The Research On The Stress Field Of Hydraulic Fracture On Damage Theory

Hydraulic fracturing is a process in which a variety of holes and micro-crack growsunder the strong fracturing fluid cross and eventually through, into macro-hydraulic fractureand macroscopic crack growth within a rock micro crack group thereby increasing the seepa-ge of oil and gas reservoir seepage volume increased to a certain extent, but also cause irrev-ersible damage deterioration of the mechanical properties of the whole rock. With the researchmethods and theoretical results of the damage mechanics to hydraulic fracturing fracturingfluid in the construction process to analyze the effect of this degradation of the stratigraphicrock description, and thus can accurately calculate the effective spread range of hydraulicfractures.In this paper, the author used methods and theoretical results in damage mechanics andfracture mechanics to describe the fracturing process of fracturing the reservoir rock damagedeterioration effect on the mechanism of in-depth study of cracks, to solve practical engineer-ing problems with some guiding significance and innovation.First, a brief introduction to the concepts and theories of damage mechanics used in thisarticle, focusing on the formulation of the concept of the damage variable and damagevariable, the equivalence principle of damage mechanics, especially the analysis andelaboration of the equivalent strain principle; Second, it describes the mechanicalcharacteristics of the cracks in the rock surrounding the fracturing operation, a rock formationand evolution mechanism of injury, reasonable simplification σ-ε curve of rock on the basisof this premise, combined with appropriate assumptions derivation out based on the damagetheory of the formation rock constitutive model; assumed rock holes dual-permeability media,inthe considered stress field, seepage field effect, combined with fracture mechanics theoryderived expression of the cracks in the audience stress analysis element by the force, obtaineddifferential balance equations; damage mechanics model of artificial cracks, cracks thesurrounding rock mass is divided into non-destructive zone, damage zone and destruction zo-ne, all regions of the boundary equations and the stress state is calculated solving to determinethe different regions of extension of the radius and the stress distribution of the rock mass tocalculate the crackdamage stress conditions in the state of actual construction and analysis.