ConocoPhillips' (NYSE:COP) stock has hit a rough patch since this summer. The stock had been down as much as 22% off its recent high before cutting some of those losses.

COP Chart

COP data by YCharts

Still, the stock is down more than 15% of its most recent high as the sell-off in oil has really hurt the stock. While there is reason to be optimistic that ConocoPhillips' stock could head higher even with lower oil prices, investors need to realize that the stock could still have more downside. Here are three risks in particular that could cause ConocoPhillips' stock to resume its descent.

Oil prices keep plunging

Like all oil companies, ConocoPhillips' stock price is closely tied to the rise and fall of the price of oil. As we look out over the past decade the company's stock price has followed the price of oil rather closely.

COP Chart

COP data by YCharts

Because of this we can almost guarantee that if oil prices keep falling it will take ConocoPhillips' stock down as well. This is despite the fact that ConocoPhillips produces very low cost oil and is focused on growing its highest margin production. The market doesn't see these things, it sees oil falling and sells off all oil stocks, despite the fact that some oil companies are less reliant on oil prices to make money.

More dry holes

Even if oil prices don't fall there are other risks that could take down ConocoPhillips' stock price. One area that could have a big impact on the company's stock price is a failure in the company's exploration efforts to find future sources of oil. We saw a warning sign here in the third-quarter when the company announced that its Coronado prospect in the Gulf of Mexico didn't live up to its initial enthusiasm. Because of that the company was forced to expense the initial wildcat well as a dry hole. The worry here is that Shenandoah might turn out to be a dry hole too, because of its close proximity to Coronado as noted on the map below.

Source: ConocoPhillips Investor Presentation.

As that slide also noted, Coronado first appeared to be a pretty decent find as the company and its partners encountered 400 feet of net pay, which is the area of rock that contains hydrocarbons. ConocoPhillips, and its partners, encountered more than twice the net pay at Shenandoah, so if it too turns out to be an uncommercial well it could send the stock lower as investors will call into question the company's future in the Gulf of Mexico.

In addition to the Gulf, ConocoPhillips is drilling exploration wells offshore Angola and Senegal. While the company did recently find oil in Senegal, there is always a risk that the initial discovery could turn out to be a dud. Likewise, there's a risk in Angola, where the company just recently drilled a dry hole. A couple more of these in a row could cause investors to begin to lose faith in the company's exploration program and start to sell off the stock.

Major project start-up issues

The final area of risk is the fact that ConocoPhillips is right in the middle of starting up several major projects. These project start-ups don't always go smoothly and could impact results. For example, ConocoPhillips had expected to sell ramp gas to a third-party LNG project next quarter as part of the start-up of APLNG, but that's no longer going to happen. Further, the company is expecting a delay in the full ramp up of its KBB project in Malaysia do to third-party pipeline issues. Because of this the company's guidance for next quarter is lower than it originally expected, though it's still within the guidance range.

Source: ConocoPhillips

Looking ahead to 2015, the company has several major projects starting including Eldfisk II in the North Sea, APLNG and two start-ups in the Canadian oil sands. A start-up delay at one or more of these projects could impact the company's ability to meet its projections, which could send the stock lower.

Investor takeaway

While we're not expecting to see ConocoPhillips' stock keep falling, there are always risks that could impact the stock price. The top three right now are falling oil prices, exploration issues, and major project start-up problems. If any of these risks do impact the stock, investors will need to consider if this is just a temporary setback or part of a longer-term issue. As long as the issue is short-term a falling stock price could actually be a buying opportunity for long-term investors in ConocoPhillips' stock.