Its third quarter operating income more than doubled to $846 million. That follows healthy results from

Schlumberger,

SLB 0.18%

which recently rebranded as SLB. Revenue for SLB increased 28% in the third quarter compared with a year earlier, its most rapid growth since 2011, and its pretax operating margins hit their highest level since 2015.

Halliburton’s top line benefited from its greater exposure to North America, which continues to see activity grow at a faster pace. Its revenue in the region grew 63% in the third quarter compared with a year earlier. Smaller competitor

Liberty Energy,

LBRT -2.73%

which focuses solely in North America, saw revenue grow 82% over the same period.

Short-cycle activity has been more subdued in the Middle East because of production-cut plans by the OPEC+ cartel, but both Halliburton and SLB said the region will see stepped-up spending as countries such as Saudi Arabia start their capacity expansion projects. 

Despite a healthy run-up in margins, oil-field service firms still appear to have room to squeeze out more profitability. Conditions remain tight for equipment: Liberty Energy Chief Executive

Chris Wright

said last Thursday that the North American fracking market is “near full utilization of available capacity.” As such, customers seem to be willing to shell out more for technological enhancements. 

Notably, both Halliburton’s and SLB’s third quarter revenues remain lower than 2019 levels but have recovered more than global rig count, which was 17% lower than in the same quarter of that year, per

Baker Hughes

data. Part of that reflects customers’ willingness to purchase add-on services to get the most out of those rigs.

In an earnings call last Friday, SLB Chief Executive

Olivier Le Peuch

said the company’s customers are more focused on “critical assets” for which they want performance enhancements. That has driven demand for high margin technology products such as SLB’s FIT Technologies, which specializes in lab analysis of rock and fluids.

Importantly, oil and gas operators themselves seem to be expecting pricing increases, which should help oil-field service firms pass them through. In a survey published in July, oil and gas operators surveyed by oil and gas research and consulting firm Kimberlite expected pricing for drilling equipment and services to increase by an average of 15.9% globally in the following 12 months. Remarkably, Halliburton Chief Executive

Jeff Miller

said on Tuesday’s earnings call that pricing hasn’t yet recovered to prepandemic levels.

And while oil-field service firms themselves are stepping up capital expenditures, they are doing so mostly to replace old equipment with newer, lower-emissions fleets. Liberty’s Mr. Wright said that service providers will be spending their stepped-up capital expenditure budgets on building out newer fleets at a rate that is enough to offset aging legacy equipment. 

After sharply underperforming a basket of oil and gas producers last year, oil-field service stocks finally are getting recognized. SLB’s shares are up 74% year to date, while Halliburton is up about 50%. Both companies’ enterprise value as a multiple of respective forward earnings before interest, taxes depreciation and amortization have recovered to prepandemic levels. 

Investors, too, are starting to pay up for oil-field service firms’ pricing power.

Write to Jinjoo Lee at jinjoo.lee@wsj.com