复杂金属矿体地震波正演模拟研究——以庐枞盆地罗河、泥河和大包庄矿床为例
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摘要
地震勘探在金属矿勘查中发挥越来越重要的作用,但复杂的介质结构和矿体形态通常使金属矿地震解释异常困难,为深入研究复杂金属矿体的地震波场特征,有效开展金属矿地震解释,本文以庐枞矿集区的罗河、泥河和大包庄矿床为例,在详细开展物性测量和地质与地球物理建模的基础上,对均匀介质复杂矿体模型、简化矿体模型和随机介质简化矿体模型进行了金属矿地震波场模拟研究。使用波动方程交错网格有限差分法对模型进行正演模拟,并对模拟结果做叠后偏移处理,分析了各种模型的波场特征,并与实际矿区地震反射剖面进行了对比。结果表明:含磁铁矿、黄铁矿的金属矿体与火山沉积岩、熔岩等围岩都有明显的波阻抗差异,理论上可以用反射地震方法进行深部矿床勘探;对似层状的复杂矿体,当其厚度远大于(4～5倍)地震信号的理论分辨率(λ/4)时,反射地震可以探测复杂矿体的结构形态;当矿体陡倾时,反射能量明显减弱或消失,随机介质与实际介质更接近;当不均匀程度大于5%或更大时,散射噪声将淹没矿体有效反射信号。波场模拟与实际地震剖面对比结果表明,反射地震在实际矿区的应用,面临的挑战要大很多,其中干扰、介质的不均匀性、矿体的形态是影响地震勘探效果的主要因素。
Seismic exploration plays an increasingly important role in the metal ore exploration,but seismic interpretation for the ore districts is often extremely difficult due to the complex structures and orebody shape.This article takes Luohe,Nihe and Dabaozhuang mineral deposits in the Luzong ore area as an example to study the wave field characteristics of complex metal deposits and conduct effective seismic interpretation.Based on petrophisical property measurement and geophysical modeling,seismic wave field modeling for metal ores was studied in this article using the models of homogeneous complex orebody,simple orebody,and random simple orebody.Wave equation staggered-grid finite difference method was used to conduct forwarding simulation and modeling results was processed after post-stacked shift.Characteristics of the wave fields produced by various models were analyzed and compared with actual seismic reflection profiles in the ore district.The results show that there are obvious impedance difference between ore body containing magnetite and pyrite and volcanic sedimentary rocks and lava rocks,and theoretically,the reflection seismic method can be used in deep mineral deposits exploration.For the stratiform orebodies,reflection seismic method can be used to presume structure of complex orebody when the thickness is much larger than or 4～5 times larger than the theoretical resolution (λ/4) of seismic signals,but the reflection energy is obvious weakened or fade away when the orebody is steeply dipping.For random medium similar to actual medium,the reflection signal will be submerged in scattering noise when the heterogeneous level is greater than 5%.The comparative analysis of wave field simulation and the actual seismic profiles indicates that seismic reflection method faces great challenges in the actual application,in which interference,heterogeneous medium,and orebody shape are the major factors affecting result of seismic exploration.
Seismic exploration plays an increasingly important role in the metal ore exploration,but seismic interpretation for the ore districts is often extremely difficult due to the complex structures and orebody shape.This article takes Luohe,Nihe and Dabaozhuang mineral deposits in the Luzong ore area as an example to study the wave field characteristics of complex metal deposits and conduct effective seismic interpretation.Based on petrophisical property measurement and geophysical modeling,seismic wave field modeling for metal ores was studied in this article using the models of homogeneous complex orebody,simple orebody,and random simple orebody.Wave equation staggered-grid finite difference method was used to conduct forwarding simulation and modeling results was processed after post-stacked shift.Characteristics of the wave fields produced by various models were analyzed and compared with actual seismic reflection profiles in the ore district.The results show that there are obvious impedance difference between ore body containing magnetite and pyrite and volcanic sedimentary rocks and lava rocks,and theoretically,the reflection seismic method can be used in deep mineral deposits exploration.For the stratiform orebodies,reflection seismic method can be used to presume structure of complex orebody when the thickness is much larger than or 4～5 times larger than the theoretical resolution (λ/4) of seismic signals,but the reflection energy is obvious weakened or fade away when the orebody is steeply dipping.For random medium similar to actual medium,the reflection signal will be submerged in scattering noise when the heterogeneous level is greater than 5%.The comparative analysis of wave field simulation and the actual seismic profiles indicates that seismic reflection method faces great challenges in the actual application,in which interference,heterogeneous medium,and orebody shape are the major factors affecting result of seismic exploration.
引文
①安徽省地质调查院.2007.安徽省泥河铁矿外围地区地质图.
②安徽省地质局庐枞地区铁矿会战指挥部.1980.安徽省庐江罗河铁矿详细地质勘探报告.
③吴明安等.2010.泥河矿区勘探报告.
