The key techniques include strata-bound velocity analysis,high-resolution parabolic Radon transform,optimized offset stack,and poststack F-X domain filter to suppress residual multiple.On seismic processing results of Gaoshiti-Moxi 3 D,seismic data has a better correlation with logging data;ultra-deep low-angle sheet multiples are effectively eliminated;seismic imaging quality is significantly improved;and characteristics of ultra-deep stratigraphic structures are clearer.
The Pre-Sinian in Central Sichuan is under-explored up to now,which is far from meeting the needs of deep geological research.At present,the research on Pre-Sinian is mainly based on seismic data.However,seismic energy attenuation is quite fast and signal energy is rather weak due to ancient strata,high formation pressure,and small impedance difference.Besides,some strong reflections at middle and shallow layers cover up weak deep signals,which greatly reduce the signal-to-noise ratio(SNR)of deep and ultra-deep seismic data.All these will result in structure or formation illusions and mislead the geological interpretation.For this reason,deep seismic reflection characteristics are analyzed on the basis of deep seismic data in Central Sichuan.It is believed that strong multiples exists in Cambrian and Sinian,and multiples at ultradeep Pre-Sinian are originated from shallow strong reflections,which leads very low SNR in deep and ultra-deep seismic data.To remove this kind of multiples,a strategy of multiple suppression combining prestack and poststack is proposed.The key techniques include strata-bound velocity analysis,high-resolution parabolic Radon transform,optimized offset stack,and poststack F-X domain filter to suppress residual multiple.On seismic processing results of Gaoshiti-Moxi 3 D,seismic data has a better correlation with logging data;ultra-deep low-angle sheet multiples are effectively eliminated;seismic imaging quality is significantly improved;and characteristics of ultra-deep stratigraphic structures are clearer.
引文
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[11] 杨昊,戴晓峰,甘利灯,等.反射率法正演模拟及其在多次波识别中的应用——以四川盆地川中地区为例[C].中国石油学会2017年物探技术研讨会,2017:310-313.
[12] Arthur B W.Multiple attenuation: An overview of recent advances and the road ahead[J].The Leading Edge,1999,18(1):40-44.
[13] 吴艳辉,唐博文,柯本喜,等.GeoEast多次波压制技术在陆上地震资料处理中的应用[J].石油地球物理勘探,2014,49(增刊1):93-98.WU Yanhui,TANG Bowen,KE Benxi,et al.Multiple elimination methods provided by GeoEast for land seismic data[J].Oil Geophysical Prospecting,2014,49(S1):93-98.
[14] Foster D J and Mosher C C.Suppression of multiple reflection using the Radon transform[J].Geophysics,1992,57(3):386-395.
[15] Roy E W.Signal and noise estimation from seismic reflection and using spectral coherence methods[J].Proceedings of the IEEE,1984,72(10):1340-1356.
[16] 谭军,宋鹏,李金山,等.基于同相轴追踪的三维地震资料多次波压制方法[J].石油地球物理勘探,2017,52(5):894-905.TAN Jun,SONG Peng,LI Jinshan,et al.3D multiple suppression based on event tracing[J].Oil Geophysical Prospecting,2017,52(5):894-905.
[17] 宋家文,Verschuur D J,陈小宏,等.多次波压制的研究现状与进展[J].地球物理学进展,2014,29(1):240-247.SONG Jiawen,Verschuur D J,CHEN Xiaohong,et al.Research status and progress in multiple elimination[J].Progress in Geophysics,2014,29(1):240-247.
[18] 朱生旺,魏修成,李锋,等.用抛物线Radon变换稀疏解分离和压制多次波[J].石油地球物理勘探,2002,37(2):110-116.ZHU Shengwang,WEI Xiucheng,LI Feng,et al.Se-parating and suppressing multipies by sparse solution of parabolic Radon transform[J].Oil Geophysical Prospecting,2002,37(2):110-116.
[2] 邹才能,杜金虎,徐春春,等.四川盆地震旦系—寒武系特大型气田形成分布、资源潜力及勘探发现[J].石油勘探与开发,2014,41(3):278-293.ZOU Caineng,DU Jinhu,XU Chunchun,et al.Formation,distribution,resource potential and discovery of the Sinian-Cambrian giant gas field,Sichuan Basin,SW China[J].Petroleum Exploration and Development,2014,41(3):278-293.
[3] 徐春春,沈平,杨跃明,等.乐山龙女寺古隆起震旦系—下寒武统龙王庙组天然气成藏条件与富集规律[J].天然气工业,2014,34(3):1-7.XU Chunchun,SHEN Ping,YANG Yeming,et al.Accumulation conditions and enrichment patterns of natural gas in the Lower Cambrian Longwangmiao Fm reserviors of the Leshan Longnüsi Paleohigh,Sichuan Basin[J].Natural Gas Industry,2014,34(3):1-7.
