First Break - Volume 19, Issue 8, 2001

The diversity, ingenuity and effectiveness of E&P software today is too easily taken for granted. Our profile of Landmark Graphics' John Gibson which begins this month's Special Topic provides a taste of the business, technology, personnel and pressure to perform bearing on leading companies and their executives in this field. We also include: -'How to stake a claim to your intellectual property', by Houston lawyer William P. Jensen -'Integrated software - are we there yet?' By Anthony Fogg and John Coffin -'Gulf of Mexico deepwater exploration exploits modern software', from Geo Quest -'Volume-based visualisation and interpretation of seismic data', by Rob Bond

In the last five years WesternGeco has completed more than 15 3D, four-component (4C) surveys in the North Sea, using proprietary Nessie* 4C technology. These multicomponent surveys have provided greatly improved imaging in a variety of applications. The results have enabled better development drilling decisions and, hence, reduced risk. In this paper, after an introduction to 4C technology, three North Sea datasets are presented. Examples from the Brent and Beryl 4C surveys will illustrate the use of P-waves to gain dramatically improved resolution of highly faulted and compartmentalized reservoirs. The Chestnut 4C dataset will illustrate the use of converted waves to illuminate Eocene sands that have low P-wave acoustic impedance contrast with surrounding shales.

The data obtained from well logs and surface seismic profiles have opposite but complementary characteristics. The first are very precise in depth, but they measure only the local physical properties; the second have a lower resolution, but sample a much larger rock volume. A Vertical Seismic Profile (VSP) is the natural bridge between the two data types: its resolving power is intermediate, and it is recorded in time at well-known depths. Thus, it can directly check the conversion between the time domain of surface profiles and the depth domain of well logs.