采用COMSOL Multiphysics软件，对管道极化电位和管地电位进行模拟计算，从套管有涂层和无涂层的两个方面，研究了涂层孔隙率对套管处埋地管道的阴保电位影响规律。结果表明: 套管内管道涂层质量越差，管道所需的极化电流就越多，管道的阴保效果就越差; 加涂层套管在环形空间内的电位比无涂层套管的更正，但在地表处却稍微偏负，所以仅仅依靠管地电位来判断管道的极化电位是有误差的; 当套管无涂层时，只要环形空间内有电解质，其对管道的极化电流无屏蔽作用，所以利用密间隔电位测量(CIPS)、直流电压梯度法(DCVG)和交流电压梯度法(ACVG)等地面检测方法可以判断出套管内管道防腐层的质量和阴极保护的等级状况。

Using COMSOL Multiphysics software, the influence rule of coating porosity on polarized potential of buried pipelines and pipe-to-soil potential was investigated from two aspects of casing with coating and without coating. Results show that the worse the pipeline coating quality is, the more polarization current is required, so the results of cathodic protection is more undesirable. The potential in coating casing annular space is more positive than that in uncoated casing, but more negative on ground surface, so it is inaccurate to determine the polarization potential of pipeline just rely on the pipe-to-soil potential. When the casing has no coating, there is no shield influence to polarization current of pipe as long as electrolyte is in the annular space. So CIPS, DCVG, ACVG can be used to determine the pipe coating quality and cathodic protection level.