基于溴化镧探测器的负源距密度测井研究
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摘要
为弥补传统双源距密度测井仪器纵向分辨率低、受井眼影响大的缺陷以及碘化钠(NaI(Tl))探测器的不足,提高密度测井识别油气层的能力,我们采用MCNP5蒙特卡罗模拟程序模拟研究了密度测井在负源距下增加溴化镧(LaBr_3(Ce))探测器.首先对比研究了LaBr_3(Ce)探测器与NaI(Tl)探测器的探测效率、能谱和响应特征;然后模拟计算LaBr_3(Ce)探测器源距与光子通量的关系、负源距光子通量能谱、负源距探测深度与源距的关系、气层负源距光子通量与密度的关系.结果表明:LaBr_3(Ce)探测器在密度测井中比NaI(Tl)探测器探测效率高、能峰高、峰总比大;负源距探测器与传统长、短源距探测器的响应规律近似相反;负源距探测器源距小,纵向分辨率高;探测深度浅,主要反映泥饼的性质,从而为泥饼校正提供丰富数据.因此,在双源距密度测井负源距区增加LaBr_3(Ce)探测器可以提高地层密度的灵敏度、测量精度、纵向分辨率和改善泥饼及薄层校正效果,为有效勘探开发油气藏提供测井技术支持.
To make up for the defects of dual detector density logging instrument,such as low vertical resolution,large borehole influence and the shortcomings of NaI(Tl) detectors and to improve the ability of identifying gas reservoirs,a study of adding LaBr_3(Ce) detector in negative spacing range is done with MCNP5 Monte Carlo numerical simulation program. The study begins with detection efficiency of LaBr_3(Ce) detector,energy spectra and response characteristics compared with NaI(Tl) detector. Then the relationship between spacing and photon flux,spectra in negative spacing,the relationship between radial investigation depth and negative spacing range,the relationship between flux and density in negative spacing are simulated. As a result of this study,LaBr_3(Ce) detector has higher efficiency,higher peak and bigger peak to total ratio than NaI(Tl) detector. Compared with traditional long and short source spacing detectors,negative spacing detector has approximately opposite response characteristics. Negative spacing detector has shorter spacing,higher vertical resolution,shallower radial investigation depth,larger effect from mud cake and it can supply abundant data for mud cake correction. Therefore,it's feasible to add LaBr_3(Ce) detector in negative spacing range which can improve sensitivity,measurement accuracy,vertical resolution and the correction of mud cake and thin layer,providing technical supports for effective exploration and development of natural gas reservoirs.
To make up for the defects of dual detector density logging instrument,such as low vertical resolution,large borehole influence and the shortcomings of NaI(Tl) detectors and to improve the ability of identifying gas reservoirs,a study of adding LaBr_3(Ce) detector in negative spacing range is done with MCNP5 Monte Carlo numerical simulation program. The study begins with detection efficiency of LaBr_3(Ce) detector,energy spectra and response characteristics compared with NaI(Tl) detector. Then the relationship between spacing and photon flux,spectra in negative spacing,the relationship between radial investigation depth and negative spacing range,the relationship between flux and density in negative spacing are simulated. As a result of this study,LaBr_3(Ce) detector has higher efficiency,higher peak and bigger peak to total ratio than NaI(Tl) detector. Compared with traditional long and short source spacing detectors,negative spacing detector has approximately opposite response characteristics. Negative spacing detector has shorter spacing,higher vertical resolution,shallower radial investigation depth,larger effect from mud cake and it can supply abundant data for mud cake correction. Therefore,it's feasible to add LaBr_3(Ce) detector in negative spacing range which can improve sensitivity,measurement accuracy,vertical resolution and the correction of mud cake and thin layer,providing technical supports for effective exploration and development of natural gas reservoirs.
引文
Briesmeister J F. 2000. MCNPTM-a general Monte Carlo N-particle transport code[R]. Version 4C,LA-13709-M,Los Alamos: Los Alamos National Laboratory.
Ellis D V. 1988. Gamma ray scattering measurements for density and lithology determination[J]. IEEE Transactions on Nuclear Science,35(1): 806-811.
