Treatment of Collapse, Buried Drill and Stuck Accident

1) small displacement circulation, repeatedly lift or lower the drilling tool for observation, and form a small displacement channel until it can circulate normally. After the circulation is stable, slowly increase the viscosity and shear force of drilling fluid to improve its carrying capacity, strive to bring the collapsed rock to the ground, and try to solve the sticking problem. It is also possible to forcibly trip out and remove the sticking under the condition of ensuring the drilling tool tension and the safe load of the drilling rig.

2) The circulation can't be established due to serious collapse, and the drilling tool is completely stuck. Use the ground jar to release the sticking. The tonnage of the jar is gradually adjusted from low to high, and the drilling tool is lifted until it is stuck.

3) jarring to release the card, and tripping in the downhole hydraulic jar to release the card. It can speed up the processing of stuck cards. Run the downhole jar until it gets stuck. The hydraulic jar has been debugged by indoor drilling rig, and the effect is good (Figure 4.2).

Fig. 4.2 Hydraulic jar in hole

4) If the impact is ineffective, it should be reversed by milling sleeve to release the card. Or adopt a long barrel sleeve milling with a male cone and a fishing spear, so that the sleeve milling can be reversed once.

5) Back-off treatment, as shown in Figure 4.3, use a back-off fishing spear to go deep into any part of the drill pipe hole for back-off. For example, Shandong Zhao Jin Group Exploration Co., Ltd. constructed a deep exploration borehole in Zhaoyuan zhang jia zhuang mining area. When the designed borehole depth was 2740m m and the borehole depth was 2295m, the stratum was broken, the drilling was lost, the drilling stopped and water gushed out. When the hole depth was 2398m, the drilling tool did not lift off the broken hole section, which led to the influx of rock powder and collapsed fragments into the hole and caused drilling accidents. When the strong pulling is invalid, reverse the drill pipe in the hole. Because XY-8 deep hole vertical drilling rig is used, it is difficult to feel whether it is upside down, which leads to the drill pipe being upside down in many places in the hole. Then the traditional anti-wire male cone is used for fishing, and the fishing times are few each time, and the processing process is slow. When the depth of the well is close to 900 meters, the telescopic fishing tool developed by me is used. In order to dispel the worries of field personnel about the new technology, after many performances on the ground, a small number of φ 50 outer flat anti-filament drill pipes were first lowered into the inner wall of No.N drill pipe for fishing, and 6 drill pipes were fished out for the first time, 24 for the second time, 37 for the third time, 83 for the fourth time and 88 for the fifth time. Of the 37 drill pipes salvaged for the third time, 10 has been removed. The captain lamented that it would take at least five days for the number of rescuers in 1 to lift the drill in 10.

Figure 4.3 Telescopic inverted fishing spear

6) Cutting and fishing in sections. The 47ZK3 hole constructed by Henan No.3 Team in Luanjiahe Gold Mining Area, Zhaoyuan, Shandong Province, was designed to be 2570m deep. When it was drilled to 2297m, an accident occurred in the hole. Because it is difficult to deal with the falling fish, an eccentric wedge is used to bypass the obstacle. In the process of steering and deflecting, a drilling accident happened suddenly. The 2250m rope coring drill pipe broke from the thread of 80 1m drill pipe joint, and the remaining 1449m drill pipe fell to the bottom of the hole. The use of anti-threaded drill pipe in deep holes over 2000 meters has the disadvantages of long treatment period, high mechanical failure rate and large consumption of anti-threaded drill pipe. Finally, the treatment scheme of sectional cutting and sectional fishing is adopted, as shown in Figure 4.4 to Figure 4.6.

Figure 4.4 Telescopic fishing spear

Figure 4.5 Hydraulic Inner Cutter

Figure 4.6 Cutting drill pipe

7) If the sticking cannot be removed due to uniform grinding and vibration, considering the time and economic factors, the well should be closed and sidetracked to reduce economic losses.