REFRACKING BRINGS 'VINTAGE' OIL AND GAS WELLS TO LIFE
Excerpt of Haynesville Shale portion of article. Link to full article at the end.
REUTERS By Anna Driver and Ernest Scheyder
HOUSTON/WILLISTON NORTH DAKOTA (Reuters) - A fracking boom isn't enough for U.S. oil and gas producers – they're now starting the re-fracking boom.
Wells sunk as little as three years ago are being fracked again, the latest innovation in the technology-driven shale oil revolution. Hydraulic fracturing, which has upended global energy markets by lifting U.S. crude oil output to a 25-year high, has been troubled by quick declines in oil and gas output.
The development highlights how producers must constantly invest and tinker, both to raise overall oil recovery rates that can be as low as 5 percent and to limit steep drops in production suffered by wells drilled into tight oil deposits.
Canada's Encana Corp invested $2 million to refrack two wells in Louisiana's Haynesville shale formation earlier this year, after seeing its production in the area dip 27 percent from 2012 levels.
"There were a significant number of wells that we considered understimulated," said David Martinez, Encana's senior manager for Haynesville development.
Using minuscule plastic balls, known as diverting agents, pumped at high speeds with water into the old wells, most of which are three to five years old, Encana blocked some the older fractures, or cracks.
"The thought is that the diverting agent will go to the cracks with the least amount of pressure," bypassing cracks with higher pressure and boosting the pressure of the entire well so output climbs, Martinez said.
He said the process can't be as precisely controlled as an initial round of hydraulic fracturing, in which water, chemicals and sand into are blasted into rock to unlock oil and gas.
Fracking has been used on about 1 million wells bored since 2007, and oil and gas companies now fracture as many as 35,000 wells each year, according to FracFocus, the national fracking chemical registry.
Drilling wells are pictured in Los Angeles, California December 11, 2013. The United States has a lo …
Refracking cost Encana about $1 million per well, compared with about $12 million for wells it drilled in 2012. Encana is no longer drilling new wells in the Haynesville formation, executives said.
Since it isn't clear how long the benefits of a refracking last, Encana plans to collect more data when it refracks five more Haynesville wells this quarter, Martinez said.
If those prove fruitful it may consider expanding the practice to its holdings in the Denver-Julesburg Basin of Colorado and the Eagle Ford formation in Texas.
Another Haynesville operator, Dallas-based Exco Resources Inc, said it boosted output from a 2010 refracked test well by 1.3 million cubic feet of gas per day. It didn't say how much gas it was producing before the refracking. Average initial production from new wells Exco drilled in the second quarter was 12.9 million cubic feet per day.
Some of Exco's Haynesville wells after four years were producing about a fifth of what they did in their first year, with output declining 69 percent that first year alone, according to the company.
Exco believes the technology can be applied to 400 of its so-called "vintage" wells that were drilled several years ago using what is now outdated technology.
The company is planning a refracking campaign for 2015, Hal Hickey, Exco's president, told investors on a July 30 conference call.
"We've been at the forefront" in the Haynesville, he said.
Link to full article:
http://news.yahoo.com/refracking-brings-vintage-oil-gas-wells-life-...
Views: 2948
Replies to This Discussion
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Permalink Reply by tc on
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If this works for oil bearing shale, it would be huge for our oil supply. Think of the old fields that used to sold for pennies as "stripper?" wells, now old shale fields could be much more valuable, if they could be refrac. Think of the benefits for a field like the TMS, where the original well costs are high.
Even though this is being tested in the Haynesville, it could be more bad news for the Haynesville as again other fields with more liquids are refrac and the associated NG production from these refracs keeps the price of NG low.
One question I have, is what type of frac crews does this process use, and what would it do to pricing for original fracs as that market is already some what tight.
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Permalink Reply by Skip Peel - Mineral Consultant on
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A lot of the detail remains unknown outside of the companies experimenting with re-fracs. Articles on the subject are just beginning to be more numerous. The diverting agent approach using the plastic balls would seem limited in ability to re-frac all the perforations that might potentially benefit from re-stimulation. The price of natural gas should remain range bound for years to come. The object of NG focused companies has shifted to production cost per mcf. Not all NG wells may experience sufficient increased production to make re-fracs economic.
I'm unsure how re-fracs, especially this method, might benefit the TMS and other oil plays where there is little formation pressure and production is maintained by artificial lift.
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Permalink Reply by Steve P on -
anyone know which wells EnCana has or will be doing the refracking on?
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Permalink Reply by Skip Peel - Mineral Consultant on
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Read through this discussion on Encana refracs in the DeSoto Parish Group.
http://www.gohaynesvilleshale.com/group/desotoparishnetwork/forum/t...
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Permalink Reply by Donna Thornton on
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Is there any hope for a collapsed or caved in well? One of our wells in Sabine Parish, the TJ Sistrunk #2 well S9 T9N R12W, caved in while in maybe only its 3rd month of production purportedly because of the of the Theresa Spears wells that was being drilled. Any thoughts on this? Thanks
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Permalink Reply by Skip Peel - Mineral Consultant on
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Donna, I believe that the horizontal wellbore must be intact to be refraced. Depending on where the wellbore collapsed I think It would be technically possible to re-stimulate the portion up hole from that point. So it really matters where the wellbore collapsed.
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Permalink Reply by Donna Thornton on
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Thanks for the reply Skip. I guess we can remain hopeful. It was a shame that it collapsed while in the first few months of production while at its peak.
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Permalink Reply by Chris Linder on
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If the zone collapsed I would highly doubt anything can be done that would be economical. I would image (pending on the well bore) the well could be re-completed. One problem you might have is that if the zone collapsed u could have pulled sand in tubing. I currently work off shore in Gulf of Mexico and the Platform that I work on has a well that has had this happen. Only difference it happened 10 years ago when natural gas was almost twice the price and Devon Energy got greedy and kept opening choke. You may have just depleted the zone or have a dry hole
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Permalink Reply by Donna Thornton on
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It was not dry. It was producing. And several subsquent ones in the section came into production afterwards and are still producing. My original thought was whether they could drill to down below the cave in and reconnect. Admittedly, I do not know the technical particulars either. I know very little about this and you are more knowledgeable. Of course, as you stated, economics plays a big part. Thanks, Chris.
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