Design And Experimental Study On Self-propelled Rotatory Jet Bit For Radial Horizontal Drilling

The radial horizontal well technology using high-pressure water jet rock breaking between the reservoir and the oil well formation crude oil channel,and effectively improve the environment of oil production in low permeability oil field and increase oil production,has a wide application prospect in the field of petroleum.Reverse jet traction jet bits as radial horizontal well of the main rock breaking device,in radial horizontal wells to fractured rock and traction high-pressure hose forward.So it has a direct impact the expected effect of radial horizontal well.Currently used in field jet bits are reverse jet traction porous jet bit,built-in impeller rotating jet bit and combined jet bit,above the jet bits in the rock breaking drilling are whole,broken rock and expanding capacity can not take into account issues such as rock breaking hole,the high pressure hose produce larger friction and hinder the jet drilling,resulting in radial horizontal extension length limited.An ontology can rotary spraying jet bit structure scheme of traction.It aims to further improve the jet drill reaming,drilling circle degree and self feeding force and radial horizontal well technology to provide technical support is presented in this paper.Design two kind of reverse jet traction spin jet drilling bit structure,through the establishment of reverse jet traction spin jet bits of physical model,using CFD numerical simulation method,analysis of the radial horizontal well borehole self rotating jet bit flow structure characteristics,on this basis,through the ground testing,analyzes the designed spin jet bits of self into property and rock breaking characteristics,bit structure parameters,distance from the nozzle and the pressure of inlet parameters for spraying traction spin jet bits in force and effect of broken rock were investigated.The results of the study showed that:(1)In the positive and negative flow ratio and operating parameters,compared with the other jet bits,the equivalent diameter of spin jet hole drill ability best and drilling is more smooth and rounded,self feeding force and hole jet bit is approximately equal to and greater than the straight rotary jet bit.(2)Combined with the numerical simulation results and experimental results,with the jet bit rotation and multi strand jet in bottom hole rotation to form a complete circular impact surface,drilling circle whole and the jet hole drill ability.At the same time,due to the rotation of the jet bit,the impact radius of the forward jet is different,and the erosion degree of the rock is different,so the annular step surface is formed at the bottom of the bottom.(3)The experimental results show that the rock breaking effect is related to the injection hole arrangement.At the same time,the energy utilization rate of the spin jet bit is higher than other bits,and the rock breaking efficiency is more than the other jet bit in the later stage of erosion.(4)The experimental results show that,in the same time,the flow ratio and the equivalent diameter,the jet bit type,inlet flow and shaft diameter are the influencing factors of the self propulsion of the jet bit.As the inlet flow rate increases,the jet bit increases linearly,and the spin jet bit and the jet bit self force are similar and are larger than that of the straight rotary jet bit.The self force of the spin jet bit in different well diameter has the maximum value near the 60 mm well diameter.