Experimental Research And Numerical Simulation Of Paricles Flowing Property In Particle Impact Drilling System

Particle impact drilling technology (PID) is a new drilling technology,which is designed especially to solve the oil and gas exploration of hardterrane. In recent years, due to its advantages, PID has been developing rapidly.In PID technology, it is an important factor to adjust appropriate drilling fluidflow rate for steel particles reflux, and erosive wear on the drillpipe byparticles has a direct impact on the life of the system. Based on simulation andexperiments, this paper studied particles reflux in annular gap, andmathematical model is built to analysis the relationship between annular gapand drilling fluid flow rate employing dimension analysis method. Then thispaper studied erosive wear on the drillpipe through experiment.The methods of this paper were mainly simulation and experiment.Simulated software used FLUENT, and a set of experimental apparatus wasdesigned independently.The problem, which is fluid carrying particles to flow in annular gap, was simulated by FLUENT. Fluid mediums are water and mud. There are fourviscosity of the slurry. According to volume fraction and velocity vector ofparticles, critical fluid velocity values can be obtained in annular gap.Simulation data has been analysed using dimensional theory. In specialconditions, the relational expression between the ratio of annular gap andparticle diameter and particle Reynolds number was obtained, the relationalexpression between the ratio of annular gap and particle diameter and particleFroude number was obtained, and the relational expression between the gapsand critical fluid velocity was obtained. The simulated results show that withthe increasing ratio of annular gap and particle diameter, particle Reynoldsnumber and Froude number gradually decrease, and with the increasingannular gap the critical flow rate also gradually decreases.The two problems, which are particles reflux in annular gap and erosivewear on the drillpipe by particles, are studied using experimental methods. Inparticles reflux, water critical flow can be obtained relying on observationwhen water was carried particles in annular gap. Experimental data has beenanalysed using dimensional theory. Three Empirical formula were obtained inspecial conditions, and they reflected the influence among annular gap,particle diameter, particle Reynolds number and Froude number. Theexperimental results show that with the increasing ratio of annular gap andparticle diameter, particle Reynolds number and Froude number graduallydecrease, and with the increasing annular gap the critical flow rate also gradually decreases. At the same time, the simulation results can be verifiedby experiment. In erosive wear experiment, the quality of drillpipe which havethree shapes can be weighed by electronic scales, and amount of wear ofdrillpipe per length can be calculated. The experimental results show that withincreasing erosion time amount of wear of drillpipe per length graduallyincreases. But the amount of them is very small and negligible. It is of greatsignificance to study the subject to the development of particle impact drillingtechnology.