The Propellant Difference
Although shorter in length than hydraulic fractures, propellant fracture geometry promotes greater complexity and higher surface areas in the formation. This gives each producing zone in the formation greater access to hydrocarbons. Testing at Sandia National Laboratory is indicating that fractures produced quickly using propellants are too complex (shattered) to simply close shut, unlike hydraulic fractures that require proppants (sand) to remain open. During hydraulic fracturing, if the pumping company runs out of sand when they’re squeezing it down the well in a slick water slurry, the fracture will close up and not contribute to production; ouch. Self-propping fracturing is possible with propellants, meaning elimination of these large amounts of sand needed for typical hydraulic fracturing jobs.
(Source data from Advanced Well Completion Engineering, 3rd edition, Renpu 2011)
Fracking, it’s still crazy out west and in the world’s deserts. It’s not just that 6,000,000 gallons of water per well. It’s also about the sand and slick water, and maybe less so the chemical additives. Today, some in the industry can brag about some hydraulic fracturing jobs taking 8,000 pounds of sand per foot, in 9,000-foot-long lateral production zones... That’s whole a bunch of sand to dig up and drive anywhere. Also, chemicals are added to the water just to move all that sand into the formation. Another obvious problem is that those cool, expensive specialty chemicals used to free up the sticky oil are largely wasted coating all that sand, not the source rock its meant for. That’s because of the massive surface area created between all those sand grains, rather than rock fissures where the hydrocarbons are located. The difference in physical environmental impact between hydraulic methods and propellants is staggering. Let’s do the truck count.
- 80 Pumper and Tool Trucks
- 600 Water truck loads
- If not available locally
- 6,000,000 gal/well
- 10,000 gal/truck
- 20 Chemicals/slick water truck loads
- 175 Sand truck trips
- 7,000,000 lbs sand per well
- 20 tons per truck
- 200 Waste Water Trucks
- Or onsite treatment of the contaminated water
- Pond construction/remediation
U.S. Energy Information Administration. (2016). Trends in U.S. Oil and Natural Gas Upstream.
- 2 Small Propellant trucks, ~16 drums (55 gal/ea.)
- 8 drums/truck
- @ 1 lb propellant/ft. of lateral
- 2 Tool and equipment trucks
- 1 Propellant loading truck
- 1 Crew/instrumentation truck
- 0 Water trucks
- 0 Waste Water trucks
Just 6 or 7 truckloads/trips for propellant fracturing, meaning a 150x reduction in road traffic, infrastructure and carbon footprint for the fracture job.
Globally, water is the major barrier to developing new shale basins. For desert regions like Argentina, Australia, Algeria, South Africa, Saudi Arabia, Mexico, and Nevada, there is just no surface water to waste and only meniscal groundwater that won’t replenish quickly. Whereas, in the eastern United States where there is water readily available, infrastructure in place and high production rates, there’s little reason to change. Alternatively using CO2 to replace the water works, if you can make your own CO2. Why? You can’t buy it, because there isn’t enough manufactured or captured.