Mechanical Analysis And Safety Evaluation Of High Temperature And High Pressure Completion

With the oil demand rising and the continuous development of supporting technology, drilling and completion technology in our country keep developing against the deep strata of high pressure, high temperature and complex aspects. With the increase of temperature and pressure, the length and force condition changes and results in strings’breakage and the packer seal’s malfunction.All of this threaten packer’s sealing performance and tubing stings’ security.Therefor, in order to reduce accidents in oil and gas well, predicting the force status and evaluating reliability accurate that provide scientific basis for selection of parameters draw more and more attention.This paper, based on extensive literature research and theory of heat transfer and fluid dynamics, using conservation of momentum, conservation of energy, established a forecast pressure coupling calculation model of temperature field distribution in wellbore and analyzed output, gas market share and other factors impact on wellbore pressure and temperature profiles by means of the recursive and iterative algorithm.According to the investigation of the well-known foreign companies’ advanced high temperature and high pressure packer, this paper established a mechanical model of different types of downhole packer such as mechanical and hydraulic type, carried out extensive comparative analysis and sensitivity studies, analysed and calculated the plastic tube sealing deformation and mechanical properties of the deformation process of institutional, studied the distribution of slips anchor packer sleeve contact stress between the institutions and thus evaluated the safety of the packer.The high temperature and high pressure completion string as the object of study,taking into account pressure and temperature effects on the column axial deformation andaxial force, established a mathematical models of dual packer complex string in piston effect,ballooning effect,temperature effect and buckling effect. This article analysed three-dimensional stress of the dangerous section column, gave the basic formula of column strength check, proposed the impact of dual packer sealed annulus thermal expansion effects on tubing string performance, provided a theoretical basis for safety evaluation of the pipe string.Combined with mechanical packer model and completion string mathematical model established under high temperature and pressure environment, the paper programmed the corresponding mechanical packer system behavior and safety evaluation software in VB language. Besides, there is no difference to compare with Landmark. According to the site conditions and dynamic data of the production, provided a theoretical basis for oil completion string safety and construction parameters reasonable choice.Finally, on the basis of theoretical research, the paper carried out stress analysis and safety evaluation on XX well tubing string in Sichuan.