Halliburton Co., the world's largest fracking company, has grown its fleet of pressure pumping equipment by 700,000 horsepower over the past year, a giant growth spurt that comes as U.S. drillers pump more crude from shale plays.

That surge brings the Houston oil field service company's high-pressure pumping equipment to more than 4 million horsepower, about 1.6 million horsepower more than its top competitor Schlumberger has, Norwegian energy research firm Rystad Energy said in a report on Tuesday.

Rystad believes U.S. fracking companies expanded their high-pressure pumping fleets by 3.3 million horsepower last year and could add another 3.3 million this year, as demand rises for hydraulic fracturing, the process of blasting water, sand and chemicals underground to open shale rock formations to oil and gas production, in places like West Texas and Oklahoma.

The rise in demand for fracking could increase spot prices for pressure pumping between 10 percent and 25 percent in the second quarter, squeezing margins that U.S. drillers make on bringing wells into production.