Search

Managing Solid Breaker: Crosslinked Frac Operational Realities


Summary

  • Operational issues with breaker are often undetected, the post-frac report only tells part of the story

  • Breaker issues can reduce gel stability time causing proppant to drop out of suspension: stuck tools, difficulty circulating, and expensive downtime

  • Polymer damage is minimized through effective cleanup of the proppant pack and filter cake if breaker is run properly


Solid Breaker and How It’s Run


Breaker is one of the most critical chemicals on a crosslinked frac from an operational cost & production perspective. It must run consistently for predictable break times, to reduce polymer damage and promote proppant pack cleanup.



This is a video I took on a very recent well where breaker was running inconsistently for a large portion of the job, sometimes not at all.


The frac hands had to manually break up the breaker so it had even a chance at feeding into the blender unit predictably through the chicken feeder. The chicken feeder is a small hopper that sits atop the blender. It fits a few pails of breaker and has a small auger at the bottom that feeds the breaker into the blender tub.



This breaker in the image above is ammonium persulfate, a strong oxidizing agent that is a white granular solid. It's not supposed to have huge chunks, and needs to be finely granular so it can feed into a small auger and dissolve in the frac fluid before heading down-hole.


The post-frac report for this well didn’t mention this issue & from the operator's perspective in the data van the chemicals seemed to be running smooth…


…but clearly, they were not.


Maybe you’re thinking back to the last post-frac report you were sent, how confident are you this type of thing isn’t happening on your wells?


Why breaker issues are dramatically under-reported

Have you ever read a post-frac report that mentioned issues like these? Breaker issues are more common than post-frac reports might suggest.


Breaker issues are under-reported – I have spent a lot of time climbing on blender units and conducting break tests and have seen issues on a large percentage of wells.


1. Service company personnel forget to turn the breaker on

2. Worn-out equipment fails to meet job rates

3. Delays in the breaker starting to run

4. Uncalibrated equipment running incorrect volumes of chemicals


We have yet to see any mention of these operational realities on a pressure-pumping company's post-frac report.


The way that granular breaker consumption is reported is based on the auger rpm in the breaker hopper. If the auger is spinning, breaker consumption is being recorded, whether or not the hopper is empty, or uncalibrated. It’s unreported because there is a total reliance on the integrity of the service company personnel to report their own mistakes, failures, and issues.


The photographs below are from a stage where they didn’t pump any breaker; I believe the chemical van operator simply forgot to flick the switch to turn it on. This shows the fluid viscosity 4-days after the frac was completed & after 9 hours in the hot bath at 70°C (formation temperature). This stage will likely not clean up properly and is a total write-off for the producer.


Viscosity of sample is still over 50cP after 4 days in hot bath at formation temperature, typically samples are at 2-3 cP at this point.


Same sample as above showing cloudiness and high viscosity after 4 days in the hot bath at formation temperatures. Typically, samples clarify and read 2-3 cP at this point.


Operational Impacts


Breaker issues can impact the frac operations through loss of proppant suspension resulting in:

  • Screen outs & high pressure events

  • Stuck tools

  • Plugged wellbores

  • Reduced decision-making time


If the breaker is not running properly, some blender operators will try to average out the overall breaker consumption, which can cause dramatic variations in break times and operational issues. Consider the case where the blender operator notices breaker hasn’t been running for multiple stages. The hopper is still full but should be ready to be re-filled. I’ve witnessed blender operators increasing the breaker loadings for the following stages, throwing all of the breaker in at the end of the stage or, more often, just writing down on the post frac report what they “think” they were supposed to pump.



Production Impact of Breaker issues


This can obviously have a huge impact on well performance, the subsequent analysis of the well, and the completion effectiveness. An unbroken gel will cause:

  • Poor Proppant Pack Cleanup

  • Reduced Fracture Conductivity

  • Reduce the Wells Productivity Index

  • Increase the Production Analysis Complexity

  • Increase the Completion Analysis Complexity


Summary


When frac fluids aren’t consistently characterized on a per-stage basis, performance impacts are often attributed to geology. The industry often takes post-frac reports at face value, assuming that whatever has been designed is what was executed in the field, often that is not the case.


In the next post we’ll go over how Lab Site brings transparency and solutions to these issues.

If you have any questions or comments don't hesitate to get in touch, we love talking about fracs.


Thank you for reading.