Gao X,He Y J. 2014. The Research Progress of LaBr3:Ce3+Scintillator Crystal[J]. Nuclear Electronics and Detection Technology (in Chinese),34(7): 917-920.高鑫,何元金. 2010. LaBr3:Ce3+闪烁晶体研究进展[J]. 核电子学与探测技术,30(1): 5-11.
Gu Z W,Yan W Q,Liu W B,et al. 2015. Comparison of performance of Lanthanum Bromid,Sodium Iodide and plastic scintillator detector[J]. Laboratory Research and Exploration (in Chinese),34(4): 64- 67.谷钲伟,闫文奇,刘文斌,等. 2015. 溴化镧、碘化钠和塑料闪烁探测器性能比较[J]. 实验室研究与探索,34(4): 64- 67.
Liu X L,Sun Z. 2012. Litho density logging method and its application[J]. Foreign Well Logging Technology(in Chinese),(3): 58- 60.刘信鲁,孙泽. 2012. 岩性密度测井方法及应用[J]. 国外测井技术,(3): 58- 60.
Luycx M C,Torrees V C. 2017. Resolution and Accuracy of Neutron-Gamma Density Measurements Compared to Conventional Gamma-Gamma Density Measurements[C]//SPE Annual Technical Conference and Exhibition. Society of Petroleum Engineers.
Mao Z Q,Tan T. 1996. The correlativity of density logging and neutron logging and its application in identifying natural gas reservoirs[J]. Journal of Geophysics(in Chinese),39(01): 125-133.毛志强,谭廷栋. 1996. 密度测井和中子测井的相关性及其在识别天然气层中的应用[J]. 地球物理学报,39(01): 125-133.
Odom R C,Wilson R D,Ladtkow R K. 2001. Log examples with a prototype three-detector pulsed-neutron system for measurement of cased-hole neutron and density porosities[C]//SPE Rocky Mountain Petroleum Technology Conference. Society of Petroleum Engineers.
Pei L C,Zhang X Z. 1980. Monte Carlo method and its application in particle transport problems (in Chinese)[M]. Beijing: Science Press.裴鹿成,张孝泽. 1980. 蒙特卡罗方法及其在粒子输运问题中的应用[M]. 北京: 科学出版社.
Stoller C,Darling H L,DasGupta T,et al. 1997. Density logging in slim holes with a novel array density tool[C]//SPE Annual Technical Conference and Exhibition,Society of Petroleum Engineers.
Tan T D. 1987. New Method of Gas Bearing Zone Identification by Well Logging[J]. Acta Petroleum Sinica (in Chinese),8(1): 35- 43.谭廷栋. 1987. 识别气层的测井新方法[J]. 石油学报,8(1): 35- 43.
Tan T D. 1992. A Special Interpretation Method of Gas Finding by Neutron and Density Logging[J]. Acta Petroleum Sinica (in Chinese),13(4): 31- 40.谭廷栋. 1992. 中子和密度测井找气的一种特殊解释方法[J]. 石油学报,13(4): 31- 40.
Wang X G,Zhang Q Y,Zhang F,et al. 2015. Simulation and optimization of high-resolution density logging instrument with Monte Carlo code[M]//2015 SEG Annual Meeting,Society of Exploration Geophysicists,781-785.
Wu W S. 2003. Effects and correction of thin layer by three detector density logging[J]. Natural Gas Industry (in Chinese),23(3): 38- 40.吴文圣. 2003. 三探测器密度测井的薄层影响及校正[J]. 天然气工业,23(3): 38- 40.
Wu W S,Huang L J. 2004. Monte Carlo simulation of three-detector density logging[J]. Journal of Geophysics (in Chinese),47(1): 164-170,doi: 10.3321/j.issn:0001-5733.2004.01.025.吴文圣,黄隆基. 2004. 三探测器密度测井的Monte Carlo模拟[J]. 地球物理学报,47(1): 164-170,doi: 10.3321/j.issn:0001-5733.2004.01.025.
