Particle Impact Drilling Hydraulic Parameters Design And Software Development

Particle impact drilling technology uses high-hardness,high-abrasive steel particles in particle jets to break rock at high speeds and high-frequency impact strata,which can significantly increase the penetration rate of deep hard formations and strong abrasive formations.The addition of particles makes the flow law of the drilling fluid change.At the same time,the special process technology has new requirements on the hydraulic parameters such as bit pressure drop,so it is necessary to study the design of the hydraulic parameters of particle impact drilling.Firstly,the forces of the particles in the drilling fluid were theoretically analyzed.Based on the empirical calculation formula of the particle sedimentation velocity,based on the experimental determination of the sedimentation velocity of the steel particles in the drilling fluid,the steel particles with different particle sizes and volume fractions were obtained.The empirical formula for the settling velocity of particles in the drilling fluid provides the basis for calculating the minimum return velocity of particle drilling fluid in the annulus.Afterwards,an experimental method was used to study the effect of particle diameter and volume fraction on drilling fluid density,viscosity,and filter loss.The study found that: the addition of particles will significantly increase the drilling fluid density,and at the same time as the particle volume fraction increases,the viscosity of the drilling fluid increases,and the smaller the particle size,the greater the degree of viscosity change;the filter loss of the drilling fluid will follow the particle.As the volume fraction increases,the smaller the particle size of the particles,the greater the effect of increasing volume fraction on the filter-off volume.Based on the experiment,the relationship between the particle diameter and volume fraction on the density and viscosity of the drilling fluid was concluded.The influence of drilling fluid flow rate,viscosity,and particle parameters on the flow frictional resistance of drilling fluid was studied using an experimental method.The results show that under the same conditions,the smaller the diameter of the pipe,the greater the flow frictional resistance;the increase of the particle volume fraction,the flow friction increases.With the increase of the viscosity of the drilling fluid,the flow frictional resistance pressure drop of the pipeline with a diameter of 108 mm has a smaller change,and the pressure drop of the pipeline with a diameter of 72 mm changes greatly.The influence of the factors on the flow frictional pressure drop of the particle impact drilling fluid from big to small is: flow rate> viscosity> particle volume fraction.On the basis of the calculation model of fluid frictional pressure drop of drilling fluid without particles,the friction resistance pressure drop model of particle drilling fluid was obtained by correcting the density and viscosity through the relationship between particle parameters and drilling fluid density and viscosity.Finally,on the basis of deducing the influence of particles on drilling fluid flow,the hydraulic parameters of particle impact drilling are designed with the desired drilling speed as the goal,and the corresponding software is formed.Thus,it provides theoretical and technical support for the engineering application of particle impact drilling technology.