④安徽省地质局三二七地质队.1981.安徽省庐江县大包庄硫铁矿床详细普查地质报告.
常印佛,刘湘培,吴言昌.1991.长江中下游铜铁成矿带.北京:地质出版社,71~76.
董良国,马在田,曹景忠,王华忠,耿建华,雷兵,许世勇.2000.一阶弹性波方程交错网格高阶差分解法.地球物理学报,43(3):856~864.
贺冬生.1994.九江—瑞昌地区金属矿地震勘探方法技术研究.物探与化探,18(1):76~79.
吕庆田,侯增谦,史大年,赵金花,徐明才,柴铭涛.2004.铜陵狮子山金属矿地震探测结果及对区域找矿的意义.矿床地质,23(3):390~398.
吕庆田,史大年,赵金花,严加永,徐明才.2005.地震学方法:问题与前景——铜陵矿集区的应用实例.地质通报,24(3):211~218.
吕庆田,韩立国,严加永,廉玉广,史大年,颜庭杰.2010.庐枞矿集区火山气液型铁硫矿床及控矿构造的反射地震成像.岩石学报,26(9):2598~2612.
吕庆田,廉玉广,赵金花.2010.反射地震技术在成矿地质背景与深部矿产勘查中的应用:现状与前景.地质学报,84(6):771~787.
马中高,解吉高.2005.岩石的纵、横波速度与密度的规律研究.地球物理学进展,20(4):905~910.
任启江,刘孝善,徐兆文,胡受奚,胡文.1991.安徽庐枞中生代火山构造洼地及其成矿作用.北京:地质出版社,1~206.
王庆海,崔占荣.1993.试论金属矿地震勘探技术.物探与化探,17(5):354~361.
奚先,姚姚.2001.二维随机介质及波动方程正演模拟.石油地球物理勘探,36(5):546~552.
奚先,姚姚.2002.随机介质模型的模拟与混合型随机介质.地球科学——中国地质大学学报,27(1):67~71.
奚先,姚姚.2004.二维弹性随机介质中的波场特征.石油地球物理勘探,39(6):679~685.
奚先,姚姚.2005.非平稳随机介质模型.石油地球物理勘探,40(1):71~75.
徐明才,高景华,荣立新,刘建勋,柴铭涛,王广科.2003.散射波地震方法在蔡家营多金属矿区的试验研究.物探与化探,27(1):49~54.
徐明才,柴铭涛,荣立新,王广科,刘建勋,高景华.2007.拜仁达坝多金属矿区的地震方法试验研究.物探与化探,31(3):221~225.
姚姚,奚先.2002.随机介质模型正演模拟及其地震波场分析.石油物探,41(1):31~36.
翟裕生,姚书振,林新多.1992.长江中下游地区铁铜矿床.北京:地质出版社,1~120.
周涛发,范裕,袁峰,陆三明,尚世贵,David R Cooke,SebastienMeffre,赵国春.2008.安徽庐枞(庐江-枞阳)盆地火山岩的年代学及其意义.中国科学,38(11):1342~1353.
Eaton D W,Milkereit B,Salisbury M.2003.Seismic methods fordeep mineral exploration:mature technologies adapted to newtargets.The Leading Edge,June,580~585.
Fornberg B.1989.Pseudospectral approxi mation of the elastic waveequation on a staggered grid.59th Ann.Intenat.Mtg.,Soc.Expl.Geophys,Expanded Abstracts:1047~1049.
Gardner G H F,Gardner L W,Gregory A R.1974.Formationvelocity and densitythe diagnostic basics for stratigraphic traps.Geophysics,39:770~780.
Korn M.1993.Seismic Waves in Random Media.J.appl.Geophys.29:247~269.
Li T L and Eaton D W.2005.Delineating the Tuwu porphyrycopper deposit at Xinjiang,China,with seismic-reflectionprofiling.Geophysics,70(6):B53~B60.
L T Ikele,S K Yung.1993.2-D random media with ellipsoidalautocorrelation functions.Geophysics,58(9):1359~1372.
Pretorius C C,Jamison A A,and Irons C.1987.Seismicexploration in the Witwatersrand basin,Republic of SouthAfrica.Exploration87,Proceedings,3,241~253.
Milkereit B,Eaton D,Wu J,Perron G,Salisbury M,Berrer E,andMorrison G.1996.Seismici maging of massive sulfide deposits,Part II:Reflection seismic profiling.Economic Geology,v91:829~834.
Salisbury M H,Milkereit B,and Bleeker W.1996.Seismici magingof massive sulfide deposits:Part I.rock properies.EconomicGeology,91(5):821~828.
Yil maz.1987.Seismic data processing,Series:Investigation inGeophysics.Volume2.Tulsa:Society of ExplorationGeophysicists,1~526.
②安徽省地质局庐枞地区铁矿会战指挥部.1980.安徽省庐江罗河铁矿详细地质勘探报告.
