Visualization and VR – PDM reviews the state of the art (October 1998)

PDM trolled the exhibition floor at the NewOrleans SEG, attended some talks and a post convention workshop on the Future of 3DSeismic Visualization. Virtual Reality may give you great insight into your seismicdataset but taking notes inside the CAVE is pretty tricky, especially with the funnyglasses. The following is what we managed to decipher from the scribbling..

The hot topic at the SEG’s annual conference and exhibition was the arrival of a multitude of offerings in the realm of Virtual Reality (VR). Several vendors on the exhibition floor were showing their virtual wares and VR, together with visualization was the focus of a half-day post conference workshop. For an iconoclastic overview see this month’s editorial; for a less impassioned discussion of the topic, read on.

Mons Midttun (Norsk Hydro Research Center) in his paper "A VR system for interdisciplinary petroleum exploration and production" explained that natural hand movements could be used to ‘slice through 3D data efficiently’ and to follow well tracks intuitively. Midttun believes that working with the Cave gives an intuitive presentation of complex data and allows different disciplines to share data more effectively. Current focus is on well planning, and spans geology, geophysics, reservoir engineering and drilling. A 3D mouse with 6 degrees of freedom allows for complex interaction with data. Hydro’s research center is testing the several tools for 3D VR interpretation such as the Volume Window Tool (VWT). The VWT allows for the visualization of semi-transparent sub-volumes (such as channel sands in the reservoir). A novel technique, ‘region growing’ can be performed by seeding a data point in a 3D volume, generating an autopick of neighboring localities with similar property values. Precise picking of points along a proposed well trajectory can be achieved in 3D.

Hardware is one limiting factor and necessitates some compromises in terms of rendering performance. A Silicon Monster Reality machine boasting 16 RISC CPU’s, 4 graphic pipelines and 4GB of RAM is used. The maximum 64MB of texture memory is another constraint for the VR research team. Hydro’s VR installation will be used for well planning and geo-steering on the Troll field later this year. While the CAVE-type installations are the only way that these massive data sets can be presented today, Midttun is convinced that as the technology improves, lightweight LCD head-mounted glasses are the way forward. These are in use at the present time, but are limited in terms of resolution. The main limiting factor in the deployment of VR is the availability of industrial strength software. Questioned on this, vendors stated that they were waiting for sales before porting their software to CAVE type environments.

Jim Foran, Silicon Graphics’ Director of Visualization Technology gave a top level overview of SGI’s latest applications – using that time-honored visualization tool, the overhead projector. Foran described SGI’s work with the Spanish Government in flight simulation. The whole of Spain has been digitized at 20 meter resolution. Texture data can be rolled off disk at multiple resolutions – with image quality improving as the scenery nears. Flyers can roam through the data sets at will. This technology has been used in the Bosnian theatre to pre-fly missions. Could there be an application here in exploration, flying around a regional dataset looking for prospects?

Mike Zeitlin (Texaco) is convinced that it is ‘imperative’ to do visualization. Zeitlin made the following cost comparison – a 3D seismic survey costs around $14 million and a dry hole in the Gulf of Mexico (GOM) around $40 million. To Texaco’s management therefore the investment of a mere $3 million in a Virtual Reality Center was ‘a no brainer’. Zeitlin is an avowed big spender, he told Computerworld recently "Money is not an issue for me. How many IT groups can do what they need to do without money being an issue?'' Pointing out that GOM permits are getting bigger, a 3D data volume may contain 23GB of information per seismic attribute. The only way to handle such volumes is through powerful visualization technology. Despite the whopping investment in a massive SGI Onyx2 system and his boasts to Computerworld, Zeitlin admits that cost is still a constraint on the system’s development.

Texaco’s system offers the interpreter a 25 x 8 foot screen (Cinemascope size!) with a 160° field-of-view and 4000 x 1200 pixel resolution. Texaco’s VR software is Geoprobe, used to look at seismics and complex geological bodies at the same time. The project was initiated in June 97 and has since been used to interpret 60 3D surveys. A reduction in cycle time for a 3D survey from 4 weeks to 3 days is claimed. Well location accuracy is ‘up’ and ‘positive drilling results’ have been reported. According to Zeitlin, every well location that had been previously planned using conventional techniques has moved when scrutinized with Geoprobe – usually by ‘hundreds of meters’. The system allows thousands of lines of seismics to be viewed before zooming in to a single sample. Cooperative working in this environment between geologists and geophysicists is ‘an emotional experience’. Questions from the floor focused on data quality – particularly in terms of positional information. Zeitlin stated that the QC ‘was presumed to have been done’ but that they were sometimes ‘very nervous about this’.

Roger Anderson of the Lamont-Doherty Earth Observatory has been collaborating with the University of Houston’s Virtual Environment Technology Laboratory (VETL) on the interpretation of 4D time lapse seismic. Anderson believes that 4D seismics will be VR’s "killer" application, allowing for the visualization of well bores in impedance space over time. Ever the showman, Anderson conducted a fly through of a developing oil field whose depletion was causing gas to come out of solution. A roomful of bespectacled time and space travelers were shown red voxels – where gas was coming out of solution – and green ones indicating bypassed oil. Anderson believes that this technology will allow for the "direct application of seismics to petroleum engineering".

But the prize for the most exaggerated claim goes to Chevron’s Donald Paul. Giving the keynote address to the SEG conference, Paul claimed boldly that the interdisciplinary nature of the Cave would enable not only the usual cohort of geoscientists and engineers to cooperate on an interpretation, but that we actually require an oil trader in there, "touching the wall". Apart from the delightful improbability of such a fantasy, at current oil prices, the presence of an oil trader in the Cave would be in danger of causing a collective suicide!