South Pars/North Dome Gas-Condensate field
Based on Wikipedia: South Pars/North Dome Gas-Condensate field
Deep beneath the waters of the Persian Gulf lies a hydrocarbon formation so vast that it nearly equals the combined reserves of every other gas field on Earth. This is the South Pars/North Dome field—a geological colossus that straddles the border between Iran and Qatar, representing one of the most consequential natural resources ever discovered. It is, according to the International Energy Agency, the world's largest gas field.
The sheer scale defies intuition. The field encompasses 9,700 square kilometres of seabed—3,700 square kilometres in Iranian territorial waters (South Pars) and 6,000 square kilometres in Qatari territory (North Dome). Beneath this relatively shallow water (65 metres deep) lies an estimated 1,800 trillion cubic feet of natural gas in-place, equivalent to roughly 360 billion barrels of oil. To grasp what this means, consider that the recoverable reserves—about 1,260 trillion cubic feet—represent roughly 19% of all recoverable gas on Earth.
Yet for all its geological immensity, South Pars has become a theatre of geopolitical tension. On 18 March 2026, before the Iran war erupted later that year, Israeli Air Forces attacked sections of the field. Initial reports revealed the damage constituted nearly 12 percent of Iran's total gas production. Two refineries with combined capacity of 100 million cubic metres per day were halted; multiple phases were shut down to contain the fire. United States officials denied coordination or approval of the strike—but oil prices jumped from $103 to $108 per barrel, and European gas prices rose 7% amid fears of Iranian retaliation against Gulf energy infrastructure.
This attack underscored a strange paradox: despite sharing Earth's largest gas reservoir, Iran and Qatar have extracted it with wildly different efficiency. Qatar's Qatari side currently produces roughly 18.5 billion cubic feet daily—accounting for approximately 80% of government revenues—while Iran's southern section yields only about 2 billion cubic feet per day. The disparity stems not from the geology but from history, sanctions, and management. Iranian inefficiency has caused gas to migrate toward Qatari waters, where pressure has been better maintained.
The field's geological architecture is remarkably layered, a detail that makes its exploitation both challenging and promising. The reservoir consists of four independent formations—K1 through K4—each separated by impermeable anhydrite barriers. K1 and K3 are primarily dolomites and anhydrites; K2 and K4, the major gas-bearing layers, comprise limestone and dolomite. A massive formation called the Nar member separates K4 from underlying K5 units of poor reservoir quality.
The gross pay zone extends approximately 450 metres thick in South Pars, narrowing to roughly 385 metres in North Dome, spanning depths between 2,750 and 3,200 metres. These strata dip gently northeastward—a gentle geometry that has shaped extraction strategies for decades. As in neighbouring reservoirs across the Qatar Arch structural feature, this field is cut by NNW-SSE trending faults, a pattern inherited from the Zagros fold and thrust belt that bounds it to the north and northeast.
The Kangan-Dalan formations—Permian-Triassic stratigraphic units—constitute the primary gas-bearing sequences. These carbonate-evaporite series, known regionally as the Khuff Formation, have proven extraordinarily prolific. The field yields approximately 40 barrels of condensate for every million cubic feet of gas extracted—a ratio that reflects its richness in liquids.
Well productivity tells another story. Average production at South Pars/North Dome stands at 100 million cubic feet per day per well—extraordinary by any standard. Compare this to Iran's average well productivity, which hovers at merely 1.5 million cubic metres per day: an order of magnitude lower. The Qatari side has long protected its reserves from over-development; in early 2005, QatarEnergy grew concerned that North Dome was being depleted too rapidly, potentially damaging long-term production potential. A moratorium on new development followed—a pause that raised questions about the actual proven reserves on the Qatari side.
The numbers are staggering for both nations. Iran's section holds approximately 500 trillion cubic feet in-place—360 trillion cubic feet recoverable—which constitutes roughly 36% of Iran's total proven gas reserves and only 5.6% of the world's proven supply. The Qatari side contains an estimated 900 trillion cubic feet of recoverable gas, nearly 99% of Qatar's total proven reserves and 14% of global reserves.
Condensate tells a similar tale: Iranian holdings contain roughly 9 billion barrels recoverable; Qatari sides hold at least 10 billion barrels. Altogether, the field represents what the IEA called in 2008 "the world's biggest conventional hydrocarbon accumulation"—a definition that has held true for nearly two decades.
Yet the March 2026 attack changed everything. Iran halted gas flows to Iraq—a nation dependent on Tehran for between a third and 40% of its power needs. Firefighting operations continue at the field; casualties were not immediately reported, though production losses proved significant. In the aftermath, the world watched as one of Earth's greatest natural treasures became a flashpoint in regional conflict.
The South Pars/North Dome field is not merely a hole in the ground. It is a testament to geological fortune—and a reminder that even nature's grandest gifts can become contested ground.