一种基于地震约束的井控匹配追踪煤层强反射消除技术
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摘要
鄂尔多斯盆地东缘临兴-神府区块太2段致密砂岩气层是该区主力气层,其上下均有煤层发育,煤层屏蔽了含气砂体的反射特征,利用常规地震储层预测方法不易识别。通过对鄂尔多斯盆地东缘临兴-神府区块太2段附近强反射振幅特征的分析,明确其产生机理,提出了一种基于地震约束的井控匹配追踪煤层强反射消除技术,即利用井旁地震道提取合理的煤层反射匹配波形,通过改进的匹配追踪算法动态调整匹配子波控制参数,获取煤层反射特征之后再从原始地震中将煤层强反射去除,突出砂岩反射特征。通过理论模型、合成记录及实际地震剖面进行了效果验证,消除煤层屏蔽的地震剖面目标砂体得以突出,反演预测结果与已钻井砂岩厚度吻合度较高。
The Linxing-Shenfu block is located in the eastern margin of Ordos basin.The Tai-2tight sandstone is the main gas productive reservoir in this block.Because the reflectance signature of gas sand is sheltered by the coal seam developed above and beneath the Tai-2formation,it is difficult to identify the gas layer using the conventional seismic reservoir prediction methods.We proposed a seismic constraint-based technology for elimination of strong coal seam reflection via well-control and matching pursuit on the basis of analyzing the strong reflection amplitude characteristics of the Linxing-Shenfu block in the eastern margin of Ordos basin and identifying its genetic mechanism.This technology extracts the reasonable matched waveform of coal seam using well-side seismic traces,then dynamically adjusts the matching wavelet control parameters with the improved matching pursuit algorithm,and eliminates strong coal seam reflection from original seismic after obtaining the reflectance signature to highlight the reflectance signature of tight sandstone.The feasibility of this method is verified through numerical modelling,synthetic seismogram and the actual seismic profile,the target sand body is highlighted through eliminating the sheltering of coal seam,and the prediction results are in good agreement with the thickness of drilled sandstone.
The Linxing-Shenfu block is located in the eastern margin of Ordos basin.The Tai-2tight sandstone is the main gas productive reservoir in this block.Because the reflectance signature of gas sand is sheltered by the coal seam developed above and beneath the Tai-2formation,it is difficult to identify the gas layer using the conventional seismic reservoir prediction methods.We proposed a seismic constraint-based technology for elimination of strong coal seam reflection via well-control and matching pursuit on the basis of analyzing the strong reflection amplitude characteristics of the Linxing-Shenfu block in the eastern margin of Ordos basin and identifying its genetic mechanism.This technology extracts the reasonable matched waveform of coal seam using well-side seismic traces,then dynamically adjusts the matching wavelet control parameters with the improved matching pursuit algorithm,and eliminates strong coal seam reflection from original seismic after obtaining the reflectance signature to highlight the reflectance signature of tight sandstone.The feasibility of this method is verified through numerical modelling,synthetic seismogram and the actual seismic profile,the target sand body is highlighted through eliminating the sheltering of coal seam,and the prediction results are in good agreement with the thickness of drilled sandstone.
引文
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[12]张繁昌,刘汉卿,张立强,等.复数道动态匹配追踪算法的改进[J].石油地球物理勘探,2016,51(1):183-189.ZHANG Fanchang,LIU Hanqing,ZHANG Liqiang,et al.Improved complex-trace dynamic matching pursuit algorithm[J].OGP,2016,51(1):183-189.
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[15]张繁昌,李传辉,印兴耀.三角洲砂岩尖灭线的地震匹配追踪瞬时谱识别方法[J].石油地球物理勘探,2012,47(1):82-88.ZHANG Fanchang,LI Chuanhui,YIN Xingyao.Delta fringe line recognition based on seismic matching pursuit instantaneous spectral characteristics[J].OGP,2012,47(1):82-88.
[16] MALLAT S G,ZHANG Z.Matching pursuits with time-frequency dictionaries[J].IEEE Transactions on Signal Processing,1993,41(12):3397-3415.
[2]马灵伟,杨勤勇,李宗杰,等.利用波形分解技术识别塔中北坡强反射界面之下的储层响应[J].石油地球物理勘探,2017,52(2):326-332.MA Lingwei,YANG Qinyong,LI Zongjie,et al.Identifying reservoirs response under strong reflection interfaces with waveform decomposition in the Center Tarim Basin,China[J].OGP,2017,52(2):326-332.