Wu W S,Huang L J. 2010. Spacing optimization for three-detector density logging tool[J]. Nuclear Techniques (in Chinese),33(11): 849-853.吴文圣,肖立志. 2010. 三探测器密度测井仪器的源距优化[J]. 核技术,33(11): 849-853.
Xie X C,Lai W C,Zhao Z L,et al. 2014. Test and comparison of Lanthanum Bromide and Sodium Iodide detector[J]. Nuclear Electronics and Detection Technology (in Chinese),34(7): 917-920.谢希成,赖万昌,赵祖龙,等. 2014. LaBr3(Ce)与NaI(Tl)闪烁探测器的性能研究与比较[J]. 核电子学与探测技术,34(7): 917-920.
Yu H W. 2011. The fundamental research of the pulsed-neutron density logging while drilling (in Chinese)[Ph. D. thesis]. Qingdao: China Universaty of Petroleum.于华伟. 2011. 随钻环境下脉冲中子测量地层密度的理论基础研究[博士论文]. 青岛: 中国石油大学.
Zhang F,Guo J F,Wang X G. 2010. Monte Carlo simulation of neutron porosity logging response under the condition of air drilling [J]. Journal of Jilin University(Earth Science Edition,in Chinese),40(1): 209-214.张锋,郭建芳,王新光. 2010. 空气钻井条件下中子孔隙度测井响应的蒙特卡罗模拟[J]. 吉林大学学报(地球科学版),40(1): 209-214.
Zhang H W,Wang L,Leng F Q,et al. 2017. Properties and Application Studies of LaBr3(Ce) Scintillation Detector[J]. SPECTROSCOPY AND SPECTRAL ANALYSIS,37(7): 2298-2304.
Zhang S,Tang B. 2012. Monte Carlo Study of LaBr3 Detector in the Application of Gamma-ray Logging[J]. Science and Technology Square (in Chinese),(1): 45- 47.张硕,汤彬. 2012. 溴化镧探测器在伽马测井应用中的MC研究[J]. 科技广场,(1): 45- 47.
Ellis D V. 1988. Gamma ray scattering measurements for density and lithology determination[J]. IEEE Transactions on Nuclear Science,35(1): 806-811.
Gao X,He Y J. 2014. The Research Progress of LaBr3:Ce3+Scintillator Crystal[J]. Nuclear Electronics and Detection Technology (in Chinese),34(7): 917-920.高鑫,何元金. 2010. LaBr3:Ce3+闪烁晶体研究进展[J]. 核电子学与探测技术,30(1): 5-11.
Gu Z W,Yan W Q,Liu W B,et al. 2015. Comparison of performance of Lanthanum Bromid,Sodium Iodide and plastic scintillator detector[J]. Laboratory Research and Exploration (in Chinese),34(4): 64- 67.谷钲伟,闫文奇,刘文斌,等. 2015. 溴化镧、碘化钠和塑料闪烁探测器性能比较[J]. 实验室研究与探索,34(4): 64- 67.
Liu X L,Sun Z. 2012. Litho density logging method and its application[J]. Foreign Well Logging Technology(in Chinese),(3): 58- 60.刘信鲁,孙泽. 2012. 岩性密度测井方法及应用[J]. 国外测井技术,(3): 58- 60.
Luycx M C,Torrees V C. 2017. Resolution and Accuracy of Neutron-Gamma Density Measurements Compared to Conventional Gamma-Gamma Density Measurements[C]//SPE Annual Technical Conference and Exhibition. Society of Petroleum Engineers.
Mao Z Q,Tan T. 1996. The correlativity of density logging and neutron logging and its application in identifying natural gas reservoirs[J]. Journal of Geophysics(in Chinese),39(01): 125-133.毛志强,谭廷栋. 1996. 密度测井和中子测井的相关性及其在识别天然气层中的应用[J]. 地球物理学报,39(01): 125-133.
Odom R C,Wilson R D,Ladtkow R K. 2001. Log examples with a prototype three-detector pulsed-neutron system for measurement of cased-hole neutron and density porosities[C]//SPE Rocky Mountain Petroleum Technology Conference. Society of Petroleum Engineers.
