Safely drilling

When it comes to deep borehole drilling, the worst-case scenario is a blowout, where liquid, oil or natural gas is uncontrollably released into the environment. The images of Deepwater Horizon in the Gulf of Mexico, one of the worst environmental catastrophes in history, are still engraved in our memories. 

Blowout preventers (BOPs) are designed to avoid precisely such a worst-case scenario. Positioned directly above the borehole and often weighing several hundred kilograms, they are the last line of defense against blowouts and help ensure the safety of wildlife and the environment. Depending on the specific site, each borehole has three to five BOPs, each requiring annular style or ram style seals. With sealing elements like the “Ultra Annular,” Freudenberg Oil & Gas Technologies supplies essential components for BOPs. The Ultra Annular utilizes a radical new insert design and proprietary Freudenberg Oil & Gas Technologies elastomer to enhance the performance of the packing unit in elevated temperatures. 

Pressure Control

The operating conditions below the surface, and therefore at the borehole and ultimately for BOPs at the surface, are extreme – in terms of pressure and temperature. When drilling through pockets of high pressure, immense quantities of gas and oil can shoot up toward the surface. The experts refer to this a “kick.” The force of a blowout can have grave consequences for oil platforms, the personnel working on them, and the environment – not to mention financial ramifications for their operators. 

The fundamental principle for drilling sites, maintenance work, and especially any malfunctions is “pressure control.” To cope with these extreme pressures, and potential “kicks”, boreholes are equipped with a multi-stage safety system. With such a backup strategy, several BOPs with different designs are stacked one atop the other, like a series of shutoff valves. They operate sequentially, producing a mutually reinforcing effect.

Freudenberg’s Ultra Annular is a ring-shaped packing unit that sits within the BOP housing. During the drilling process, it must perform two completely different safety-relevant functions: on the one hand, within the BOP the unit has to seal the ring-shaped opening when the drill pipe is inserted. On the other, it must deliver reliable sealing when there is no drill pipe present. Freudenberg Oil & Gas Technologies is continually refining their existing products: excellent reliability and a long service life contribute to their sustainability.

The Ultra Annular was developed to prevent borehole blowouts. The element was designed to minimize resource waste and prevent harm to the environment

Robert Costolnick, Global Sales Manager, Pressure Control Products

Outstanding ability to withstand high temperatures

What sets the Ultra Annular apart – in addition to consistent pressure resistance – is its outstanding ability to withstand temperatures up to 177 degrees Celsius (350 degrees Fahrenheit): the highest known temperature rating of an annular BOP element on the market today. This unique selling feature is partly thanks to the choice of elastomer, a tailor-made proprietary material that offers exceptional quality and durability. “Elastomers used in the annular BOP packing units to be extremely ductile, flexible and nevertheless robust to seal large boreholes and hold back high pressures,” explains Aaron Smith, Engineering Manager, BOP Products, regarding the demanding specifications. In addition to the choice of material, the innovative design of the reinforcing metal inserts, which are bonded with the elastomer at the core of the Ultra Annular, is a cut above a conventional solution. 

The packing unit, which has proven its value as a long-lived, dependable safety component for pumping natural gas and oil, can also be used in geothermal drilling, where its high-temperature resistance makes the Ultra Annular a top candidate. Why? “Geothermal drilling targets zones beneath the Earth’s surface with extremely high temperatures. The liquids extracted are still extremely hot when they are pumped to the surface,” Smith explains. Sealing materials must be able to withstand and function reliably under such conditions.

Geothermal energy is sustainable and regenerative, and can be used for heating, cooling, or producing electricity. In other geothermal applications, too, sealing technologies from Freudenberg offer dual benefits by delivering, just as the Ultra Annular does, a combination of safety and sustainability. “The Ultra Annular was developed to prevent borehole blowouts. The element was designed to minimize resource waste and prevent harm to the environment,” summarizes Robert Costolnick, Global Sales Manager, Pressure Control Products.