油井套管井下阴极保护电位计算方法研究

A NEW METHOD FOR CALCULATING THE DOWNHOLE CATHODIC PROTECTION POTENTIALS OF WELL CASINGS

提出了一种利用阴极保护地面测量参数和油井套管完井数据来计算油井套管井下阴极保护电位分布的新方法．将这种方法应用到美国得克萨斯Ａ井的结果表明,计算值和实测值非常吻合,最大相对误差小于２%．

Although cathodic protection has been widely applied to oil well casings, it is a challenging job to determine the cathodic protection level of well casings at any depth without interruption of production. In this paper, a new method was established to calculate the potential distribution of well casing cathodic protection with several wellhead electrical measurements( including the applied current, the cathodic protection potential and the native- state potential) and well completion data(such as lengths and unit length resistances of outer and inner casing). When the method was applied to Well A in Texas, the excellent agreement was obtained between measured and calculated cathodic protection potentials, the maximum percent difference was less than 2 % .