水平井中双侧向测井的围岩校正

将双侧向测井（ＤＬＬ）电极系的一小段近似看成一点电极，则电极系在空间任一位置产生的总电位为各点电极电位沿电极系求线积分，考虑到电极系电流密度分布的均匀性，计算了深、浅侧向的电极系系数，其计算值与实验值的相对误差分别为３．１％和６．８％。在水平井中，假设电极系轴平行于地层界面，忽略井眼和侵入带的影响（春影响另行考虑），利用镜像法求解的结果表明：对于两层模型，邻层对深侧向（ＬＬｄ）的影响明显大于浅侧向

The Shoulder Bed Correction for Dual Laterolog in Horizontal Wells

little length of electrode system of dual laterolog tool is considered asa point electrode.The total potential of the tool on any place in the space can be obtainedby integrating the point source potential along the electrode array. When theinhomogeneity of the current density is taken into account, the array factors of deep andshallow laterolog are about 3. 1% and 6. 8%, respectively. In horizontal wells, influencesof the hole and the invaded zone are neglected. The mirror image method is used in thepaper. According to the calculated results of two layers model, the effect from the adjacentbed for deep laterolog is more intensive than that of shallow laterolog. For a bed with twohalf infinite shoulders, when the thickness of the bed is above 20 feet, there is littleinfluence from the shoulders for shallow laterolog. But for deep laterolog, there is mucheffect from shoulders even if the bed thickness is above 50 feet. While the bed thickness isa constant value, the response of shallow laterolog is sensitive to the distance between thetool axis and the boundary. But for deep laterolog, if the bed is a high resistance one, theresponse is sensitive to the distance. While for low resistance bed, the response is notalmost influenced by the distance