A good look inside a crater

Red Wing Data Has Big Impact

Seismic intersect image, Red Wing Creek Field. Image courtesy of Roger Barton and True Oil.
Seismic intersect image, Red Wing Creek Field. Image courtesy of Roger Barton and True Oil.

What the Red Wing Creek Field, located within North Dakota’s oil-rich Williston Basin, has been doing since its discovery in 1972 is not the story.

In fact, the nine-kilometer diameter creek structure has been producing oil – lots of it, approximately 17 million barrels, most of it in the Mission Canyon and Charles formations.

This story, though, isn’t just how much more is down there, but how we see it. Literally.

Since 2001, a 3-D seismic data set has been employed to better interpret the images and complexities of the site.

And that can mean more oil – and that’s the point.

Paul Weimer, professor at the University of Colorado Department of Geological Sciences, past AAPG treasurer and co-author of a paper explaining what has been distilled from this 3-D imaging, believes this data “across a producing meteorite impact field” is some of the most important ever produced for impact craters.

Weimer and AAPG Student member Ben Herber were two of the authors of a paper on the project presented last month at the annual 3-D Seismic Symposium in Denver. The project is part of Herber’s master’s thesis.

Specifically, the 3-D data has been used to better understand the distribution of the extensive fault patterns, with an emphasis toward better field development.

“The 3-D data,” Weimer said, “have allowed us to better image the field in greater detail than was previously possible.”

A Gift From Above
Paul Weimer
Paul Weimer

Weimer says the Red Wing Creek Field is one of a handful of oil and gas fields in the world that is known to produce from a structure that formed associated with a meteorite impact. In addition to the barrels of oil, the field also has produced approximately 25 Bcf of gas from 26 wells, of which 22 are still producing.

Of the competing claims as to what might have caused the field, Weimer brushes aside all other theories, especially about this field.

“The 3-D seismic data unequivocally demonstrate that Red Wing Creek is a meteorite impact feature,” he said.

The data, he added, will go a long way toward enabling the ultimate recovery of the field, a recovery which may be as much as 60 million barrels of oil – meaning more than 70 percent of the field is still untapped.

This is possible because the data illuminates the impact crater in more detail than what was presently known.

Experts in the field have known the crater consists of a structurally high central core with two surrounding structurally high areas, and an inner and outer rim. The total deformed area is about 65-square-kilometers; the central core area is 2.6-square-kilometers.

“Production is primarily from reservoirs in the central core that consist of highly deformed carbonate strata of the Upper Mississippian Madison/Mission Canyon Formation,” Herber said, “and occurs from highly fractured strata with less than 1 mD of permeability.”

“What we’re trying to do,” adds AAPG member Roger Barton, chief geologist with True Oil and another of the paper’s co-authors, “is to develop a geological model to be used in reservoir studies … to define reservoir properties.”

“Until the 3-D survey,” Weimer said, “the data set consisted of wireline logs, production information, some 2-D seismic profiles and a few cores.”

‘One of the Best’
Ben Herber
Ben Herber

Herber and Weimer first delivered the findings at the Denver 3-D symposium, a Rocky Mountain Association of Geologists/Denver Geophysical Society event held annually for 16 years.

The specific purpose of this presentation was to give a history of how the 3-D seismic data have been interpreted so far – and what may be on the horizon.

“Ben gave a real-time demo of the data set on the large screen discussing how different seismic attributes were used to arrive at the best structural interpretation,“ Weimer said.

This is important, according to Herber, because interpretation of a 3-D seismic data set using select attributes allows for the detailed mapping of the faults and deformed strata within the impact feature.

“A combination of coherency, curvature, edge stacking and dip azimuth attributes were used iteratively to determine the best interpretation,” he said. “These attributes indicate that faults deform primarily the outer and inner rims, and the central core.

“Specifically, the outer rim has a radius of 3.3 to five kilometers, and is defined by a series of arcuate normal faults, which are, in essence, an updip slide escarpment.”

Individual faults, he said, are up to 2.5 kilometers in length, with offsets up to 110 meters, and the inner rim has a radius of two kilometers.

“Along the inner rim, faults have normal to high-angle reverse motion with offsets” up to 135 meters and up to 1.6 kilometers in length,” he said. “Faulting density is greatest in the central core. Faults are up to 0.8 kilometers in length, and have a radial to crosscutting pattern within the core.”

Herber and Weimer are quick to share the credit for the project and the presentation, specifically including co-authors Chunju Huang, Shu Jiang and Stan Hammon.

It is Barton, though, who has been in charge of the exploration, who may have best summed up the excitement surrounding this specific 3-D study:

“This new interpretation by Ben probably will be one of the best ways to figuring out Red Wing Creek Field.”

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The poster “3-D Interpretation of a Meteorite Impact Field, Red Wing Creek Field, Williston Basin, Western North Dakota” will be presented Tuesday afternoon, June 9, at the AAPG Annual Convention and Exhibition in Denver.

Emphasis: Offshore Developments