Experiment On A Hydraulic Pulsed Jet Tool For Improving ROP In Slim Hole Well

Most domestic oil fields has been in the mid-late development,with increasing difficulty and cost for development.Improving rate of penetration(ROP)and reducing drilling and development cost are goals pursued in the petroleum field.Researches and field applications show that,slim-hole drilling is an effective method to reduce drilling materials and cost owe to its relatively small well diameter.Hydraulic pulsed jet drilling technology can be applied to improve ROP dramatically.But up to now,there exists uncertainties of the structural properties of small-sized hydraulic pulsed jet tool.Few researches can be found on hydraulics design and application of slim-hole drilling with hydraulic pulsed jet tool.Through numerical simulation and laboratory experiment respectively,for different flow rates and number of blade of impeller,the structural properties of slim hydraulic pulsed jet ROP-improving tool were investigated including pressure pulse amplitude,pressure loss and pulse frequency.On the basis of conventional hydraulics design,slim-hole drilling hydraulics were designed,by considering the effects of rotating,eccentricity and joint of drill pipes on slim-hole annulus pressure loss.Field experiment was conducted by applying slim hydraulic pulsed jet ROP-improving tool.Also,analysis on adaptability of formation and drilling parameters for hydraulic pulsed jet drilling technology was conducted.Findings drawn from this study include: hydraulic pulsed jet tool can generate strong pulsed jet;with the increasing of flow rate,the outlet pulsed amplitude increases,pressure loss increases quadricly and pulsed frequency increases linearly;with the increasing of impeller blades,pulsed amplitude decreases,pressure loss decreases and frequency increases;ROP was improved by 131.3% in field drilling test;hydraulic pulsed jet tool can be applied with several BHAs and different types of bits under different conditions for several wellbore radiuses in different formations,and ROP can be improved substantially and the lifetime of the tool is qualified for field application.