Before starting to drill with any particular rig,thoroughly read and understand the manufacturer’smanual for the machine. Make sure the drilling table, orplatform, is clean, dry as possible, and free of looseobjects. Doing so will help prevent personal injury andloss of tools down the drill hole. For safety, ensure thatthe sheave guards remain in place over moving gearsand chain drives while the rig is operating. Drillers learnfrom experience why a well is dug in a certain way andcan visualize conditions at the bottom of the hole. Noset rules have been established to follow for adjustingspeeds of rotation and bit pressures.In general, you proceed to set up the rig as follows:Move the rig into position on the selected site. Use thehydraulic outriggers to level the rig and take the weightof the rig off the axles. Next, raise the mast and lock itin place. Now check to see that the rig is slightly higherin the rear to allow for settling during the drillingoperation.For kelly-drive rotary drilling you continue bydoing the following:1. Run the kelly through the turntable and threadthe pilot bit to the kelly.2. Place the turntable transmission in the propergear for the soil formation being drilled.3. Engage the turntable clutch and release the kellybrake slowly to lower the bit into the ground.4. Engage the mud pump and lower the kelly afterthe bit has spudded into a depth of 6 to 12 inches.5. Proceed to drill to the depth of the kelly. Raisethe drill bit 6 to 10 inches, circulate to bring all cuttingsto the surface, than shut off the mud pump and stop theturntable.6. Next, raise the kelly until the pilot bit reaches thesurface. Remove the pilot bit and lift the kelly clear ofthe turntable.7. Move the turntable from its position over thehole. Raise, then lower, a surface casing into the hole,using the hoisting drum. The surfacing casing keeps thewell from caving-in from the surface.8. Once again, position the turntable over the hole.9. Next raise, then lower, a length of drill pipe intothe hole through the turntable, using the hoisting line.The slips will hold the drill pipe in place in the turntable.10. Follow up by lowering the kelly and attaching itto the drill pipe. To keep these parts from seizing, applydope on the kelly coupling.11. Using the kelly drum, raise the kelly andattached drill pipe just enough to enable the slips to beremoved.12. Lower the kelly and drill pipe so the kellybushing nut slips into the turntable.13. Engage the turntable and start the mud pump. Indoing so, you lower the kelly to drill again.14. The slips hold the drill pipe in place until thebreakout thongs are attached to the kelly. Rotate theturntable slowly until the kelly is unscrewed from thedrill pipe.15. Raise the kelly far enough so another length ofdrill pipe can be added to the pipe remaining in the hole.Reconnect the kelly and lower into the turntable.16. Start drilling again until you reach the end of thekelly.Keep repeating this procedure until you have drilledto the desired depth. You are now ready to complete thedrilling operation. Proceed to remove the drill pipe bypulling it out with the hoisting line. Finally, lower thecasing with the screen to the desired depth.If you must change bits before the desired depth isreached, disconnect the kelly and attach the hoisting lineto the drill pipe. Pull the drill pipe a length at a time,placing the bottom ends on a board to help keep themclean.Top-Head Drive Rotary Well Drilling RigThe top-head drive rotary well drilling rig is aspecial top-head drive ISO/airtransportable waterwell-drilling rig (ITWD) (fig. 9-12) that thedevelopment and production effort was conducted orcontrolled by NAVFAC towards providing the NCFwith the capability for rapid water well drilling in avariety of environments.The self-propelled ITWD design has a lightweightderrick a telescoping mast, and a top-head rotary driveactuated by hydraulic cylinders able to accommodate20-foot-long sections of drill pipe and well casings.When the derrick is lowered for transport, the entire rigweighs 23,000 pounds and is capable of fitting inside astandard cargo container without disassembly and is airtransportable on board a C-130 aircraft. The ITWD iscapable of rotary drilling12 1/4-inch holes to1,250-foot depths and down-hole-drilling (DHD)hammer (percussion) drilling, 6-inch holes to1,500-foot depths. The ITWD will travel at a top speed9-10
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