Coiled Tubing Glossary...

Sack: A measure for cement. One sack is equal to one cubic foot.

Sandstone: A sedimentary rock composed of individual grains of sand that are cemented together by silica, calcium carbonate, iron oxide and so forth. Sandstone is a common rock in which petroleum and water accumulate.

Scratcher: A device fastened to the outside of casing that removes the filter cake from the wall of the hole. Designed to improve the bond of the cement to the formation face.

Secondary Cementing: any cementing operation after the primary cementing operation. Secondary cementing includes a plug-back job, in which a plug of cement is positioned at a specific point in the well and allowed to set. Wells are plugged to shut off bottom water or to reduce the depth of the well.

Sedimentary Rock: A rock composed of materials that were carried to their present position by wind or water. Sandstone, shale, and limestone are sedimentary rocks.

Sequestering Agents: A chemical that is used with an acid in a well treatment to inhibit the precipitation of insoluble iron hydroxides.

Set Casing: To run and cement casing at a certain depth in a wellbore.

Shale: A fine-grained sedimentary rock composed of silt and clay or mud. Shale is the most common sedimentary rock.

Shear Rams: The rams in a well control device which are designed to shear the coiled tubing located directly across the ram position.

Shear/Seal Ram: Combination ram, which provides function of a shear ram and blind ram in one ram body.

Shoe Joint: The length of casing between the float collar and the guide shoe. Designed to hold contaminated cement ahead of the wiper plug.

Shore's Hardness: This is a rating system to define the applicability of rubber to a pressure environment. Thus the higher the number the greater the hardness and therefore the applicability for higher pressures is assured. The rating applies to o-rings and stripper rubbers.

Shut-off Valve: A valve that closes a hydraulic or pneumatic supply line.

Silica Flour: A silica ground to the fineness equal to that of portland cement.

Slip Rams: The rams in a well control device which are equipped with coiled tubing slips that, when engaged, prevent movement of the coiled tubing but do not isolate pressure or control flow.

Slip Ring: A term for the Collector. See above.

Slurry Weight: The density of a cement slurry expressed in pounds per gallon.

Slurry Yield: The volume of slurry obtained when one sack of cement is mixed with water, expressed in cubic feet per sack.

Slurry: A mixture of cement and water that is pumped into a well to harden. A mixture of frac fluid and proppant pumped into a well to increase permeability.

Snubbing: Condition for working coiled tubing though a pressurized stripper, where wellbore pressure applied against the cross-sectional area of the tube creates an upward acting force greater than the weight of the tubing in the wellbore. In this condition, mechanical assistance is required to apply thrust to the tubing while injecting or to maintain control of the tubing when extracting. This condition is commonly called "light pipe operations".

Sodium Chloride: NaCl - Salt

Solution: A uniform mixture of two or more substances.

Sour Gas: A natural gas containing Hydrogen sulfide. (H2S)

Specific Gravity: The ratio of the weight of a given volume of a substance to the weight of the same volume of water, as a means of comparison, at the same temperature.

Spinner, Fullbore: This tool is supplied by the logging company and measures flow contribution from the formation. The impeller is protected by a centralizer and requires only simple calibration runs. It is susceptible to failure due to foreign matter clogging the impeller.

Spinner, Inline: Unlike the Fullbore Spinner this tool requires more passes for calibration and is generally not as reliable as the full bore version, however it is a lot more fragile.

Spool (CT): See reel

Spool (Pumping Services): same as casing head.

Spot: To pump a specific quantity of fluid to a predetermined interval in the well.

Spud: To begin the drilling operation.

Squeeze Cementing: the forcing of cement slurry by pressure to specified points in a well to cause seals at the points of squeeze. It is a secondary-cementing method used to isolate a producing formation1 seal off water, repair casing leaks, etc.

Stabilizer: A sub utilized in the BHA to prevent excessive lateral movement of the CT during DMUR operation.

Stable Spiral: Describes the section of CT, which is beyond the Neutral Point and is therefore in the Unstable region. By definition the CT has formed a helical spiral all sections of which are in contact with the completion tubulars.

Stable: A CIRCA term to define the CT. When a section is described as stable it is impossible to have helical buckling in that particular section given the conditions. The stable section ends at the Neutral Point with the section below to TD being classed as the Unstable section.

Stall: A situation during DMUR operations when the applied WOB results in the Torque required to turn the bit is greater than the Torque supplied from the motor. A sharp CT circulating pressure rise will be seen upon this occurring.

Stator: The stationary rubber element of the PDM motor. The Rotor is held in place by the stator, which until the application of fluid pressure, prevents the Rotor from turning. The stator provides the internal seal to enable pressure build-up.

Stiff Wireline: BJ Services name for wireline installed into coiled tubing.

Stimulation: Any process undertaken to enlarge old channels or create new ones in the producing formation of a well.

Stored Hydraulic Fluid Volume: The fluid volume recoverable from the accumulator system between the maximum designed accumulator operating pressure and the precharge pressure.

Strain Gauge: The term used to describe an electronic load cell. The strain gauge measures weight by calibrating the changes in resistance as a result of the load, either positive or negative, applied to it.

Strap: To measure the fluid level in a tank.

Stress: The force acting on a formation that controls the orientation of a fracture.

String: An entire length of coiled tubing, casing, tubing or drill pipe run into a well.

Stripper Rubber: Inserts made of rubber compounds run inside stuffing boxes to seal well pressure in the well bore as the coiled tubing is being run into or being withdrawn from the well.

Stripper: A device with a resilient elastomeric element used to effect a seal in the annulus. This device is used primarily to isolate well pressure from the atmosphere when injection or extracting the coiled tubing in live wellbores.

Stripping: Condition for working coiled tubing through a pressurized stripper, where wellbore pressure applied against the cross-sectional area of the tube creates an upward acting force less than the weight of the tubing in the wellbore. In this condition, mechanical assistance is required to apply thrust to the tubing while injecting or to maintain control of the tubing when extracting. This condition is commonly called "light pipe operations".

Stub Acme Thread: A parallel thread form with 10 threads per inch with square sided threads. A fine version of the AW and BW Threads.

Stuffing Box: A device that prevents leakage around the coiled tubing as it is being run into and out of the wellbore.

Supercharge: The pressure output of the discharge pump on a stimulation blender.

Surface Casing: The first string of casing set in a well after the conductor pipe. Required by law in the continental United States to protect fresh water zones.

Surface Pressure: the pressure measured at the wellhead.

Surfactant: A material that alters physical characteristics or properties, such as surface tensions or wettability, between fluids and solids. Surfactants are useful because they ensure that the surface of one substance or object is in thorough contact with the surface of another substance.

Surging: The release of well pressure back through surface valves.

Swab Valve: The top most valve on the tree installed above the flow "T" so that tools may be lubricated out of the well with the well flowing.

Swabbing: The lowering of the hydrostatic pressure in the wellbore due to upward movement of pipe and/or tools.

Swage: A threaded connection used to connect a treating line to the well tubulars.

SWBPV: An abbreviation for the Stiff Wireline Back Pressure Valve. The valve is used exclusively on Stiff Wireline operations.

Please inform ICoTA to add a glossary term.