New technology and higher oil prices have helped make the Wilcox sands an inviting target.
Mention Tertiary Wilcox sands to almost near anyone who has worked the Gulf Coast region in pursuit of hydrocarbons, and it rings a bell.
The Wilcox Trend extends from south Texas across central Louisiana to the Mississippi border. The formation has been an on-again, off-again moneymaker for the E&P crowd since the early 1920s, according to AAPG member Tim Rynott, owner of Durango-based Ridge Resources.
“Until the 1980s, the Wilcox in southern Louisiana had been a very active exploration play, producing over 180 MMbo and 1.13 Tcf,” Rynott said.
“Insufficient porosities in the Middle/Lower Wilcox and problematical petrophysical evaluations, combined with poor commodity prices, virtually eliminated the Wilcox as an exploration target during most of the 1980s and throughout the 1990s,” he noted.
“After the easily identified structures had been drilled, and commodity prices crashed in the mid-1980s,” Rynott noted, wryly, “the Wilcox took on the name of ‘Won’t-cox’ in some circles.”
Today, it’s one of the rejuvenation darlings of the Oil Patch, thanks to high oil prices and technology applications, such as hydraulic fracturing.
“Since 2003, over 180 wells have been drilled in southern Louisiana for the Wilcox formation, with a completion rate greater than 90 percent,” Rynott said. “To date, these 180 wells have produced over 13 MMbo and 55 Bcf, with EURs ranging from 100 to 500 Mboe per well (70 to 90 percent liquids).”
It’s a popular hunting ground for mom ‘n’ pop shops, along with smaller-to-midsize independents, in general.
This scenario is a “one-eighty” from the old days.
Treasures Left Behind
A testimony to the Big Boys’ interest during earlier times is the Pine Prairie Field in Louisiana’s Evangeline Parish. Pine Prairie is a piercement salt dome discovered in 1908 and developed during World War II, for the most part. It’s said to harbor 30 productive horizons.
The majors were out in force, drilling away in the 1940s. Trouble was, the structure is relatively small. They each could have a little piece, but not a big chunk.
They soon packed up and moved on to south Louisiana (which the non-native citizens view to be anything south of I-10), where they had begun making lucrative, high production discoveries.
The targets there are deeper, geologically more complex and pricier to drill – but considerably more profitable when the drill bit hits the spot marked “X.”
These guys left a lot of black gold behind for the likes of independents such as publicly-traded Mid-States Petroleum Co., which has re-entered Pine Prairie and several other south-central Louisiana Wilcox fields where target depths range between 9,000 and 17,000 feet.
Production from the myriad zones at Pine Prairie can be commingled, as opposed to the early days when this was prevented by state regulations.
The company’s results: significantly revved-up production via modern-day horizontal drilling and multi-stage fracturing technology.
These applications can be crucial to tapping production in that the upper, middle and lower Wilcox sands are known to be made up of considerable shale and clay content, being classified as “dirty sands.”
Other companies working the Trend include Halcon Resources, Hilcorp, Swift Energy and EP Energy, according to Rynott.
‘Oil and Gas Farming’
Some explorers prefer to take a stab at it pretty much on their own, even if they’re not actually present in the neighborhood.
Louisiana-native Rynott doesn’t let his current far-away domicile in Colorado hinder his Wilcox activity.
“With all the communications available today, it’s really effortless,” he emphasized. “I’m now on the third 3-D I’m selling in the Wilcox, and through these I hope to see anywhere from 50 to maybe a couple hundred wells drilled.
“The three of these seismic sets combined add up to 450 square miles of 3-D,” he said.
“Louisiana, and south Louisiana in particular, is a very oily area,” Rynott continued, “where you have the luxury of drilling deep tight sands and serendipitously finding some shallower conventional sands. You have so many stacked layers of prospective formations in south Louisiana, and it’s just ripe for the pickings because of that.
“It’s for those small and medium independents who have not gotten into the sweet spots in resource plays,” Rynott noted. “A lot of people in south Louisiana don’t want to get into resource plays, so this is where they need to go.
“Also, the lease terms are better than the hot resource plays where you’re drilling in a grid – doing oil and gas farming, as I call it.”
Working for a Living
If you’re convinced to join the other believers, be prepared to work long hours and contribute plenty of sweat equity in the quest to identify prospects. This is a region of mature basins that are picked over fairly well, leaving behind smaller accumulations.
You have to unravel all the secrets to make sure you have a drillable prospect, according to Rynott.
He was upbeat about the production possibilities from acquiring 3-D surveys in areas of Louisiana that have not been shot.
“You can take advantage of the 3-D technology, the fracturing technology and at the same time hope it could turn into a horizontal play in the near- to intermediate future,” he said.
“You have the potential for the perfect combination of the three big technologies.”