If you want to know about the Eagle Ford play in Texas, AAPG member Art Donovan is a man you want to be talking to.
And if you want to actually take a trip to study the Eagle Ford, Donovan probably is THE man you want to be talking to.
And the numbers of geoscientists in both those groups have been growing over the past few years, because exploration in and around Eagle Ford in Texas, which Donovan is expertly familiar, has been a huge success story – and “huge” may be an understatement.
Since 2008, in fact, it has become one of the most heavily drilled targets in the United States with more than 7,000 wells having been drilled – and another 5,500 having been approved by state regulators for future exploration.
And Donovan, a professor at the Department of Geology and Geophysics at Texas A&M University who will be leading a field trip to the area as part of this year’s AAPG Annual Convention and Exhibition in April, is not surprised.
“The Eagle Ford is a great source rock,” he said.
“In the onshore U.S., we have pretty much gone through the better conventional reservoirs and what’s left are unconventional things like tight gas, tight oil, shale gas and shale oil,” he added.
Unlike the Bakken play in North Dakota, however, Eagle Ford’s success is pretty unique, according to Donovan, who is BP’s senior geoscience adviser for unconventional reserves.
“Due to local overpressure in the oil window, it’s probably the only successful shale oil play in the U.S.,” he said. “The Bakken in North Dakota and most of what’s happening in Permian Basin in west Texas is really a tight oil play.”
There are other factors, Donovan said, for an area to be such a vibrant, successful play, and Eagle Ford has all of those going for it.
“It has full product spectrum of product type, from volatile oil to dry gas,” he said, comparing it with the Haynesville, which is mainly a dry shale gas play.
Also, it’s an excellent source rock that in south Texas is carbonate-rich and clay poor, which gives it the proper mechanical stratigraphy to be a great unconventional shale oil to shale gas reservoir.
“It also has regions of overpressure,” he added, “that allow the shale oil window to actually work.”
Up Close and Personal
Much of this region will be on display during the field trip that Donovan, along with AAPG members Scott Staerker, Rand Gardner, Aris Pramudito and Jonathan Evenick, will be leading.
All concerned have worked the Eagle Ford, as well as other unconventional mudstone plays in the subsurface of North America, and bring with them a wealth of multi-discipline expertise, knowledge and experience to the subject of unconventional mudstone reservoirs and the area.
“It will be,” Donovan said, “an opportunity for folks to examine the entire Eagle Ford succession in spectacular outcrops within Lozier Canyon.”
Interestingly, the outcrops are on private property and had been off limits to over a generation. According to Donovan, not until BP’s geologists in its land department gained access rights in 2010 were research and field trips even available.
“Since 2010, BP has funded research to graduate students to better understand the Eagle Ford within Lozier Canyon,” he said.
For ACE attendees, that means a chance to see the area, literally, up close and personal.
“With this framework in place, folks can walk up to and examine the exact portions of the Eagle Ford, underlying Buda, and overlying Austin in outcrop, that is of interest to them in the surface,” Donovan said.
Field trips like these at conferences are always part fun, part educational. In this case, the trip aims to clearly demonstrate, explain, and predict the Eagle Ford outcrops and unconventional reservoirs, while also increasing discussion on the geologic, engineering, petrophysical, geochemical, geophysical and drilling challenges associated with exploring and exploiting oil and gas resources from the Eagle Ford, as well as other unconventional mudstone reservoirs.
This trip, Ford says, will be an opportunity to display the research efforts of those graduate students.
“I should also note the work we have done has allowed us to port the subsurface Eagle Ford stratigraphy directly into the outcrops,” he said, while adding, “basically, we don’t get bogged down in local terminology and provincial stratigraphic usage.”