Development And Experimental Research Of Plastic Sealing Device For Oil Field Cable Joint

Aiming at the problem of poor reliability of cable joints in the working environment of high temperature,high pressure and acid corrosion underground in oil fields,a new insulation sealing method is proposed.The method is to coat the cable joints with a layer of plastic melt and form an insulation seal on the cable joints after it cools and solidifies.In order to realize this method,a set of secondary plastic packaging device for cable joints was developed.Based on the device,a secondary plastic packaging experiment of two-wire connector was carried out.The experimental samples were tested after being subjected to 30 MPa pressure,150℃ heating and soaking in acid corrosion solution to simulate the downhole environment of oil fields.The test results show that the cable connector is sealed well without any expansion,softening and leakage phenomena,and can be used for cable secondary connector technology in downhole operation environment.Firstly,a new treatment method is proposed,which coats a layer of plastic melt on the outer layer of the cable joint to achieve the effect of insulation and sealing of the cable joint.Based on moldflow,the molding process of the plastic melt and the relationship between the molding process parameters and the molding quality of the plastic melt were analyzed.The influence degree of each process parameter and the optimal combination of molding process parameters were obtained through orthogonal analysis.Then,based on heat transfer theory and rheological theory of polymer materials,a set of portable secondary plastic packaging device for oil field cable joints is designed,and the key parts are calculated and designed to fully meet the design requirements and operation requirements.Based on the heat transfer theory and the finite element theory,the temperature field mathematical model of the heat conduction of the die of the device is established,and the solving conditions are given,which provides theoretical basis for the finite element heat transfer analysis and thermal structure coupling analysis of the die of the device.Through ANSYS thermal conduction simulation and thermal-structural coupling simulation,the temperature field analysis and thermal-structural coupling analysis of the device die in different stages are carried out.Finally,the feasibility of the device and the correctness of the optimal process parameters are verified through several sets of indoor experiments.After the plastic packaging experiment was completed,the test samples were tested.Through statistical analysis of experimental data,the curve relationship between different process parameters and qualified rate was obtained.Through statistical analysis of data,the best molding process was obtained,and the correctness of simulation results was verified.