震电效应下平面SV波与井孔的耦合
摘要
本文从全频域的Biot理论和震电效应的Pride理论出发,对震电效应下,倾斜井轴入射的平面SV波及伴随电磁场与井孔耦合问题进行了理论研究和数值计算。
首先推导了井内外声场和电磁场的理论表达式,按表达式进行了MATLAB编程,把声电耦合系数L趋于0时的计算结果与已有的不考虑震电效应的文献进行对比,此时两者符合得很好,从而验证了理论公式和程序的正确性。
以此为基础,针对井外为硬、软地层两种情况,对不同入射角下井内外声电场进行了计算和分析,得到了井内外声电场随频率的变化规律,并进一步研究了地层孔隙度、渗透率和饱和流体的矿化度对井内外电场的影响,还考察了井内电场随径向的变化规律以及不同方位角时井周处电场随频率的变化。
本文的研究都是至今无人做过的工作,具有一定的创新性。
The seismic-electric effect,in essence,is the transformation between mechanical energy and electromagnetic energy. In many industry sectors, the seismic-electric effect has widespread and the actual use. Because seismic-electric effect is relative with the underground porous media double electric layer, in addition, the seismic-electric effect is relative with reservoir accumulation medium's porosity, permeability, fluid nature, thus we can differentiate the oil, the gas, the water material ingredient through the seismic-electric effect. The domestic and overseas researches showed the importance and the possibility of seismic-electric exploration from the theory and the scene experiment
The phenomenon of the elastic waves coupled with the electromagnetic waves in porous media is seismic-electric effects. It is peculiar phenomenon, and recently becomes more interesting research field in porous acoustics. Pride’s governing equations describe such seismic-electric phenomenon. This text is begin with Pride coupling elastic waves-electromagnetic waves equation, deduce the numerical formulation of acoustic and electromagnetic field in and out borehole ,when plane SV-wave obliquely incident upon a well ,and coupling to the borehole。Then we utilize the acoustics and electromagnetic boundary conditions at interface of between porous formation and fluid medium to confirm the coefficient of each field, and solve the theoretical expressions. At last, we simulated field’response curve.
The elastic formation is an ideal circs, the result is not satisfied to the practical need. In actually acoustic logging, the Biot porous media is more important. In this situation, this text advises that out well porous media is both hard formation and soft formation. This text is compared with literature [6], we find that in both hard formation and soft formation, seismic-electric effect has little effect to liquid pressure in a hole. For hard formation whenΦ0 is 10?1 1, round the axis of the borehole, one can receive 10 mv/m electric field and 10?1 2 A/m magnetic field. High frequency appeared a series of formant. It is because that liquid in well happens radial resonance. At frequency is 9 kHz appears the first formant, at 17 kHz appears the secondly formant. For soft formation, round axes have mv/m electric field and 10?1 3 A/m magnetic field. When incident angle is 15°、30°and 45°, at 8kHz, electric field has a wave crest. When incident angle is 90°, swing is 0, electric (magnetic) field does not produce resonance. When incident angle is 60°and 75°,and frequency is less than 5kHz, electric(magnetic) field is 0. Electric (magnetic) field has a series of wave crest as the frequency’s augment. When incident angle is 75°,the wave crest is acute。
Because permeability、porosity and mineralization are important for the exploitation of oil. So this text analyzes importantly these parameters affect to electric (magnetic) inside well and outside well. For the hard formation,The porosity and the mineralization’s influences to the electromagnetic field are very big, under the identical frequency, the amplitude of electromagnetic field reduces as the porosity reduces, reduces along with the mineralization increases. The influence of permeability to electromagnetic field inside well is very small, but to electromagnetic field outside well is very big, under the identical frequency, the electromagnetic field′s amplitude reduces as the permeability increases. For the soft formation,under the identical frequency, the electromagnetic field′s amplitude reduces as the porosity reduces, reduces along with the permeability increases. The influence of mineralization to electromagnetic field inside well is very small. Electric field outside well reduces as the porosity reduces, reduces along with the mineralization increases. Therefore we find the conclusion that it is not feasible to use the electric field to calculate the permeability in the hard formation,but for soft formation, that is feasible.
