近日，陕煤40006队引进油套管在线监测系统，成功完成了延21-P2井的套管下放作业。该系统的引进为套管下放环节提供了安全保障。

油套管在线监测系统是利用水的密度和重力来阻止气体或液体的泄漏。当气体或液体通过密封层时，由于水的密度大于气体或液体，会产生阻力使其停止泄漏。同时,由于水的重力作用，水密封层会形成一个封闭的屏障，有效地阻止了气体或液体的扩散和泄漏，对套管之间的密闭性进行有效检测。在下套管作业过程中，每一根套管下入井中，工人就会立即将监测仪器放入最顶部的套管内部对其进行试压检测。只有当检测数据合格，满足密闭性要求后，方可继续进行下一根套管的作业。

延21-P2井为水平井，井深结构对于下套管作业难度很大，该系统的应用不仅提高了作业效率，更重要的是显著降低了因套管密闭性不足而引发的安全风险和不必要的工作量。

Recently, Shaanxi Coal 40006 team introduced the oil casing online monitoring system and successfully completed the casing lowering operation of Yan21-P2 well. The introduction of this system provides a safe guarantee for the casing lowering link.

The oil casing on-line monitoring system uses the density and gravity of water to stop the leakage of gas or liquid. When the gas or liquid passes through the sealing layer, because the density of water is greater than that of gas or liquid, resistance will be generated to stop the leakage. At the same time, due to the gravitational action of water, the water seal layer will form a closed barrier, effectively preventing the diffusion and leakage of gas or liquid, and effectively detecting the tightness between the casing. During the casing operation, each casing was run into the well and a monitoring instrument was immediately placed inside the top casing to test its pressure. Only when the test data is qualified and the tightness requirements are met, the next casing operation can be continued.

Yan21-p2 is a horizontal well, and the well depth structure is very difficult for casing operation. The application of this system not only improves the operating efficiency, but more importantly, significantly reduces the safety risk and unnecessary workload caused by insufficient casing tightness.