Posted on 08/21/2014 9:24:35 AM PDT by ckilmer
HOUSTON/WILLISTON, NORTH DAKOTA: 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 per cent 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 per cent from 2012 levels.
"There were a significant number of wells that we considered unstimulated," 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.
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.
ping
I had wondered if this were a possibility. It makes sense that the same hole can be re-fracked a limited number of times. I doubt each successive re-fracking will yield the initial production, but it’s cheaper than drilling an entirely new hole.
A little more on the subject
http://www.reuters.com/article/2014/08/20/energy-refracking-idUSL2N0QP28220140820
What’s the difference between re-fracking and water flooding an oil well?
275,000,000 BC was a very good ‘vintage’....................
To be ‘refracked’ wouldn’t it have to have been ‘fracked’ first?...................
Yes. This is going back into wells a few or many years old and doing more hydraulic fracturing from the original well bore.
Then some oil must have seeped back in from somewhere..................
Water flood is a continuous enhanced oil recovery method where injection sites on the outer edges of the field have water injected to push more oil into existing producing wells more towards the middle.
Hydraulic Fracturing, regardless if the first time, or a repeated process on an older well, is pushing water, sand and some chemicals down the production well to create cracks in the formation with the sand left to hold the cracks open. The water is removed and the oil/gas flows out through the cracks left open.
Each can be more involved and use different materials, but they are very different processes.
No. This is creating more cracks to reach farther into the formation to get to oil that was not reached in the original stimulation.
Remember these shale fields are very tight with low ability for the oil in place to flow out. Many shale wells are only getting a 3~5% of the oil in place. Hydraulic Fracturing again is trying to get more of the 95~97% of the oil that was still in the ground in the first place.
Thanks for the explanation.
Whatever happened to that technology that would essentially strip mine shale formations and haul the rocks to a crushing/heating furnace and extract the oil? Too slow or costly?.................
Most water flood projects involve fracking the production wells before commencing water injection on the periphery.
Both, and very very dirty....
You are talking about Retorting shale, and that is entirely different. Sadly, the industry uses two confusing terms that add to the confusion, shale oil versus oil shale.
Shale oil, like what is produced in the Bakken, Eagle Ford, etc is produced by drilling. It is oil that has already been cooked out of the shale by nature. In many cases, the oil doesn’t even remain in the shale layer but trapped nearby.
Oil Shale is the rock that contains still contains hydrocarbons that can be cooked out of the rock. It has to be retorted either in situ like Shell has experimented with in Colorado, or mined, crushed and cooked on the surface.
More expensive, but also they are different resources. Green River is Oil Shale. Bakken and Eagle Ford are producing Shale oil, but oil shale may also remain there as well.
That’s confusing as hell!.....................
Yeah, if you decide to invest in a related start-up company, you will want to understand the difference.
I invest only in Snake Oil companies.....................
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