Insistence Proved ‘Unwanted’ Block a Winner

After World War II – possibly as part of the Marshall Plan – Shell was obliged to give an American company a half interest in the acreage it held in Netherlands.

Shell held most of the country’s acreage, and a jointly owned company was set up with Esso, a forerunner of ExxonMobil, which was the Nederlandse Aardolie Maatschapij – better known as NAM, which operated a few small oilfields in Netherlands.

In 1960 NAM found the giant 100 TCF Groningen gas field, a discovery that helped wean Western Europe from coal.

When offshore acreage became available Shell and Esso decided to continue with the 50/50 joint venture in both the Dutch and UK sectors, with Shell being appointed operator.

Come the UK Third Round of North Sea block offerings, toward the end of 1969, the Shell/Esso partnership had to reach agreement about which blocks to include in their application. We agreed on a dozen or so, including block 211/29 – which, at the last moment, Shell discovered was outside the area designated in the Shell/Esso North Sea agreement.

The agreement had to be hastily amended. That block, in the East Shetland Basin, now contains the Brent Field, the largest oilfield in the UK sector.

Shell also wanted to apply for block 30/16, but our partners were not interested.

One of our seismic interpreters, Bill Wheatley, came to me and urged me to try to get the block restored to our application list. In those days the final decisions were made by the most senior managers involved – who knew little about the local geology. However, my manager – George Williams, also a geologist, who is now 95 and still going strong – managed to persuade the Esso chief in New York to include the block, as long as it was in the lowest category at the bottom of the list.

The prospect Wheatley saw was a huge fault block sealed by a major fault on the west and adjacent to the Kimmeridge oil kitchen down dip to the north and east. (Shell had known about source rocks and maturity well before 1969.) The reservoir was to be the Permian Rotliegend sandstone at the fairly shallow depth of 7,800 feet, and should have been of passable quality.

Anyway, we were allocated Block 30/16, no one else having applied.

To Test or Not To Test

One favorable feature of the block (which did not occur to us at the time) was that it lay far enough south to allow our small semi-submersible rig “Staflo” to drill there during the winter. Many more interesting locations further north had to be ruled out for insurance reasons.

So, in 1971 we came to spud well 30/16-1.

The main Rotliegend objective contained only dead oil, but we had encountered live oil shows while drilling through a thin, unexpected Permian Zechstein carbonate section.

“Not worth testing,” said the petroleum engineers, who then ordered a helicopter to take out the necessary bits for abandonment.

But Rico Kempter, the area geologist responsible, strongly disagreed. He had read about a new Schlumberger tool called “Tricore,” which allegedly would cut triangular slices out of the sides of the hole.

Kempter rang Schlumberger in Aberdeen, Scotland, and found that they had the tool but had never used it.

Anyway, somehow he got it on to the helicopter and we ran it over the Zechstein section. It worked superbly, and the vuggy dolomite samples recovered were streaming live oil!

The well was tested at 5,900 B/D of 37 degrees API oil on a restricted choke, with an extremely high productivity index.The way he was: J. Myles Bowen, an AAPG Pioneer Award recipient, stands in front of the flare at the Nelson Field, a major discovery.

What’s In a Name?

The 30/16-1 was our first commercial discovery, and when we realized that I sat down with George Williams to choose a name.

The southern North Sea gas fields were mostly named after marine features (banks, shoals, deeps, etc.) but there were few such named features in the northern area other than Sea Area Forties, which BP already had appropriated. On the Norwegian side Phillips was using Norwegian fish names, so being a bit of an ornithologist I suggested North Sea birds in alphabetic order – hence, its name became Auk.

We announced our discovery and I received a call from the Texan manager of one of our competitors – obviously not an ornithologist – who asked me “What is this name Auk?”

So I couldn’t resist replying, as a leg-pull, “Field A – UK, of course.”

He then observed that if we were lucky enough to find six fields we might have a problem. I replied that we would be delighted to deal with that when the time came.

We did have a problem with the next discovery, as proper North Sea birds beginning with B were in short supply, so I offered my boss Barnacle (a goose) or Brent (also a goose) – and I guess you know which one he chose.

Auk, originally estimated at some 35 mbbl of recoverable oil, was a bit pathetic compared with BP’s giant Forties discovery, but with Brent, we got back on equal terms. Auk eventually produced some 90 mbbl.

All’s Well That Ends Well

A few years on and once more, for the same reason, we needed a southerly location – and about the only one we had was, surprise-surprise, again in block 30/16, this time a Jurassic prospect down dip from Auk.

There was a reasonably-sized closed structure but we had grave doubts as to the presence of reservoir, which we thought might have a maximum thickness of about 120 feet, if we were very lucky.

Again our partners were not fully convinced, but we had no option.

One old east-west seismic line showed a horizontal event across the structure. Could it be an oil-water contact?

No way, we all thought, as to be one would require a massively thick reservoir.

Which, of course, is what we found, against all expectations, in our seventh oil discovery, the 545-million-barrel Fulmar Field in 1975.

The line with the horizontal event disappeared, as did the event when it was reprocessed. Shell denies that it ever existed – but it did, and it tied in about 100 feet below the actual OWC suggesting the reservoir may have leaked.

Undoubtedly Bill Wheatley’s effort to secure North Sea Block 30/16 in 1969 paid good dividends!

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Historical Highlights - Myles Bowen

J. Myles Bowen is the 2011 recipient of AAPG’s Pioneer Award. He was involved in various discoveries around the world, most notably Brent, Nelson and several other major North Sea finds. As a young man in Borneo in 1957 he was the first to climb King Edward’s Peak (13,480 feet) on Mount Kinabalu via what became known as Bowen’s Route. He now lives in retirement in Devon, England, with his wife, Margaret.

Historical Highlights

Historical Highlights - Hans Krause

Hans Krause is an AAPG Honorary Member, Distinguished Service Award winner and former chair of the AAPG History of Petroleum Geology Committee.

A History-Based Series, Historical Highlights is an ongoing EXPLORER series that celebrates the "eureka" moments of petroleum geology, the rise of key concepts, the discoveries that made a difference, the perseverance and ingenuity of our colleagues – and/or their luck! – through stories that emphasize the anecdotes, the good yarns and the human interest side of our E&P profession. If you have such a story – and who doesn't? – and you'd like to share it with your fellow AAPG members, contact the editor.

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About the Author...

J. Myles Bowen is the 2011 recipient of AAPG’s Pioneer Award. He was involved in various discoveries around the world, most notably Brent, Nelson and several other major North Sea finds. As a young man in Borneo in 1957 he was the first to climb King Edward’s Peak (13,480 feet) on Mount Kinabalu via what became known as Bowen’s Route. He now lives in retirement in Devon, England, with his wife, Margaret.