The score was tied after the first two big exploration and production companies reported their quarterly results on Thursday. Indeed, somewhat amazingly, both Big Oil member ConocoPhillips (NYSE:COP), the third-largest U.S.-based oil company and independent Occidental Petroleum (NYSE:OXY) which ranks fourth, each saw their profits decline by an identical 80% year over year, as crude prices plummeted from their earlier 2008 levels.

Conoco generated earnings of $840 million, or $0.56 per share, for the quarter, versus $4.14 billion, or $2.62 a share, in the first quarter a year ago. Backing out one-time items, the per-share figure was $0.52 a share. That was a whole 10 cents higher than the consensus number that had been anticipated by the analysts who follow the company.

But with crude prices plunging from their year-ago upward spiral, the company's upstream (exploration and production) unit brought in just $700 million in earnings, compared to $2.9 billion in the first quarter of 2008. Nevertheless, despite the price slide, the company managed a nearly 8% improvement in its average upstream production during the quarter.

In the downstream portion of its operations, Conoco, of which Warren Buffett is the largest shareholder, saw its profits slip 61% from a year ago. The company attributed part of the decline to planned facilities maintenance that cut its average refinery utilization to 80%, down 10% from last year’s period.

California-based Occidental generated net income of $368 million, or $0.45 per diluted share, down substantially from last year's $1.85 billion, or $2.22 a share. Nevertheless, like Conoco, the company managed a nearly 8% hike in its oil-equivalent production from a year ago.

But, as will clearly be the case with all exploration and production companies for the March quarter, reduced commodities prices pushed upstream core earnings significantly lower, to $553 million. And while Oxy doesn't operate a downstream segment, earnings from its chemical unit declined to $169 million, from $179 million in the year-ago period.

So all in all, there was surprisingly little difference between the results of ConocoPhillips and the smaller Occidental. Beyond that, I'd anticipate similar directional effects next week when the two largest U.S. oil companies, ExxonMobil (NYSE:XOM) and Chevron (NYSE:CVX) report. Ditto for European companies BP (NYSE:BP) and Shell (NYSE:RDS-A).

Nevertheless, because I expect crude prices to work themselves slowly higher during the next couple of years, I'd be very careful about ignoring this sector. Indeed, I'd pay special attention to behemoth ExxonMobil and the smaller -- but eminently successful -- Occidental.

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Fool contributor David Lee Smith doesn't own shares in any of the companies mentioned. He does, however, welcome your comments, questions, and kibitzing. The Fool has a disclosure policy.