Occidental Petroleum Corp. said Thursday its quarterly production was boosted by Texas shale, but income was down for the third quarter.

Occidental, known commonly by its ticker symbol Oxy, said reported income for the third quarter was $1.2 billion, compared with $1.6 billion for third quarter 2013. The company blamed the decline in part on the drop in oil prices since the second quarter.

In terms of production, the company said output increased 20,000 barrels per day year-on-year.

"For the fifth consecutive quarter, we have delivered strong year-over-year domestic oil production growth, bolstered by strong results from Permian [shale] resources, which grew by over 26 percent," President and Chief Executive Officer Stephen Chazen said in a statement.

Aggregate production from the Permian basin increased 58 percent from 2007 to reach 1.35 million bpd last year, which represents 18 percent of total U.S. crude oil production.

Oxy subsidiary California Resources Corp. said Wednesday oil prices were in part responsible for the 20 percent decline in net income from third quarter 2013. It posted a record, however, with 100,000 bpd during the latest quarter.