WHAT IS ‘Re-fracking’
Re-fracking is oil companies’ practice of returning to older shale-oil and shale-gas wells they had fracked in the recent past to capitalize on newer, more effective extraction technologies. Re-fracking can be effective on especially tight deposits where the shale produces low yields, as it may expand their productivity and extend their life span.
For example, organizations are re-fracking in the Bakken shale deposit of North Dakota to revisit a number of wells drilled between 2008 and 2010, due to improved hydraulic fracturing technologies. According to the North Dakota Pipeline Authority, organizations have re-fractured more than 140 wells in the Bakken as of mid-2017, and most saw an increase in production as a result. Similarly, companies are re-fracking in other well-established, large shale formations in the U.S. such as Eagle Ford and Barnett, both in Texas.
BREAKING DOWN ‘Re-fracking’
Re-fracking in its most basic form is shooting a mixture of sand and water into an underperforming well to boost production. Companies have been using this function to some degree for decades. The mixture can help hold the cracks open once they form, allowing oil to flow more rapidly, boosting the amount that the company can extract from the formation.
Re-fracking has come to the fore recently as companies are now employing this long-used technique with vertical drilling processes and technologies, allowing access to deposits that they previously couldn’t access.
To that end, companies are now re-fracking some wells sunk as little as three years ago. One technique in the re-fracking process involves sealing up larger cracks in the well’s shale with small plastic balls so that new proppant can find its way into tighter cracks with the help of a higher well pressure.
Pros and Cons of Re-fracking
Wells can cost many millions of dollars to drill and complete, and some have a very low recovery rate, as well as large sections of deposits that produce either nothing or next to nothing. The appeal of re-fracking is that it can allow new technology to extend the life of existing wells, where exploration and production companies already have found some success.
Another advantage for exploration and production companies is that re-fracking projects often cost much less than new vertical wells.
As is the case with fracking in general, however, re-fracking is controversial because of the amount of natural resources required, and more notably, because of the negative effects it can have on the air, water and soil of the areas where fracking has taken place. For example, one of the main chemicals used in the fracking process is methane, which escapes into the atmosphere during extraction. Because methane is 25 times stronger than carbon dioxide in terms of trapping heat, the release of this gas is detrimental to air quality in the vicinity of fracking sites.