欠压实低速泥岩对地震反射及AVO的影响
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摘要
莺歌海盆地高温高压地层由于晚期快速沉降和快速沉积形成了巨厚的欠压实低速泥岩带,目前东方区中深层已发现多个高温高压气藏,其岩石物理规律清晰,气层顶面地震反射特征以强振幅波谷反射为主,AVO特征明显。然而,乐东区高温高压地层地震反射特征与东方区截然不同,AVO特征复杂,严重制约了乐东区高温高压气藏的勘探。从区域地震岩石物理统计规律出发,总结了乐东区地震反射振幅和AVO特征的影响因素,研究发现,乐东区高温高压地层欠压实趋势复杂,低速泥岩速度变化范围大,直接影响气层顶面的地震反射特征和AVO特征。AVO理论模拟表明,受上覆低速泥岩速度范围的影响,AVO-孔隙度模板发生明显变化,通过分析上覆低速泥岩的速度,可以有效预测储层的孔隙度大小,实际钻井结果验证了该方法预测孔隙度的有效性,为莺歌海盆地乐东区高温高压地层下一步有利目标搜寻和勘探提供了有效的指导。
Under compacted formation is formed by rapid subsidence which caused huge undercompacted shale belt to form at mid-deep strata of Yinggehai Basin,where several high temperature and high pressure gas reservoirs are found.The rock physical features and AVO are clear of Dongfang gas sand,showing as bright spot.Howerver,the Ledong high temperature and high pressure layers show very different seismic reflection and AVO features compared with the Dongfang high temperature and high pressure layers,which restrict severly the exploration in this area.We firstly analyzed the seismic rock physical features by large well-log data in this basin,then summarized the main influence factors for the seismic reflection and AVO in Ledong area and found that the main factor is the velocity range of overlying undercompacted lowvelocity shale.Numerical modeling shows that the AVO-porosity template depends on the velocity range of overlying undercompacted shale,which means we need to analyse the velocity of undercompacted shale before applying AVO-porosity template.The real drilling data show that the AVO-porosity template is effective.The study of this paper is beneficial for the target search and exploration at high temperature and high pressure layers of Yinggehai Basin.
Under compacted formation is formed by rapid subsidence which caused huge undercompacted shale belt to form at mid-deep strata of Yinggehai Basin,where several high temperature and high pressure gas reservoirs are found.The rock physical features and AVO are clear of Dongfang gas sand,showing as bright spot.Howerver,the Ledong high temperature and high pressure layers show very different seismic reflection and AVO features compared with the Dongfang high temperature and high pressure layers,which restrict severly the exploration in this area.We firstly analyzed the seismic rock physical features by large well-log data in this basin,then summarized the main influence factors for the seismic reflection and AVO in Ledong area and found that the main factor is the velocity range of overlying undercompacted lowvelocity shale.Numerical modeling shows that the AVO-porosity template depends on the velocity range of overlying undercompacted shale,which means we need to analyse the velocity of undercompacted shale before applying AVO-porosity template.The real drilling data show that the AVO-porosity template is effective.The study of this paper is beneficial for the target search and exploration at high temperature and high pressure layers of Yinggehai Basin.
引文
[1]李绪深,欧本田,李强,等.莺歌海盆地三维压力场与油气运移[J].地质科技情报,200 5,24(3):70-74.
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[5]周家雄,刘薇薇,马光克,等.高温高压储层的精细地震属性预测技术:以莺歌海盆地为例[J].地质勘探,2013,33(2):7-11.
[6]周家雄,李芳,马光克,等.利用密度差值识别和预测莺歌海盆地高温高压气藏[J].石油物探,2014,53(5):609-616.
[7]马光克,李芳,周家雄,等.高温高压欠压实地层烃类检测方法研究[J].地质科技情报,2015,34(6):221-226.
