Much of the world’s remaining oil and gas is locked under basalt, a rock that has baffled those attempting to ‘see’ through it. Now, thanks to new techniques developed at Cambridge, imaging beneath basalt is opening up vital new hydrocarbon reserves.

The UK government says that 70% of British energy requirements are still likely to be met by oil and gas well into the 2040s

Striking oil

By developing a way of imaging beneath the basalt that covers much of the Earth’s surface, Professor Robert White of the Department of Earth Sciences in collaboration with Dr Phil Christie of Schlumberger Gould Research has enabled oil companies to locate potentially important new oil and gas reserves.

The methods pioneered by White & Christie at Cambridge over a decade ago are now implemented with modern technology by oil companies worldwide, helping firms explore the continental margins of northwest Europe, Africa, South America and India, and since 2008 their approach has become the industry standard on basalt dominated continental shelves.

As well as developing techniques to explore new fields, White’s work is helping oil companies reprocess existing survey data, helping them find new oil in previously explored areas.

Working collaboratively with major oil companies, White’s work has given them a valuable competitive advantage, and provided academic researchers with skills to share with other universities from Dalhousie to Durham, and industrial players such as BP and Statoil.

Rising to the energy challenge

As the global population continues to grow and develop, meeting our ever-increasing demand for energy is one of humankind’s greatest challenges. According to oil major BP, global energy consumption is predicted to increase 41% between 2012 and 2035.

Despite the drive to develop renewable sources of energy, hydrocarbons will continue to play a major role for the foreseeable future. The UK government says that 70% of British energy requirements are still likely to be met by oil and gas well into the 2040s.

As demand for hydrocarbons continues to rise, supplies are diminishing. Remaining reserves – either under the sea, in shales and coals, and particularly under basalt and salt – are more challenging to extract.

Basalts cover more than 70% of the Earth’s surface, mostly forming the crust beneath the deep ocean floor. They are also found in many prospective areas in continental margins, as well as on land in India, Siberia and Brazil. Seismic surveying at sea is performed by ships towing long ‘streamers’ up to 12km. Thousands of hydrophones are built into the streamer, and these detect signals from an acoustic source such as airgun arrays. Producing seismic profiles of potential hydrocarbon reserves under basalt, however, is a major challenge because of the rock’s structure and variability.

Imaging through basalt

White’s research has resulted in new seismic imaging techniques capable of ‘seeing’ with greater accuracy the size and shape of potential hydrocarbon reservoirs lying beneath basalt.

He realised that by using two ships instead of one, towing extra-long streamers or using seismometers on the sea bed, and working with low frequencies, extra information could be returned to produce clearer images from below the basalt.

Since the mid-1990s, White has worked with major players in the oil industry to test his research in North Sea oil fields. Together with US oil company Amerada Hess, he used the two-ship approach to successfully image below the basalt layer in the Faroe-Shetland region. After producing a series of regional maps, White’s team then used new ocean bottom seismometers plus new software to process and model these wide-angle seismograms recorded at sea.

Building on this, he helped establish a joint industry-academic partnership with Liverpool University, Badley Geoscience and Schlumberger Gould Research known as iSIMM, which attracted collaboration from eight major oil companies.

Exploring the future

With investment by the UK oil and gas industry put at £13bn in 2014, White’s work looks set to continue to contribute to future exploration around the European Atlantic Margin. And his novel imaging techniques should be used to support future exploration and production license applications, and to advise the industry on exploration and appraisal drilling.