Study On Mechanical Problems Of Well Washing Process And Analysis Of Influence Of Slip Structure Parameters On Anchoring Performance

At present, most of the injection Wells are well depth, large Angle, high temperature and high pressure, the string deformation will increase easily if the pipe has a the long-term work under the bad environment, which will lead to pipe string produced peristalsis, at the same time, it has an effect on packer layered and string center performance.According to the above problems, Based on layered water injection project in Da Gang oilfield, this paper mainly aims at the well-flushing string mechanics state and slip, in the process of researches on the working condition and existing problems of centralizer. In order to analysis the well-flushing string mechanics correctly, the research on the string was commonly used in engineering structure, the way on washing and the process on washing, in order to find the factors that may influence the effect of flushing; Through the establishment of impurity particles in the flushing fluid mechanics model, the washing well flushing fluid velocity and impurity particles sedimentation velocity are studied, the study shown that the flushing fluid return rate must be 2 times to the impurity particles sedimentation speed, if the flushing fluid has ability to carry rock to ground. A string mechanical model is established based on the true borehole trajectory, the factors of weight of the tubing string and liquid pressure and temperature are considered on the string force, superposition method is used to analytic the string's mechanic problems, a method which is used to compute the different location string axial force and the accumulative deformation on string is putted forward, a law of axial force which is produce by well depth, pressure and flow rate to string is acquired; the engineering example shows that the theoretical calculation of pipe string axial force contrasts with the field data error is 9.56%, it conforms to the requirement of the project.In order to reduce the influence which is produced in the process of washing well to the neutral on pipe string, the application of the centralizer is studied, according to the principle of centralizer's structure, the characteristics of different types of centralizer and applicable environment is studied; the Fourier series is used to descript the deformed string's curve between centralizers, according to the principle of function the deflection problem of different model on string deformation is studied, the criterion on the installation of centralizer spacing is putted forward with different types.The string deformation may be caused displacement on the packer in the progress of well-flushing, a large displacement may cause the failure of layered, in order to prevent packer move too much, According to slip casing between the actual working condition, the relationship on force between slip casing and pipe is analyzed, the results indicate that the frictional resistance between slip casing and pipe is related with slip Angle, the friction of slip between the cone Angle and other factors; the real working state is simulated by ABAQUS, the rule of slip's stress and strain was studied under different pressures, respectively; the results indicate that the distribution of slip's stress existing a problem is disproportionate, in order to improve the stress distribution of the slip, parameters such as cone Angle, tooth surface inclination Angle are studied by ABAQUS, the study found that when the slip Angle and tooth surface inclination are all four degrees, and the material slip friction Angle tangent value is 0.1, slips anchor have a best qualitative.