井下低熔点合金封堵套管的密封性OA

For the sealing performance between Bi-based alloys and casing in downhole low-melting-point metal plugging,an experimental setup for alloy plug formation and gas sealing was constructed.Then,experiments were conducted to evaluate the pressure bearing capacity and gas sealing performance of the alloy plug after bonding with the casing.The microstructure of the sealing interface was analyzed using optical microscopy,and the effects of axial pressure and ambient temperature on the sealing performance of the alloy plug were investigated as well.Experimental results show that the sealing performance of the formed alloy plug is significantly influenced by ambient temperature.As the ambient temperature increases,the bonding capability between the alloy plug and the casing weakens,leading to a reduction in pressure-bearing capacity.During the so-lidification and formation of the alloy plug,the application of axial pressure is beneficial for enhancing its pressure-bearing and gas sealing capabilities.When the alloy plug is displaced,shear failure and movement occur at the interface with the in-ner wall of the casing,but the gas sealing performance is not entirely damaged.As a novel material for downhole casing plug-ging,Bi-based alloys can achieve casing sealing through the expansibility of the material itself.