Traditionally, the oilfield service companies' largest player, Schlumberger (NYSE:SLB), kicks off earnings reporting for the group, something that will occur next week on Friday morning.

Along with the company's latest financial and operating results -- which, until recently, tended to surprise on the high side -- I look forward to a detailed discussion of general energy trends from CEO Andrew Gould. Unfortunately, unless I miss my bet, the remarks this time around will be about as negative as they've been in several years.

Of course, crude oil prices sank again last week, and natural gas has fallen sharply, as demand shrinks and supply expands. In addition, Schlumberger and its sidekick Halliburton (NYSE:HAL) have announced layoffs.

But you may not be aware of the full effect that commodity price slides have had on contract drilling activity. In North America as a whole, after peaking near 2,450 in September, the number of total rigs working was down to about 2,350 in November, and early estimates show the figure for December will be down another 250 or so.

And according to Baker Hughes (NYSE:BHI), which has kept a weekly rig count since the 1940s, 1,589 rigs were working in the U.S. last week, a decline of 34 from the previous week. There are those who believe that as many as 1,000 rigs will be taken out of service -- "stacked" is the industry term -- before things turn. Beyond that, at a time when we are rapidly approaching glut status in natural gas, more than 75% of the working U.S. rigs are still trying to find even more.  

None of this is going to benefit the oilfield services sector, either the drilling contractors or the companies like Schlumberger and Weatherford (NYSE:WFT) that help companies find and produce oil and gas. It seems that the hardest-hit stocks in the sector could be the ones that concentrate on drilling on land -- companies like Helmerich & Payne (NYSE:HP) and Nabors Industries (NYSE:NBR).

I'm somewhat less sanguine than some of my peers about when commodities prices will go up. On that basis, I can't warm up to the land drillers, and indeed, the only contractor of any ilk I'd pay careful attention to these days is deepwater king Transocean (NYSE:RIG). Even then, I'd be looking at a longer-than-usual investment time horizon.   

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Fool contributor David Lee Smith doesn't have a financial interest in any of the companies mentioned above. He does, however, welcome your questions or comments. The Fool has a disclosure policy.