The Effect of Weighting Materials on Cement

AttapulgiteAttapulgite  belongs  to  a  quite  different  family  of  the  clay  minerals  Attapulgite-based  muds have excellent viscosity and yield strength and retain these properties when mixed with salt water. However, they have the disadvantage of suffering high water loss thereby giving poor sealing properties across porous and permeable formations.
Organophillic Clays Organophillic clays are made from normal clays (bentonite or attapulgite) and organic cations. The organic cations replace the sodium or calcium cations originally present on the clay plates. Organophillic clays can be dispersed in oil to form a viscous structure similar to that built by bentonite in water. POLYMERS:Polymers   are   used   for   filtration   control,   viscosity   modification,   flocculation   and   shale stabilisation. When added to mud, polymers cause little change in the solid content of the mud. Polymers  are  chemicals  consisting  of  chains  made  up  of  many  repeated  small  units  called monomer…

The Effect of Weighting Materials on mud

BariteBarite  (or  barytes)  is  barium  sulphate,  BaSO4  and  it  is  the  most  commonly  used  weighting material in the drilling industry. Barium sulphate has a specific gravity in the range of 4.20 - 4.60. The specific gravity of Most commercial barite contain impurities including quartz, chert, calcite, anhydrite, and various silicates which slower its specific gravity. It is normally supplied to a specification where the specific gravity is about 4.2.  Barite is preferred to other weighting materials because of its low cost and high purity. Barite is normally used when mud weights in excess of 10 ppg are required. Barite can be  used to achieve densities up to 22.0 ppg in both water- based and oil -based muds. However, at very high muds weights (22.0 ppg), the rheological  properties  of  the  fluid  become  extremely  difficult  to  control  due  to  the  increased solids content.
2. Iron MineralsIron ores have specific gravities in excess of 5. They are more erosive than other weig…


Blowout preventers (BOPs) Blowout preventers (BOPs), in conjunction with other equipment and techniques, are used to close the well in and allow the crew to control a kick before it becomes a blowout. Blowout preventer equipment should be designed to: 1. Close the top of the hole. 2. Control the release of fluids. 3. Permit pumping into the hole. 4. Allow movement of the inner string of pipe.
You may also like this topicHandling Tools for Drilling

BOPs  equipment  are  selected  based  on  the  maximum  expected  wellbore  pressures.  The pressure  rating,  size  and  number  of  BOP  components  must  be  determined  by  the  Drilling Engineer prior to drilling the well. Basic  types  of  blowout  preventers  on  drilling  rig  are:  annular  preventers,  ram  preventers, rotational preventers and diverters. BOPs are rated by API as 3M (3000 psi), 5M, 10 M and 15 M. For HPHT, BOPS are either 15 M or 20 M. The recommended component codes for designation of BOP stack arrangements are as follows:
• A = …

Handling Tools for Drilling

Spinning ChainA relatively short length of chain attached to the tong pull chain on the manual tongs used to make up drill pipe. The spinning chain is attached to the pull chain so that a crew member can wrap  the  spinning  chain  several  times  around  the  tool  joint  box  of  a  joint  of  drill  pipe suspended in the rotary table. After crew members stab the pin of another tool joint into the box  end,  one  of  them  then  grasps  the  end  of  the  spinning  chain  and  with  a  rapid  upward motion of the wrist "throws the spinning chain"—that is, causes it to unwrap from the box and coil  upward  onto  the  body  of  the  joint  stabbed  into  the  box.  The  driller  then  actuates  the makeup cathead to pull the chain off of the pipe body, which causes the pipe to spin and thus the pin threads to spin into the box.

You may also like this topicDrilling Mud Circulation System
TongsThe  large  wrenches  used  for  turning  when  making  up  or  breaking  out  drill  pipe,  c…

Bottom hole assembly

 Float CollarsA float collar is a one way valve placed at one or two joints above the shoe. The float collar provides the same functions as a float shoe by preventing fluid back flow into the casing: mud backflow during running in hole and cement slurry backflow after cement displacement. The distance between the shoe and float collar is called Shoe Track. The float valve can either be a ball type or a flapper, Figure below. Flapper type valves are normally used where a small hydrostatic pressure difference is expected, providing a better seal than a ball type valve.

You may also like this topicDrilling Rig Rotary Table Sizes Centralisers

A centralizer is a mechanical device attached to the outside of casing. The primary purpose of this equipment is to center the casing in the hole and provide a uniform flow passage with relatively equal frictional pressure losses surrounding the casing. Another major function of centralizers in a deviated hole is to help prevent differential pipe sticking. Cemen…

Introduction to Drilling Bits ROLLER CONE BITS

DRILLING BITS:ROLLER CONE BITS:As the name implies, roller cone bits are made up of (usually) three equal-sized cones and three identical  legs  which  are  attached  together  with  a  pin  connection.  Each  cone  is  mounted  on bearings which run on a pin that forms an integral part of the bit leg. The three legs are welded together and form the cylindrical section which is threaded to make a pin connection. The pin connection  provides  a  means  of  attachment  to  the  drill  string  Each  leg  is  provided  with  an opening  for  fluid  circulation.  The  size  of  this  opening  can  be  reduced  by  adding  nozzles  of different sizes. Nozzles are used to provide constriction in order to obtain high jetting velocities necessary for efficient bit and hole cleaning. Mud pumped through the drillstring passes through the bit pin bore and through the three nozzles, with each nozzle accommodating one third of the total flow, if all the nozzles were of the same size. There are two types of r…

Introduction Drilling Mud Function and Performance

DRILLING FLUIDSDrilling fluids include both gases and liquids, liquids are called drilling mud, where the drilling mud is one of the most important elements of any drilling operation. The mud has a number of functions which must all be optimized to ensure safety and minimum hole problems Failure of the mud to meet its design functions can prove extremely costly in terms of materials and time, and can also jeopardise the successful completion of the well and may even result in major problems such as stuck pipe, kicks or blowouts There are basically two types of drilling mud: water-based and oil-based, depending on whether the continuous phase is water or oil. the water-base mud is the most commonly used. The use of oil-base mud is usually limited to drill extremely hot formations or formations that are affected adversely  by  water-base mud .  Where  the  use  of  gasses  is  limited  to  formations  that  are competent  (hard)  and  impermeable.  Gas–liquid  mixtures  can  be  used  when  only …