SIMULATIONS FOR HYDRAULIC FRACTURING TREATMENTS AND METHODS OF FRACTURING NATURALLY FRACTURED FORMATION

摘要

A hydraulic fracture design model that simulates the complex physical processof fracture propagation in the earth driven by the injected fluid through awellbore. An objectivein the model is to adhere with the laws of physics governing the surfacedeformation of thecreated fracture subjected to the fluid pressure, the fluid flow in the gapformed by the opposingfracture surfaces, the propagation of the fracture front, the transport of theproppant in thefracture carried by the fluid, and the leakoff of the fracturing fluid intothe permeable rock. Themodels used in accordance with methods of the invention are typically based onthe assumptionsand the mathematical equations for the conventional 2D or P3D models, andfurther take intoaccount the network of jointed fracture segments. For each fracture segment,the mathematicalequations governing the fracture deformation and fluid flow apply. For eachtime step, the modelpredicts the incremental growth of the branch tips and the pressure and flowrate distribution inthe system by solving the governing equations and satisfying the boundaryconditions at thefracture tips, wellbore and connected branch joints. An iterative technique isused to obtainthe solution of this highly nonlinear and complex problem.