Sanctions on Iran are because of Southern Pars gas field, not its nuclear program

I started writing these blogs in June 2012. Over the years my focus remained on Iranian nuclear program, which is often termed the main cause of sanctions. However, when I posted my last blog on Leviathan gas field, offshore gas project of Israel, it dawned that the real cause of sanctions on Iran is its Southern Pars gas field, not the nuclear program. I quickly accessed Wikipedia and managed to put together some information.  

Pars field comprising of Southern Pars and North Dome fields is a natural-gas condensate field located in the Persian Gulf. It is by far the world's largest natural gas field, with ownership of the field shared between Iran and Qatar.

According to the International Energy Agency (IEA), the field holds an estimated 1,800 trillion cubic feet (51 trillion cubic metres) of in-situ natural gas and some 50 billion barrels (7.9 billion cubic metres) of natural gas condensates.

On the list of natural gas fields it has almost as much recoverable reserves as all the other fields combined. It has significant geostrategic influence.

This gas field covers an area of 9,700 square kilometres (3,700 sq miles), of which 3,700 square kilometres (1,400 sq mile) (South Pars) is in Iranian territorial waters and 6,000 square kilometres (2,300 sq mile) (North Dome) is in Qatari territorial waters.

The field is 3,000 metres (9,800 feet) below the seabed at a water depth of 65 metres (213 feet), and consists of two independent gas-bearing formations: Kangan (Triassic) and Upper Dalan (Permian). Each formation is divided into two different reservoir layers, separated by impermeable barriers. The field consists of four independent reservoir layers K1, K2, K3, and K4.

According to International Energy Agency (IEA), the combined structure is the world's largest gas field.

In-place volumes are estimated to be around 1,800 trillion cubic feet (51 trillion cubic metres) gas in place and some 50 billion barrels (7.9 billion cubic metres) of natural gas condensate in place. With in place volumes equivalent to 360 billion barrels (57 billion cubic metres) of oil (310 billion boe of gas and 50 billion boe of natural gas condensate) the field is the world's biggest conventional hydrocarbon accumulation.

The field recoverable gas reserve is equivalent to some 215 billion barrels (34.2 billion cubic metres) of oil and it also holds about 16 billion barrels (2.5 billion cubic metres) of recoverable condensate corresponding of about 230 billion barrels (37 billion cubic metres) of oil equivalent recoverable hydrocarbons.

The gas recovery factor of the field is about 70%, corresponding of about 1,260 trillion cubic feet (36×1012 m3) of total recoverable gas reserves which stands for about 19% of world recoverable gas reserves.

The estimates for the Iranian section are 500 trillion cubic feet (14×1012 m3) of natural gas in place and around 360 trillion cubic feet (10×1012 m3) of recoverable gas which stands for 36% of Iran's total proven gas reserves and 5.6% of the world's proven gas reserves.

The estimates for the Qatari section are 900 trillion cubic feet (25×1012 m3) of recoverable gas which stands for almost 99% of Qatar's total proven gas reserves and 14% of the world's proven gas reserves.

Since the field is a common field and the reservoir is highly homogenous, the ultimate recoverable reserves of each country may vary from this technical assessment which only considers the static data and does not include rate of gas migration. Therefore, it is better to say that the ultimate recoverable reserves of each country would be a factor of cumulative gas production by each of them.

The Iranian section also holds 18 billion barrels (2.9 billion cubic metres) of condensate in place of which some 9 billion barrels (1.4 billion cubic metres) are believed to be recoverable, while Qatari section believed to contains some 30 billion barrels (4.8×109 m3) of condensate in place and at least some 10 billion barrels (1.6 billion cubic metres) of recoverable condensate.

The South Pars Field was discovered in 1990 by National Iranian Oil Company (NIOC). The Pars Oil and Gas Company, a subsidiary of NIOC, has jurisdiction over all South Pars-related projects. Field development has been delayed by various problems - technical (i.e., high levels of mercaptans and foul-smelling sulfur compounds), contractual issues and, recently, politics.

Gas production started from the field by commissioning phase 2 in December 2002 to produce 1 billion cubic feet per day (28 million cubic metres per day) of wet gas. Gas is sent to shore via pipeline, and processed at Assaluyeh.

As of December 2010, South pars gas field's production capacity stands at 75 million cubic metres (2.6 billion cubic feet) of natural gas per day. Gas production at South Pars rose by nearly 30% between March 2009 and March 2010. The field's reserves are estimated at 14 trillion cubic metres (490 trillion cubic feet) of natural gas and 18 billion barrels (2.9 billion cubic metres) of natural gas condensates.

NIOC is planning to develop the field in 24 to 30 phases, capable of producing about 25 billion cubic feet (710 million cubic metres) to 30 billion cubic feet (850 million cubic metres) of natural gas per day. Each standard phase is defined for daily production of 1 billion cubic feet (28 million cubic metres) of natural gas, 40,000 barrels (6,400 m3) of condensate, 1500 tons of liquefied petroleum gas (LPG) and 200 tons of sulfur.

However some phases have some different production plans. Each of the phases is estimated to have an average capital spend of around US$1.5 billion, and most will be led by foreign oil firms working in partnership with local companies.