A Piper International Company
Introduction
The Torus Annular Blowout Preventer is a unique design in well control technology. Unlike other annular units, the Torus employs no metal fingers in its packing element. This allows the BOP to close around irregular shaped or multiple objects in the well bore as well as over open hole, without damage to delicate equipment such as electric submersible pump cable or fiberglass tubing.
In addition, the Torus has no moving mechanical parts such as pistons and dynamic seals that are easily damaged by foreign material in the closing fluid. The outer packer acts as a diaphragm to transfer the hydraulic pressure to the inner packer which closes the BOP.
Packer Element Facts
One big advantage of the Torus BOP is the design of the Packing Elements. The inner packing element is mostly a ‘doughnut’ of solid rubber. There are two metal rings at the top & bottom of the outside edges, to promote even closure. This is how the Torus can seal around various objects in the bore, without cutting or damaging items such as Electric Submersible Pump cables.
The packing element of the Torus, requires time to ‘relax’ to the fully open position. The amount of time required depends on several factors, such as; temperature and the duration and extent of the closure. Our warranty does not cover left closed overnight.
Under the coldest conditions, it can take up to several hours to for the unit to completely open. Under ideal conditions, it will take only a few minutes. We recommend the Torus BOP be heated in extreme cold service. This will enhance the sealing ability at a given closure pressure and speed opening of the unit, improving productivity and product life. Our warranty does not cover damage from cryogenic operation (while frozen solid).
After each cycle, the blowout preventer bore should be inspected to determine the packer position. When completely open, the packer recedes into the steel body of the blowout preventer and will not contact objects moving through the bore. Failure to allow the BOP to completely open can result in damage to the inner packer.
Operating the Closing Unit:
During normal drilling and work over operations the 4-way shear seal valve should be placed in the “Open” position. As stated above, the Torus is a pressure-close/vent-open blowout preventer. Placing the 4-way/3-position shear seal valve in the “Open” position eliminates the possibility of pressure being trapped in the annular cavity of the BOP which may result in partial closure of the packing element while running tools in and out of the well bore, resulting in unnecessary wear and possible damage of the inner packing element.
The closure pressure applied to the inlet of the Torus Blowout Preventer can be adjusted to minimize packing element stress, and pressure on through bore items, however you can apply closure pressure up to the full rated working pressure of the BOP.
CAUTION!!! Closing pressure MUST NOT exceed the rated working pressure of the BOP unit. Injury or damage could result.
Routine Operation of the Torus BOP:
-Move the 4-way/3-position shear seal valve to the “Close” position. Closure is obtained when the audible sound of hydraulic fluid passing through the manifold of the closing unit ceases.
-Move the 4-way/3-position shear seal valve to “Block” (or “Neutral”) position.
Verify closure by visual inspection of the packing element
-Moving the 4-way valve to the “Block” position traps hydraulic fluid in the annular cavity of the Torus. This allows the Torus to hold well bore pressures far above the blocked pressure, because hydraulic fluid is non-compressible.
CAUTION!!! Leaving the 4-way shear seal valve in the “Close” position only contains well bore pressures below the regulated hydraulic pressure. If well bore pressure exceeds the regulated hydraulic pressure, hydraulic fluid could be vented to the hydraulic fluid reservoir, resulting in communication of wellbore fluids and wellbore pressure to atmosphere, causing possible injury or death.
To open the Torus:
Relieve all annular pressure (below the BOP). Move the 4-way/3-position shear seal valve to the “Open” position. The closure fluid will will then return to the reservoir of the closing unit relieving closure pressure and allowing the packing elements to retract into the BOP body.
Fluid required for full closure of the Torus BOP:
Nominal Size Closure fluid
7-1/16″ Unit = 4.5 Gallons
9″ Unit = 8.5 Gallons
11″ Unit = 11 Gallons