Parr excellence – a west of Shetland story of skill and perseverance
As Clair Ridge prepares to celebrate first oil, BP’s operations west of Shetland are once again in the spotlight. But, it’s not the only milestone being marked in the region. Some 20 years after the start of the production from the Schiehallion field, BP Magazine talks to senior geophysicist Ronnie Parr, whose role in its discovery would be crucial in not only unlocking these vast reserves, but also in paving the way for future major North Sea plays. Here, he recalls how it was achieved with only rudimentary data and a lot of determination
It was 1990 and Ronnie Parr was part of a small exploration team working in the west of Shetland area. His colleagues had drilled dozens of wells and only come up dry. “There was a bit of a push to leave the area,” the senior geophysicist says.
“We had drilled 80 wells and, apart from the Clair field, which we didn’t have a solution for then, there wasn’t another commercial discovery. The west of Shetland team was packing up. “We had gone from working west of Shetland with 100 people to working the area with about three,” Parr says. But then, a breakthrough came, 190 kilometres west of Shetland.
Major finds
Not knowing what else to do, Parr had cleaned up the seismic data for the region and presented it to his manager. He says: "My boss with 20 years’ experience looked at it and said: ‘This is a 250 million-barrel find!’ I remember asking him if that was a big number.
“I had just joined the company six months previously, so he could have said one million or 250 million barrels and it would have made no difference to me." The discovery was named Foinaven and encouraged by the results
Parr and the team were keen to discover further resources in the region. It wouldn't be long before they did. It was 1993 and Parr had grabbed any seismic data he could find for the surrounding area and stretched the printed sheets across the floor. Those ten lines of data – a series of squiggles to the untrained eye – would lead to the discovery of the huge Schiehallion field. “I laid them out on the floor, from one end of the room to the other,” Parr recalls. “I identified half a dozen of these blobs."
The best of those turned out to be Schiehallion another huge find located 175 kilometers west of Shetland. But, pinpointing where to drill had its own challenges. “My manager left me alone for a month with the data. I tried a number of things and the breakthrough finally came when I threw away one-third of the data set. When you discard the third that is really ‘noisy’, the rest begins to make a lot of sense and tie into the wells. And that’s what we ended up drilling the wells on.”
Parr recently recreated the exercise for the European Association for Exploration Geophysicists (EAEG). “They wanted a real-life example of what could happen," he says. "So, we took them back to 1993 and said: ‘Go find Schiehallion.’ It’s actually incredibly difficult to do without modern 3D technology. I’m not even sure I could do it again. Our seismic database at the time was incredibly sparse. These fields were basically designed or identified on 10 lines of 2D seismic. Today, we use millions.”
Digging for victory
Schiehallion started producing in 1998. It successfully delivered 400 million barrels of oil through the original Schiehallion floating production, storage and offloading (FPSO) vessel, before the multi-billion-pound Quad204 project, involving the new Glen Lyon FPSO to replace it, was designed to completely redevelop and maximize production from the Schiehallion and Loyal fields.
Now some decades since the Schiehallion discovery, there are still lessons to be learned from it, according to Parr. “We wouldn’t roll the seismic on the floor now, but having the time to do that then and wander along it was a breakthrough. These days, I consume thousands of lines an hour. It’s just a completely different scale,” he says. “Explorers today have so much more data, knowledge and ability at their fingertips. But, something must be said for the importance of the ‘digging’ skills.
“The truth is, if I hadn’t had a month to play with seismic data on Foinaven and Schiehallion, the oil west of Shetland would probably still be down there. Nobody would be looking. My most recent discoveries have always had an element of digging attached to them. It can’t always be about the big, easy stuff.”
Commenting on the west of Shetland region and what it means to him, Parr adds: “You only ever get one billion-barrel field in your life and I happened to get mine within two years of joining BP.”
From deep sea to mountain high
Having played a crucial role in their discovery, Ronnie Parr was given the privilege of naming two of BP’s North Sea fields, and so turned to his love the countryside for inspiration. In 1993, he named Schiehallion after his favourite Munro (the name Scots give to their tallest mountains) in Perthshire. In Gaelic, Schiehallion roughly translates as ‘fairy hill of the Caledonians’.
Then, 15 years later, he made a very personal choice when he named the Kinnoull field after the Scottish hill where he grew up. His father used to say that he would drill for oil in the back garden. Parr adds: “This was geologically nonsense as it is a big lump of volcanic rock, but I wanted to name the 2008 field discovery after Kinnoull to prove him right.”
Although the Foinaven field also shares its name with a Scottish mountain, Parr recalls another, lesser-known reason for its selection. In 1967, an Irish racehorse called Foinavon had defied the bookmakers' odds to win the Grand National. “If you looked at the well’s modelling, it had a one in 400 chance,” says Parr. “Foinaven should not have existed.” Like the racehorse, it had certainly exceeded all expectations.