首先推导了井内外声场和电磁场的理论表达式,按表达式进行了MATLAB编程,把声电耦合系数L趋于0时的计算结果与已有的不考虑震电效应的文献进行对比,此时两者符合得很好,从而验证了理论公式和程序的正确性。
以此为基础,针对井外为硬、软地层两种情况,对不同入射角下井内外声电场进行了计算和分析,得到了井内外声电场随频率的变化规律,并进一步研究了地层孔隙度、渗透率和饱和流体的矿化度对井内外电场的影响,还考察了井内电场随径向的变化规律以及不同方位角时井周处电场随频率的变化。
本文的研究都是至今无人做过的工作,具有一定的创新性。
The seismic-electric effect,in essence,is the transformation between mechanical energy and electromagnetic energy. In many industry sectors, the seismic-electric effect has widespread and the actual use. Because seismic-electric effect is relative with the underground porous media double electric layer, in addition, the seismic-electric effect is relative with reservoir accumulation medium's porosity, permeability, fluid nature, thus we can differentiate the oil, the gas, the water material ingredient through the seismic-electric effect. The domestic and overseas researches showed the importance and the possibility of seismic-electric exploration from the theory and the scene experiment
The phenomenon of the elastic waves coupled with the electromagnetic waves in porous media is seismic-electric effects. It is peculiar phenomenon, and recently becomes more interesting research field in porous acoustics. Pride’s governing equations describe such seismic-electric phenomenon. This text is begin with Pride coupling elastic waves-electromagnetic waves equation, deduce the numerical formulation of acoustic and electromagnetic field in and out borehole ,when plane SV-wave obliquely incident upon a well ,and coupling to the borehole。Then we utilize the acoustics and electromagnetic boundary conditions at interface of between porous formation and fluid medium to confirm the coefficient of each field, and solve the theoretical expressions. At last, we simulated field’response curve.
The elastic formation is an ideal circs, the result is not satisfied to the practical need. In actually acoustic logging, the Biot porous media is more important. In this situation, this text advises that out well porous media is both hard formation and soft formation. This text is compared with literature [6], we find that in both hard formation and soft formation, seismic-electric effect has little effect to liquid pressure in a hole. For hard formation whenΦ0 is 10?1 1, round the axis of the borehole, one can receive 10 mv/m electric field and 10?1 2 A/m magnetic field. High frequency appeared a series of formant. It is because that liquid in well happens radial resonance. At frequency is 9 kHz appears the first formant, at 17 kHz appears the secondly formant. For soft formation, round axes have mv/m electric field and 10?1 3 A/m magnetic field. When incident angle is 15°、30°and 45°, at 8kHz, electric field has a wave crest. When incident angle is 90°, swing is 0, electric (magnetic) field does not produce resonance. When incident angle is 60°and 75°,and frequency is less than 5kHz, electric(magnetic) field is 0. Electric (magnetic) field has a series of wave crest as the frequency’s augment. When incident angle is 75°,the wave crest is acute。
Because permeability、porosity and mineralization are important for the exploitation of oil. So this text analyzes importantly these parameters affect to electric (magnetic) inside well and outside well. For the hard formation,The porosity and the mineralization’s influences to the electromagnetic field are very big, under the identical frequency, the amplitude of electromagnetic field reduces as the porosity reduces, reduces along with the mineralization increases. The influence of permeability to electromagnetic field inside well is very small, but to electromagnetic field outside well is very big, under the identical frequency, the electromagnetic field′s amplitude reduces as the permeability increases. For the soft formation,under the identical frequency, the electromagnetic field′s amplitude reduces as the porosity reduces, reduces along with the permeability increases. The influence of mineralization to electromagnetic field inside well is very small. Electric field outside well reduces as the porosity reduces, reduces along with the mineralization increases. Therefore we find the conclusion that it is not feasible to use the electric field to calculate the permeability in the hard formation,but for soft formation, that is feasible.
引文
1、Biot, M.A., Theory of propagation of elastic waves in a fluid-saturated porous solid. I. Low frequency range, J. Acoust. Soc.Am., 1956(a) 28: 168-178.
2、Biot, M.A., Theory of propagation of elastic waves in a fluid-saturated porous solid. II. Higher frequency range, J. Acoust. Soc.Am., 1956(b) 28:179-191.
3、Biot, M.A., Mechanics of deformation and acoustic propagation in porous media. J. Appl. Phys., 1962,33:1482-1483.
4、王克协,J.E. White,伍先运, Biot 介质中 P 波与井孔的耦合。地球物理学报,1996,39(1):103-112。
5、张玉君,崔志文,王克协,震电效应下 P 波与井孔的耦合,中国地球物理,2004。
6、苏洋,倾斜井轴入射的平面 SV 波与井孔耦合的理论研究与数值分析,吉林大学硕士学位论文,2007,23-82。
7、崔志文,多孔介质声学模型与多极源声电效应测井和多极随钻声测井的理论与数值研究,吉林大学博士学位论文,2004,52-74。
8、Pride,S.R., Gangi,A.F., and Morgan,F.D., Deriving the equations of motion for porous isotropic media: J.Acoust. Soc.Am. 1992, 92: 3278 -3290.
