Mechanical Analysis And Calculation Of Horizontal Well Acidification Fracturing

The thesis firstly have investigated the development of the horizontal well staged fracturing string, and concluded the fracturing string mechanical model. The way is to use cubic spline data interpolation method to obtain continuous well depth structure data, for example function of deviation Angle and azimuth of hole depth.The method is used to solve the equation, and the spatial coordinates of any deep well O (N, E, D), curvature k, torsion T value is obtained. The string axis and the borehole trajectory do not overlap, the data that well track curves and deflection Angle a was used to describe acidification string in underground space。The string stress situation was complex in-cycle work was complex, Such as the gravity of Pipe string; the pressure of the fluid by inside and outside, the string friction resistance. If string and borehole wall extrusion contact occurred, the casing wall contact reaction force and the friction on the string; To string infinitesimal body as the research object, it also has internal force and moment. In this paper, the differential equation of deformation of tubing string is established from the Angle of energy:Firstly, it is the energy of bending deformation; Secondly, the fluid pressure on the string inside and outside is equivalent to an axial force, and a volume force, which Calculate the total internal force to do the work after the deformation of tubing string; The force merged with string internal force and fluid pressure fictitious force calculate total internal force after the deformation of tubing string to do the work;It is Doing work, that pipe string distributed load on the string deformation direction,Using the method of minimum potential energy, elastic body under the action of external force is in balance, the total potential energy of the first-order changed into zero, so the fracture string deformation differential equation was obtain. It is to do dimensionless processing, make the deformation equation is simplified of deformation differential equation of acid fracturing string. Considering the boundary condition parameters of straight wells, inclined section, the bending section, it is to verify the deformation differential equation of acid fracturing string. Considering the geometric relationships between deflection Angle a and well depth s under acid fracturing string sinusoidal buckling and Helical buckling,the characteristics of the helical buckling critical load parameters and sinusoidal buckling critical load parameters, from acid fracturing string deformation differential equation. It is to divided Acid fracturing string model for finite element, ANSYS software is used to compile the corresponding command flow program, to Simulation of the tubing string temperature effect, Wellhead suspension force effect and fluid wellhead pressure effect on the deformation of tubing string stress and displacement; it is to do the finite element analysis of the packer under the condition of stress and displacement deformation.Acid in different cases for the downhole pressure pipe string axial stress and displacement deformation calculation results are output.