There hasn't been a lot for Ensco's (VAL) shareholders to cheer about in the past year. The stock is down 56%, and the dividend was recently slashed 80% to $0.15 per share. Plunging oil prices have left the offshore drilling industry in a standstill, and no one knows exactly when demand will pick up again.

While the market focuses on the downside of offshore drilling, here are the three best reasons to own Ensco's stock over the long term.

Image source: Seadrill.

A better balance sheet than most
The biggest near term danger for offshore drilling companies is that they'll run out of funding for operations. If credit markets freeze up and they don't have balance sheets that can withstand the hit, they could go under very quickly. On that front, Ensco is fairly well positioned.  

At the end of the fourth quarter, Ensco had $5.9 billion in debt and $1.4 billion in cash and short-term investments. That's not bad when compared to a balance sheet like Seadrill's (SDRL), which includes $13.0 billion in debt and $1.5 billion in cash an short-term investments, or Transocean's (RIG 2.15%) $10.1 billion in debt and $2.6 billion in cash.  

A good balance sheet will only last so long if operations suffer, but it'll ease the blow while the industry adjusts to new realities in offshore drilling.

Ensco is still profitable... for now
The offshore drilling market may not look good in the future, but for now Ensco remains highly profitable. After pulling out the $3.5 billion loss on impairment, fourth-quarter operating income was $478.1 million and full year operating income was $1.82 billion. Cash from operations last year was $2.06 billion.

Those profits and cash flows may not continue if oil prices stay low for the next year or two, but they show that there's a cushion to accept lower dayrates to keep rigs operational. If offshore drilling markets improve, operations could continue to be highly profitable, and the upside for investors could be 100% or more.

Diverse customer base
The final reason to like Ensco is its very diverse customer base. From the U.S. to Asia and small independents to national oil companies, Ensco isn't overly exposed to any particular market. You can see below that its diversification couldn't get much better.  

Image source: Ensco Q4 earnings presentation.

One of the key customers on this chart is national oil companies. Saudi Aramco has leased 8 jack-up rigs with contracts that end between June 2016 and March 2019. It has a particularly long view on oil production, and is unlikely to cut capital spending plans just because oil prices are depressed.

Reliance on one segment of the offshore market, whether it's geographical or water depth, is a risk, and Ensco has lowered that risk for investors.

I don't think the risk/reward profile of Ensco makes the stock a buy today compared to a stock like Seadrill, but these are the positives investors have to point to. The bottom line is that no matter what offshore companies do, they're dependent on rising oil prices for future earnings. If oil doesn't rise, they're all in serious trouble.