高倾角井眼中的阵列感应测井响应特征
|
摘要
倾角对阵列感应测井响应的影响特征研究是测井数据倾角校正的基础。基于COMSOL多物理场有限元软件实现高倾角井眼中阵列感应测井响应的三维数值仿真计算。计算和分析泥浆电导率、目的层与围岩对比度、目的层厚、井径、仪器偏心、倾角对阵列感应测井响应的影响。结果表明:井眼的存在弱化了倾角引起的"犄角"现象,井径越大、阵列间距越短,弱化现象越明显;当仪器在井眼与地层法线构成平面内偏心,倾角影响使仪器记录点偏移,偏移量等于偏心距除以倾角的余弦;倾角影响和井眼影响近似独立,可以分别校正,用直井方法实现井眼校正;通过有无井眼两种情况下层界面空间电流线分布和平面电流流向分析,揭示井眼弱化"犄角"的机理,解释倾斜地层中仪器穿过低电导率到达高电导率边界时,测井响应曲线出现展宽或压缩的现象。
The three-dimensional numerical calculation of the response of array induction logging in high angle borehole is complemented based on a COMSOL Multiphysics software. The influences of the mud conductivity,conductivity contrast between target bed and shoulder bed,the thickness of the target bed,the borehole diameter,tool eccentricity and dip are calculated and analyzed. Results show that the existence of the borehole weakens the " horns" phenomenon caused by the dip effect,the bigger the caliper,the shorter the array spacing,and the more obvious the weakening. When the instrument is eccentric in the plane of the borehole and the formation,the dip effect makes reference point offset,the offset is equal to the eccentricity divided by cosine of dip. Dip influence and borehole effect are independent approximately,so they can be corrected separately by the method of vertical borehole correction. The analysis of distribution of the space eddy current line at interface and plane eddy current flow distribution reveal the mechanism of borehole weakening " horns" and explain the phenomenon that the logging response curve is broadened or compressed when the tool goes through a high conductivity boundary from the low conductivity.
The three-dimensional numerical calculation of the response of array induction logging in high angle borehole is complemented based on a COMSOL Multiphysics software. The influences of the mud conductivity,conductivity contrast between target bed and shoulder bed,the thickness of the target bed,the borehole diameter,tool eccentricity and dip are calculated and analyzed. Results show that the existence of the borehole weakens the " horns" phenomenon caused by the dip effect,the bigger the caliper,the shorter the array spacing,and the more obvious the weakening. When the instrument is eccentric in the plane of the borehole and the formation,the dip effect makes reference point offset,the offset is equal to the eccentricity divided by cosine of dip. Dip influence and borehole effect are independent approximately,so they can be corrected separately by the method of vertical borehole correction. The analysis of distribution of the space eddy current line at interface and plane eddy current flow distribution reveal the mechanism of borehole weakening " horns" and explain the phenomenon that the logging response curve is broadened or compressed when the tool goes through a high conductivity boundary from the low conductivity.
引文
[1]江国明,等.大斜度井中的感应测井响应计算方法综述[J].勘探地球物理进展,2005,(2):97-101+9.
[2] C Kruger. The challenges of deviated wells. Society of Petroleum Engineers[J]. January 1,2007,Doi:10. 2118/108270-MS.
[3]仵杰,等.阵列感应测井在斜井和水平井中的响应特性[J].测井技术,2016-2:152-160.
[4]桂彩云.阵列感应测井倾斜校正研究[D].西安石油大学,2011.
[5]仵杰,桂彩云,解茜草.阵列感应测井斜井信号处理方法研究[J].石油仪器,2011,(2):68-70,102.
[6]桂彩云,等.大斜度井中倾斜校正方法[J].电子测试,2010,(10):47-51.
[7]张建华,刘振华,仵杰.电法测井原理与应用[M].西安:西北大学出版社,2002:121-125.
[8]晁立东,仵杰,王仲奕.工程电磁场基础[M].西安:西北工业大学出版社,2002:154-192.
[9]仵杰,等.基于COMSOL仿真软件的阵列感应测井偏心响应计算方法[J].测井技术,2012,(4):357-360.
[2] C Kruger. The challenges of deviated wells. Society of Petroleum Engineers[J]. January 1,2007,Doi:10. 2118/108270-MS.
[3]仵杰,等.阵列感应测井在斜井和水平井中的响应特性[J].测井技术,2016-2:152-160.
[4]桂彩云.阵列感应测井倾斜校正研究[D].西安石油大学,2011.
[5]仵杰,桂彩云,解茜草.阵列感应测井斜井信号处理方法研究[J].石油仪器,2011,(2):68-70,102.
[6]桂彩云,等.大斜度井中倾斜校正方法[J].电子测试,2010,(10):47-51.
[7]张建华,刘振华,仵杰.电法测井原理与应用[M].西安:西北大学出版社,2002:121-125.
[8]晁立东,仵杰,王仲奕.工程电磁场基础[M].西安:西北工业大学出版社,2002:154-192.
[9]仵杰,等.基于COMSOL仿真软件的阵列感应测井偏心响应计算方法[J].测井技术,2012,(4):357-360.