Drilling Or Drilling Operations

PDC DRILL BITS NOMENCLATURE

Parts of a PDC Drill Bit

Nomenclature for PDC drill bits consists of one letter and three numbers. The letter indicates body type: M for matrix,S for steel, and D for diamond The next three numbers indicate the following:

  • Formation Type To Be Drilled
  • Cutting Structure
  • Bit Profile

PDC CUTTING STRUCTURE

Very soft (1) to medium (4) formation type PDC bits have one dominant size of PDC cutter. PDC cutting structure is denoted in the following way:

  • 2 - This bit has mostly 19mm cutters
  • 3 - This bit has mostly 13 mm cutters
  • 4 - This bit has mostly 8 mm cutters
For example: M431
  • M=Matrix,
  • 4=This bit will perform well in medium formations,
  • 3=Cutting Structure consists of primarily 13 mm PDC cutters,
  • 1=Bit Profile

Formation types 6, 7 and 8 are somewhat different. These bits are designed for the harder, more difficult drilling. Their cutting structures are denoted as follows:

  • 1 - Natural Diamond
  • 2 - TSP (Thermally Stable Polycrystalline)
  • 3 - Combination
  • 4 - Impregnated Diamond
BIT PROFILE
  • Short Fishtail
  • Short Profile
  • Medium Profile
  • Long Profile
For example: M612
  • M=Matrix,
  • 4=this bit will perform well in medium hard formations,
  • 1=Cutting Structure consists of natural diamond,
  • 2=Short Profile
Consulting

ENGINEERING CLASSIFICATION FOR ROCK HARDNESS

Classification

Compressive Strength

Very Low Strength
Low Strength
Medium Strength
High Strength
Very High Strength

<4000
4,000-8,000
8,000-16,000
16,000-32,000
>32,000

Cone Equipments

Wellhead And Valve(Gate)

  • working pressure:2000PSI~20000PSI
  • working medium : oil , nature gas , mud , consist of H2S & CO2gas .
  • working temp. : -46°C~121°C
  • PSL:PSL1 ~ 4
  • PR:PR1 ~ 2
  • Working pressure :2000 PSI~5000 PSI
  • Working medium : oil , nature gas , mud , consist of H2S & CO2gas
  • Temp.:-46℃~121℃
  • Products specification level :PSL1~4
  • Performance requirements level :PR1~2
  • Working pressure:2000PSI~20000PSI
  • Working medium : oil , nature gas , mud , consist of H2S & CO2gas
  • Working temp.:-46°C~121°C
  • Products specification level :PSL1~4
  • Performance requirement level :PR1~2
  • Working pressure :2000PSI~20000PSI
  • Nominal bore :1.13/16~9 (46mm~230mm)
  • working medium : oil , nature gas , mud , consist of H2S & CO2 gas
  • working temp.:-46℃~121℃
  • PSL:PSL1~4
  • PR:PR1~2
  • The surface of gate and seat is weld overlay with hard alloy, which has feature of corrosion resistance and washing resistance
  • Working Pressure:2000Psi~20000Psi
  • Nominal Bore:1-13/16"~9"(46mm~230mm)
  • Working medium: Oil, Natural gas, Mud
  • Working temperature:-46℃~121℃
  • Specification level:PSL1~PSL4
  • Performance Requirements:PR1~PR2
  • Non-rising stem, compact structure ,Save space, have flange and thread connection
  • Working Pressure:2000Psi~20000Psi
  • Nominal Bore:1-13/16"~9"(46mm~230mm)
  • Working medium: Oil, Natural gas, Mud
  • Working temperature:-46℃~121℃
  • Specification level:PSL1~PSL4
  • Performance Requirements:PR1~PR2
  • Valve back seal type lower switch torque,convenient to install and maintain
  • Full bore design eliminates efficiently pressure drop and vortex, and eliminates washing by solids in fluid
  • Metal-to-metal seal is used between bonnet and body, gate and seat, body and seat
  • The surface of gate and seat is weld overlay with hard alloy, which has feature of corrosion resistance and washing resistance
  • Slab type structure, switch driving consist of gearwheel and worm gearing, lower operating moment.
  • Apply to the structure of big bore high pressure valve
  • Working Pressure:2000Psi~20000Psi
  • Nominal Bore:1-13/16"~9"(46mm~230mm)
  • Working medium: Oil, Natural gas, Mud
  • Working temperature:-46℃~121℃
  • Specification level:PSL1~PSL4
  • performance Requirements:PR1~PR2
  • Can be supplied with Flanged End Connections, Hammer Union Ends, Threaded Connections or Butt Weld Ends
  • APPLICATIONS = Oil and Gas lines, Crude Oil and Sour Gas, Well Treating Chemicals
  • Available with Pressure Ratings up to 10000psi for 2", 3", 4", 5" Valve Sizes
  • Valve seat and gate are sealed by Metal to Metal Sealing
  • Manufactured and Tested in Accordance with API Spec 6A
  • Material Classes according to NACE MR-01-75
  • Forged Steel Body and Bonnet
  • API 6A PSL 1, 2 and 3 available
  • Low Operating Torque
  • Quick Release Hand Wheel
  • Both thrust bearings with large load capacity and composite rubber-plastic stem lip packing minimize operational torque.
  • Manufactured and Tested in Accordance with API Spec 6A
  • Simple structure and renewable gate and seat assembly.
  • One-piece and double-acting gate with long service life.
  • Can be used in the 350℉ or 650℉ high temperature
  • nominal size from 1-13/16" through 4-1/16"

