Geologists have successfully and creatively for 50 years correlated well logs and built cross sections -- on paper.
Despite widespread computerization, they have not had the technology to completely replace inefficient paper methods.
Today, four years after its introduction, smart raster technology is coming of age, as large and small companies are embracing the software and converting tens of thousands of paper well logs into smart raster format.
"With 'smart' raster technology," says one geologist, "I correlated approximately 1,200 wells in two days. If I'd had to use hard-copy logs, this would have been impossible."
The movement started during the 1980s and early '90s, when 3-D seismic interpreters rapidly migrated out of the paper world onto interactive workstations. Emboldened by this success, software vendors began offering new tools for the analysis and interpretation of digital well log data.
Many assumed that geologists would convert to digital methods as whole-heartedly as their geophysical colleagues. Well . . .
Certainly geologists adopted computer applications for many of their tasks, mapping in particular. But -- be honest -- most continued to slide paper well logs across drafting tables, marking tops with a pencil, and cutting-and-pasting photocopies of their curves to construct wall-sized cross sections.
The problem? Digital well logs were simply not available in many basins, either domestic or international. And the cost of digitizing large numbers of well logs often exceeded the budget. Paper, it appeared, was here to stay.
On the information superhighway of the 1990s, geologists seemed stuck in the slow lane.
Origins and Growth
In 1995, things began to change. Denver-based start-up company Interpretive Imaging released the industry's first "smart" raster well log technology, combining a whole new data format, along with log interpretation software.
The software's well logs married digital depth information with standard raster bitmaps. Every row of pixels, therefore, was calibrated with depth. This enabled geologists to stretch, squeeze, splice, pick and otherwise manipulate well logs onscreen with amazing speed and flexibility -- similar to their digital counterparts, but at a fraction of the cost.
Today, not surprisingly, competing software products have sprung up, both validating and expanding the market:
Neuralog, geoPLUS and Riley all offer raster-based cross section programs for the PC now.
Software developers such as GeoGraphix have recently added rasters to their existing array of digital formats. The latest smart raster software also can handle digital LAS logs as effectively as raster data.
Interpretive Imaging recently merged with A2D Technologies, providing oil companies with access to both smart raster and digital well log information.
The industry's raster data infrastructure is maturing. Smart raster technology is rapidly moving from the early adopters to the mainstream. As a result, geologists are finally experiencing productivity gains comparable to their geophysical associates.
Storing and Managing
Storing rasters on a hard disk or network drive is a cost-effective alternative to physical paper file space, according to several geologists.
"If you can convert your file room to raster images, then your paper data storage costs will go down significantly," said Rob Mathis, a geologist with Hilcorp Energy in Houston.
When he worked for a major oil company back in 1996, Mathis attempted to convince management to have all the well log files scanned and stored on a server.
"Their annual bill for offsite storage was huge," he said. "It was costing more than a million dollars a year to store well data that few people were using . . . But old habits die hard. They didn't want to throw the paper away."
"Traditional managers feel good walking into a gigantic file room, seeing all those well logs on a shelf," added Dennis Comis, chief information officer for Houston-based Frontera Resources. "They think they have an asset there -- at Frontera, we think all they have is a paper jungle."
Founded three years ago, Frontera Resources took a radically paperless approach to data management from the beginning. All technical documents -- both raw materials and final output such as well logs, maps, photographs, cross sections and engineering reports -- are scanned, indexed and stored on network file servers, accessible to all E&P professionals and partners via the company's extranet.
"Smart rasters form an integral part of the overall plan," Comis said. "Well logs are the building blocks we put into our (vendor's) software to make a cross section. Then we create an output file of that cross section, a digital replication, and upload it to a folder on the extranet.
"When our people are overseas, 15,000 miles away, they can log onto the Internet, go to that folder and download the file," he continued. "If they need to, they can plot a hard-copy version for a presentation or offsite meeting."
However, even when users print a paper copy, they usually throw it away afterward. "We have no file rooms or file clerks," Comis said.
"Frontera has gone into places like Azerbaijan and Georgia and evaluated pretty much the whole country's asset base by being able to quickly and efficiently scan logs, maps and other data," he said. "With knowledgeable people, we create value from a simple scanned image.
Smart raster well logs are used today in a wide variety of basins, plays and projects, notably in:
- The East Texas Cotton Valley Reef play.
- The South Mississippi Tuscaloosa trend.
- The Morrow formation of southeastern New Mexico.
- Regional exploration in South Louisiana.
- Field studies in the Permian Basin.
- International operations in Azerbaijan and Georgia.
The number of wells involved ranged from 100 to 30,000.
Projects most likely to use the technology are those areas with little or no digital well log data available -- and either too many wells to correlate or too many geological interpretations to generate using traditional paper methods.
"When you go into a new country, there is no digital data. You have to make it yourself," Comis said. "In our Georgian operations, for example, we started with all raster logs, and did lots of evaluations with them. It's an evolutionary process. Now we have all digital data.
"In Azerbaijan, I'd say 85 percent of our data is raster, 15 percent is digital."
Hilcorp Energy's Mathis recalled using the technology in early 1996, when he was "starting out from scratch" in the East Texas basin and had to evaluate that area quickly.
"But we had no digitized well logs," he said. "I knew sliding logs on top of a drafting table wasn't going to cut it."
Using the Software
According to Comis, the best smart raster software is developed by earth scientists rather than programmers, by people who "feel the pain of what a geologist has to go through to create a cross section."
According to experienced users, smart raster well log interpretation enables them to: (click on image, left, to view closeup)
- Combine raster logs with digital LAS logs in the same application.
- Rescale, stretch, squeeze and drag-and-drop logs onscreen to facilitate correlation.
- Rearrange non-standard log tracks from old or international wells.
- Display well logs in true vertical depth.
- Preserve critical hand-written notes on old logs.
- Automatically post production-test data on well log depth tracks.
- Pick tops onscreen and automatically store them to a database.
- Pick porosity, net sand, net pay or gross interval thicknesses.
- Export tops and interval picks to leading mapping applications.
- Create structural or stratigraphic sections; change datums and re-hang instantly.
- Apply color, annotations and other graphics to plot presentation sections.
"Productivity improvements are significant," Mathis said. "I can literally make a cross section and take a finished product to the plotter in 15 minutes, 30 at most. To make the same cross section with paper logs could easily have taken several hours or days."
Mathis adds that the technology is "not as big as 3-D seismic yet," but it is a growing market.