The other week we talked about how everyone hates natural gas, with "everyone" referring to oil and gas independents like Denbury Resources (NYSE: DNR) and SandRidge Energy (NYSE: SD). Those companies have been involved in recent deals that shift each firm's asset profile in favor of oil and away from gas. Meanwhile, firms like Carrizo Oil & Gas and Goodrich Petroleum are joining the stampede into the liquids-rich Eagle Ford shale play in South Texas.

Of course, not everyone exhibits such an aversion to the cleaner-burning hydrocarbon. Big Oil, for one, seems pretty gas-happy these days.

One of the most obvious domestic moves of this sort is ExxonMobil's (NYSE: XOM) proposed takeout of XTO Energy. But there's also StatoilHydro's (NYSE: STO) global search for new shale plays with partner Chesapeake Energy (NYSE: CHK), and the advancement of new Australian LNG projects by folks like ConocoPhillips and Chevron (NYSE: CVX).

A recent Bloomberg story tied the oil majors' recent tilt toward gas to the issue of access. That's a huge one. While firms like Exxon and BP (NYSE: BP) punch above their weight in terms of global production, national oil companies (NOCs) like Saudi Aramco totally dominate when it comes to proved reserves. Countries around the world have thrown up tough entry barriers over the past few decades. Just last week, Gabon announced that it plans to establish an NOC by the end of the year. To see what kind of headache these NOCs can create for the majors, see ExxonMobil's recent struggle to acquire Kosmos Energy's stake in a major Ghana oilfield.

This matter of resource access is joined at the hip with the issue of reserve replacement. This is perhaps the majors' and supermajors' biggest challenge today: replacing what is produced, year after year.

Smaller E&Ps have no trouble posting eye-popping reserve replacement ratios each year. Their biggest concern today is low gas prices, which impact independents' operations to a much greater extent than those of the well-financed majors. For the latter group, temporarily depressed gas prices are quite tolerable, especially given the opportunity to top up reserves with gas from North America, Australia, and other friendly jurisdictions. The majors can also more comfortably look to the long-term outlook for natural gas demand, which is stellar.

Chesapeake Energy is a Motley Fool Inside Value recommendation. Statoil ASA is a Motley Fool Income Investor pick. The Fool owns shares of Chesapeake Energy, Denbury Resources, and XTO Energy. Try any of our Foolish newsletters today, free for 30 days.

Fool contributor Toby Shute doesn't have a position in any company mentioned. Check out his CAPS profile or follow his articles using Twitter or RSS. The Motley Fool has a disclosure policy.