Talking about the daily maintenance and use of NQ

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Talking about the daily maintenance and use of NQ rope coring drilling tools

rope coring drilling is an advanced drilling method that takes cores from the drill pipe without lifting the drill. It has the characteristics of simple structure, high drilling efficiency, good rock core quality, long drill life and low labor intensity. In practical work, the use environment of rope drilling tools is relatively poor. At present, the structure of domestic wireline coring tools is relatively complex, and there are many vulnerable parts. In the harsh service environment, vulnerable parts will become more vulnerable to damage. Compared with domestic drilling tools, q series rope coring drilling tools have the advantages of simple structure, less vulnerable parts and high coring rate. The accurate use and maintenance of Q series rope coring drilling tools plays a significant role in reducing costs and improving work efficiency

1 application scope and structure

1.1 application scope

(1) geological conditions. NQ rope coring tool can be used to drill various formations, and the effect is the best in medium hard rock formations of 6 ~ 9 levels. Under the current technical conditions, it is generally not suitable to drill into grade 10 ~ 12 rocks, especially extremely hard rocks with dense rock organization, fine particles and no abrasiveness, such as quartz diorite, quartz glutenite, quartz magnetite, etc., or hard, brittle and broken rocks with strong abrasiveness. Because the drill bit is easily worn and the drilling efficiency is very low when drilling the above rocks, the advantages of NQ rope coring drilling cannot be brought into full play

(2) drilling depth. NQ rope coring tools can be used in shallow holes (100 ~ 300 m) and deep holes. Generally, the deeper the hole is, the better the economic and technical effect is. However, the maximum depth of NQ rope coring drilling is limited by the strength of the drill pipe, and it should be checked.

(3) bit life. If NQ rope coring drilling is adopted, if the service life of the drill bit is short and the drill bit is often lifted and replaced during the drilling process, the significance of rope coring drilling will be lost

1.2 drilling tool structure

nq drilling tool structure is divided into two parts: inner pipe assembly and outer pipe assembly. The inner tube is composed of 5 parts: spring clip assembly, inner tube, circlip seat, circlip and circlip ring. The outer tube is composed of 5 parts: retainer, spring clip chamber, outer tube, retainer ring, seat ring, reamer and drill bit

2 use of NQ rope cored drilling tools

2.1 relevant technical data

(1) WOB. The bottom lip area of NQ wireline coring bit is larger than that of ordinary diamond bit (about 1/4 larger), and the required WOB increases by 25%

(2) speed. The rotation speed can be calculated according to the rounding speed of ordinary diamond bit (surface mounted bit 0.5 ~ 2 m/S; impregnated bit 1.5 m/s), but the drilling depth should be considered

(3) pump capacity. Since the annular clearance of NQ rope coring tool is small and the bottom lip of the bit is large, the pump volume is calculated according to the flushing fluid consumption per unit of the bottom lip of the bit, which is slightly larger than that of ordinary diamond drilling

2.2 selection of flushing fluid

due to the small annular gap between the NQ rope coring tool and the hole wall, and the internal pipe needs to be dropped through the center of the drill pipe string, when the formation conditions permit, clean water and lubricant should be used as the flushing fluid as far as possible. Such as polyacrylamide washing liquid, water glass washing liquid and other solid-free washing liquid. This is not only conducive to the lifting and lowering of the inner core tube in the drill pipe, but also reduces the rotation resistance of the drill pipe

2.3 mud drilling

when the drilled formation cannot use clean water as flushing fluid, NQ rope coring still needs to use mud as flushing fluid. According to the characteristics of NQ rope coring drilling, the mud used in drilling should have the characteristics of low viscosity, low relative density, fast sand setting, good fluidity and anti collapse performance. Generally, low solid fine dispersion mud must be used

3 daily maintenance

after each coring is completed, the drilling tool assembly should be checked in time and simply maintained to eliminate the hidden danger of failing to coring smoothly in the next coring

3.1 maintenance of inner tube assembly

(1) circlip and circlip seat. After each coring, remove the circlip seat and clean the circlip and the circlip seat. Put a small section of core into the circlip and pull it to check whether the circlip is clamped tightly; If the core is out of card, the circlip needs to be replaced; When reinstalling the circlip, apply lubricating oil on the circlip seat to prevent wear, clip the retaining ring into the slot, and check to ensure the correct position of the retaining ring

(2) test method for smoke density of burning or decomposition of building materials gb/t 8627 ⑴ 999 inner tube. First, wipe the counterbore on the inner tube with cloth to ensure that it is clean. Then check the inner and outer walls of the inner tube for dents, notches or wear. Because the serious depression will cause the blockage of the core, it is generally necessary to replace the inner pipe when the situation is serious. However, if the depression is very close to the end, it does not need to be replaced. When in use, just turn over the inner tube and install the smoother end without serious depression on the snap ring seat

(3) snap assembly. Remove the inner pipe cap on the main shaft and apply lubricating oil after cleaning; Clean the compression spring and the bearing on the main shaft; Check whether the ball bearing is damaged or grooved, and whether there is idling. Replace the bearing as required; Check the wear and straightness of the main shaft. Although slight wear does not hinder the operation, if there is abrasion or slotting, it is necessary to replace the main shaft, and screw the locking nut onto the main shaft at the same time. Be careful not to let the bearing idle when tightening; Check the flexibility of the shrapnel, and apply lubricating oil on the spring caliper and recovery pipe. If there is too much wear on the spring caliper, it needs to be replaced; Check the bearings of all parts, and inject lubricating oil into the thrust bearing until the oil flows out; Check whether the fishing spear head is damaged. If it is damaged, knock down the elastic pin to remove and replace it

3.2 maintenance of the outer tube assembly

(1) carefully check the overall condition of the outer tube assembly after exploration and coring. If there is a groove or indentation in the outer tube, it may cause the blockage of the core and need to be replaced

(2) remove the snap stop. Pay attention to the welded surface hardening belt. If the surface hardening belt is excessively worn, the basic material has also been worn, and this part needs to be replaced at this time; In addition, check the inner side of the snap stop head. If there is damage, the snap stop head will be crushed by the snap caliper when drilling a hard rock layer, resulting in the phenomenon that it cannot be salvaged smoothly

(3) remove the snap chamber from the outer tube and check the flank of the thread for wear

(4) remove the outer 3. Close the stay ring on the oil return valve pipe to solve the white pollution problem caused by plastic bags. Check the wear of stay ring. If the stay ring is worn or broken, turn it over and reinstall it; If both are worn, replace them; When reinstalling the main operating characteristics of the electrode tension tester, pay attention to lubricating with lubricating oil

(5) remove the centralizer ring on the outer pipe. Check the wear of the centralizer ring and install it into the inner pipe. If the gap is greater than 0.3 mm, the centralizer ring needs to be replaced

(6) reinstall the outer pipe, replace all worn parts, and clean the interface thread, lubricate the interface with "Texco threadtex" or equivalent quality lubricating oil to ensure that the interface is tightened

4 conclusion

the correct use and maintenance of NQ rope coring tool is helpful to improve the efficiency of rope coring, reduce costs and improve economic benefits in the production process

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