Study On The Influencing Factors Of Crack Propagation In Hydraulic Fracturing

Hydraulic fracturing technology has become one of the main measures to increase production in the exploitation of low permeability oil and gas fields,and has been widely used.For some unconventional reservoirs,such as low-permeability reservoirs,reservoirs with thin reservoirs,the production of oil in the reservoir using horizontal wells is high,the formation penetrates to a large extent,large oil drainage area,high oil and gas reserve extraction rate and can effectively bypass complex obstacles.So horizontal well fracturing technology has gradually become the main means of developing low permeability and other unconventional oil and gas reservoirs.In this paper,using the ABAQUS finite element calculation software,combining the theory of rock mechanics,seepage mechanics and fracture mechanics,using the maximum tensile stress criterion,using the pore pressure cohesive element to simulate the cracks,the calculation model of fracture expansion of hydraulic fracturing is established,and the influence factors of fracture expansion are analyzed.A two-dimensional hydraulic fracturing calculation model is established,and the influence of the angle of perforation and the maximum horizontal principal stress direction,the fracturing fluid output volume and the minimum horizontal principal stress on the fracture morphology is preliminarily analyzed,and the different horizontal stress differences,the different natural cracks and the maximum horizontal principal stress angle and tensile strength of rock at the natural crack on the intersection of hydraulic fractures and natural fractures are analyzed.The three-dimensional finite element model of hydraulic fracture is established,and the three-dimensional fracture is simulated by preloading the pore pressure cohesive element layer,and the influence on the length,height,width and pore pressure and width at the injection point of the crack expansion are analyzed considering the fracture fluid viscosity,the fracturing fluid output volume,the minimum horizontal principal stress in the oil layer,the direction of the minimum horizontal principal stress and the spacing of the perforation clusters.The law of its influence on the fracture propagation pattern is obtained,so as to provide reference for hydraulic fracturing design and construction.