The last thing the global oil industry needs now is more supply. The negotiations concluded this month between the Islamic Republic of Iran and the P5+1 countries (China, France, Russia, U.K. and the U.S., plus Germany) were a victory for global nuclear nonproliferation, but have been billed as yet more bad news for oil companies worldwide.

Once an agreement had been reached in Lausanne, where the talks were taking place, news quickly spread that the EIA estimated that oil prices could fall a further $15 per barrel next year if sanctions were lifted. Oil executives envisioned horrifying sub-$40 prices going into 2016. But events are unlikely to unfold so dramatically.

Obstacles dampen the enthusiasm

In 2013, Iran produced an average of 3.5 million barrels per day (bpd), down from pre-2012 levels of 4.3 million bpd. In June 2013, oil exports dipped to a low of 700,000 bpd as Asian customers dropped their orders — a third of previous export levels.

The National Iranian Oil Company (NIOC) has high ambitions and wants to raise output to 5.7 million bpd by 2018, but analysts have calmed the markets by highlighting a series of obstacles preventing a quick return to the presanctions level of output.

Firstly, the Lausanne agreement is only a "framework deal," meaning the parties have until June 30 to hammer out the details. Provocative moves by Russia to begin exporting arms to Iran has already threatened the unity of the P5+1 side of the deal.

Even then, implementation of the deal will take time and will need to allow for compliance checks on Iran's nuclear facilities and the unraveling of layer after layer of sanctions by both the U.S. and European Union.

Hopes will also rest on which measures are lifted. If sanctions targeted at Iran's nuclear program are lifted, U.S. companies in particular will still have to face other pre-existing sanctions relating to human rights abuses and other issues.

Prospective investors should not get ahead of themselves. Lausanne is a first step and not yet likely to provoke industry watcher Steve LeVine's projected "stampede" of oil majors back into the country.

It may not be long until we see a spike in exports. Iran has a reported 30 million barrels sitting in floating storage on supertankers in the Gulf, the release of which onto the market could see an uptick in the short term.

But serious infrastructural investment will be needed for more sustainable export growth and, after years of sanctions, Iran's oil and gas infrastructure is in poor shape. Reversing production decline at older reservoirs will require capital-heavy investment, and most analysts are predicting little significant and sustained change in export volumes before 2016.

Secondly, much will depend on the conditions offered to the international oil companies who might be able to provide that capital. When Iran's investment regime was loosened up in the 1990s investors were offered "buy-back" contracts.

These "buy-backs" were in fact a hybrid between production-sharing agreements (PSAs) and Iraq-style service contracts but closer to the latter, whereby the government pays the contractor an agreed price for volumes produced and the contractor searches for oil at its own risk and expense. This contractual mechanism is unpopular with foreign investors, who are left shouldering all of the risk.

While there is no thought of going back to the pre-1979 days when concessions were handed out to BP and other oil majors by the Shah, it is doubtful whether Iran will introduce more investor-friendly PSAs that some hope for due to constitutional restrictions. There is likely, however, to be a good degree of flexibility introduced. Iran is well aware of the lack of interest in buy-back contracts and has tinkered with the model in the past.

Iran will have its work cut out to lure back investors, as the country is not the only game in oil and gas. The global oil market is oversupplied, and oil majors have scaled back investments while they look out for a price rebound. As I have discussed in the past, despite optimism over the nuclear deal, Iran still implies high political risk for most international investors, and oil companies may want to test the water before they dive in.

The race for contracts

BP has a long and often controversial history in Iran and is an obvious contender for a return. But the British company is not in the best financial shape to be entering into large-scale projects. Total and Eni too have a recent history in Iran and are also seen as likely to return. U.S. majors ExxonMobil and ConocoPhillips also make Oil Minister Bijan Zanganeh's investor wishlist.

But Europe and the U.S. are not the only players eager to reboot economic ties. Russia seems to be ahead of the pack in announcing an oil-for-goods deal with Iran, under the terms of which Russia would sell arms, wheat and other products to Iran in exchange for up to 500,000 barrels per day of Iranian oil.

Zanganeh also made his first visit to Beijing just a week after the framework deal was signed, and China is Iran's biggest oil client and trade partner. China is still the hungry end of the hydrocarbons market, despite its slowdown, and CNPC and Sinopec already work in Iran's Khuzestan province. CNPC subsidiaries are also interested in part-financing the Iran-Pakistan "peace pipeline", which has been delayed due to U.S. dissent.

Iran's oil and gas resources are vast and relatively cheap to produce, and its re-entry onto the scene will mean big changes in an already oversupplied market. If Iran is finally able to participate in the strategic, Azerbaijan-led, Southern Gas Corridor project to bring non-Russian gas supplies to Europe, gas transport networks may also transform.

However, it may be some months if not years until the stampede arrives.