Study On Optimization Technology Of Source Charge Structure In Well Excitation Earthquake

As a non-renewable resource,oil reserves decrease year by year with the increase of consumption.It is a way to solve the energy shortage to explore new mining areas and to reexplore old exploration areas to improve resource utilization.By optimizing the source charge structure of traditional explosive,it can adapt to the underground environment of high temperature and high pressure and full of liquid.While generating enough energy for the source,it can also reduce the damage of the well casing as far as possible,so as to achieve the purpose of using the current oil well as the exploration well for seismic exploration.In this paper,ANSYS/LS-DYNA simulation software is used to carry out numerical simulation to study the dynamic response of shell source when it is excited in oil casing under different charge diameter.On the basis of shell source simulation,a sieve source is added and numerical simulation is carried out to study the dynamic response of sieve source when it is excited in oil casing under different charge diameters,and to optimize the pore size and porosity of sieve pressure relief hole.The numerical simulation of the blind hole source is carried out,and the energy output of the blind hole source is improved by optimizing the source shell.After the numerical simulation,the ground test of shell source,screen source and blind hole source is designed using the simulation data to verify the results of the numerical simulation,which proves the feasibility of shell source and screen source.The results of numerical simulation and surface test show that: 1)Adding screen tube to shell source can effectively recover shell fragments and reduce the pollution of downhole environment;2)The energy output of shell and sieve source is directly related to the charge diameter,but less related to the charge length;3)Casing and sieve source can produce obvious plastic deformation when the charge diameter is12-20 mm.When the charge diameter is 20 mm,casing expansion rate is about 5% under the constraint of downhole structure and low stress.4)When the porosity of the screen is about7.7%,the expansion diameter of the screen can be controlled at about 6.5mm.The increase of charging shell wall thickness is conducive to reducing the explosion energy inside the screen to protect the screen and casing,and the shell wall thickness should not be less than 8 mm.5)Under the condition of the same charge amount,the energy gathering effect of the source shell produced by the double cone Angle is stronger.The source shell with 24-40 g charge can all break through the blind hole and produce a certain plastic deformation in the area near the casing operation point.6)The numerical simulation and ground test verify that,under the condition of the same charge amount,the blind hole source can have a certain impact on the casing,but the energy generated by the shell and screen source is much greater than that of the blind hole source.The explosive source is preferred as the seismic exploration,considering the protection of the well environment.The sieve source is more suitable for well exploration.