【正文】 position in stripping out. The fluid in string is allowed to be drained into annular space. But screw drill can not rapidly discharge the fluid by itself. Usually a section of heavy fluid is added into the top of string before stripping out, to press the fluid in the pipe smoothly to drain. After screw drill is stripped out to the location of bypass valve, disassembly the parts on the top of valve holes. Firstly wash it from the valve top with clean water, and then press down the valve stem with hammer handle or wood stick, loosen it for free movement. As soon as cleaning is pleted, twist lifting nipple and trip out the screw drill. Install the bit assembly and disassembly device to clamp the s。綜合考慮鉆具使用過程中的各種因素，歸納為表2。若暫停使用或長時間擱置不用，建議向鉆具內(nèi)注入少量礦物油防銹（注：不允許加入柴油）。6．4．2裝好鉆頭裝卸器，卡牢鉆具外殼，反轉(zhuǎn)鉆頭（俯視反旋）把馬達中殘存的泥漿從旁通閥排出，卸下鉆頭。，卸下旁通閥口上各部件，先用清水從旁通閥頂部進行沖洗，然后使用木棒或錘柄等將閥芯按下、松開使其移動無阻。起鉆時，旁通閥處于開位，允許鉆柱中的鉆井液瀉入環(huán)空。如果循環(huán)壓力高于計算值，而且側(cè)鉆造成壓力升高的因素已排除，循環(huán)壓力仍高于計算值，則可能是鉆頭水眼被堵或轉(zhuǎn)動軸被卡死，此時循環(huán)壓力要比計算壓力高得多。它能使司鉆及時了解鉆具工作情況。清理干凈后，，校對壓力值，記錄下來。清理井底，尤其是打斜井，井底必須足夠“干凈”，因為井底堆積或沉淀的巖屑影響轉(zhuǎn)速或造斜。 each time), gradually to clean up the bottom. Then lift screw drill for , calibrate and record the pressure value. Gradually enhance drilling weight when tripping into the bottom again. Meanwhile, motor torque increase, riser pressure on gauge increases ,too. The pressure value should conform with the motor pressure loss specified for any type of screw drill. The increased value on the gauge indicates motor load is normal or not, and also shows the added weight is appropriate or not. Therefore, motor torque and drilling weight shall be kept stable only by limiting the riser gauge reading to the remended range. This makes drillers know screw drill operation timely.When the bit is not in the bottom , if recycling pressure is lower than the calculated value, it is possible that bypass valve locates in “open” position, or it is caused by drill pipe damage or well leakage etc.If recycling pressure is higher than the calculated value ,and the factor of pressure rise caused in reentry is eliminated, but it is still over the calculated value, possibly the bit nozzle is plugged or drive shaft is sticked .Now recycling pressure is much higher than the calculated value. Trip Out: Screw drill tripping out is similar to the conventional tripout. Bypass valve is in open在井內(nèi)，鉆井液若不能迅速通過旁通閥閥口，進鉆柱中，應減慢下井速度，或不時停下來充灌泥漿，下鉆時，注意不可墩鉆或?qū)@具直接放進井底。I In case the fluid can not rapidly flow through the holes of bypass valve in the borehole, the stripin speed should be slowed down or suspended regularly for mud filling. Again in stripping in, take care, there occurs no percussion or direct stripin. Start Screw Drill : If screw drill is located at the hole bottom, you must lift it for . Then start the pump and record the readings of riser pressure. As pared with the calculated pressure value, it is also normal if it is over the pressure of hydraulic calculation. This is caused from lateral drilling.Clear the hole bottom. In particular, for slant hole, the hole bottom must be very “clean” ,since the cuttings packed and deposited in the bottom affect the torque or deflection. It is best to clean it with normal recycling . While cleaning, slowly turn the screw drill or turn it by times(turning 30176。如果用彎接頭或彎殼體，鉆頭側(cè)面就更容易碰上井壁的硬巖層和套管鞋等，因此要周期性的轉(zhuǎn)動鉆具組合，以消除側(cè)鉆的影響。6．2把鉆具及其組合下到井眼里：盡管鉆具本身外形簡單，且有足夠的剛性，司鉆下放鉆具時，仍需控制下放速度，否則易被井眼中的沙橋、井眼臺肩、套管鞋所損壞。為防止操作中移扣，建議裝卸過程中應牢記：鉆頭接頭相對于殼體的旋向為俯視反時針方向。將彎接頭擰入旁通閥之前，如果用斜口管鞋座造斜，應檢查造斜鍵，保證斜口管鞋座處于正常的工作位置，并保證與接頭的彎頭刻線對準。泵未完全停止之前，不要把旁通閥提到轉(zhuǎn)盤以上，防止污染井臺。 The energy loss will be shown from the pressure loss. Total pressure loss can be calculated by accumulating pressure loss in each portion. After calculation of total pressure loss according to the determined drilling depth, it can be a parameter to determine the pump pressure. It is plicated to calculate large amount of pressure loss. Therefore, the site operator can adapt a simple method. Only by lifting the bit a little bit from the bottom, the reading on the pressure gauge of main pipe shall be the mentioned total pressure loss at the rated flow rate.6. Application When selecting the screw drill and its bination, you should work out drilling program, fully consider hole size, hole trace, bit type, specification, formation structure and hydraulic calculation. Surface Checking Before Tripping in Except lifting the connections between nipple and bypass valve, other connections on shell of screw drill shall be coated with locking agent. Assembly bit on the handling device, Counter clockwise rotate the drive shaft ends only with chain wrench to protect the inside threads from loosening . Hoist lifting sub and put screw drill into turntable and bypass valve into the center in easy watch position. And then clamp tightly screw drill with slips, and disassembly lifting sub. Check bypass valve: Press downward the valve stem with hammer handle or wood stick. Fill water from the top into the valve ,there should no leakage from the valve and no great drop of water level .And then loosen the stick, the valve stem is springed up to its original position. The filled water shall flow out evenly from the side holes. This is normal .6．1．5 Connect and low down the kelly. Put bypass valve under the kelly in easy watch position. Start pump, and gradually increase flow rate till bypass valve is closed. Lift the screw drill to watch bit rotating. Now bypass valve is in “close” position. There should be no fluid flowing out of bypass hole. To do this is only for checking bit rotation. It should not last longer. In the operation, it should prevent the bit from touching wellhead blowout preventer and flow line. After pump stops, check bypass valve in open position or not, and fluid flowing out of bypass valve or