Historic Offshore Forties Oil Field Reaches 40

Published at 11:08AM - 03/11/15

The mighty North Sea Forties field reaches a milestone today, as it celebrates 40 years since it was inaugurated and its oil flow to the UK mainland officially switched on by Her Majesty the Queen.

The Forties field is commonly known as the oil field that started offshore oil production throughout the North Sea. 

At the time almost every engineering and technological step was a fist, as the biggest field in the North Sea set to break all boundaries in a bid to achieve production.

In the words of former Wood Group CEO, Sir Ian Wood “quite frankly, it was science fiction type engineering developments”

Forties Discovery

Owner and operator of the field, BP, officially announced the find of commercially viable oil on the 7th October 1970, 110 miles (180 km) east northeast of Aberdeen. 

The oil discovery had been made by BP’s own semisubmersible offshore drilling rig, the Sea Quest.

A further four appraisal well were drilled by Sea Quest to help establish the magnitude of the Forties’ reservoir.

Construction & Installation

Over the next five years, BP set about an engineering and construction program that would not only be one of the biggest in UK history, but broke boundaries and laid out a blue print for future development of the entire North Sea

From the engineering and fabrication of the steel jackets and platform topsides, the subsea Forties Pipeline System enabling produce to be pumped 105 miles (170 km) back to shore, to its very own crude oil terminal at Grangemouth refinery.

BP not only had to build equipment to drill and produce oil offshore, but an entire portfolio of infrastructure, that would see the offshore oil process right from discovery through production and refining all the way to consumers at its own roadside fuel stations.

First Production

First oil was produced and pumped down the Forties Pipeline System to shore in September 1975.  On the 3rd November 1975, HM Queen Elizabeth II inaugurated the Forties project, pushing a gold plated button to officially start production at a rate of 10,000 barrels per day.

Over the next year, further wells were brought into production across the four platform Forties field, until 130 wells were in operation, and production peaked at 500,000 thousand barrels of oil per day.

80s Billions Of Barrels

By May of 1982, the Forties Field had hit a production milestone of 1 billion barrels of oil. 

Further investment was allocated throughout the 80s, with a fifth platform, the Forties Echo added to the field in 1986, and the then pioneering Artificial Gas Lift system commissioned in the late 80s.

The Forties Artificial Lift project  (FALP) utilised produced gas to be pumped back down the well in order to aid the flow of oil up the well.  The work commended in 1989, with first gas being introduced to the Forties Alpha and Delta platforms in 1991.

In May of 1989,Forties reached its second production milestone, having produced its second billon barrels of oil.

90s Falling Production

At the time of discovery, BP’s engineers and geologists predicted that the Forties field would have a life expectancy into the early 90s.

By now, the Forties platforms and infrastructure were approaching 20 years of age and the end of their design life.

The subsea Forties Pipeline System had already started to corrode, so by 1991, BP took the decision to install a new, larger 32 inch pipeline, at the cost of GB£1 billion (US$1.5 bn).

Initially the new pipeline to shore enabled production to increase from 630,000 barrels per day to 900,000 barrels per day.

However, as the 90s continued, production from the field was rapidly in decline, falling to 75,000 barrels of oil per day in 1997 and again even lower 66,000 barrels per day in 1999.

Much of the industry was now expecting BP to start to wind up the Forties operations, with a final shutdown in around 2000.

00s BP Sells to Apache

By 2003, production from Forties had fallen to around 45,000 barrels of oil per day, around 855,000 barrels lower that just over ten years previously.

In mid January of 2003, BP made the decision to sell to the entire Forties field and infrastructure to  US based Apache Corporation.

At the time, the deal brought much public and political backlash, as the sale was seen as BP selling off its crown jewels, and the UK loosing the ownership of one of its biggest producing fields.

However BP kept ownership of the Forties Pipeline System, ensuring that they were paid to transport all oil produced at the field to shore.

With other North Sea oil fields utilising the pipeline, it is estimated that today it transports around 30% of all UK North Sea oil to shore.

At the time of sale, BP estimated that the field, having produced over 2.4 billion barrels of oil had around 144 million barrels left in place.

Apache immediately set about undertaking a full seismic reevaluation of the field, which pretty quickly found a further 800 million barrels of oil previously unaccounted for.   

Apache set about a new drilling campaign, drilling 12 new wells in 2004 and upping production to 61,680 barrels per day, from 40,950 barrels during handover from BP.

Foggy Forties Keeps Marching On

Since first taking over from BP, Apache has invested around GB£3 billion (US$4.6 billion) in the Forties field.

Work has involved seismic modelling of the Forties reservoir, drilling new wells and installing a new platform, the FASP, next to the Forties Alpha, giving the field greater power capabilities and production capacity of 25,000 barrels.

Production today continues to be in the regain of a steady 60,000 barrels of oil per day.

In 2012, first oil was produced from the Bucchus field, an oil field that ties back to Forties utilising the fields infrastructure, heightening Forties importance in the North Sea.

Due to the success of the operation, the new Aviat field will be tied back to the Forties in the coming months.

Apache’s investment and work, is expected to see the Forties offshore field continue to produce oil at a commercially viable rate for a further 15 to 20 years, to around the early 2030s, around 60 years total life span and 40 yeas after it was originally expected.