9、Pride,S.R. and Haartsen,M.W., Electroseismic wave properties: J. Acoust.Soc. Am., 1996, 100(3),1301-1315.
10 、 Pride,S.R, Governing equations for the coupled electromagnetics and acoustics of porous media, Phys. Rev,1994,B50,15678-15696.
11、Pride,S.R. and Flekkoy,E.G., Two-phase flow through porous media in the fixed-contact-line regime, Phys. Rev E,1999,60,4285-4299.
12、胡恒山,王克协,井孔周围轴对称声电耦合波:(Ⅱ)声电效应测井数值模拟,测井技术,2000,第 24 卷,第 1 期,3-13。
13、胡恒山,王克协,井孔周围轴对称声电耦合波:(Ⅰ)理论,测井技术,1999,第 23 卷,第 6 期,427-432。
14、胡恒山,刘家琦,王洪滨,王克协,基于简化的 Pride 理论模拟声电效应测井响应,地球物理学报,2003,第 46 卷,第 2 期,259-264。
15、胡恒山,李长文,王克协,朱正亚,声电效应测井模型实验研究,测井技术,2001,第 25 卷,第 2 期。
16、胡恒山,声电效应测井的理论、数值与实验研究,吉林大学博士学位论文 2000,51-68。
17、J.R.Lovell and B.E.Hornby, Borehole coupling at sonic frequencies, Jeophysics. 1990, Vol. 55, No. 7, P. 806-814.
18、Carcione,J.M. and Picotti,S., P-wave seismic attenuation by slow -wave diffusion: Effects of inhomogeneous rock properties, Geophysics,2006,Vol71,No.3,1-8.
19、Pride,S.R.,Morgan,F.D., Electrokinetic dissipation induced by seismic waves.Geophysics,1991,56:914-925.
20、闫慧欣, Biot 介质中倾斜入射平面 P 波与井孔的耦合,吉林大学硕士学位论文,2007,21-44。
21、马大猷,《现代声学理论基础》,科学出版社,2004。
22、苏巍,刘财,陈晨,震电效应理论及其研究进展,地球物理学进展,2006,Vol21,No.2(June),379-385。
23、江万哲,章成广,周成当,震电效应在地球物理勘探中的应用,内蒙古石油化工,2007,第八期,177-180。
24、陈本池,震电效应在油气勘探开发中的应用,物探与化探,2007,Vol31,No.4(Aug.),333-338。
25、张元中,肖立志,楚泽涵,李剑浩,井孔声电效应转换电磁波的特征,地球物理学报,2005,Vol48,No.2(Mar.),452-458。
26、石昆法,震电效应原理和初步实验结果,地球物理学报,2001,Vol44,No.5(Sep.),720-728。
27、裘慰庭,震电效应在油气勘探中的应用前景,石油仪器,1996,Vol10,No.2(Apr.),8-14。
28、周来江,井外声源激发井孔声波场及井间地震的理论研究与数值模拟,吉林大学硕士学位论文,2006。
29、Benchi Chen, Yongguang Mu, Experimental studies of seismoelectric effect in fluid-saturated porous media,2005,J.Geophy.Eng.2。
30、刘洪,震电效应研究在资源勘探中的应用前景,地球物理学进展,2002,Vol17,No.2(Jun.),211-217。
31、闫有平,顾春桥,高峻,井种地震勘探技术和仪器的最新进展,物探装备,2003,13(1),1-6。
32、Cheng N, Cheng C H and Toksoz M N, Borehole wave propagation in three dimensions. J. Acoust. Soc. Am., 1995, 97(6).:3483-3493.
33、董世振,杜春,井中地震勘探仪器的现状与发展,物探装备,2002,12(4),227-234。
34、王秀明,李占咸等,裸眼井中软地层多极子源激发的弹性波的传播,地球物理学报,1992,35,510-520。
35、王克协,董庆德,渗透性地层油井中声场的理论分析与计算,石油学报,1986,7,59-68。
2、Biot, M.A., Theory of propagation of elastic waves in a fluid-saturated porous solid. II. Higher frequency range, J. Acoust. Soc.Am., 1956(b) 28:179-191.
3、Biot, M.A., Mechanics of deformation and acoustic propagation in porous media. J. Appl. Phys., 1962,33:1482-1483.
