Study On Mechanical Properties Of The System Of Main Seal And Decompression In Snubbing Service Device Of Gas Well

In today's China,industrial production and people's life highly depend on oil and gas resources,whose consumption increasingly grows.However,since both are nonrenewable resources,their production is decreasing year by year and many oil and gas wells will expire soon.Therefore,there is a substantial increase in yield increase and well workover.However,since the mid-term oilfields suffer a considerable decline of gas and hydraulic pressure,pressurizing through injecting water is adopted to ensure the output of the oil well.It requires the killing job is required.The traditional killing job adopts killing before the hydraulic well or decompression through blowout or overflow,which will cause environmental pollution as well as even formation plugging.However,the adoption of snubbing can protect the ground.The new gas well snubbing device is a set of pressure working device especially developed for gas well R & D.When working in gas well,it requires maintaining the internal pressure while ensuring zero leakage of hazardous gases during the work process.The snubbing main blockout prevention and pressure relief system in this paper guarantees security.The snubbing main blockout prevention and pressure relief system,different from normal pressure working device,adopts two spherical BOPs,connected by a short blocked liquid column in the middle.By applying the principle of liquid blocking gas and secondary pressure relief,the system effectively realizes blocking.Moreover,equipped with an autonomous sprinkler,it reduces the friction between the plastic core and tubing.At first,the paper briefly explains the snubbing main blockout prevention and pressure relief system and then carries out theoretical analysis and researches on the system's spherical BOP.Then,its structure and work principle are introduced.The three-dimensional model of the spherical BOP is established with the solidworks software.With different friction coefficients,sub-network,load and calculations are conducted with Abaqus,concluding with the deformation process and contact stress trend of the BOP's glue during the process of blocking the well,thereby identifying the packer pressure.Based on it,it analyzes the blocking effect of the main blockout prevention and pressure relief system as well as normal pressure job.After comparing the downhole pressure limit of the two,it concludes that the main blockout prevention and pressure relief system boasts greater pressure limit and better blocking effect.Finally,based on the blocking pressure,the paper conducts the mechanical analysis of tripping operation petroleum string.It calculates and analyzes with Abaqus by adding displacement load that changes over time on the Finite Element Model.By checkingand comparing the plastic heart deformation and mechanical properties of two kinds of coefficients of friction conditions,it finds the main blockout prevention and pressure relief system enjoys noticeable advantages in tripping operation petroleum string.