The US multinational oil operator Chevron announced on Friday a $6.6bn drop in revenues in the fourth quarter of 2019, driven by $10.4bn in upstream impairments and write-offs related to its shale gas production, primarily in Appalachia and deep-water projects in the Gulf of Mexico.

The company earned $1.49 per share excluding items for the quarter, a decrease from $1.95 per share a year earlier. The company’s full-year earnings reached $6.27 per share for 2019, down from $8.07bn in 2018.

Chevron shares dropped by 3.85% on Friday after the company reported $36.35bn of revenue for the period, a 14% decline year-over-year, influenced by a dramatic decline in earnings from its upstream division. The company’s total earnings for 2019 fell 80% to $2.924bn, compared to $14.824bn in 2018.

Sales and other operating revenues in Q4 2019 were $35bn, compared to $40bn in the same quarter in 2018.

Chevron chairman and CEO Michael Wirth said: “Cash flow from operations remained strong in 2019, allowing the company to deliver on all our financial priorities.

“We paid $9bn in dividends, repurchased $4bn of shares, funded our capital programme and successfully captured several inorganic investment opportunities, all while reducing debt by more than $7bn,” he added. “Earlier this week, we announced a quarterly dividend increase of $0.10 per share, reinforcing our commitment to growing shareholder returns.”

Oil-equivalent production at 3.08 million barrels per day for Q4 2019 remained the same year over year, although the company said its annual daily production had exceeded three million barrels per day for the first time.

The company’s average sales price per barrel of crude oil and natural gas liquids was $47 in fourth quarter 2019, down from $56 a year earlier.

ExxonMobil has also reported a 5% drop in earnings, which totalled $5.7bn in Q4 2019. Earlier this week, Hess said it had recorded a bigger loss for Q4 2019 compared to the same period a year before.

US West Texas Intermediate crude prices are down more than 15% this month, while international benchmark Brent crude is down by around 12%.