Research And Application Of Subsidy Operation Technology For Casing Damage Tube Expansion

In the process of oil and gas exploration and oil and gas well stimulation operations, the casing has some common problems, such as the casing deformation, wear, corrosion perforation, collapse phenomenon. These will lead the old oil wells to appear casing damage especially in the old oilfield with a long development time. Casing damage will result in production decline, pay zone contamination, comprehensive cost rising. In order to solve these casing damage problems, it is need to drill a new borehole in the side to resume normal production or scrap treatment of serious casing damage wells, which will cause serious losses to the oil and gas industry. Therefore, this paper has carried out the research work of the expansion tube subsidy operation technology, which provides a reliable technical support for the casing damage subsidy scheme design of the oil field.The types and factors of casing damage are summarized, and the basic principle and construction technology of the expansion tube are investigated;In this paper, the optimum design of the expansion cone Angle structure is carried out with the finite element simulation, and analyzes the law of expansion pressure, pressure fluctuations, expansion at the outlet of reduced diameter, the inner diameter of the expansion pipe, the expansion pipe wall thickness and expansion pipe axial dimension along with change of cone angle of the material that we choose. Through the comprehensive analysis, it is found that the optimal design of the expansion cone angle is 15 degrees.This paper designed thread connection mode using the negative angle buttress structure and carried out the laboratory experiment. The analysis results showed that the expansion pressure is 26MPa when the expansion ratio is 10%, the required.The expansion pressure corresponding to different friction factors is analyzed, and the optimum friction factor of 0.15 is determined.On the basis of the optimization design of the expansion cone, the pressure expander assembly chamber has been designed, and testing the device of the expansion tube subsidy in indoor as well as carrying on the field application.This paper studies have shown that the expansion pipe subsidies conventional technology can effectively solve the problem of the well casing damage control, effectively reducing work over time, thereby reducing the cost of construction work field, provide guidance and reference for the future to further develop and promote the use of the expansion tube technology.