水平井和大斜度井中阵列侧向测井响应数值模拟

Numerical Simulation of Array Laterolog Response in Horizontal and Highly Deviated Wells

针对水平井和大斜度井中阵列侧向电极系的工作原理,利用多电场叠加方式进行电场合成,采用三维有限元方法模拟仿真各个分电场的场分布,进而利用电场线性叠加原理得到阵列侧向测井响应。在基于计算机仿真的基础上,得到阵列侧向五条测井曲线的径向探测深度,阵列侧向径向探测深度要小于深侧向探测深度。考察了三维地层模型下井斜和侵入深度变化对阵列侧向测井响应的影响,分析了水平井和大斜度井中阵列侧向测井响应特征。模拟结果表明,在井斜小于15°时,阵列侧向测井响应受井斜影响小,可以不进行井斜校正;井斜超过60°的大斜度井以及水平井中,阵列侧向测井响应视地层厚度逐渐增大,测井响应值与直井条件下响应值差别较大,必须进行井斜校正。

According to the operating principles of array lateral electrode arrays in horizontal wells and highly deviated wells ,electric field is studied by using multiple electric field superposition method , and the 3D finite element method is employed to simulate electric field distribution of various points ,and then electric field linear superposition principles are used to get the array lateral logging response .Based on the computer simulation ,five array lateral logging curve radial investigation depths are obtained .The array lateral radial detection depth is smaller than the deep lateral detection depth .The effect of well deviation and variation of depth of invasion on log response in the 3D formation model is examined ;and the characteristics of array lateral log response in horizontal wells and highly deviated wells is analyzed . The simulation results are as follows :well deviation has a small impact on array lateral log response when the well deviation is less than 15° ,and correction of well deflection is not necessary ;while the well deviation must be corrected when the horizontal well deviation is more than 60° in a highly deviated well due to a greater difference of array lateral log response between highly deviated wells and vertical wells .