Tehran’s challenge is no longer simply one of sanctions. Iran's oil and gas sector faces a combination of structural, technical, financial and geopolitical obstacles that cannot be quickly resolved, even if the agreement ultimately leads to a broader settlement with the United States.

The reality is that Iran's energy sector is no longer constrained primarily by its ability to sell oil. Its greater challenges lie in sustaining production, attracting investment, accessing advanced technology and reconnecting to the global financial system.

Aging infrastructure, declining capacity

Much of Iran's oil and gas infrastructure has reached the latter half of its operational life. Years of underinvestment, limited access to modern technology and the departure of major international energy companies have left many fields grappling with increasingly complex technical problems.

The challenge extends far beyond the natural decline of mature fields. Veteran figures within Iran's energy industry have repeatedly warned about reservoir degradation, declining pressure, scaling, well damage and the growing difficulty of maintaining stable production.

Former oil executives and industry specialists say a significant share of the sector's efforts is now devoted to managing technical problems that require equipment and expertise not readily available inside the country.

Nowhere is this more evident than in South Pars, the giant gas field that underpins Iran's energy security. Natural pressure decline began years ago, and reversing it will require tens of billions of dollars in investment, advanced offshore infrastructure and the participation of companies that are predominantly based in the West.

Even if political barriers disappeared tomorrow, the planning, engineering and construction required for such projects would take years—time an economy struggling with inflation, budget deficits and capital shortages can ill afford.

World not waiting for Iranian Oil

Many discussions about Iran's future still view today's energy market through the lens of a decade ago.

Before sanctions tightened, a significant portion of the global market relied on Iranian crude. The world of 2026 looks very different.

The United States has become one of the world's largest energy producers and exporters. Canada, Brazil and Guyana have expanded output dramatically.

Qatar and the United States have transformed the global LNG market, while major consumers have spent years diversifying supply chains and reducing dependence on any single producer.

Many customers that found alternative suppliers during years of sanctions are unlikely to return simply because restrictions are eased. Re-entering global markets requires not only competitive pricing but confidence in Iran's long-term reliability as a supplier.

The banking problem

Even if Washington permits the return of major energy companies to Iran, another obstacle remains: the international financial system.

The experience of the 2015 nuclear deal demonstrated that political agreements do not automatically translate into investment flows. Despite official support from Western governments, many major banks remained unwilling to accept the risks associated with doing business in Iran.

Crucially, the Islamic Republic is currently on the FATF blacklist, and the process of exiting this list entails a time-consuming verification period. Iran's failure to meet FATF standards, concerns over financial transparency, money-laundering risks and the extensive role of military-linked institutions in the economy continue to discourage foreign investors.

For many global financial institutions, both credit risk and reputational risk associated with Iran remain exceptionally high.

Russia is not a substitute

In the absence of Western companies, Tehran has repeatedly looked to Russia as an alternative partner.

Yet the experience of the past two decades suggests Moscow has shown limited interest in helping Iran re-emerge as a major competitor in global energy markets.

Even Russian firms with significant technical capabilities have, at various points, slowed, suspended or withdrawn from Iranian projects.

Russia's interests do not necessarily align with a full-scale revival of Iran's energy sector.

As a major energy exporter itself, Moscow has strong incentives to preserve its own position in global markets rather than facilitate the rise of another competitor.

Regional stability

There is another actor in this equation that often receives less attention than it deserves: the Persian Gulf states.

Iran’s Arab neighbors are undertaking some of the largest investment programs in their history. Infrastructure, artificial intelligence, logistics, technology and tourism have become central pillars of their economic strategies.

From their perspective, the overriding concern is not ideology but stability.

Rising geopolitical tensions have already increased insurance costs, raised financing expenses and complicated long-term investment planning across the region.

As a result, many in the region have concluded that even a successful Tehran-Washington agreement may not, by itself, provide the level of certainty required for the massive investments envisioned under their long-term development plans.

Taken all that together, one can argue that Iran’s oil economy faces far more than a sanctions problem.

Even if the newly signed memorandum evolves into a broader deal, rebuilding Iran's lost energy capacity will require years of work, tens of billions of dollars in investment and the restoration of confidence among international investors and financial institutions.

The agreement signed this week may ease some short-term pressures and improve economic sentiment. But on its own, it is unlikely to reverse the long-term erosion confronting Iran's oil and gas sector.