基于反射声波测井有限元方法的井旁裂缝分布特征
|
摘要
基于声波传播理论,利用声波有限元方法研究存在井旁裂缝情况下的反射波波形特征。以井眼为对称轴,对有声阻抗不连续界面的一侧进行二维轴对称有限元建模,分别建立井旁存在交叉裂缝和弧状裂缝的交叉裂缝反射界面计算模型和弧状裂缝反射界面有限元计算模型。通过对相同源距条件下不同接收点接收的波形数据进行处理,得到反射波波至时间等参数,进而判断出页岩储层井旁裂缝的分布规律。结果表明:反射波的波至时间随声源纵坐标变化而呈现的规律与井旁裂缝的形态表现出了很好的一致性,井旁存在交叉裂缝时,根据波至时间计算得到井旁裂缝倾角为10.13°和20.19°,与解析模型对比的误差率分别为1.31%和0.95%。井旁存在弧状裂缝时,由反射波波至时间得出反射界面的坐标,并与计算模型结果进行对比,得到裂缝中心位置与反射点坐标相对误差为1.70%。声波有限元方法可以有效地反演出井旁裂缝的位置和形态特征。
Based on the theory of acoustic wave propagation,reflected wave characteristics are studied by the finite element method in the presence of well fracture. 2 D axial symmetry finite element modeling is applied on one side of discontinuous acoustic impedance. The models to computing cross fracture reflection interface and arc fracture reflection interface are established for the cases where cross fracture and arc fracture exist on the side of well. Waveform data from the same source received by the different receivers are processed and the parameters(e.g.,reflection phase arrival time) are obtained. The distribution character of wellbore fracture in shale reservoir is obtained accordingly. The results show that the variations in the arrival time of the reflected wave owing to the changes in the vertical coordinates of sound source is consistent with the shape of the wellbore fracture. In the presence of a cross shaped fracture near the wellbore,inclination angles of the side fracture obtained using the arrival time of reflected wave are 10. 13 degrees and 20. 19 degrees,respectively,which are within 1. 31%and 0. 95% of the analytical model. In the case of an arc shaped fracture near the wellbore,the location and shape feature of the wellbore fracture can be effectively derived by the coordinates of the reflecting interface. The relative error between the central position of fracture and the coordinate of reference point is within 1. 70%.It is concluded that the acoustic finite element method can effectively infer the position and morphology of fracture near the wellbore.
Based on the theory of acoustic wave propagation,reflected wave characteristics are studied by the finite element method in the presence of well fracture. 2 D axial symmetry finite element modeling is applied on one side of discontinuous acoustic impedance. The models to computing cross fracture reflection interface and arc fracture reflection interface are established for the cases where cross fracture and arc fracture exist on the side of well. Waveform data from the same source received by the different receivers are processed and the parameters(e.g.,reflection phase arrival time) are obtained. The distribution character of wellbore fracture in shale reservoir is obtained accordingly. The results show that the variations in the arrival time of the reflected wave owing to the changes in the vertical coordinates of sound source is consistent with the shape of the wellbore fracture. In the presence of a cross shaped fracture near the wellbore,inclination angles of the side fracture obtained using the arrival time of reflected wave are 10. 13 degrees and 20. 19 degrees,respectively,which are within 1. 31%and 0. 95% of the analytical model. In the case of an arc shaped fracture near the wellbore,the location and shape feature of the wellbore fracture can be effectively derived by the coordinates of the reflecting interface. The relative error between the central position of fracture and the coordinate of reference point is within 1. 70%.It is concluded that the acoustic finite element method can effectively infer the position and morphology of fracture near the wellbore.
引文
[1]董大忠,邹才能,杨桦,等.中国页岩气勘探开发进展与发展前景[J].石油学报,2012,33(增1):107-114.DONG Dazhong,ZOU Caineng,YANG Hua,et al.Progress and prospects of shale gas exploration and development in China[J].Acta Petrolei Sinica,2012,33(sup1):107-114.
[2]KHOSROLHAVAR R.Shale gas formations and their potential for carbon storage:opportunities and outlook[M]//Mechanisms for CO2Sequestration in Geological Formations and Enhanced Gas Recovery.Delft:Springer International Publishing,2016:595-611.
