The United States is overflowing with oil. In fact, the Energy Information Administration thinks the country could realistically produce 6 million to 8 million barrels of oil per day over the next three decades. The institution's high estimate exceeds 10 million barrels per day. Canadian production isn't doing too bad, either, although supporting infrastructure is less developed for our northerly neighbors. That bodes well for the companies pumping it out of the ground, but it also represents a big opportunity for the companies transporting and refining crude oil.

Here are four of the best investments supporting oil drillers.

Canadian National Railway (CNI 1.56%)
Canadian National Railway is one company trying to bail-out Canada's ailing pipelines. In 2010 the company didn't move one carload of crude oil. This year it is expected to "choo-choo" its way to 60,000 carloads of oil from the country. This business in particular has boosted sales and income each year since 2010. Investors have to like that growth and where things are headed in the long term. Canadian National is cutting checks totaling $1.9 billion this year to repair its railways, accommodate growth needs, and purchase new freight cars, including new natural-gas powered models.  

Chevron (CVX 1.04%)
Although I believe most of Chevron's growth will come from natural gas assets in Australia and Asia, the company owns more than 500,000 bpd of refining capacity from the two largest refineries in California. That could provide a sleeper growth opportunity if the United States ever chooses to develop the Monterey shale in the central and southern parts of the state. Recent estimates peg the total reserves in the formation as high as 15.4 billion barrels -- twice that of the Bakken. There are serious water and environmental concerns that are lacking solutions at the moment, but the formation would be a big boon to refiners on the West Coast. Aside from potentially lowering gasoline prices for drivers in the region, the influx in cheap oil would certainly attract Asian countries that have fallen over each other to get to Canada's land-locked oil sands. The margins on Monterey exports could be huge, depending on recovery economics and oil quality.  

Kinder Morgan Energy Partners (NYSE: KMP)
The pipeline leader has fallen under the spell of volatility this year, but some of that is inherent to limited partnerships. Kinder Morgan Energy Partners operates 46,000 miles of pipelines and 180 terminals that transport not just crude oil, but also natural gas, refined products, ethanol, biodiesel, and carbon dioxide. It is perhaps the most diverse way to play North America's energy boom, with major operations in Texas, Canada, and California, among other locations. The limited partnership has not only paid a distribution since its market debut in 2003, but has also managed to increase it each year. Investors should feel pretty comfortable getting paid on a regularly basis with this pipeline leader.

Phillips 66 (PSX -0.35%)
The refiner's top and bottom lines have exploded in recent years thanks to America's energy renaissance. Net income in 2012 was 461% higher than in 2010 and 766% higher than during the recession in 2009. That's incredible for a company of such size, but can it continue? Both sales and income slipped compared with 2011, and it seems as if the market is pricing in a continuing trend. The company trades with a P/E below 8 and a dividend yielding more than 2%, both potential steals for investors. Better yet, the profit margin in the first quarter of this year was 143% higher than that from the year ago period. It looks as if Phillips 66 can keep its profit machine going so long as domestic oil prices maintain their advantage on the international market. 

Foolish bottom line
The key takeaway is to remember to include follow-on industries in your investing. What good is drilling for oil if the infrastructure isn't in place to take it from fields to refiners, from refiners to the market? These are just four of the best investments to consider in oil transportation and refining, but the entire industry should benefit from improving development. Do you think another company deserves to be mentioned? Let me know in the comments section below.

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