Analysis Of Expansion Law Of Hydraulic Fracture In Perforated Perforation Of Isotropic Continuous Media

The fracturing of hydraulic fracturing is a very complicated process. In the study of the law of hydraulic fracturing, the following problems are solved: the quantification of fractured fractures is not mature, The main cause of fracture propagation is unclear, and the method of surface perforation is not perfect.The extended finite element method (XFEM) method in ABAQUS finite element software is used to model the hydrodynamic fracturing problem. The input file is rewritten and the influence factors are taken into account to realize the simulation calculation of the crack propagation process. The influence of perforation parameters and the direction of perforating surface on the fracture propagation is analyzed, which can provide reference for the design of fractured hydraulic fracturing. The new method can promote the extension of the fracture and increase the oil discharge area at the same time to form the system And the effect of improving the yield potential of low permeability oil wells is significant.The finite element method is used to simulate the new crack unit based on the finite element method. The fracturing element is used to simulate the expansion of the crack in the process of hydraulic fracturing. Process, the initiation criterion of XFEM unit is the maximum tensile stress of rock unit, and is extended according to the law of linear separation, and the degree of tangential and normal opening of rock unit is in accordance with BK criterion.The main research contents are as follows: The theoretical method of hydraulic fracturing numerical simulation with XFEM under the condition of constant perforation is analyzed. The influencing factors of the fracturing law of hydraulic fracturing are discussed briefly. The influence of the perforation length, the angle and the spacing on the crack propagation law is analyzed, and the influence of the location of the perforation surface on the crack propagation is analyzed.Effect of propagation of cracks on the surface by the perforation parameters and perforating direction:?The perforation spacing is larger than the perforation length of perforation, fusion between fracture has little effect on the crack will be easier fusion; the perforation angle is small,the crack extension direction to horizontal and vertical direction. ?The crack extension direction tends to be in surface and maximum perforation the main stress levels face angle 45 degrees, 45 degrees vertical case, with the increase of the perforation angle, the crack propagation direction of deflection angle decreases first and then increases and finally tends to be stable, and the vertical angle of 45 degrees of magnitude greater crack height, width increases with the increase of the angle between the perforating direction along the maximum.?The direction of the principal stress, the crack propagation direction is not deflected; perforated surface and the maximum principal stress is horizontal angle, can be used to increase fixed surface perforation on the crack propagation direction to lead Guide; perforated surface and the maximum principal stress is vertical angle, increasing the fixed surface perforation angle, to guide the direction of crack propagation, but the angle is not too large, otherwise it would not lead to the perforation.?The angle between the 30 cases, with the increase of perforated surface and the maximum principal stress surface horizontal angle the deflection angle of crack growth, crack change little lateral extension range; perforation angle between the 30 degree case, with increasing perforation surface and the maximum principal stress plane vertical angle, deflection angle of crack increases, lateral expansion range decreases.By summarizing the calculated law of hydraulic fracturing expansion, it has a good reference for the hydraulic fracturing design and the prediction of hydraulic fracturing expansion.