PULSED JET TO IMPROVE RATE OF PENETRATION IN DRILLING DEEP WELL

摘要

Improving the rate of penetration in deep well is long-term problems for drilling industry. Pulsedjet drilling which has been proved in field is a cost-effective way to improve the rate ofpenetration. An adjustable frequency pulsed jet generating tool was developed in this paper. Themain parts of the adjustable frequency pulsed jet generating tool include turbine, valves, and aresonance pulse chamber. Rotary valve is driven by the turbine. Rotation of the rotary valvecauses the state of drilling fluid flow from the continuous to the periodic. So, the periodic flowhas frequency and amplitude. In order to obtain higher amplitude, a resonance pulse chamberwas used to amplify the amplitude of the periodic drilling fluid flow. The pulsed jet is formedwhen the periodic drilling fluid flow is issued from the nozzles of the bits. The frequency of thepulsed jet can be easily adjusted by changing the parameters of the rotary valves. In this paperthe working principle of the adjustable frequency pulsed jet generating tool was analyzed. Theadjustable frequency pulsed jet generating tools have been tested in several wells. The field testresults show that the rates of penetration were improved by 21.31%-59.17% and the tool canmeet the operation requirements. Adjustable frequency pulsed jet generating tool as an effectiveapproach to improve rate of penetration (ROP) has great application potential in deep welldrilling.