round drill collar
There are different kinds of drill collars,including round drill collar,spiral drill collar,non-magnetic drill collar,square drill collar and so on.Ordinary
drill collar is the circular cross section, the center has a water
hole,the wall thickness is larger,the nozzle is smaller, the weight
of per unit length is greater than the size of drill pipe almost 4-
5 times .The majority of drill collar is thread processing directly
on the pipe body , but some of them also use the replaced joint.
(1)Eccentric-weight drill collar is an effective anti-deviation
drilling tool,with high drill pressure used in oblique
areas,rectifying oblique as well.
(2)When drilling directional wells eccentric-weight drill collar is
an effective tool to reduce oblique or straighten the well hole
using high drilling pressure.
(3)Eccentric-weight drill collar has the advantages of simple
structure,convenient use,connected directly to common drill collar
without centralizers,greatly convenient for sinking in,fishing and
(4)Eccentric-weight drill collar runs downhole safely,danger of
leakage or bit freezing hard to appear.
(5)Pay much attention to avoid mud balling and prevent effect of
|O.D.||cutting depth||Lead ±25.4|
|114.3～130.2||4 1/2～5 1/8||5.6±0.79||965|
|133.4～146.1||5 1/4～5 3/4||6.4±0.79||1067|
|149.2～161.9||5 7/8～6 3/8||7.1±1.59||1067|
|181.0～200.0||7 1/8～7 7/8||8.7±1.59||5.6±0.79||1626|