4 5/8 Inch Api Standard Steel Tooth Rock Roller Tricone Drill Bit In China

Drill bit application instructions

1 bit selection

1.Please reading lithology description and bit records of adjacent wells carefully,and analyzing formation characteristics.

2.Selecting appropriate type in accordance with lithology.

2 Preparation before drilling

1.Inspect previous bit for body damage, lost cutters or inserts etc. Make sure there are no any junk on buttom hole, and clean the bottom hole if necessary.

2.Bit must be handled with care in order not no damage cutters and hard substances.

3.Check if there is any damage on bit cuttes and if there any foreign matter inside the bit.

4.Check if installing nozzle is meet requirements, and replace nozzles if necessary.

3 Marking up the bit

1.Clean bit threads and apply grease on threads.

2.Fit the breaker to the bit, lower the drill string onto the pin and engage the threads.

3.Locate the bit and breaker in the rotary bushing, and make-up the bit to be recommended torque.

4 Tripping in

1.Remove the breaker and carefully lower the bit through the wellhead device in order not to damage it.

2.Shrinkage,shoulder,dogleg and key seat of borehole should be cautious when bit through blank hole.

3.Start pump and cycle drilling fluid to wash buttom hole when drill to a point about 30 meters to bottom of the hole, and rotate drill string at the low speed not more than 60rpm

4.Approach the bottom approximately half meter. Circulate for 5 to 10 minutes with full flow.

5 Reaming

1.Reaming long sections of undergauge hole is not recommended.

2.If reaming operation is necessary, it is strongly recommended that the reaming operation should be done with maximum flow rate circulation,specific weight on bit not exceed 90N/mm (diameter),rotary speed not exceed 60 rpm where stuck was encountered when tripping in.

6 Bit break-in

1.Overusing display instruments when bit approch bottomhole. If the WOB and torque increase,that shows bit have attived at bottomhole.Use not more than 90N/mm,weight –on =bit and 40to 60rpm to establish the bottomhole pattern at least half meter.

2.Bit break-in is finished and should be adjusted RPM to obtain optimal drilling parameter combination.

3.Drilling parameters adjustment should be selected within the limits of the recommended parameters refer to recommended drilling parameters optimization method.

Table of classification of formation hardness and bit selection

Guidance of tricone Bits ChoiceTricone Bits Tooth Type

Bits Size