When extracting high wax and high asphaltene crude oil from self flowing wells,cable are commonly used to heat the precipitates to solve the problem of wellbore blockage.However,there is insufficient research on the sealing performance of wellhead high-pressure blowout prevention devices that can be used in conjunction with cables.A packing sealing structure suitable for heating cable blowout preventers was proposed,and a theoretical model and finite element model of the packing ring in the compression deformation stage and fluid penetration stage were established.The sealing performance coefficient was proposed to evaluate the packing sealing performance under different influencing factors.The results indicate that the stress is concentrated on the top of the main and secondary sealing surfaces after the packing sealing is compressed and deformed,and the sealing performance of the secondary sealing surface is better than that of the main sealing surface after fluid pressure penetration.The sealing performance coefficient of the main and secondary sealing surface of the packing sealing can be improved by increasing the pre-tightening stress of the pressure valve,reducing the fluid pressure and reducing the friction coefficient between the cable and the packing.With the increase of interference,the effective contact stress on the main and secondary sealing surfaces increases,but the effective contact length shows a trend of first increasing and then decreasing.When the interference is greater than 0.06 mm,the sealing performance coefficient decreases,and the sealing performance of the packing actually deteriorates.