Not being afraid of the computer and trusting the knowledge of the people who created the software and other tools can lead to better understanding the production potential of rocks in unconventional plays.
With a backdrop of examples, which included technology that identifies probable spots for surface unconformities using seismic data as well as digitized logs and deviation surveys, Drillinginfo CEO Allen Gilmer spoke about the importance of geology, geophysics and petrophysics—each with their own nomenclature—successfully integrating to create productivity and something meaningful for both reservoir and drilling engineers.
“All of these pieces come together to start answering the questions: what are the things that drive production; what are the engineering parts; and what are the geological parts,” Gilmer said during the NAPE Business Conference in Houston. “The better the rock that you’re in, the more benefits you get from engineering. The worse the quality of rock [is], the less benefit you’re getting from engineering.”
The company provides drilling information in online oil and gas databases and maps, with information derived from sources such as courthouse documents and regulatory information as well as proprietary data from oil and gas companies themselves.
“Our goal is … that when anything interesting takes place—when someone goes out there and fracks a new zone—we can put it into context right away and identify whose had their value change nearly instantaneously,” Gilmer said. “We do Tier 1 cleaning of the datasets, and … now we have teams of geologists, engineers and statisticians that are going out there to build these earth models because those are the front end of doing analytics.”
They are seeking answers to how best to drill a well in a particular play and how to maximize production. With a tool set to be released in third-quarter 2014, Gilmer spoke about how the methodology looked at seismic data, identified where surface unconformities probably lie, and then extracted those unconformities automatically with little input from an interpreter.
“It is essentially using the embedded knowledge of very bright people that are building these things—so not being afraid of the computer, and then these things lead into the building automatically nearly of relative geological time scales,” he said, noting the next step is automatic strategic stratigraphy, which has been difficult to integrate with seismic.
Showing a co-rendered piece of the sequence stratigraphy with the seismic, Gilmer pointed out the ability to render the seismic and see in real time, or in a time-referential period, areas where there is no deposition within that sequence.
“You can see where areas [had] things deposited and where things were not,” he said. “The reason this is important is because along these surfaces is where you start to see porosity developments. This is where you start seeing things that lead toward sweet spots. They’re areas in which you can have variation in total organic carbon.”
Drillinginfo used the same probabilistic analytic concept with faulting, and “let the machine do it.”
“We’re very fascinated with regard to identifying whether faults hinder or help production in these unconventional plays. If you’re going out there and drilling these horizontal wells, do you want to be close to or away from [faults]? The answer is mixed. It depends on where you are,” Gilmer continued.
However, in the Eagle Ford, he said there is a negative relationship to distance with faulting.
“If you are too close to a fault, you’re going to see a substantive decrease in the production of what you have probably because the fault is absorbing a lot of your frack energy,” he explained. “The farther you get away from that the more your production goes up. We can quantify exactly how much that is.”
Other examples of how geological information can be put into formats and used to predict how wells could produce included:
- Digitized logs. Digitized logs of a southwest-northeast cross section of the Niobrara showed the lithology and tracked the location of wellbores as well as how long they stayed in each zone. The log showed during the conference illustrated the complexity of what is thought to be a simple play. “In this case, the depositional area was kind of in the center area below the Codell,” Gilmer said. “As we deepened out, all of a sudden the basin shifted way to the south, and then it shifted back up to the north, and you start seeing these various thickenings and thinnings. And it turns out that each of these benches actually has some production potential.”
- Real-time solutions. Staying in the zone while drilling horizontal wells is important. Technology allows oil and gas operators to render logging while drilling, and the tool updates the geological model in real time while drilling is underway. “The really cool part about this is we’re now just starting to work with a few companies,[and] they are bringing in their historical MWD data into the system so that we can start doing predictions as to whether there might be well failure or how good the well might be based off various signatures that come through,” Gilmer added.
Research from universities could also lead to new ways to evaluate plays and characterize reservoirs.
Bob Hardage, of The University of Texas at Austin’s Bureau of Economic Geology, uncovered a way to isolate transverse shear (S) waves from compressional (P) wave surveys, which creates a less-expensive route to getting information about rock properties, including density.
This methodology provides an opportunity to take P-wave surveys and invert toward data that engineers would like to have, Gilmer said, noting that the most important advice he gives geophysicists is to learn how to speak to engineers and deliver projects that make their life easier and better.
“We have a lot of people that are 55 and up that are retiring, and every new person coming into the industry with a technical degree is replacing 1½ to two people that have a lot of experience,” Gilmer added. “They’re also coming into an industry that has more proven undeveloped locations and more possible locations to drill than have ever existed in the history of the oil business. So there is a lot of work going forward, and that work is a lot different than the work that came in the past.”
Contact the author, Velda Addison, at email@example.com.
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