③吴明安等.2010.泥河矿区勘探报告.
④安徽省地质局三二七地质队.1981.安徽省庐江县大包庄硫铁矿床详细普查地质报告.
常印佛,刘湘培,吴言昌.1991.长江中下游铜铁成矿带.北京:地质出版社,71~76.
董良国,马在田,曹景忠,王华忠,耿建华,雷兵,许世勇.2000.一阶弹性波方程交错网格高阶差分解法.地球物理学报,43(3):856~864.
贺冬生.1994.九江—瑞昌地区金属矿地震勘探方法技术研究.物探与化探,18(1):76~79.
吕庆田,侯增谦,史大年,赵金花,徐明才,柴铭涛.2004.铜陵狮子山金属矿地震探测结果及对区域找矿的意义.矿床地质,23(3):390~398.
吕庆田,史大年,赵金花,严加永,徐明才.2005.地震学方法:问题与前景——铜陵矿集区的应用实例.地质通报,24(3):211~218.
吕庆田,韩立国,严加永,廉玉广,史大年,颜庭杰.2010.庐枞矿集区火山气液型铁硫矿床及控矿构造的反射地震成像.岩石学报,26(9):2598~2612.
吕庆田,廉玉广,赵金花.2010.反射地震技术在成矿地质背景与深部矿产勘查中的应用:现状与前景.地质学报,84(6):771~787.
马中高,解吉高.2005.岩石的纵、横波速度与密度的规律研究.地球物理学进展,20(4):905~910.
任启江,刘孝善,徐兆文,胡受奚,胡文.1991.安徽庐枞中生代火山构造洼地及其成矿作用.北京:地质出版社,1~206.
王庆海,崔占荣.1993.试论金属矿地震勘探技术.物探与化探,17(5):354~361.
奚先,姚姚.2001.二维随机介质及波动方程正演模拟.石油地球物理勘探,36(5):546~552.
奚先,姚姚.2002.随机介质模型的模拟与混合型随机介质.地球科学——中国地质大学学报,27(1):67~71.
奚先,姚姚.2004.二维弹性随机介质中的波场特征.石油地球物理勘探,39(6):679~685.
奚先,姚姚.2005.非平稳随机介质模型.石油地球物理勘探,40(1):71~75.
徐明才,高景华,荣立新,刘建勋,柴铭涛,王广科.2003.散射波地震方法在蔡家营多金属矿区的试验研究.物探与化探,27(1):49~54.
徐明才,柴铭涛,荣立新,王广科,刘建勋,高景华.2007.拜仁达坝多金属矿区的地震方法试验研究.物探与化探,31(3):221~225.
姚姚,奚先.2002.随机介质模型正演模拟及其地震波场分析.石油物探,41(1):31~36.
翟裕生,姚书振,林新多.1992.长江中下游地区铁铜矿床.北京:地质出版社,1~120.
周涛发,范裕,袁峰,陆三明,尚世贵,David R Cooke,SebastienMeffre,赵国春.2008.安徽庐枞(庐江-枞阳)盆地火山岩的年代学及其意义.中国科学,38(11):1342~1353.
Eaton D W,Milkereit B,Salisbury M.2003.Seismic methods fordeep mineral exploration:mature technologies adapted to newtargets.The Leading Edge,June,580~585.
Fornberg B.1989.Pseudospectral approxi mation of the elastic waveequation on a staggered grid.59th Ann.Intenat.Mtg.,Soc.Expl.Geophys,Expanded Abstracts:1047~1049.
Gardner G H F,Gardner L W,Gregory A R.1974.Formationvelocity and densitythe diagnostic basics for stratigraphic traps.Geophysics,39:770~780.
Korn M.1993.Seismic Waves in Random Media.J.appl.Geophys.29:247~269.
Li T L and Eaton D W.2005.Delineating the Tuwu porphyrycopper deposit at Xinjiang,China,with seismic-reflectionprofiling.Geophysics,70(6):B53~B60.
L T Ikele,S K Yung.1993.2-D random media with ellipsoidalautocorrelation functions.Geophysics,58(9):1359~1372.
Pretorius C C,Jamison A A,and Irons C.1987.Seismicexploration in the Witwatersrand basin,Republic of SouthAfrica.Exploration87,Proceedings,3,241~253.
Milkereit B,Eaton D,Wu J,Perron G,Salisbury M,Berrer E,andMorrison G.1996.Seismici maging of massive sulfide deposits,Part II:Reflection seismic profiling.Economic Geology,v91:829~834.
Salisbury M H,Milkereit B,and Bleeker W.1996.Seismici magingof massive sulfide deposits:Part I.rock properies.EconomicGeology,91(5):821~828.
Yil maz.1987.Seismic data processing,Series:Investigation inGeophysics.Volume2.Tulsa:Society of ExplorationGeophysicists,1~526.
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