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Working in the oil field and loving to share knowledge.

Drill Bits VDO Training

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Drilling bits are one of the key tools to achieve good performance drilling and there are several types of bits. Therefore, personnel need to understand in order to use the right bits for the task. Today, we would like to share this excellent VDO teaching you about drilling bits. This VDO is excellent for everybody because it has a lot of illustrations and animations along with full explanations. As usual, we have full VDO transcript for anyone who cannot catch the wording from this footage.

VDO Transcript

drilling-bit

As we discussed in the last section, crew members install the bit on the on the bottom drill collar. Two kinds of bits are roller cone bits and fixed cutter bits. Fixed cutter bits are also called fixed head bits. Roller cone bits usually have three cone shaped devices with teeth or cutters. As the bit rotates the cone and cutters rotate to drill a head. Fixed head bits also have cutters but manufacturers embed them in the bit’s head. The bit’s head moves only when the bit rotates. It has no moving parts like the cones on a roller cone bit. Both roller cone bits and fixed head bits come in sizes ranging from 2 or 3 inches or about 50 – 75 millimeters in diameter to more than 36 inches about 1 m in diameter.

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What You Need To Know About Drilling Bit Balling Up and How To Troubleshooting It

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Bit balling is one of the drilling operational issues which can happen anytime while drilling. This issue can cause several problems such as reduction in rate of penetration and surface torque, increase in stand pipe pressure. Personnel may eventually need to pull out of hole the BHA in order to clear the balling issue at the bit. This article will teach you about the bit balling and how to prevent it in the planning phase and how to effective detect and clear the balled up bit before it becomes a worse problem.

bit-balled-up

How You Recognize the Bit Balled Up While Drilling

Drilling Torque – Drilling torque will be lower than normal drilling torque since most of the cutters are covered up by cuttings.

Rate of Penetration – The ROP will decrease more than projection. If you drill 100 fph and later on the ROP drops to 50 fph without any drilling parameters changed, this might be this problem.

Standpipe Pressure – Standpipe pressure increases with no changes in flow rates or drilling parameters. Balling up around the bit reduce annular flowing area resulting in increasing pressure.

Factors Affecting Drill Bit Balling Up

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Adriatic IV Blowout and Platform Burning

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Adriatic IV Blowout incident is one of the worst oilfield incidents happened in our industry. We need to learn and understand about it so we can prevent this incident to reoccur again in the future.

In the month of August 2004, Adriatic IV was placed near the Temsah gas production platform, off Port Said situated in Egypt (Mediterranean). The rig was busy drilling a natural gas well and there was a gas explosion which took place. It has been vindicated through reports that the blast was followed by a fire which later escalated to the Petrobel-run platform where it was raging persistently for about 7 days after which it was taken care of. About 150 personnel on the jack-up were saved and all the production and functions were stopped.

It was vindicated through studies and reports by Global Santa Fe that the Adriatic IV was completely submerged and could not be saved or restored. Joint owners of the platform were Italy’s ENI, BP & Egypt’s General Petroleum Corporation and the platform was completely in a dilapidated condition and hence the Egyptian Petroleum minister commanded to destroy it completely. In about 12 months following the catastrophe, the Temsah field and its production activities were restored in a full-fledged manner.

Always ensure that SIMOP’s are properly conducted.

Ref: Rigzone

Abnormal Pressure Caused By Faulting

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Fault is a discontinuity in a geological structure and it sometimes can create abnormal pressure. Hence, you need to really understand how the geological fault can cause higher pressure even though it comes from the same reservoir.

abnormal-pressure-by-faulting

There are three fault types which are as follows;

  • Strike-slip, where the offset is predominately horizontal, parallel to the fault plane.
  • Dip-slip, offset is predominately vertical and/or perpendicular to the fault plane.
  • Oblique-slip, combining significant strike and dip slip.

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Behavior of Gas in a Horizontal Well Kick

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Gas kick behavior in horizontal wells is different from the gas behavior in normal wells (vertical and deviated wells). Gas follows Boyle’s gas law when it moves up to the shallower section of the wellbore. However, in the horizontal section, there is no change in volume because gas will move up to high side of the wellbore and there is no change in pressure.

behaviors-of-Gas-in-a-Horizontal-Well-Kick-cover

The gas kick volume will increase when the kick is circulated out of the horizontal section because the reduction in hydrostatic pressure results in expanding of gas as per Boyle’s gas law (see below).

Boyle’s Law

P1 x V1 = P2 x V2

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