[8]裴健翔,潘光超,朱沛苑,刘峰.莺歌海盆地超压带低速泥岩陷阱的甄别及对勘探的启示[J].石油地球物理勘探,2016,51(2):361-370.
[9]Rutherford S R,Williams R H.Amplitude-versus-offset variations in gas sands[J].Geophysics,1989,54(6):680-688.
[10]Castagna J,Swan H W.Principles of AVO cross plotting[J].The Leading Edge,1997,16(4):337-342.
[11]Shuey R T.A simplification of the Zoeppritz-equations[J].Geophysics,1985,50(1):609-614.
[12]Batzle M,Wang Z.Seismic properties of pore fluids[J].Geophysics,1992,57(11):1396-1408.
[13]Xu S,White R E.A new velocity model for clay-sand mixtures[J].Geophysical Prospecting,1995,43(1):91-118.
[14]Xu S,White R E.Poro-elasticity of clastic rocks:A unified model[C]∥Anon.Transactions of the 36th Annual SPWLA Symposium.[S.l.]:[s.n.],1995:205-311.
[15]Xu S,White R E.A physical model for shear-wave velocity prediction[J].Geophysical Prospecting,1996,44(1):687-717.
[16]Gassmann F.Uber die elastizitat poroser medien[J].Vier Natur Gesellschaft,1951,96(1):1-23.
[17]Kuster G T,Toksoz M N.Velocity and attenuation of seismic waves in two-phase media[J].Geophysics,1974,39(5):587-618.
[2]郝芳,李思田,龚再升,等.莺歌海盆地底辟发育机制与流体幕式充注[J].中国科学:地球科学,2001,31(6):471-476.
[3]何家熊,杨计海,陈志宏,等.莺歌海盆地中深层天然气成藏特征[J].天然气工业,2003,23(3):15-19.
[4]裴健翔,于俊峰,王立峰,等.莺歌海盆地中深层天然气勘探的关键问题及对策[J].石油学报,2011,32(4):573-579.
[5]周家雄,刘薇薇,马光克,等.高温高压储层的精细地震属性预测技术:以莺歌海盆地为例[J].地质勘探,2013,33(2):7-11.
[6]周家雄,李芳,马光克,等.利用密度差值识别和预测莺歌海盆地高温高压气藏[J].石油物探,2014,53(5):609-616.
[7]马光克,李芳,周家雄,等.高温高压欠压实地层烃类检测方法研究[J].地质科技情报,2015,34(6):221-226.
[8]裴健翔,潘光超,朱沛苑,刘峰.莺歌海盆地超压带低速泥岩陷阱的甄别及对勘探的启示[J].石油地球物理勘探,2016,51(2):361-370.
[9]Rutherford S R,Williams R H.Amplitude-versus-offset variations in gas sands[J].Geophysics,1989,54(6):680-688.
[10]Castagna J,Swan H W.Principles of AVO cross plotting[J].The Leading Edge,1997,16(4):337-342.
[11]Shuey R T.A simplification of the Zoeppritz-equations[J].Geophysics,1985,50(1):609-614.
[12]Batzle M,Wang Z.Seismic properties of pore fluids[J].Geophysics,1992,57(11):1396-1408.
[13]Xu S,White R E.A new velocity model for clay-sand mixtures[J].Geophysical Prospecting,1995,43(1):91-118.
[14]Xu S,White R E.Poro-elasticity of clastic rocks:A unified model[C]∥Anon.Transactions of the 36th Annual SPWLA Symposium.[S.l.]:[s.n.],1995:205-311.
[15]Xu S,White R E.A physical model for shear-wave velocity prediction[J].Geophysical Prospecting,1996,44(1):687-717.
[16]Gassmann F.Uber die elastizitat poroser medien[J].Vier Natur Gesellschaft,1951,96(1):1-23.
[17]Kuster G T,Toksoz M N.Velocity and attenuation of seismic waves in two-phase media[J].Geophysics,1974,39(5):587-618.