4、王克协,J.E. White,伍先运, Biot 介质中 P 波与井孔的耦合。地球物理学报,1996,39(1):103-112。
5、张玉君,崔志文,王克协,震电效应下 P 波与井孔的耦合,中国地球物理,2004。
6、苏洋,倾斜井轴入射的平面 SV 波与井孔耦合的理论研究与数值分析,吉林大学硕士学位论文,2007,23-82。
7、崔志文,多孔介质声学模型与多极源声电效应测井和多极随钻声测井的理论与数值研究,吉林大学博士学位论文,2004,52-74。
8、Pride,S.R., Gangi,A.F., and Morgan,F.D., Deriving the equations of motion for porous isotropic media: J.Acoust. Soc.Am. 1992, 92: 3278 -3290.
9、Pride,S.R. and Haartsen,M.W., Electroseismic wave properties: J. Acoust.Soc. Am., 1996, 100(3),1301-1315.
10 、 Pride,S.R, Governing equations for the coupled electromagnetics and acoustics of porous media, Phys. Rev,1994,B50,15678-15696.
11、Pride,S.R. and Flekkoy,E.G., Two-phase flow through porous media in the fixed-contact-line regime, Phys. Rev E,1999,60,4285-4299.
12、胡恒山,王克协,井孔周围轴对称声电耦合波:(Ⅱ)声电效应测井数值模拟,测井技术,2000,第 24 卷,第 1 期,3-13。
13、胡恒山,王克协,井孔周围轴对称声电耦合波:(Ⅰ)理论,测井技术,1999,第 23 卷,第 6 期,427-432。
14、胡恒山,刘家琦,王洪滨,王克协,基于简化的 Pride 理论模拟声电效应测井响应,地球物理学报,2003,第 46 卷,第 2 期,259-264。
15、胡恒山,李长文,王克协,朱正亚,声电效应测井模型实验研究,测井技术,2001,第 25 卷,第 2 期。
16、胡恒山,声电效应测井的理论、数值与实验研究,吉林大学博士学位论文 2000,51-68。
17、J.R.Lovell and B.E.Hornby, Borehole coupling at sonic frequencies, Jeophysics. 1990, Vol. 55, No. 7, P. 806-814.
18、Carcione,J.M. and Picotti,S., P-wave seismic attenuation by slow -wave diffusion: Effects of inhomogeneous rock properties, Geophysics,2006,Vol71,No.3,1-8.
19、Pride,S.R.,Morgan,F.D., Electrokinetic dissipation induced by seismic waves.Geophysics,1991,56:914-925.
20、闫慧欣, Biot 介质中倾斜入射平面 P 波与井孔的耦合,吉林大学硕士学位论文,2007,21-44。
21、马大猷,《现代声学理论基础》,科学出版社,2004。
22、苏巍,刘财,陈晨,震电效应理论及其研究进展,地球物理学进展,2006,Vol21,No.2(June),379-385。
23、江万哲,章成广,周成当,震电效应在地球物理勘探中的应用,内蒙古石油化工,2007,第八期,177-180。
24、陈本池,震电效应在油气勘探开发中的应用,物探与化探,2007,Vol31,No.4(Aug.),333-338。
25、张元中,肖立志,楚泽涵,李剑浩,井孔声电效应转换电磁波的特征,地球物理学报,2005,Vol48,No.2(Mar.),452-458。
26、石昆法,震电效应原理和初步实验结果,地球物理学报,2001,Vol44,No.5(Sep.),720-728。
27、裘慰庭,震电效应在油气勘探中的应用前景,石油仪器,1996,Vol10,No.2(Apr.),8-14。
28、周来江,井外声源激发井孔声波场及井间地震的理论研究与数值模拟,吉林大学硕士学位论文,2006。
29、Benchi Chen, Yongguang Mu, Experimental studies of seismoelectric effect in fluid-saturated porous media,2005,J.Geophy.Eng.2。
30、刘洪,震电效应研究在资源勘探中的应用前景,地球物理学进展,2002,Vol17,No.2(Jun.),211-217。
31、闫有平,顾春桥,高峻,井种地震勘探技术和仪器的最新进展,物探装备,2003,13(1),1-6。
32、Cheng N, Cheng C H and Toksoz M N, Borehole wave propagation in three dimensions. J. Acoust. Soc. Am., 1995, 97(6).:3483-3493.
33、董世振,杜春,井中地震勘探仪器的现状与发展,物探装备,2002,12(4),227-234。
34、王秀明,李占咸等,裸眼井中软地层多极子源激发的弹性波的传播,地球物理学报,1992,35,510-520。
35、王克协,董庆德,渗透性地层油井中声场的理论分析与计算,石油学报,1986,7,59-68。