Various Specifications of the Casing Shoe

A tool joint connected to the bottom of a string of casing designed to guide the casing past irregularities in an open hole; usually rounded at the bottom in shape and composed of drillable materials.

A casing shoe prevents lateral forces on the casing and allows smooth landing of the casing string. The shoe is available in various specifications to suit various drilling applications.

Float Collar

The Float Collar is an accessory that is used in the drilling of oil and gas wells. This device is used to prevent the backflow of cement slurry from the bottom of the casing string when pumping stops. It is a special coupling that is inserted one or two joints above the bottom of the casing string.

It is also known as a casing guide shoe. It is a short, heavy, cylindrical piece that is attached like NWcasing pipe to the bottom of the casing string. It contains a check valve that allows fluids to pass downward but not upward through the casing.

Another important feature of a float collar is its integral back pressure valve, which is needed to stop the backflow of cement slurry from entering the bottom of the casing string. This is important because the slurry that is pumped down to drive the top cement plug through the well bore and push the remaining slurry up through the annulus is not as dense as the mud that is used to create the wellbore.

Besides preventing the backflow of cement slurry, a float collar also serves as a bearing ring and backpressure valve for the top portion of the casing string. This means that it is important to use this component correctly in order to avoid damage to the casing or the derrick or mat.

In the drilling of oil and gas wells, there are several different specifications of the casing shoe that must be used. This is because each casing shoe has a unique purpose and is designed to perform differently.

These shoes can help a drilling crew to run the casing string into the wellbore. They can also help to control the buoyancy force of the casing string during casing running operations, and they can help to control the height of the cement plug in the casing pipe accurately during the cementing process.

This equipment can be used in a variety of applications, including vertical, horizontal and deviational wells. It is made of high quality seamless casing grade steel.

It can be procured in single or double valve configurations, and is PDC drillable. It can also be manufactured to withstand various differential pressures. All of these factors make it a great choice for any rig operation.

Reaming Collar

Various specifications of the casing shoe can be found on the market. They include:

Float Collars and Float/Guide/Reamer Shoes are located at the bottom of a liner system and prevent backflow of gases and fluids in the liner after displacement is complete. The Float/Guide Shoe features an aluminium guide nose and a dart-type poppet valve-system for preventing backflow of gases.

These are used in conjunction with a reaming collar or a float shoe to overcome well bore obstructions and ream the casing string through potentially unstable formations. A hemispheric or conic aluminium guide nose climbs and negotiates ledges while the reamer shoe cuts out tight spots to guide the casing string to total depth.

One particular application is for drilling 444 mm surface holes in hard, highly dipped formations. In these conditions, conventional drill collars often create excess annular clearance and have insufficient axial stiffness for optimal deviation control of HDD drill pipe. This causes the bit to drill perpendicular to formation strata and increases the cost of drilling a surface hole.

However, there is a way around this problem. Gulf Canada has successfully deployed two large diameter drill collars that have allowed them to significantly reduce the time needed to drill a 444 mm surface hole in a number of foothill wells.

To achieve this, the company has developed a reaming assembly that is connected to a drillable collar. The reaming assembly has a mud motor having, on its end, a 12 1/4 inch drill bit which is connected to the drillable collar.

After the reaming assembly is in place, the casing string is run into the borehole and cemented. This will secure the reaming assembly to the casing string and will set the reaming collar in an appropriate formation surrounding the borehole.

Various other apparatus have also been developed for the purpose of assisting in the reaming of side-tracked holes that run off of the casing string. These are referred to as sacrificial reaming assemblies and they can be constructed using a mud motor with a drill bit that has been removed from the borehole.

Drilling Guide Shoe

The drill guide shoe, also known as the casing shoe, is a tapered, often bullet-nosed piece of equipment placed at the end of a casing string to minimize problems associated with hitting rock ledges or washouts in the wellbore as the casing is lowered into the hole. The outer portions of the guide shoe are made from steel, typically matching the casing in size and threads, if not steel grade.

The inner portion of the guide shoe includes an annular body 31 that is formed from a thermoset material, including an unsaturated polyester, alkyd, epoxide, furan, phenolic, or polyurethane cast elastomer, and/or vinyl esters. This material cures or fuses with heat (often above 200 deg C), and/or by a chemical reaction or irradiation to create a stronger form.

Alternatively, the guide shoe annular body 31, which includes an outer portion 30, inner portion 32, inner spokes 34, and inner collar 36, may comprise a steel shell. The steel shell is shaped into a rounded nose with a central orifice (Fig. 1).

Guide shoes can be manufactured from heavy-duty steel, aluminum or composite materials that are designed to withstand high load weights and high temperature applications. In addition, long nose guide shoes can be manufactured that are shaped to ease movement past bridges or obstructions downhole.

These guide shoes can be used to run casing strings over doglegs, ledges of HWcasing pipe or soft formations, reducing end loadings by up to 90% and providing a more efficient circulation and cementing operation for the operator. The nose can be shaped to reduce drag and buckling, or can rotate, enabling the casing to be run in either direction.

In addition to the use of a guide shoe to assist in the run of a casing string, it may be necessary to ream and cement the casing after installation. The reaming and cementing operations help to seal the casing string in place and prevent the migration of fluids between the wellbore and the formations through which the casing has passed. The reaming and cementing can be performed by lowering the casing string into the wellbore, and then pumping the slurry of mud and cement through the reaming and cementing shoe to seal the wellbore and the casing string.

Reaming Float Shoe

The float shoe is used during the cementing of the casing in order to prevent slurry from flowing back into the well. It also provides a check valve to keep fluids from entering the bottom of the casing and allows circulation down through the casing. The float shoes are often installed at two joints above the float collar.

The Reaming Float Shoe is a stabilizer that is used to ream unstable wellbore sections or sections with swelling or caving clays by rotating the string. It consists of a casing and hard alloy screw-type support elements, including the shoe rotating tip and float collar. The stabilizer is made of 40X steel, connected threads are made of VK8 hard alloy and are phosphatized and lubricated.

Designed to overcome difficult wellbore conditions such as ledges, swelling shale, mud cake build-up on porous formations and sand bridges in the well bore, our Reamer Shoe system is compatible with all casing hanger assemblies. The eccentric guide nose climbs ledges and negotiates obstructions while the cutting structure reams out tight spots or obstructions in the wellbore, thus providing effective protection against unexpected or anticipated casing and liner running problems.

It is available in both single and double valve configurations, and is compatible like diamond core barrel with all BHGE ream-down liner systems. It is available in 4 1/2" to 30" casing sizes and can be customized to meet any application needs.

Our Reamer Shoe system is designed to be installed on casing or liner and screen prior to drilling and in the wellbore after drilling. It has an aluminum eccentric guide nose that climbs ledges and negotiates obstructions as well as the cutting structure that reams out tight spots or obstructions.

The reamer shoe is PDC drillable and can be supplied in single or double valve configurations, and is compatible with any type of collar. It can be provided with round cement noses to deflect offledges or obstructions, ports/jets and a ball deflector.

A 95/8-in. casing was run in the Hoton well after the hole had caving to 2,500 m, but it took several trips to get it down to bottom. It was picked up and a reamer shoe was drilled out with a BB1290 PDC bit to help the casing get down to bottom. It was run successfully and a reaming shoe is a critical tool in this situation.