Study On Low Permeability Oil Layers Exploding Technology In Hydraulic Fracture

Due to the characteristics of the low saturation,permeability and pressure with complicated formation conditions existing in the low permeability oil and gas fields,conventional fracturing measures can’t match the requirement of stable increase of the petroleum and gas production.The fracturing technology in deep formation urgently need to be studied and explored.So this paper has carried out the study on low permeability oil layers exploding technology in hydraulic fractures.Based on the needed performance requirements of liquid explosives exploding in the inner layer,this paper studied liquid explosive formulation which was applied to exploding in small size fracture,carried out the experiment of liquid explosive explosion in the simulated reservoir fracture environment,calculated the liquid explosive detonation performance parameter;Then the construction process and technical characteristics of tip sereenout fracturing technology were analyzed,the process parameters of tip sereenout fracturing technacal were calculated,fracture mechanism of explosive fracturing under different detonation modes was analyzed,the fracture length produced by explosive stress wave was calculated,the mathematical model of crack propagation by explosive gas fracturing was established,the dynamic state of the crack propagation and the rock particles produced by liquid explosive exploding in the crack were simulated.The studies showed that the developed liquid explosive can be detonated in 2-5mm cracks and proved the feasibility of liquid explosives exploding in the inner layer from the view point of experiment,The developed liquid explosive has high explosion capacity,explosion heat,explosion temperature and low detonation velocity,which provided the premise good for liquid explosives exploding fracturing reconstruction.A broad short crack can be produced in the formation to meet the critical initiation size of the liquid explosive in the layer by tip sereenout fracturing and then provides a precondition for the successful explosive fracturing of liquid propellant.The rock particle size of the liquid explosive fracturing in the layer is millimeter,which can provide supporting effect for the fracture.The crack produced by the burst pressure of explosive gas in the liquid layer is longer than that of the stress wave,and the crack propagation is mainly caused by the formation of explosive gas;At the same condition,the greater the volume of liquid explosive volume,the longer explosivefracturing length;The explosion in the layer can press out multiple cracks in the wall of hydraulic fracture,so as to realize the more effective fracturing of the deep stratum.