Pei L C,Zhang X Z. 1980. Monte Carlo method and its application in particle transport problems (in Chinese)[M]. Beijing: Science Press.裴鹿成,张孝泽. 1980. 蒙特卡罗方法及其在粒子输运问题中的应用[M]. 北京: 科学出版社.
Stoller C,Darling H L,DasGupta T,et al. 1997. Density logging in slim holes with a novel array density tool[C]//SPE Annual Technical Conference and Exhibition,Society of Petroleum Engineers.
Tan T D. 1987. New Method of Gas Bearing Zone Identification by Well Logging[J]. Acta Petroleum Sinica (in Chinese),8(1): 35- 43.谭廷栋. 1987. 识别气层的测井新方法[J]. 石油学报,8(1): 35- 43.
Tan T D. 1992. A Special Interpretation Method of Gas Finding by Neutron and Density Logging[J]. Acta Petroleum Sinica (in Chinese),13(4): 31- 40.谭廷栋. 1992. 中子和密度测井找气的一种特殊解释方法[J]. 石油学报,13(4): 31- 40.
Wang X G,Zhang Q Y,Zhang F,et al. 2015. Simulation and optimization of high-resolution density logging instrument with Monte Carlo code[M]//2015 SEG Annual Meeting,Society of Exploration Geophysicists,781-785.
Wu W S. 2003. Effects and correction of thin layer by three detector density logging[J]. Natural Gas Industry (in Chinese),23(3): 38- 40.吴文圣. 2003. 三探测器密度测井的薄层影响及校正[J]. 天然气工业,23(3): 38- 40.
Wu W S,Huang L J. 2004. Monte Carlo simulation of three-detector density logging[J]. Journal of Geophysics (in Chinese),47(1): 164-170,doi: 10.3321/j.issn:0001-5733.2004.01.025.吴文圣,黄隆基. 2004. 三探测器密度测井的Monte Carlo模拟[J]. 地球物理学报,47(1): 164-170,doi: 10.3321/j.issn:0001-5733.2004.01.025.
Wu W S,Huang L J. 2010. Spacing optimization for three-detector density logging tool[J]. Nuclear Techniques (in Chinese),33(11): 849-853.吴文圣,肖立志. 2010. 三探测器密度测井仪器的源距优化[J]. 核技术,33(11): 849-853.
Xie X C,Lai W C,Zhao Z L,et al. 2014. Test and comparison of Lanthanum Bromide and Sodium Iodide detector[J]. Nuclear Electronics and Detection Technology (in Chinese),34(7): 917-920.谢希成,赖万昌,赵祖龙,等. 2014. LaBr3(Ce)与NaI(Tl)闪烁探测器的性能研究与比较[J]. 核电子学与探测技术,34(7): 917-920.
Yu H W. 2011. The fundamental research of the pulsed-neutron density logging while drilling (in Chinese)[Ph. D. thesis]. Qingdao: China Universaty of Petroleum.于华伟. 2011. 随钻环境下脉冲中子测量地层密度的理论基础研究[博士论文]. 青岛: 中国石油大学.
Zhang F,Guo J F,Wang X G. 2010. Monte Carlo simulation of neutron porosity logging response under the condition of air drilling [J]. Journal of Jilin University(Earth Science Edition,in Chinese),40(1): 209-214.张锋,郭建芳,王新光. 2010. 空气钻井条件下中子孔隙度测井响应的蒙特卡罗模拟[J]. 吉林大学学报(地球科学版),40(1): 209-214.
Zhang H W,Wang L,Leng F Q,et al. 2017. Properties and Application Studies of LaBr3(Ce) Scintillation Detector[J]. SPECTROSCOPY AND SPECTRAL ANALYSIS,37(7): 2298-2304.
Zhang S,Tang B. 2012. Monte Carlo Study of LaBr3 Detector in the Application of Gamma-ray Logging[J]. Science and Technology Square (in Chinese),(1): 45- 47.张硕,汤彬. 2012. 溴化镧探测器在伽马测井应用中的MC研究[J]. 科技广场,(1): 45- 47.