Well Control Systems

Sigra Wire Line Coring Well Control Suite

Sigra manufactures a suite of well control tools specifically for use in HQ size wire line coring. They are ideally suited for use in coal exploration where gas may be expected. The system may also be used for open hole drilling.


Sigra Well Control System



The suite of tools is comprised of:

  • Annular blow out preventer
  • Pressure relief choke
  • Activation unit
  • Wire line stripper

Annular Blowout Preventer

Sigra blow out preventers are small, lightweight annular devices that operate in the lower pressure ranges where most coal reserves are found. Their inflation is via water or water –glycol mixes such as is used in vehicle coolant.
They are actuated by hand or motorized pumps with accumulator storage.
Sigra makes a range of BOPs in different sizes. Those available are by internal diameter:

  • 101mm (4”)
  • 128mm (5”)
  • 168mm (6 5/8”)

Their working pressure ratings vary between 7 MPa (1000psi) and 13MPa (1900psi).
All units come fitted with choke and kill ports.
They may be fitted with minimal height overflow mud collectors, or with static or rotary seals.

Height, mm Diameter, mm Weight, kg
101mm (4”) 800 200 85
128mm (5”) 1030 220 135
178mm (6 5/8”) 620 275 100

Pressure Relief Chokes

Sigra chokes are not just restrictive valves – they are pressure relief valves that are made from an energized steel reinforced elastomer. This makes well control operations much easier as no constant pumping rate is required to maintain back pressure in the well.

Sigra chokes may be used for well control in underbalanced drilling. Their unique capability to pass fluid and cuttings at a maintained back pressure makes them ideally suited to this application.

Sigra chokes are manufactured in a number of sizes to suit varying flow rates.
They are categorized by their internal diameter:

20mm – design max flow rate = 100l/min
25mm – design max flow rate = 250l/min

All devices are capable of maintaining a regulated pressure relief setting between 0 and 10MPa (1450psi).

Sigra Choke Size

  • 1800mm long × 75mm diameter plus activation accumulator and hoses
  • Weight = 45kgs

Wire Line Stripper

Sigra manufactures wire line strippers which are designed to prevent swabbing of a borehole while pulling an inner tube. They can also be energised to seal around a wire line in the event of a blowout.

They contain a pressure gauge port fitted with a quick connect and a bleed or kill port.
They are lightweight devices designed to 89mm (3 ½”) outside diameter and fitted with HRQ or HQ threads.
The seals are readily replaced and the units are energised by a hand hydraulic pump.
They are capable of holding back up to 10MPa pressure (1450psi).

Sigra Wire Line Stripper Size

  • 300 mm high × 89mm diameter plus pump and hoses
  • Weight = 8kgs

Activation Unit

The Sigra manual activation unit is for use with both the 101 mm blow-out preventer and the 20 mm choke. It can be located up to 15 meters from the devices and provides a one-step centre for well control. It is air operated with a manual pump for backup. Activation is by hydraulics.
At 60 kgs it is portable and compact.
The unit is simple to operate and provides excellent control of the BOP and choke.

Sigra Activation Unit Size

  • 900mm long × 800mm high × 500mm deep
  • Weight = 60kgs