Sand is mined. It is washed. It is dried. Then it gets wet again.
Such is the unassuming life cycle of most every grain of sand ever pumped down a horizontal well along with millions of gallons of water and into the freshly opened fractures of a tight-rock formation in the US.
But what if the sand never had to be dried?
To start with, the unconventional sector could save tens or hundreds of millions of dollars a year, simply by cutting out the capital-intensive drying process.
That might mean mines of the future could be made small enough to follow operators as they sail slowly across their vast acreages.
Wet sand also lends itself to safer and more regulatory-friendly worksites, an important consideration given that more-stringent air-quality standards are coming into effect in the US next year.
A wet-sand revolution may also represent a major boon for the industrywide effort to reduce CO2 emissions - making each horizontal well completed with wet sand a bit greener than one that used dry sand.
This is all according to a newly shared case study (SPE 199975) from sand supplier PropX and US shale producer Ovintiv. Since the highlighted field test was completed last year, PropX has pumped more than 1 billion pounds of wet sand down wells in Texas and Oklahoma.
“What we propose in this paper is the next logical step in the supply-chain reduction,” of the unconventional sand sector, said Brian Dorfman. “That is, the removal or the significant scaling down of the drying facility.”
Dorfman is a business development manager at PropX and one of the authors of the whimsically titled paper, “Can Wet Sand Be Used for More Than Building Sand Castles on the Beach?”
On a multiwell pad in Oklahoma, Ovintiv found that wet sand - defined as having a moisture content of 1-10% - could be used to stimulate more than a hundred fracture stages in under 2 weeks. Addressing any concerns over efficiency, the operation saw an average of nearly 4 million pounds of wet sand pumped downhole each day - well within shale-sector norms.
Sand is washed to remove contaminants. It is then run through industrial-sized kilns because dry sand flows from a hopper and into a train car or a truck far easier than wet sand which clumps together, as any child at the beach knows well.
The people behind the papers – Zoe Grant, Tim Thomas, Anne Voss and Leigh Coultas