Hydraulic jet drilling

Abstract

As a result of a detailed survey of over 25 novel drilling techniques, a laboratory study of hydraulic jet drilling was made. In initial tests, a cannon was used to fire 1.45- gal water pulses at rocks at pressures up to 25,000 psi. These tests showed that a threshold nozzle pressure must be exceeded before hydraulic jets will drill rock. Water jets having diameters of 0.2- to 1-in. drilled holes with diameters ranging from 0.8 to 4 in. in sandstone and limestone. These holes, which were 1 to 3 in. deep, were drilled in 0.02 to 0.2 seconds. These tests showed that water jets can effectively drill sedimentary rocks. Following these tests, a 2-in.-diameter hydraulic jet drill was tested in a laboratory rig. A high-jjressure pump was used to pump water continuously through this drill at pressures up to 13,50° psi. This drill penetrated Carthage marble at 180 ft/hour, Indiana limestone at 280 ft/hour and Berea sandstone at 500 ft/hour. These tests showed that a full-scale hydraulic jet drill [3,000 hp] should drill 8-in.-diameter holes in average-strength sedimentary rocks at rates of 200 to 300 ft/ hour. These high drilling rates show that hydraulic jet drills have high potential for drilling oil wells economically.