When selecting the screw drilling tool for operation, the specification and model of the drilling tool shall be selected according to the well size, required drilling trajectory, bottom hole temperature, bit requirements, water hole pressure drop, flow rate, formation structure and other factors. The site construction must be carried out in strict accordance with the established operation plan.

Surface inspection shall be carried out before the screw drilling tool is lowered into the well.

1. Check the connection threads. Except for the connection threads between the lifting nipple and the bypass valve, check whether the other threads have used thread sealant to prevent the threads from loosening.

2 check the bypass valve: connect the drill bit to the main shaft of the drilling tool, put the drilling tool into the rotary table to observe the position of the bypass valve, clamp it firmly with a Kawa, remove the lifting nipple, press the valve core to the bottom dead point with a wooden rod, inject water from the upper part, and the bypass valve shall be free of leakage; after loosening, the valve core can be reset automatically, then the bypass valve is normal.

3 connect the upper drill pipe, remove the slips, lower the drill pipe to make the bypass valve body at the position easy to observe under the rotary table, start the mud pump, at this time, there should be mud from the bypass hole of the bypass valve body, and gradually increase the flow until the bypass valve is closed. Lift up the screw drill to see if the bit rotates. At this time, the bypass valve should be closed well and no mud will flow out.

4 after the surface inspection, connect all parts according to the designed drill string combination. When the drilling tool is running in the well, the running speed shall be controlled to prevent damage to the drilling tool due to collision with sand bridge, well wall steps and pipe sleeve shoes. When the following drilling is blocked, the pump shall be started to circulate and the hole shall be slowly reamed through. If the directional drilling tool or the screw drilling tool with bending joint is blocked, the drill string shall also be rotated to pass slowly to prevent side build.

When drilling in ultra deep well or high temperature well, the pump should be turned on periodically to reduce the bottom hole temperature. If the drilling fluid cannot flow into the drill string quickly during tripping, slow down the tripping speed or stop tripping to flush the drilling fluid. Never stop drilling or directly seat the drilling tool into the bottom of the well.

5. Start of drilling tool: when the drilling tool is 0.3-1m from the bottom of the well, start the pump for circulation, gradually increase the flow to the recommended value, record the reading of the standpipe pressure gauge, and compare with the calculated pressure value. Fully clean the bottom of the well. When cleaning, slowly rotate the drilling tool or rotate it in several times (30-45 degrees each time) to clean the objects at the bottom of the well in turn. After cleaning, lift up the drilling tool by 0.3-1m and recheck the circulating pressure.

6 drilling: lower the drilling tool to the bottom of the well, increase the WOB gradually, increase the motor torque, and increase the pressure value of the standpipe pressure gauge. The increased pressure value shall meet the motor pressure drop specified by the drilling tool. Since the screw drilling tool is a positive displacement motor, it is an important indicator tool on the vertical bar pressure gauge drilling platform to show whether the drilling tool works normally. The increase of pressure gauge reflects whether the motor works normally, whether the load is appropriate, and whether the WOB is appropriate. The driller can know the working condition of drilling tools through it. Generally, the drilling speed should not be too fast at the beginning, which is conducive to the running in of various parts inside the drilling tool. Do not apply too much WOB to prevent drilling tool brake. Uniform drilling can ensure the smooth and directional accuracy of deviated section.

7 tripping: the tripping process of drilling tools is similar to that of conventional drilling rigs. When tripping out, the bypass valve is open to allow drilling fluid to enter the annulus.