Casing and Tubing

Casing is large diameter pipe that is assembled and inserted into a recently drilled section of a borehole and typically held into place with cement.
PURPOSE = Casing that is cemented in place aids the drilling process in several ways:

  • Prevent contamination of fresh water well zones.
  • Prevent unstable upper formations from caving-in and sticking the drill string or forming large caverns.
  • Provides a strong upper foundation to use high-density drilling fluid to continue drilling deeper.
  • Isolates different zones that may have different pressures or fluids - known as zonal isolation, in the drilled formations from one another.
  • Seals off high pressure zones from the surface, avoiding potential for a blowout
  • Prevents fluid loss into or contamination of production zones.
  • Provides a smooth internal bore for installing production equipment.

Centralizer / Stabilizer

Drilling Stabilizer is a downhole equipment used in the bottom hole assembly (BHA) of a drill string. Its purpose is to mechanically stabilize the BHA in the borehole in order to avoid unintentional sidetracking, vibrations, and ensure the quality of the hole being drilled.

It is composed of a hollow cylindrical body and stabilizing blades, both made of high-strength steel. The blades can be either straight or spiralled, and are hardfaced for wear resistance. Several types of Drilling Stabilizers are used in the oilfield today. While integral stabilizers (fully machined out of a single piece of steel) tend to be the norm, other types can be used, such as:

  • Replaceable sleeve stabilizer, where the blades are located on a sleeve, which is then screwed on the body. This type can be economical when no repair facilities are available close to the well being drilled and air freight has to be used.
  • Welded blades stabilizer, where blades are welded onto the body. This type is usually not advised on oil wells due to the risks of losing blades, but is regularly used when drilling water wells or on low-cost oilfields.
Consulting

Float Equipment And Accessories

Float shoe

A rounded profile float shoe with an integral check valve attached to the bottom of a casing string prevents reverse flow, or U-tubing, of cement slurry from the annulus into the casing or flow of wellbore fluids into the casing string as it is run. The float shoe also guides the casing toward the center of the hole to minimize hitting rock ledges or washouts as the casing is run into the wellbore. By "floating" casing in, hook weight is reduced. With controlled or partial fill-up as the string is run, the casing string can be floated into position, precluding the need for the rig to carry the entire weight of the casing string. The outer portions of the float shoe are made of steel and generally match the casing size and threads, although not necessarily the casing grade. The inside (including the external taper) is usually made of cement or thermoplastic, since this material must be drilled out if the well is to be deepened beyond the casing point.

Float Collars

A float collar is installed near the bottom of the casing string. Cement plugs land on it during the primary cementing operation, thus retaining inside the casing a small portion of the cement slurry that may have become contaminated as the top plug scrapes the inside of the casing. It is similar to a float shoe; often both are used for redundancy. The internal check valves may be flapper type or spring-loaded balls.

The check-valve assembly fixed within the float collar prevents flow back of the cement slurry when pumping is stopped. Without a float collar or float shoe, the cement slurry placed in the annulus could U-tube, or reverse flow back into the casing. The greater density of cement slurries than the displacement mud inside the casing causes the U-tube effect.

Float Collar Float Shoe

Casing Size
mm (inch)

O.D.
mm (inch)

Length mm(inch)

Connections API

Float Collar

Float Shoe

 

177.8
(7)

194.5
(7 21/32)

586
(23 5/64)

535
(21 1/16)

7 LCSG

7 BCSG

244.5
(9 5/8)

270.0
(10 5/8)

720
(28 11/32)

550
(21 21/32)

9 5/8 LCSG

9 5/8 BCSG

339.7
(13 3/8)

365.0
(14 3/8)

720
(28 11/32)

585
(23 1/32)

13 3/8LCSG

13 3/8BCSG