Kinetic model of fishing in highly-deviated well and parameter optimization of fishing tool

Fishing in highly-deviated well is critical for valve inspection in gas lift oil production and for separated injection and allocation in water injection wells. The current researches in this aspect only focus on design of processes and tools, but there is no appropriate theoretical model available as a guide. In this paper, an energy-based kinetic model of fishing was established for highly-deviated wells which are developed by gas lift, using the kinetic principle and the formula of tool undershoot velocity with and without consideration to wireline towing. The relationships between the residual undershoot energy and the well deviation in fishing section and diameter/length of the fishing tool were analyzed. Moreover, a parameter optimization model of fishing tool was built on the basis of the maximum well deviation that the fishing technique can adapt to, and relevant calculations were made for the design. The results provide theoretical basis for current researches on fishing in highly-deviated wells and relevant tools, and also contribute to the future improvement of fishing technologies.