Flared-gas powered Pykrete can protect offshore rigs

Gas flaring is a waste of energy and by taking flared gas and redirecting it, it can be used to power a pykrete barrier for offshore rigs that can contain spills and protect the rigs from harsh weather and even pirates.

By Don Yates May 18, 2015

Gas flaring, coming from the offshore preproduction process, is an all-too-common waste of natural resources. The reuse of this gas can be beneficial in many cases, especially as an enhanced oil recovery technique such as reinjection. However, it has a more unusual use that can serve as added protection for offshore rigs. It can actually be used to make pykrete. When ice is combined with 14% sawdust, the resulting mix is known as pykrete. It can have surprising strength and some unique uses. 

Old technology, innovative use

Pykrete was first developed around 75 years ago during World War II when materials such as steel for ships were being used for other purposes. It was determined that there was a need to construct extra large aircraft carriers to protect supply routes across the North Atlantic and pykrete offered a viable, yet unexpected outcome. Big floating aircraft support platforms made of ice were seen as a real and practical possibility.

Presently, pykrete has been rediscovered for applications in the oil and gas industry. One clear use is in the construction of barriers that offer protection from unwanted interference by sea raiders, spill containment in worst case scenarios, and even amelioration of extreme weather damage, while supporting the normal subsea environments with sea-flushing systems.

Moreover, the sourcing of sawdust is also an environmentally friendly process as the supply of sawdust emanates from recycled shipping pallets and even cardboard. Developed countries ship cardboard waste to developing countries to be reused in packaging.

Pykrete usages

Pykrete can be formed into protective structures composed of floating elements, holding tanks, reinforced ice walls with appropriately sized mesh openings, solid barriers, bullet-proof-like progressive cushioning walls, and remotely controlled sea gates for completely surrounded protection. The system works in specific manned or unmanned offshore facilities, such as shallow-water fixed platforms and compliant towers, floating production systems, tension-leg platforms, and even subsea systems.

For pykrete to be practical offshore, the automated equipment installed (as part of the structures) needs to continuously regenerate the sawdust and ice combination, a bit like living human skin. 

The on-site often-wasted-flared gas can be used to power the entire integrated system, where the Internet of Things (IoT) is applied to actively monitor the condition of each element of the pykrete structure and then localized 3D-printing ice mix machines automatically freeze and rebuild the layers of structural ice and sawdust as needed. After the pykrete barrier is established, no extra personnel are needed to manage the integrity of the structures. And the energy input requirements to sustain the structure can be easily diverted to this task from the flared gas. The thickness of the various sections of the structural ice may vary depending on the prevailing weather conditions, waste heat sources, and even the temperatures of the sea currents. To restore the integrity of the pykrete form, the distributed ice thickness rebuilding hardware-acting like a 3D printer-can blend fiber materials and ice in layers as required. The structure build time was targeted for completion in less than a month, using a mix of short-term refrigerated-system hardware to do the heavy icing and smaller distributed long-term sustainable systems that would remain onsite.

The entire system can also be an integrated environment. For example, when deployed in shallower waters where the protective mesh-like walls reach the sea bed, fish can move through the barriers and the structure can offer reef-like protection to marine animals. 

At the end of production, a pykrete structure can be allowed to melt away and the sawdust can be gathered for reuse at another offshore site.

Location and commercialization

The ideal deployments of pykrete structures are in latitudes north of the Tropic of Cancer and south of the Tropic of Capricorn, with locations closer to the poles requiring less maintenance for structure sustainability.

The commercialization of pykrete sustainable systems would probably be driven by rig operators to reduce insurance premiums for rig replacement and environmental damage, where the risks could be better managed and the chances somewhat reduced by the inclusion of such protection.

The return on investment (ROI) is a commercial balance between the construction costs of a rig to survive and operate in a particular location with the underlying costs like insurance premiums for a range of issues, compared to the profits from the product delivery. With pykrete in the overall considerations, the returns come from more protection-against environmental spill issues and rig loss-and reduced insurance premiums.

The engineering next-steps involve major operators and producers that are keen to consider cost saving alternatives and prepared to fund consultants to do the detailed comparative cost assessments, International politics, OPEC policies, or a serious environmental disaster could be the trigger to start such initiatives. Pykrete in this form should be commercially available in the fourth quarter of 2015.

Don Yates heads up the R&D activities of the Columbus Group, a pursuit of more than 30 years and 1,400 projects in automated safer mining, smarter oil and gas extraction, storm-water recycling, light rail community linking, cost-effective renewable energy, and electronic warfare strategies. Developments that leverage the IoT are ongoing. 







Original content can be found at Oil and Gas Engineering.