[4] 张健,沈平,杨威,等.四川盆地前震旦纪沉积岩新认识与油气勘探的意义[J].天然气工业,2012,32(7):1-5.ZHANG Jian,SHEN Ping,YANG Wei,et al.New understandings of PreSinian sedimentary rocks in the Sichuan Basin and the significance of oil and gas exploration[J].Natural Gas Industry,2012,32(7):1-5.
[5] 谷志东,汪泽成.四川盆地川中地块新元古代伸展构造的发现及其在天然气勘探中的意义[J].中国科学:地球科学,2014,44(10):2210-2220.GU Zhidong,WANG Zecheng.The discovery of Neoproterozoic extensional structures and its significance for gas exploration in the Central Sichuan Block,Sichuan Basin,South China[J].Science China:Earth Sciences,2014,44(10):2210-2220.
[6] 汪泽成,姜华,王铜山,等.上扬子地区新元古界含油气系统与油气勘探潜力[J].天然气工业,2014,34(4):27-36.WANG Zecheng,JIANG Hua,WANG Tongshan,et al.Hydrocarbon systems and exploration potentials of Neoproterozoic in the Upper Yangtze Region[J].Na-tural Gas Industry,2014,34(4):27-36.
[7] 戴晓峰,张明,江青春,等.四川盆地中部下二叠统茅口组岩溶储集层地震预测[J].石油勘探与开发,2017,44(1):79-88.DAI Xiaofeng,ZHANG Ming,JIANG Qingchun,et al.Karst reservoirs seismic prediction of Lower Permian Maokou Formation in central Sichuan Basin,SW China[J].Petroleum Exploration and Development,2017,44(1):79-88.
[8] 康竹林.中国深层天然气勘探前景[J].天然气工业,2000,20(5):1-4.KANG Zhulin.The exploration prospect of deep gas in China[J].Natural Gas Industry,2000,20(5):1-4.
[9] 中国科学技术协会.深层油气地质学科发展报告[M].北京:中国科学技术出版社,2016,3-5.China Association For Science And Technology.Report on Advances in Deep Petroleum Geology Discipline[M].China Science And Technology Press,Beijing,2016,3-5.
[10] 戴晓峰,甘利灯,杜文辉,等.利用地震正演模拟实现高保真AVO处理质量监控[J].资源与产业,2011,13(1):93-98.DAI Xiaofeng,GAN Lideng,DU Wenhui,et al.AVO processing quality control through pre-stack seismicforward modeling[J].Resources & Industries,2011,13(1):93-98.
[11] 杨昊,戴晓峰,甘利灯,等.反射率法正演模拟及其在多次波识别中的应用——以四川盆地川中地区为例[C].中国石油学会2017年物探技术研讨会,2017:310-313.
[12] Arthur B W.Multiple attenuation: An overview of recent advances and the road ahead[J].The Leading Edge,1999,18(1):40-44.
[13] 吴艳辉,唐博文,柯本喜,等.GeoEast多次波压制技术在陆上地震资料处理中的应用[J].石油地球物理勘探,2014,49(增刊1):93-98.WU Yanhui,TANG Bowen,KE Benxi,et al.Multiple elimination methods provided by GeoEast for land seismic data[J].Oil Geophysical Prospecting,2014,49(S1):93-98.
[14] Foster D J and Mosher C C.Suppression of multiple reflection using the Radon transform[J].Geophysics,1992,57(3):386-395.
[15] Roy E W.Signal and noise estimation from seismic reflection and using spectral coherence methods[J].Proceedings of the IEEE,1984,72(10):1340-1356.
[16] 谭军,宋鹏,李金山,等.基于同相轴追踪的三维地震资料多次波压制方法[J].石油地球物理勘探,2017,52(5):894-905.TAN Jun,SONG Peng,LI Jinshan,et al.3D multiple suppression based on event tracing[J].Oil Geophysical Prospecting,2017,52(5):894-905.
[17] 宋家文,Verschuur D J,陈小宏,等.多次波压制的研究现状与进展[J].地球物理学进展,2014,29(1):240-247.SONG Jiawen,Verschuur D J,CHEN Xiaohong,et al.Research status and progress in multiple elimination[J].Progress in Geophysics,2014,29(1):240-247.
[18] 朱生旺,魏修成,李锋,等.用抛物线Radon变换稀疏解分离和压制多次波[J].石油地球物理勘探,2002,37(2):110-116.ZHU Shengwang,WEI Xiucheng,LI Feng,et al.Se-parating and suppressing multipies by sparse solution of parabolic Radon transform[J].Oil Geophysical Prospecting,2002,37(2):110-116.