[3]安鹏,张延庆,于志龙,等.基于“匹配追踪”算法的T2强反射层影响去除技术应用[J].物探与化探,2016,40(5):955-960.AN Peng,ZHANG Yanqing,YU Zhilong,et al.The application of T2strong reflector influence removal techniques based on pursuit matching[J].Geophysical and Geochemical Exploration,2016,40(5):955-960.
[4]张在金,张军华,李军,等.煤系地层地震强反射剥离方法研究及低频伴影分析[J].石油地球物理勘探,2016,51(2):376-383.ZHANG Zaijin,ZHANG Junhua,LI Jun,et al.A method for stripping coal seam strong reflection and low-frequency shadow analysis[J].OGP,2016,51(2):376-383.
[5]朱博华,向雪梅,张卫华.匹配追踪强反射层分离方法及应用[J].石油物探,2016,55(2):280-287.ZHU Bohua,XIANG Xuemei,ZHANG Weihua.Strong reflection horizons separation based on matching pursuit algorithm and its application[J].Geophysical Prospecting for Petroleum,2016,55(2):280-287.
[6]刘杰,张忠涛,刘道理,等.强反射背景下沉积体边界检测及流体识别方法[J].石油物探,2016,55(1):142-149.LIU Jie,ZHANG Zhongtao,LIU Daoli,et al.Sediment boundary identification and fluid detection for the seismic data with strong background reflections[J].Geophysical Prospecting for Petroleum,2016,55(1):142-149
[7]张繁昌,李灿灿,徐旺林.改进Stockwell变换法识别碳酸盐岩溶洞:以鄂尔多斯盆地奥陶系溶洞发育段为例[J].石油学报,2015,36(2):182-187.ZHANG Fanchang,LI Cancan,XU Wanglin.Identification of carbonate karst caves using modified Stockwell transform method:a case study of Ordovician karst caves in Ordos Basin[J].Acta Petrolei Sinica,2015,36(2):182-187.
[8]王宝江,张永常,王大兴,等.广义S变换用于含煤地层薄砂体预测研究[J].地球物理学进展,2012,27(3):1219-1226.WANG Baojiang,ZHANG Yongchang,WANG Daxing,et al.Predicting and detecting of the thin sand bodies by general transform in coal-bearing strata[J].Progress in Geophys.(in Chinese),2012,27(3):1219-1226.
[9]王建花,李庆忠,邱睿.浅层强反射界面的能量屏蔽作用[J].石油地球物理勘探,2003,38(6):589-596.WANG Jianhua,LI Qingzhong,QIU Rui.Energy shielding action of shallow strong reflector[J].OGP,2003,38(6):589-596.
[10]顾雯,章雄,徐敏,等.强屏蔽下薄储层高精度预测研究:以松辽盆地三肇凹陷为例[J].石油物探,2017,56(3):439-448.GU Wen,ZHANG Xiong,XU Min,et al.High precision prediction of thin reservoir under strong shielding effect and its application:a case study from Sanzhao Depression,Songliao Basin[J].Geophysical Prospecting for Petroleum,2017,56(3):439-448.
[11]谢英刚,秦勇,叶建平,等.临兴地区上古生界煤系致密砂岩气成藏条件分析[J].煤炭学报,2016,41(1):181-191.XIE Yinggang,QIN Yong,YE Jianping,et al.Accumulation conditions of tight gas in the Upper Paleozoic of Linxing Block[J].Journal of China Coal Society,2016,41(1):181-191.
[12]张繁昌,刘汉卿,张立强,等.复数道动态匹配追踪算法的改进[J].石油地球物理勘探,2016,51(1):183-189.ZHANG Fanchang,LIU Hanqing,ZHANG Liqiang,et al.Improved complex-trace dynamic matching pursuit algorithm[J].OGP,2016,51(1):183-189.
[13] WANG Y.Seismic time-frequency spectral decomposition by matching pursuit[J].Geophysics,2007,72:13-20.
[14] LIU J,MARFURT K J.Matching pursuit decomposition using Morlet wavelets[C].The 2005SEG Annual Meeting,2005:786-789.
[15]张繁昌,李传辉,印兴耀.三角洲砂岩尖灭线的地震匹配追踪瞬时谱识别方法[J].石油地球物理勘探,2012,47(1):82-88.ZHANG Fanchang,LI Chuanhui,YIN Xingyao.Delta fringe line recognition based on seismic matching pursuit instantaneous spectral characteristics[J].OGP,2012,47(1):82-88.
[16] MALLAT S G,ZHANG Z.Matching pursuits with time-frequency dictionaries[J].IEEE Transactions on Signal Processing,1993,41(12):3397-3415.