Refracturing as a technology has been around for many years. Vertical wells have been refractured since the 1970s with positive results. However, refracturing multi-stage horizontal wells is still relatively new. As oil prices fell, refracs started gaining more importance. Compared to drilling and completion costs for a new well, refracturing can be significantly cheaper (~$2MM), while recovering as much as 1Bcf of incremental gas reserves. In fact, refracs often provide such a high return on investment, that it is recommended that refrac planning be part of the initial development of a field.
But what is truly a ‘successful’ refrac? To comprehend this, it must be understood that as refracturing activity has picked up over time, operators have experimented with technologies as well as strategies in their field development plans. They haven’t quite followed a cookie-cutter approach.
When refracturing in horizontal wells began, operators were focused on reviving older wells in good rock or targeting wells where the initial completion did not show good returns. It was designed to be able to access more reservoir volumes, accelerate recovery, or slow down the rapidly declining production of the parent well. For example, in a small area chosen in the Williston basin, where refracs were done prior to 2014, we find that wells that were chosen as target refracs fall below the median IP. This implies that refrac candidates were chosen among wells whose initial completions yielded relatively low IP rates (bbl/d). Although most of these target refracs had gross perforated intervals that were approximately within the average for the area, proppant volumes pumped in the initial completion fell below the average. Consequently, in this area, the operator chose to revive wells that had relatively lower IP and were initially completed with smaller treatment volumes.
With time, as companies experimented more with refracturing practices and gained a better understanding of the effects downhole, operators started viewing refracturing as a strategy to also re-stimulate or re-energize infill or offset wells. More conversations have ensued over ‘frac hits’ and hydraulic communication between wells, and whether they have a positive or negative impact on production. In many cases, it did show a positive impact on the older wells that had been producing for a while, while in some, it negatively affected both the refrac as well as offset wells.
With this in mind, definitions of what makes a ‘successful’ refrac start to vary – some view it as slowing down the decline rate of the parent well in order to extend the well life, while others are focused on accelerating recovery within a short time frame. Ultimately, the success of a refrac is determined by its economics. Many operators only find it economic to stimulate both the parent well and positively affect offset wells.
As oil prices continue to hover around the $50 range and recompletion techniques improve, refracs will only become a more important component of operators’ long-term plans. Learning from current trends and best practices will put companies in a position to maximize their refracs.
To learn more, download the whitepaper: What Makes a Successful Refrac?