[3]IHARA M.Shale gas evolution:a tremendous increase of natural gas reserves and its effects on the LNG market(electric supplier after the Great East Japan Earthquake-natural gas development projects for stable LNG supply)[J].Journal of the Japan Institute of Energy,2012,91:96-103.
[4]邹才能,董大忠,王社教,等.中国页岩气形成机理、地质特征及资源潜力[J].石油勘探与开发,2010,37(6):641-653.ZOU Caineng,DONG Dazhong,WANG Shejiao,et al.Geological characteristics,formation mechanism and resource potential of shale gas in China[J].Petroleum Exploration and Development,2010,37(6):641-653.
[5]张大伟.加快中国页岩气勘探开发和利用的主要路径[J].天然气工业,2011,31(5):1-5.ZHANG Dawei.Main solution ways to speed up shale gas exploration and development in China[J].Natural Gas Industry,2011,31(5):1-5.
[6]张金川,姜生玲,唐玄,等.我国页岩气富集类型及资源特点[J].天然气工业,2009,29(12):109-114.ZHANG Jinchuan,JIANG Shengling,TANG Xuan,et al.Accumulation types and resources characteristics of shale gas in China[J].Natural Gas Industry,2009,29(12):109-114.
[7]乔文孝,陈雪莲,杜光升,等.相控声波测井的模拟实验研究[J].声学学报,2003,28(2):116-122.QIAO Wenxiao,CHEN Xuelian,DU Guangsheng,et al.Laboratory simulation on acoustic well-logging with phased array transmitter[J].Acta Acustica,2003,28(2):116-122.
[8]车小花,乔文孝,闫相祯.反射声波成像测井的有限元模拟[J].应用声学,2004,23(6):1-4.CHE Xiaohua,QIAO Wenxiao,YAN Xiangzhen.Numerical simulation of borehole acoustic-reflection imaging using the finite element method[J].Applied Acoustics,2004,23(6):1-4.
[9]车小花,乔文孝,李刚,等.井旁裂缝几何特性模拟实验研究[J].石油大学学报(自然科学版),2003,27(2):36-40.CHE Xiaohua,QIAO Wenxiao,LI Gang,et al.Experiment on geometrical properties of fractures near borehole[J].Journal of the University of Petroleum,China(Edition of Natural Science),2003,27(2):36-40.
[10]魏周拓,陈雪莲.井中偶极声源激励下的反射横波实验研究[J].西南石油大学学报(自然科学版),2013,35(6):1-8.WEI Zhoutuo,CHEN Xuelian.Experimental study on shear wave reflection of a borehole dipole source excitation[J].Journal of Southwest Petroleum University(Science&Technology Edition),2013,35(6):1-8.
[11]孙锋.反射声波测井资料处理方法研究[D].青岛:中国石油大学(华东),2011.SUN Feng.Study on processing method of the reflection acoustic logging data[D].Qingdao:China University of Petroleum(East China),2011.
[12]EISSA E A,KAZI A.Relation between static and dynamic Youngs moduli of rocks[J].International Journal of Rock Mechanics&Mining Sciences&Geomechanics Abstracts,1988,25(6):479-482.
[13]ENDO T,TEZUKA K,FUKUSHIMA T,et al.Fracture evaluation from inversion of stoneley transmission and reflections:proceeding of the 4th Well Logging Symposium of Japan[C].Tokyo:Society of Professional Well Log Analysts,1998:389-394.
[14]孙志峰,陈洪海,刘西恩.超声反射成像测井的有限元分析[J].应用声学,2013,32(6):495-500.SUN Zhifeng,CHEN Honghai,LIU Xien.The finite element analysis of ultrasonic reflection method used in acoustic logging[J].Applied Acoustics,2013,32(6):495-500.
[15]李增刚,詹福良.Virtual Lab Acoustics声学仿真计算高级应用实例[M].北京:国防工业出版社,2014.
[16]YAMAMOTO H,HALDORSEN J,MIKADA H,et al.Fracture imaging from sonic reflections and mode conversion[C]//Expanded Abstracts of 69th SEG Annual Meeting.Houston:Society of Exploration Geophysicists,1999.
[17]HOMBY B E.Imaging of near-borehole structure using full-waveform sonic data[J].Geophysics,1989,54(6):747-757.
[2]KHOSROLHAVAR R.Shale gas formations and their potential for carbon storage:opportunities and outlook[M]//Mechanisms for CO2Sequestration in Geological Formations and Enhanced Gas Recovery.Delft:Springer International Publishing,2016:595-611.
