大斜度井/水平井阵列侧向测井响应及围岩/层厚影响快速校正

阵列侧向测井响应受围岩/层厚影响无法准确反映储层真实电阻率,且直井条件下的围岩/层厚校正图版不再适用于水平井、大斜度井,故有必要对围岩/层厚影响进行定量校正,并研制阵列侧向测井在大斜度井、水平井条件下的围岩/层厚校正图版。通过建立三维球状介质模型,利用有限元素法对水平井、大斜度井中阵列侧向测井响应特性进行研究。在三维数值计算的基础上,建立水平井、大斜度井中阵列侧向测井围岩/层厚校正图版,并通过非线性分析技术,得出仪器响应非线性校正公式和校正图版。研究结果表明,阵列侧向测井响应受井斜大小影响明显,井斜角越大,影响越明显。当储层厚度小于2 m时,电阻率受围岩影响较大;当储层厚度大于6 m时,无论井斜角多大,电阻率不再受围岩影响。对比发现快速校正图版与数值模拟图版具有较好的一致性,可用于阵列侧向测井响应的快速实时校正。

ARRAY LATEROLOG RESPONSE AND RAPID CORRECTION OF THE SURROUNDING ROCK/LAYER THICKNESS INFLUENCE FOR HIGHLY DEVIATED/HORIZONTAL WELLS

Due to the influences of the surrounding rock/layer thickness,the laterolog response of the array can not accurately reflect the actual resistivity of the reservoir,the surrounding rock/layer thickness correcting plate in the condition of the straight/vertical well is no longer suitable for the horizontal and high-inclination wells,so it is necessary to quantitatively correct the influences of the surrounding rock/layer thickness,and moreover the corresponding correcting plate was developed.With the help of the built 3D ball-like media model and finite element method,the response characteristics of the array laterolog in the horizontal and high-deviated wells were researched.On the basis of the 3D numerical calculation,the corresponding correction plate was established and furthermore by means of the nonlinear analyzing technique,the nonlinear correcting formula and the correcting plate were obtained for the instrument response.The study achievements show that the array laterolog response is obviously influenced by the sizes of the well inclination,the more the inclined angle is,the more obvious the influence will be.When the reservoir thickness is less than 2 m,the resistance is seriously influenced by the surrounding rock;while when the thickness is more than 6 m,there are no corresponding influences no matter how much the inclination angle is.The comparison discovers that there is much better consistency between the rapid correcting plate and the one of the numerical simulation,so it can be adopted for the fast real-time correction of the array laterolog response.