|
|
|
|
|
|
|
|
|
| CSIRO | SOLVE | Issue 6 Feb 06 | |
|
|
|
ARTICLE
OIL EXPLORATION:
Charged With the Search for Oil By Gio Braidotti
Oil is a poor conductor of electricity – a handy thing to know, perhaps, when working in a workshop, but even handier when you can use this knowledge to find new oil reserves. Oil’s antipathy to electrical current forms the basis of new technology that may improve the strike-rate of oil exploration companies’ work in deep water. “Control Source Electromagnetic (CSEM) surveys,” explains Kevin Dodds of CSIRO Petroleum Resources, “involve a transmitter towed behind a survey vessel, a powerful current sent into the earth, and electric dipole receivers placed in a line on the seafloor to record electromagnetic fields at various distances from the transmitter. Because oil does not conduct electricity it appears as a ‘resistive’ geological layer.” According to the Wall Street Journal, ExxonMobil’s early investment in CSEM technology development has paid off in terms of mapping oil with dependable precision in offshore Angola. But the application of the technology in other areas that are not as well explored is still in its early days, says Bob Cassie, exploration manager for Hardman Resources Ltd, who just participated in CSEM surveys off the coast of Mauritania in north-west Africa. “The idea is to use CSEM over prospects identified by 3D seismic surveys as containing the right kind of rock structures for the accumulation of hydrocarbons,” he says. “CSEM provides an independent measurement of the potential for hydrocarbons and could be used to select the prospects with greatest chance of success. With deepwater drilling costs of about US$12–20 million, the aim is to use CSEM to better manage risk and cut costs.” While a number of contractors are competing to develop the technology and conduct the surveys, Mr Cassie sees one of the critical issues for CSEM as accumulating expertise in calibrating and interpreting the data, especially in areas still largely unexplored. “The surveys we participated in gave us a great opportunity to learn about this method, but the results are a mixed bag so far,” he says. “We went to CSIRO to give us an alternative and independent view. We see lots of potential, but there are also a number of pitfalls.” With a suite of packages already available to extend the capability of various reservoir-mapping tools, CSIRO Petroleum has a straightforward take on the situation. “It’s about the ability to take the information and understand it,” says Mr Dodds. He explains that oil is not the only resistive material present underground and that saltwater produces a shielding effect that complicates distinguishing the signal coming from oil. “Australia has been using EM for mineral exploration for many years and CSIRO helped develop the technology for land-based uses,” he says. “There are now a lot of opportunities for CSIRO to help with oil exploration, to interpret CSEM data, develop applications and suggest new technology to industry.” For further information contact: |
 IN THIS ISSUE
|
| Home | About Us | eSubscribe | Links | |
|
|
||
|
|
|
Back to main