HT and HD heavy-duty oil core barrels

HT and HD heavy-duty core barrels

 

HD coring barrels are available in standard 30 foot lengths. The HT outer tubes can be joined to form lengths 20 270ft (82m), and the HD outer tubes can be joined to form lengths to 360 ft (110m). These coring systems are fully stabilized by integral stabilizers.

 

The HT and HD heavy-duty core barrels were developed for high torque, long footage coring in highly deviated holes. They cut 2-1/8’ and 5-1/8’ diameter cores, respectively. Solidly constructed of high structural alloy steel tubing, the core barrels feature a safety tool joint upset. HD barrels incorporate double standard outer tube thread connections to enhance the strength of the tool.

 

The system uses inner tube Long Distance Adjustment (LDA) system. Wide LDA adjustment range facilitates accurate spacing of the inner tube in relation to the core bit, compensating for thermal expansion of inner tubes.

 

A. Operation

 Preparing and checking up work before use.

1. Must be sure there are not metal fish or others hard.

2. Checking up about coring barrel.
• The connection thread and friction ring of safety sub should be intact and all sealing O-rings have to be not damaged.

• The Swivel assembly must be turned smoothed.

• There are not deformations and flaws affecting strength of inner or outside barrels which screw thread should be intact.

• The core catcher be used should have proper elasticity. The tungsten carbide grains of welding layer should be of uniform size and the face of layer should be flat.

• The O.D. of stabilizer has not to be greater than coring bit but not to be four millimeters smaller than it.

 

3. Assembling core barrel

• When core barrel is assembled, the steel ball is not put in it. After the barrel be running at the bottom of well and wash at the same time, put in the ball through inner hole onto seat and then start to drill core.

• Lift up the inner barrel thread to core gripper assembly together with the outside tube thread to lower stabilizer (or difference nipple) at well site by lift nipple. The outside tube is connected to the coring bit and put in well hole like the way tripping in drill collar while it is stuck by safety slips.

• Clamp the inner barrel by chuck. Sit it on the top of the outside barrel and screw off lift nipple. Connect the selected inner barrels and outside barrels each other in order as above way. The inner barrels are screwed on firmly by chain tongs.

• After the safety sub and the swivel assembly on the rig are connected to the top of inner tube, strip chuck and lower the inner barrel to make the thread pin of safety sub be connected to the thread box of the outside barrels.

• The bottom of inner tube shoe pilot type is 8 to 13 mm apart from the inner shoulder of bit, otherwise check out long distance adjustment.

 

B. Operation

1. Operate tranquility on trip and forbid sudden force to prevent the tool from swinging violently.

2. Running the tool slowly when it meets the key seat, dogleg or narrow borehole in the course of tripping in. If it is stopped, should ream down borehole again with cone bit.

3. When the tool is stopped by sand plug (or others falling in), should circulate mud and turn drilling tool at the same time to wash down.

4. After the tool running to the bottom of well, circulate mud fully to wash inner barrel and the bottom of well, and then make sensitivity adjustment.
5. Rotating suddenly in the reverse direction is not permit to prevent safety from being screwed off.

C. Coring Operation
Lower drilling string slowly to let coring bit touch the bottom of well. Adopt low limiting speed and low drilling pressure (about 5 KN) to test run. Run the tool smoothly until the bottom of well coincides with the shape of bit and then adjust gradually coring technique parameters to recommended data.

 

D. Coring Operation

1. Drill ought to feed regularly and drill pressure ought to be increased gradually to avoid oblique-slip.

2. Forbid to run drill string strictly under large drilling pressure.

3. Drill feed ought to be operated by head driller or by special man assigned.

4. Circulating and drilling should not be slopped generally in coring operation while the coring bit does not leave the bottom of well unless an accident.