We don’t see many earnings windfalls like this. When EOG Resources (NYSE: EOG) reported first-quarter operating earnings of $1.80 a share last week, it beat analysts’ consensus estimate by 62 cents, and 52 percent.

And there was no gimmick involved, unless you want to count as the gimmick the skill of drilling surprisingly prolific oil wells and dramatically lower costs in the continent’s most lucrative new play. That would be the Eagle Ford Shale formation in South Texas, which was primarily responsible for the 33 percent year-over-year jump in production, the 28 percent cash flow surge and faster than expected declines in drilling costs, which will permit EOG to throw more resources into south Texas without exceeding is annual capital spending plans.

Positive free cash flow is in sight, and the future looks bright thanks to newly drilled Eagle Ford Wells the CEO described as “monster.” “The rate of change from this asset is not slowing,” he said. EOG’s adjusted annualized rate of return in the formation exceeded 100 percent during the most recent quarter, nice work if you can get it.

All in all, there’s a lot more price appreciation to come and we feel good about boosting the maximum buy point to $145 in mid-March, and sticking with it when the stock fell to $115 a month later.

The combination of booming domestic production growth from the most profitable and advantageously located US tight oil play could make EOG a takeover target sooner than later. The stock remains a Growth Portfolio Best Buy below $145, and we’ll review that target promptly if the stock gets there shortly, as it may.