The nine oilfields that comprise most of the Eagle Ford produced 471,258 barrels per day of crude in February, according to preliminary data cited by Bloomberg and released by the Texas Railroad Commission, the state regulator.

That compared to a year earlier when the nine fields produced 271,521 bpd, Bloomberg said.

Production figures released by the Commission usually increase after factoring in revised, corrected or late reports.

Output in January jumped to a revised figure of 462,160 bpd after a preliminary Railroad Commission report of 373,303 bpd.

The Eagle Ford has been driving the boom in US oil production over the past few years, as Texas continues to hold the top spot among oil-producing states in the US.

Preliminary state-wide oil production in February was about 1.56 million bpd, according to Commission data. A year earlier, that figure was 1.48 million bpd. In February 2011, Texas produced just 1.03 million bpd.

Total preliminary gas production for February was about 18 billion cubic feet per day, down from a final total of 22.22 Bcfpd in February 2012, according to the Commission.