Study On The Mechanism Of Ultra-High Speed Jet Penetrating Through Perforating Gun,Casing And Sandstone

With the development of perforating completion technology towards deep penetration and high hole density,the charge quantity and charge density of perforating charge are increasing,perforating high detonation energy will increase the burr height and stress of the perforating gun,which often causes safety accidents such as gun jamming and damage.The underground perforation conditions are complicated and the test is difficult.Most of the existing studies adopt ANSYS/LS-DYNA simulation,however,there are many two-dimensional simulation analysis at present,and the three-dimensional model is often incomplete,and there are still problems in the analysis such as unexpected termination of the analysis,speed overflow,and computer time.For the above questions,a three-dimensional complete finite element model of perforating bullet-perforating gun-perforating fluid-casing-sandstone is established,combined with the ALE algorithm,to realize the fluid-solid coupling between perforating fluid-jet-perforating gun-casing-sandstone,analyze the effects of different blast heights and phase angles on the perforating gun and casing burrs,aperture and stress intensity during the jet penetration process,analyze the penetration depth of the jet in the sandstone,and solve the problems of unexpected termination of analysis and velocity overflow,by optimizing the grid,the calculation time is greatly reduced.The result shows that when the height of blasting is 12 mm,the burr heights of the perforating gun and casing are 4.1mm and 3.1mm respectively;the apertures are respectively?21.4mm and ?13.4mm;the maximum stress is 1075 MPa and 835 MPa respectively.When the blast height is 18 mm,the burr heights of the perforating gun and casing are 3.9mm and2.5mm respectively;the apertures are respectively ?19.1mm and ?12.1mm;the maximum stress is 997 MPa and 817 MPa respectively.When the blast height is 24 mm,the burr heights of the perforating gun and the casing are 3.6mm and 2.2mm respectively;the apertures are respectively ?15.5mm and ?10.5mm;the maximum stress is 912 MPa and 787 MPa respectively.When the phase angle is 30°,60°,and 90°,the maximum stress of the perforating gun and casing is 1226 MPa,1114MPa,1221 MPa and 850 MPa,750MPa,835 MPa.The research shows that the burr height,aperture and maximum stress of the perforating gun and casing all decrease with the increase of the explosion height,and the penetration depth increases with the increase of the explosion height;The phase angle has little effect on the height of the burr and the aperture.When the phase angle is 60°,the maximum stress of the perforating gun and the casing is the lowest,and the stress area exceeding the yield limit of the material is also the smallest,and the safety of the material after perforation is also the highest.Through the research of this dissertation,the problems of accidental termination of analysis and velocity overrun that often occur in shaped energy detonation simulation are solved,and the burr,diameter and stress change law of perforating gun and casing are clarified.The research result can be super-strong perforation detonation.Thorough problem research provides ideas.