[3]IHARA M.Shale gas evolution:a tremendous increase of natural gas reserves and its effects on the LNG market(electric supplier after the Great East Japan Earthquake-natural gas development projects for stable LNG supply)[J].Journal of the Japan Institute of Energy,2012,91:96-103.
[4]邹才能,董大忠,王社教,等.中国页岩气形成机理、地质特征及资源潜力[J].石油勘探与开发,2010,37(6):641-653.ZOU Caineng,DONG Dazhong,WANG Shejiao,et al.Geological characteristics,formation mechanism and resource potential of shale gas in China[J].Petroleum Exploration and Development,2010,37(6):641-653.
[5]张大伟.加快中国页岩气勘探开发和利用的主要路径[J].天然气工业,2011,31(5):1-5.ZHANG Dawei.Main solution ways to speed up shale gas exploration and development in China[J].Natural Gas Industry,2011,31(5):1-5.
[6]张金川,姜生玲,唐玄,等.我国页岩气富集类型及资源特点[J].天然气工业,2009,29(12):109-114.ZHANG Jinchuan,JIANG Shengling,TANG Xuan,et al.Accumulation types and resources characteristics of shale gas in China[J].Natural Gas Industry,2009,29(12):109-114.
[7]乔文孝,陈雪莲,杜光升,等.相控声波测井的模拟实验研究[J].声学学报,2003,28(2):116-122.QIAO Wenxiao,CHEN Xuelian,DU Guangsheng,et al.Laboratory simulation on acoustic well-logging with phased array transmitter[J].Acta Acustica,2003,28(2):116-122.
[8]车小花,乔文孝,闫相祯.反射声波成像测井的有限元模拟[J].应用声学,2004,23(6):1-4.CHE Xiaohua,QIAO Wenxiao,YAN Xiangzhen.Numerical simulation of borehole acoustic-reflection imaging using the finite element method[J].Applied Acoustics,2004,23(6):1-4.
[9]车小花,乔文孝,李刚,等.井旁裂缝几何特性模拟实验研究[J].石油大学学报(自然科学版),2003,27(2):36-40.CHE Xiaohua,QIAO Wenxiao,LI Gang,et al.Experiment on geometrical properties of fractures near borehole[J].Journal of the University of Petroleum,China(Edition of Natural Science),2003,27(2):36-40.
[10]魏周拓,陈雪莲.井中偶极声源激励下的反射横波实验研究[J].西南石油大学学报(自然科学版),2013,35(6):1-8.WEI Zhoutuo,CHEN Xuelian.Experimental study on shear wave reflection of a borehole dipole source excitation[J].Journal of Southwest Petroleum University(Science&Technology Edition),2013,35(6):1-8.
[11]孙锋.反射声波测井资料处理方法研究[D].青岛:中国石油大学(华东),2011.SUN Feng.Study on processing method of the reflection acoustic logging data[D].Qingdao:China University of Petroleum(East China),2011.
[12]EISSA E A,KAZI A.Relation between static and dynamic Youngs moduli of rocks[J].International Journal of Rock Mechanics&Mining Sciences&Geomechanics Abstracts,1988,25(6):479-482.
[13]ENDO T,TEZUKA K,FUKUSHIMA T,et al.Fracture evaluation from inversion of stoneley transmission and reflections:proceeding of the 4th Well Logging Symposium of Japan[C].Tokyo:Society of Professional Well Log Analysts,1998:389-394.
[14]孙志峰,陈洪海,刘西恩.超声反射成像测井的有限元分析[J].应用声学,2013,32(6):495-500.SUN Zhifeng,CHEN Honghai,LIU Xien.The finite element analysis of ultrasonic reflection method used in acoustic logging[J].Applied Acoustics,2013,32(6):495-500.
[15]李增刚,詹福良.Virtual Lab Acoustics声学仿真计算高级应用实例[M].北京:国防工业出版社,2014.
[16]YAMAMOTO H,HALDORSEN J,MIKADA H,et al.Fracture imaging from sonic reflections and mode conversion[C]//Expanded Abstracts of 69th SEG Annual Meeting.Houston:Society of Exploration Geophysicists,1999.
[17]HOMBY B E.Imaging of near-borehole structure using full-waveform sonic data[J].Geophysics,1989,54(6):747-757.