Research on Application Technology of Laser Welding in Oil Downhole Instruments

Abstract

With the continuous development of oilfield exploitation technology, ultra-high temperature and ultra-high pressure well conditions are increasing, and the requirements for downhole instruments to resist high temperature and high pressure are also increasing day by day. The traditional fluororubber O-ring seals used in downhole instruments can no longer meet such well conditions, and such seals are also a key factor affecting the high temperature and high pressure resistance of instruments. Therefore, it is urgent to develop new sealing technologies for downhole instruments to meet the testing requirements of ultra-high temperature and ultra-high pressure wells. Taking the welding seal between the joint of downhole electronic pressure gauge and the sensor as the research object, this paper studies the influence of temperature and preload control on the welding results in the engineering application of laser welding seal between the pressure gauge joint and the sensor through thermal field simulation and welding experiment test methods under the condition of consistent welding process parameters. The simulation and experimental test results are consistent, both indicating that the absence of temperature control and preload control during the welding process will affect the laser welding results and lead to the failure of welding seal. Aiming at the above influencing factors, by intervening and controlling the welding temperature and clamping preload, under the condition of consistent welding process parameters, the laser welding quality and success rate of the sensor can be effectively improved. This paper provides theoretical, experimental data and application references for the application of laser welding seal technology in the engineering of oil downhole instruments, and helps to promote the development of downhole instrument seal technology.