MAIN FACTORS OF CAUSING HIGH PRESSURE GAS INJECTION PIPE STRING DEFORM AND THE CALCULATION METHOD

One of the main problems encountered in the course of high pressure gas injection in the miscible flood oilfield is the free from setting of packer and the permanent deforming of pipe string. During the high pressure gas injection, the exquisite variation of the temperature and pressure causes the pipe string flexing or results in the change of force exerted on it. This paper presents the main influential factors:swelling effect caused by the variation of temperature; the effect of diameter swelling, plunger and spiral bending caused by the variation of pressure; and the influence of the initial force. This paper presents models for calculating the complex pipe string based on previous study. This paper points out that the initial force is the important operable factors for preventing the pipe string from damaging, and it is closely related to the force and stress exerted on the pipe string.