Oilfield Team
Oil & Gas Books Store, Petroleum Engineering Books
  • Main
  • News
  • Photo
  • Video
  • Oilfield Jobs
  • Learning Section
  • Oil & Gas Calculator

Factors affecting the capacity to make a hole

2020.10.14
1 192

Bit pressure

Pressure (as stated previously) is often expressed in kilopascals, tonnes per square centimetre, or pounds per square inch. When a driller refers to ‘bit pressure’, he usually

means thrust on the bit. ‘Thrust’ is a force measured in newtons, although tonnes (force) and kilograms (force) are also common.

Vertical (or near-vertical) holes are often drilled using the weight of the drill collars or pipe/rods to provide thrust. Angled or upward holes require the rig to provide the thrust.

Rotary speed

Speeds of rotation are measured in revo lutions per minute (rpm). Speeds vary from very low (i.e. 5–10 rpm) for large holes and rigs using air percussion, to more than 1000 rpm for small holes and diamond drill rigs.

Torque capacity

Torque is measured in newton metres, or kilogram (force) metres, as described earlier. Smaller hammer and diamond bits are often used if only small torques are required (i.e. about 500 Nm).

The largest torques are required to turn large augers, and bucket auger machines may have a torque capacity exceeding 50,000 Nm (50 kNm or 8000 ft lb).

Hole-clearing capacity

The capacity of a rig to make hole and its hole-making eiciency will often be limited by the rig’s capability to clear cutings from the hole.

If the cutings are not cleared from the face and sides of the bit, they will be ground up. This recuting or regrinding of cutings requires additional energy, reduces the energy available to produce new cutings, and results in lower drilling eiciency. How well the cutings are removed from a cable tool hole depends entirely on the bailer and the driller.

Clearing cutings by circulation is controlled by luid:

  • up-hole velocity
  • viscosity
  • density and low characteristics.

All drills depend on good bit design to achieve botom hole clearing. Rigs employing luid circulation rely mainly on luid energy, and adequate pump or compressor capacity must be available to supply it.

Hole-clearing capacity will therefore depend on the capacity of the pump or compressor (i.e. its low and pressure rating).

 

Related Posts

FREE BOOK: Nontechnical Guide to Petroleum Geology, Exploration, Drilling & Production
2021.03.20
1 230
FREE BOOK: Nontechnical Guide to Petroleum Geology, Exploration, Drilling & Production
Third Edition
Sizes of common core holes
2020.10.14
840
Sizes of common core holes
Sizes of common core holes which are using in oil & gas drilling.
How to Calculate: Maximum Allowable Mud Weight from Leak-off Test Data
2020.07.01
2 494
How to Calculate: Maximum Allowable Mud Weight from Leak-off Test Data
Step by step hand calculation for oilfield engineers.
Winch and brake capacity
2020.06.28
1 693
Winch and brake capacity
A winch or hoist unit (often called drawworks on some rigs, including oil and gas rigs) usually cons…
Market quotes are powered by TradingView.com
© Oilfield Team, 2021
About Us  | Contact Us  | Privacy Policy  
Made in studio Zuber