Water Coning and the Aussie Cone of Silence: What Just Stop Oil Won’t Tell You

As Iran’s oil storage fills to capacity under the American naval blockade of the Strait of Hormuz, a term from petroleum engineering has suddenly acquired geopolitical weight: water coning.

Water coning describes what happens when an oil well is pumped too aggressively, or — critically — when it is shut in and then restarted. The boundary between oil and the denser water beneath it warps upward, forming a cone that invades the wellbore. The well chokes on water. Production collapses. If the operator is unlucky, the reservoir is permanently damaged.

Iran now faces exactly this lose-lose. Kpler and JPMorgan analysts estimated in late April that Tehran had between 12 and 22 days of unused storage capacity remaining. Storage at Kharg Island — through which the bulk of Iran’s exports normally pass — was at 74 per cent capacity by April 20. When tanks fill, wells must be shut in. And Iran’s ageing Khuzestan fields, many producing since the 1960s, are precisely the kind of mature, high-water-cut reservoirs most vulnerable to water intrusion during prolonged shutdowns. The Columbia Center on Global Energy Policy judged that Iran’s oil sector can likely weather shut-ins overall, but acknowledged that water coning remains a particular risk in marginal wells with high water-cuts, low reservoir pressure, or ageing infrastructure — a description that fits a non-trivial share of Khuzestan’s legacy operations.

Tehran insists it has the expertise to manage orderly shutdowns, honed through decades of sanctions. Perhaps. But the physics is unforgiving: when production halts, formation water migrates into oil-bearing zones, and when it does, the damage can become entrenched. Wells that restart after prolonged shut-ins often produce far more water and far less oil — permanently. Iran’s dilemma is not political theatre. It is reservoir mechanics imposing itself on geopolitics in real time.

The Cone of Silence

One might expect the environmental left — Extinction Rebellion Australia, the Teal independents, the activist wing of the Greens — to find this instructive. Here, after all, is a real, quantifiable mechanism through which both reckless extraction and forced shutdown destroy value and generate contaminated produced water. Water coning does not care whether the damage is inflicted by an aggressive operator or a naval blockade. The physics is symmetrical.

Yet Australia’s climate movement has never mentioned it. Not once. And that silence reveals something important about the movement’s intellectual architecture.

The demand is always binary: stop coal, stop gas, stop Woodside’s Scarborough development, stop Santos’s Barossa pipeline. Not “manage extraction more prudently.” Not “understand what happens to a reservoir when you shut it in.” Just stop. The framing is a moral claim, not a technical one, and it is deliberately constructed to resist engagement with the granular realities of reservoir engineering, energy economics, or the fact that Australia remains one of the world’s three largest exporters of liquefied natural gas — an industry that earned over A$92 billion in export revenue in 2022–23 alone.

Credit Where It Is Due

To be fair, Australia’s climate movement has achieved something that decades of sober policy advocacy did not. The Safeguard Mechanism reforms of 2023, imperfect as they are, owe something to the relentless pressure that shifted the Overton window on emissions regulation. The Teals’ breakthrough in 2022 made climate an electoral liability in seats that had been comfortably Liberal for generations. That deserves acknowledgement. But not one of those successful campaigns required its advocates to understand what is happening right now beneath Kharg Island — and that is precisely the problem. Influence over the terms of debate is not the same as influence over outcomes. And it is on outcomes — measurable, physical, environmental outcomes — that the movement’s wilful technical illiteracy exacts its cost.

The Produced Water Blind Spot

Produced water is the largest waste stream in the oil and gas industry by volume. Globally, an estimated three barrels of water are brought to the surface for every barrel of oil, and in mature fields the ratio can exceed ten to one. In Australia, the coal seam gas operations of the Surat and Bowen Basins in Queensland generate enormous volumes of co-produced water, much of it saline, posing ongoing risks to the Great Artesian Basin. A 2025 report by Queensland’s Office of Groundwater Impact Assessment confirmed that pressure impacts from coal seam gas development had begun to emerge in key aquifers.

Iran’s predicament illustrates the same problem from the opposite direction. Activists who demand that wells be shut assume the process is as simple as turning off a tap. It is not. Shutting a well disrupts pressure equilibria, allows water to migrate into oil-bearing zones, causes scaling and corrosion, and can render marginal wells permanently uneconomic. The lose-lose is structural: pump too hard and you accelerate water coning from below; shut in too abruptly and you invite water intrusion from the flanks. Either way, the reservoir pays.

A movement serious about environmental outcomes would be engaging with this complexity — campaigning for stringent produced water regulation, mandatory recycling standards, and research into the reservoir management techniques that minimise damage whether a field is producing or shutting down. Lock the Gate, to its credit, has engaged with groundwater contamination in Queensland’s gas fields at a level of specificity that most urban climate groups never attempt. But that requires accepting that the question is not simply whether to extract, but how — and how to stop. That nuance is ideologically impermissible.

The same pattern recurs with routine gas flaring. The World Bank estimates that around 150 billion cubic metres of natural gas are flared annually — enough to power the whole of sub-Saharan Africa — while releasing unburnt methane with a greenhouse warming potential more than eighty times that of carbon dioxide over twenty years. Yet flaring generates no harbour bridge banners, no gallery protests, no headlines. It is too operational, too unglamorous to fit the narrative.

The Real Option

There is a more productive framing available. In financial economics, a real option is the right but not the obligation to undertake a future action — to expand, defer, or abandon a project as new information arrives. Australia’s energy transition is, properly understood, a portfolio of real options. Some wells should be shut in — but intelligently, with reservoir management plans that minimise water intrusion. Others should be managed more carefully. New technologies — carbon capture at Gorgon (whose chronic underperformance is itself a cautionary tale), enhanced geothermal in the Cooper Basin, small modular reactors now finally entering the political conversation — should be funded as call options on a lower-carbon future.

Iran is learning in real time what happens when shut-in is imposed by geopolitics rather than chosen through engineering. The water cone does not negotiate. It does not read slogans. It rises.

Australia’s climate activists might begin by understanding what they propose to stop — and what it costs, physically, when stopping is done badly.