The speed indicates how fast the drill must be rotating in
diameter, which is the goal of the drilling process to measure the
speed of reversal. When drilling, not the same as the rock hardness
rock breaking condition is different, the impact of bit weight on
it is not the same, so bit speed on rock breaking process and
mechanical penetration rate, we should ponder rock and rock
breaking moment elements.
(1) Rotational speed during soft ground drilling When drilling in
soft, plastic and small abrasive formations (such as clay rock
formations), the thickness of the cuttings cut by the cutting teeth
is equal to the depth at which the cutting teeth cut into the rock,
and the drilling The wear of the cutting teeth is very small. As a
result, drilling in soft formations adds speed in direct proportion
to ROP while drilling is under pressure.
(2) The rotation speed of medium hard and hard formation during
drilling is hard and the hardness is hard to be pressed in, and the
grinding property is high. The cutting teeth are continuously blunt
and the area of the tooth and rock touch increases. Making the
rock crushing deformation and fracture development moment extends,
the difficulty of adding slow drilling rate, and the greater demand
for bit weight. With the improvement of formation hardness, the
time of rock breaking at the bit extends and increases the rate of
drilling, which will make the process of rock breaking progress
incompletely. The cutting teeth have not yet broken the rock
sufficiently to separate from the rock, resulting in the decrease
of rock breaking depth. Thus, subject to the rock breaking moment
constraints, in order to prevent faster wear cutting teeth, hard
and hard ground drilling can not increase the speed too much.
(3) is not the same rock drilling speed is not the same rock, drill
speed with the speed added must have changed the curve and speed
limit. Drilling in clay rocks with a penetration rate proportional
to rotation speed; drilling in solid, highly abrasive rock with
slower penetration rate due to extension of rock breaking moment
with faster limit rotation than other rock types To be small, when
the speed exceeds the limit speed, will result in lower drilling
speed. After doubled speed, the experimental roller cone drilled
different grades of rock. The results showed that the marble with
grade 4 is rock, the drilling rate is 93%, and the grade 9 is
macular granite. Only 28%, from 4 to 9, the rate of penetration
rate showed a decreasing curve. Thus, for softer abrasive
formations, progressive speed is favorable, while for strong,
high-abrasive formations, it is not significant.
· Please select the applicable formation and parameters according
to the instructions.
· Carefully check the bits appearance and to check the bits
threaded end face,whether the serial number on the box and
· Selection of WOB and RPM should be within the limits of the
recommended parameters, higher WOB and RPM cannot be used
· Bottom hole must be clean and bit must not be used for long
· Drilling process must operate smoothly, find that there is Bie
jump on abnormal phenomenon, should be timely analysis and take
· The bit should be kept indoor with dry and well ventilated
conditions at 10-33℃ and kept from sunshine and rain. Stored under
such conditions, quality of bit is guaranteed for 3 years.
|Bit Diameter||IADC||Applications||Special Features(Cutting Structure,Lug Protection)||Weight||PIN Conn||Operating Suggestions WOB/RPM|
|11 279mm||835||Extremly hard and abrasive formations with high compressive
strengths.||Ovoid on gage,ogive on inner rows;Hardmetal on lug;Wear resistant
carbide on shirttail lip and lug.||163||74||6 5/8”API||55,000-88,000Ibs/80-50RPM|
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