Mechanics Analysis Of Layered Water Injection Packer String

The pipe string of layering water injection is one of the main tools to realize layeringwater-flooding, which can have a great effect on the oilfield water-flooding development. Inthe process of layering water-flooding, the failure of water injection packer and the destructionof pipe string strength is the main cause leading to the failure of the water injection operation.Therefore, this paper analyzes the safety capability of layering water injection packer based onthe theory of mechanics.First of all, the paper introduces the process technology of layering water injection, takesthe pipe string of water injection with single packer as the research object, and builds amechanical analysis model. The paper analyzes the axial forces, the temperature, theexpansions, deformation of helical buckling appeared on the pipe string of water-injectionpacker under the circumstance of water flooding. And the paper analyzes the loading capacityand strength of the pipe string of water injection, and provides a basis for the mechanicalanalysis on the multi-packers water-injection pipe string. Then, the paper takes the separatedlayer straddle injection pipe string with multiple packers as the research object based on thetheory of pipe string bucking, analyzes the effects of the geometry size, the internal-externalpressure difference, the temperature and the axial forces when setting of pipe string on thesafety capability of pipe string at the point of the multiple packers water-injection pipe string.It comes to conclusions that the length of transition section of water-injection pipe string is farless than that of helical buckling section, and space beam-column section. Because of the largedeformation and high stress concentration, this section is the vulnerable section of the multiplepackers straddle pipe string. Thereby, it provides a basis for the optimization of setting load,pipe string combination, and the safety analysis of the separated layer injection pipe string atthe point of packers.Last, the paper takes separated layer injection packers as the research object and builds aforce modeling. By analysis on the integral forced status of separated layer injection packersand an example calculation, it provides theoretical references for further improving the stresscondition of packers, optimizing the structure of layering water-injection pipe string and thesealing of packer rubber, and improving the safety capability of separated layer injectionpackers.