Experimental Investigation On Fracture-Vug Rock Of SRV Fracturing

Laboratory tests were conducted to investigate in fracture-vug formation during hydraulic fracturing.The cohesive zone modeling was adopted to model pressure in fracture-vug,stress field,pore-pressure gradient in hydraulic fracturing.The effects of horizontal differential stress on fracturing include: Under the condition of high stress difference,there was little influence on fracture extension.The more stress difference were,the more sample the fracture morphology presented,and the fracture run through fracture-vug;Under the condition of small stress difference,there was huge influence on fracture extension.Fracture-vug show up repulsive interaction to fractures evidently and formed non-planar fractures,resulting in complex fracture path.The effects of fracture-vug on fracturing include: Stress concentration formed by fracture-vug and induced stress formed by pressure inside fracture-vug changed stress field around it.The stress concentration has bigger influence on fracturing than induced stress.The fracture-vug had repulsive interaction to fractures.The stress concentration was reduced and the repulsion was decreased with pressure inside fracture-vug going up.The breakdown pressure and extension pressure of fractures increased with existence of fracture-vug.So the paper adopted laboratory tests and numerical modeling to study SRV fracturing in fracture-vug rock.