Study On Dynamic Fracture Mechanical Model Of In-fracture Explosion In Low Permeability Reservoir

The low permeability oil field is hard to stabilize and increase production by using theconventional reservoir reforming measures because of its complex geological conditions and lowpermeability; it has to study some new reforming measures. The In-fracture explosiontechnology, as a new technology, has been studying for years and gotten some breakthroughs,such as series formula of liquid explosives，stable explosion in cirtical dimension about2-5mm，so as to set basis for next process design and ifeld test study, butit is found that there is littlestudy on the action mechanism of the In-fracture explosion, especially in mechanical modelresearch, so in this paper, based on study of the In-fracture explosion principle and the formingfracture theory by rock blasting, the author divides the producing fracture mechanism action ofthe In-fracture explosion on both sides of the hydraulic fracture in reservoir into two parts，thedynamic stress wave action and the ofllowing quasi static action. As the micro fractures systeminduced by the dynamic stress wave has a great influence on the later formed fracture initiationand its ifnal dimension, the author chooses the stress wave action period as the main studyingobject, and carires on the reservoir, along the both main hydraulic fracture’s sides, mechanicalmodel simulation researching in condition of the stress wave action.As the practical difficulties on the whole simulation of In-fracture explosion action, Theauthor raises a viewpoint which is simplifying the dynamic stress wave action in condition of theIn-fracture explosion as a simple dynamic loading action, so as to build the simplifiedmechanical models on the dynamic stress wave along the hydraulic fracture’s side. Using theAnsys-lsdyna sotfware to simulation, solve, and analysis the simplified mechanical model, sothat getting the stress distirbution nephogram. By analyzing the stress distribution nephogram,the feasibility of the simplified mechanical model has been demonstrated. It’s not only provide areference for later studying on construction of the mechanical model in condition of blasting gasaction, but also supply a possibility for estimating the fracture size by compairng the fractureinitiation-arrest criterion and the stress distirbution nephogram, so as to provide a theoreticaldirection for studying the In-fracture explosion reforming effect and its process optimization, etc.