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Introduction to casing Here you will find a list of terms use in the casing design Bell Nipple or Riser Cut off pipe that return the mud flow back to the shakers. Offshore many of to-day rig use a diverter system thus allowing any flow to be directed in in different directions. However on land the bell nipple is still used . It consists of a flange to match the top of the Annular and a outlet on the side to carry the flow back to the tanks for cleaning. Annular: Works with the use of fluid, a piston and a rubber. The fluid is pumped under pressure(800 to 1500 psi) below the piston forcing the wedge shape piston to squeeze the insert (rubber) around the pipe that forcing it to close around the pipe. The advantage of the annular is that it can be closed on open hole "not recommended too often" around a hex or square a kelly and on different sizes of pipe Diverter: works on the same principal as an annual but allows the returning fluid to be directed over the side on through a de-gassing system Blow Out Preventers: The secondary well control safety barrier. There are 3 major manufactures. Pressure ratings start at 2000 psi continuing up to 25000 psi. They are operated with the use of hydraulic pressure. that forces a set of ram's to close around the pipe. Once closed they can be locked in position. Such a B.O.P would have a operating pressure of 1500 psi.
Side Outlets: With a well closed
in it will then have to be monitored an bleed of. this is done with the
use of the side-outlets. The inside diameter of such will range from 2" to
4 !/16. The connecting flange for the hose or line is of forged steel and
cut with a groove to fit the steel sealing ring. see well
control (2).. Blind ram's are used to close the well in when nothings in the hole or when pipe has been hung off. (3)..Shear Ram's, used for cutting pipe in an emergency.
(4)..Variable
ram's, these will adjust to different size pipe. Spacer spool: This spool should go between the bottom ram and the shears or blind rams It should be a minimum of 2 feet. The purpose off such a spool. Should the pipe have to be backed off, hung of or sheared, it can rest and sit in the bottom ram's allowing the shear or blind ram's to close over the top and secure the hole.
Single Ram:
This
area has been started, however it is open to sponsorship If your a small
up and coming company and make such equipment and would like this
space. Flange & Ring Gasket; The "BX" pressure-energized ring joint gasket was designed for face-to-face contact of the hubs or flanges. Sealing takes place along small bands of contact between the grooves and the OD of the gasket. The gasket is made slightly larger in diameter than the grooves, and is compressed slightly to achieve initial sealing as the joint is tightened. Although the intent of the "BX" design was face-to-face contact between the hubs or flanges, the groove and gasket tolerances, which are adopted, are such that, if the ring dimension is on the high side of the tolerance range and the groove dimension is on the low side of the tolerance range, face-to-face contact may be very difficult to achieve. Well Head: welded onto the surface casing and will support casing heads and BOP while drilling and the production tree if the well is completed for production Casing Slips: installed around the casing and set into the casing head allowing some of the casing weight to be taken and the string to be held in a little tension. Packers: Use to isolate section of the hole for various reasons Drive Pipe:(36) Surface formations are lose and consolidated, They consist mainly of sand and stones. Due to this the surface hole will need to be cased off before any drilling can take place. Large heavy walled pipe is often driven to a point of refusal or a safe depth. I say often this may not always be the case ? Surface Casing:(20) With the conductor casing in place, it is then cleaned out and the surface hole drilled. Most country's require surface casing to protect sands and freshwater from invasion by hydrocarbons or salt water from below. Surface casing can extend from hundreds up to nearly 2500ft. Like drive pipe surface casing is big and heavy. This casing would normally be screwed together, and can be hard work unless ? Intermediate Casing:(13 3/8) The reason for this string is to cover many of the problems zones that are found higher up the hole, such as lost circulation and water flows. Such zones need to be isolated as the drilling fluid weight may have to be raise in the deeper section of the hole. Protective Casing(9 5/8) The hole will then be drilled to just above the formations on interest. Normally this will be the longest section of open hole. And is quite often the most troublesome. Such a string of pipe could be run to 21000 feet and cemented back to 5 or 600 feet inside the last casing shoe. Of all the casing string's this is the most interesting to run. Cementing such a string needed your full attention. Liner: a short string of casing hung from another string of casing often used to extend or repair Top of Liner: (TOL) This should need no explanation. However it is important that it is mentioned. Running into the TOL with a tool can do a lot of damage. Liner Lap: The area between the TOL and the last casing shoe is referred to as the liner lap. Float Shoe: This area has been started, however it is open to sponsorship If your a small up and coming company and make such equipment and would like this space. Shoe Track: Between the float collar and float shoe is referred to as the Shoe track. between 40 and 80 ft Along with it you will hear people mention the casing jewellery. They refer to the shoe, float collar. centralizer's and other bits and peaces that are added to the string Shoe: used to guide the casing in the hole can be open or have back pressure valve installed Centralizer: are installed on a given number of joint to hold the casing from the walls of the wellbore Packer: are used to isolate section of the wellbore for one reason or another |
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