钻具遇卡声波检测理论与实验研究*

石油钻探过程中,钻具经常发生陷入泥沙中不能自由活动进而卡在井下的事故。本文提出使用单发双收声系来检测钻具遇卡的方法,首先使用有限差分模拟了钻具外为自由流体和泥沙两种介质时的钻铤波响应,通过对比远近接收器的钻铤波衰减,发现泥沙卡钻情况下的钻铤波衰减要明显大于自由钻具情况。随后建立了实验模型对理论结果进行了验证。理论模拟与实验结果均表明声波方法可用以检测钻具遇卡事故,从而确定卡钻的深度位置,为解卡钻作业提供解释依据。

Theoretical and experimental research on the acoustic detection of stuck drill pipes

During oil drilling, drill pipes often get stuck in the mud or sand and cannot move freely. In this work, we propose the use of the single-emission and double-receiving acoustic system to detect locations of stuck pipes. First, we simulate the responses of collar waves using finite difference method when the annulus between the drill pipe and formation is filled with fluid and sand, respectively. By comparing the attenuation of collar waves in these two cases, we found that the attenuation in the case of stuck pipe is larger than that in the case of free pipe. An experiment is then carried out to verify the above theoretical results. Both the theoretical and experimental results show that it is feasible to use the acoustic technique to detect stuck-pipe accidents and identify corresponding depths, which help the operation of releasing stuck pipes.