Balloon-type centralizers TsTs (ЦЦ)
They are used to centralize casing columns as they are lowered and cemented in wells during operations.
Use of centralizers allows to provide uniform clearance between casing and wellbore thus eliminating any contact between them (complete and utter insulation with grout). This provides much longer service life for casing by reducing corrosion rate.
- Centralizers mounted on casing column (approximately every 10 meters) using retaining rings and twisted wedges (keys) are lowered with casing column into well filled with flushing fluid and placed in the annular space between casing and wellbore wall the middle of upward flow of flushing fluid and grouting mortar.
- Well may be curved, wellbore walls may have cavities and be covered with cake.
- Flushing fluid and grouting mortar may be abrasive and have density not more than 2,4 g/cm3.
- To avoid embrittlement of spring material as centralizers are lowered into well please keep their temperature above 35 °C.
- Temperature inside well: not more than +200 °C.
- Casing lowering rate: up to 1,2 m/s.
- Centralizer springs are made of annealed spring steel 65Grade (65Г) that received additional heat treatment thus allowing them to keep their shape even after the springs were affected by sevenfold deformation at maximum radial load (until contact with casing).
- Centralizers’ warranty period after they have been lowered into well once - not less than 3 years.
Note: TsTs-2 (ЦЦ-2) Centralizers differ from TsTs-1 (ЦЦ-1) Centralizers because they have П-shaped stamped-out area in middle part of springs which improves reliability and provides clearance (not less than 18 mm) between casing and wellbore walls.
Comparative characteristics TsTs-2 146/216 (ЦЦ-2 146/216), TsTs-2 168/216 (ЦЦ-2 168/216), TsTs-2 178/216 (ЦЦ-2 178/216) and TsTS-2 245/295 (ЦЦ-2 245/295):
|TsTs-2 (ЦЦ-2) 146/216*||TsTs-2 (ЦЦ-2) 168/216*||TsTs-2 (ЦЦ-2) 178/216*||TsTs-2 (ЦЦ-2) 245/295*|
|Outside diameter, mm||225 — 240||244 — 262||254 — 262||320 — 340|
|Inside diameter, mm||148 — 150,5||171 — 173,5||180 — 183||248 — 251|
|Maximum radial load, kN (kgf)||8,0 (815)||8,0 (815)||8,0 (815)||10,5 (1070)|
|Maximum thrust load, kN (kgf)||11,8 (1200)||11,8 (1200)||11,8 (1200)||11,8 (1200)|
|Deformation at maximum radial load, not more, mm||2||2||2||2|
|Storage temperature, °С||-50 — +60||-50 — +60||-50 — +60||-50 — +60|
|Centralizer weight, not more, kg||9,2||10,5||11,5||16,0|
|Number of springs, each||6||6||6||8|
|Number of sections, each||3||3||3||3|
|Retainer ring, pcs||1||1||1||1|
|Twisted wedges (keys), each||2||2||2||4|
* fraction’s numerator means casing diameter (mm); fraction’s denominator means wellbore diameter (mm).
Centralizers come disassembled; sets packaged in boxes: TsTs 146 (ЦЦ 146) - 60 each; TsTs 168 (ЦЦ 168) - 50 each; TsTs 245 (ЦЦ 245) - 45 each.