Sabotage and theft
Both theft and sabotage were increasingly problematic last year in Nigeria, where supermajors such as BP and Shell have significant interests.
Shell in particular suffered heavy pipeline outages in the country, which it attributed largely to stealing and deliberate destruction. As a result, its third quarter volumes were down 65,000 bpd on the year.
"We are facing headwinds from weak industry refining margins, and the security situation in Nigeria, which continue to erode the near-term outlook," Shell CEO Peter Voser said when the company's quarterly results were published in October.
(View more: Shell troubles are not new: Analyst)
The extremely unequal distribution of oil wealth in Nigeria has led to the industry being the target of anger, protest and sabotage. Meanwhile, a sophisticated industry has built up around stolen oil.
Roderick Bruce, an energy analyst at research firm IHS, said neither problem was likely to improve in 2014.
"2013 was a particularly bad year for security and instability in Nigeria and as far as I've heard from the oil companies themselves, they don't see it improving any time soon… the security situation is so bad they lose a lot of money due to pipeline outages," Bruce told CNBC.
Main warned that oil companies could face similar difficulties as they moved into other African countries.
"Sabotage happens in other African countries like Angola and Sudan — It's a function of political troubles," Main said.
(Read more: Africa now paying a 'democratic dividend')
Andy Lipow of Lipow Oil Associates said that crude oil theft had also been reported in Mexico, where the state-owned oil company Pemex had faced losses.
"I do not recall crude oil theft reports in other countries, but it is quite likely that they occur to some degree, especially if there is a lack of security," Lipow told CNBC.