感应测井几何因子理论计算及其应用  

Theoretical calculation and application of geometric factor of induction log

作　　者：彭玲[1] 潘和平[1] 

机构地区：[1]中国地质大学地球物理与空间信息学院,武汉430074

出　　处：《物探化探计算技术》2016年第1期8-18,共11页Computing Techniques For Geophysical and Geochemical Exploration

摘　　要：几何因子对于计算地层真实电阻率、了解地层特性、划分储层等起着相当重要的作用。这里建立双线圈系感应测井基本模型,分别得出纵、径向简单多层地层模型的几何因子理论曲线,从中可得知感应测井响应值受到目的层厚度、围岩电阻率、泥浆电阻率、侵入带等多种情况的因素影响,1目的层越厚,感应测井值越接近原状地层电阻率值;2在过渡带厚度不变的情况下,冲洗带深度越大,测量的电阻率越小,它的径向几何因子有下降的趋势,但是整体来说,随着冲洗带的半径增加,视电导率增加幅度变缓,且越来越接近过渡带地层的电导率;3在冲洗带厚度不变的情况下,过渡带的深度越小,越接近原始地层的电导率;4泥浆侵入会导致得到的地层电阻率与实际地层电阻率存在较大偏差。将这些结论应用于计算塔河油田石炭系区域井的真实电阻率中,得到塔河油田石炭系区域地层电阻率真值,最后解释结果与试油结果对比证实,这一过程确实提高了地层电阻率和冲洗带电阻率的精度。Geometric factor plays an important role in the respects of calculating the true resistivity of the formation,characterizing the formation properties,and distinguishing the reservoir.We established a basic model of the double coil induction logging,and derived the theoretical curves of the geometric factors of both the longitudinal and radial multi-layer formation models.The conclusion could be drawn from the curves,that the response values of the induction logging are influenced by the thickness of the target layer,the resistivity of the surrounding rocks,the resistivity of the mud filtrate,and the resistivity of the flushed zone.The response values of the induction logging will be closer to the resistivity values of the undisturbed zone when the thickness target layer is larger.When the thickness of the transitional zone is constant,the measuring resistivity will become smaller as the thickness of the flushed zone increases,and the radial geometric factor will decrease at the same time.In general,when the radius of the flushed zone increases,the increasing tendency of the apparent resistivity becomes slower,and the value of the apparent resistivity gets closer to the resistivity of the transitional zone.When the thickness of the flushed zone is constant,the response values of induction logging will be closer to the resistivity of the undisturbed zone as the thickness of the transitional zone decreases.In addition,mud invasion will cause relative big deviation between the measured formation resistivity and the real formation factor.We applied these conclusions in calculating the true resistivity of the boreholes in the carboniferous formation of Tahe oilfield,China.The calculated true resistivity of the formation was compared with the well testing results,and the accuracy of calculation of formation resistivity as well as the flushed zone resistivity was improved from this process.

关 键 词：双感应测井 几何因子 塔河油田石炭系区域 

分 类 号：P631.8[天文地球—地质矿产勘探]