Re-Fracking In The Bakken -- Idle Rambling -- June 24, 2020

Updates

June 25, 2020: from a reader with history of working in the Bakken fracking sector --

Keeping this very general sense, I guess I'll say I generally agree with your take, although I will add that there may be more re-frac activity than you think, and I think it will only continue to increase.

You're absolutely correct that infill drilling has been the priority for most operators, but of course there are some major issues when spacing continues to get tighter (frac hits).

Not every frac hit is negative, and in the Bakken I believe that approximately 60% of frac hits are considered "positive", but it is still a major concern (note: positive and negative from an overall production standpoint. Pressuring up offset wells during frac operations is almost universally seen as a negative).

It will be interesting to see what operators decide to do, especially with the current market conditions.

Original Post

A pet theme of mine on the blog: re-fracking (tagged: re-fracking or refracking). Recently a reader engaged me on this issue, in a very general sense. My comment back to the reader, not ready for prime time:

It's my impression that we've not seen much re-fracking in the Bakken. There is one exception: MRO in the Bailey oil field, or at least that's my impression.

Even in the Brooklyn oil field, where CLR is systematically drilling out the entire field, I've not seen any re-fracks.

I find it quite interesting we have not seen much re-fracking. That suggests to me the operators are not ready to start re-fracking on a general basis. If accurate, that suggests to me that operators prefer to maximize the number of middle Bakken and Three Forks infill wells before going back in and re-fracking.

If so, the operators must have some "feelings" or data suggesting that re-fracks will work best when maximum number of initial fracks have been accomplished in any given location.

But re-fracks seem to be such a no-brainer that when I see so few re-fracks, there must be a reason.

Note that "re-fracking" and "MRO_refracking" are tags. Generally speaking these tags also involve re-fracking:

• advantaged_oil;
• fracking_halo_effect:
• post_shut_in_production_jump;
• post_shut_in_production_jump_second;

Note the new tag with this post: frack_hits.

For more on "frac-hits," see this article over at mrt.

With all those wells vying for space, “frac hits” occur when hydraulic treatment from one well -- the active or child well -- communicates with another well -- the passive or parent well.

“A lot of companies are focused on infill drilling, and they have to figure out how close is too close,” said Reece Roberts, owner of Permian Petrolink and chairman of the Permian Basin section, Society of Petroleum Engineer’s Completions and Operations Study Group.

The consequences of a frac hit are loss of production and mechanical, physical or chemical damage to offset wells that may or not be immediately apparent in production, King said.

Schlumberger is in the process of studying the issue. The oil field services company amassed case studies of wells in the Eagle Ford and 4,000 each in the Barnett and Bakken shales, said panelist Jason Baihly, commercial and risk assessment manager. He said Schlumberger also is gathering case studies from Permian Basin wells.

“We’re in the early innings of understanding parent-child well interaction over a year’s time,” Baihly said. “(That’s) the biggest issue in unconventionals long-term or even mid-term: trying to get more production out of the child wells,” he said.

So: my enthusiasm for increased production in daughter wells due to new fracking, initially seen as a positive, could be a problem down the road.

From April, 2017.

A frac hit is typically described as an interwell communication event where an offset well, often termed a parent well in this setting, is affected by the pumping of a hydraulic fracturing treatment in a new well, called the child well. As the name suggests, frac hits can be a violent affair as they are known to be strong enough to damage production tubing, casing, and even wellheads.

Claudio Virues, a senior reservoir engineer with CNOOC Nexen, said frac hits have become a top concern in the shale business because they can affect several wells on a pad, along with those on nearby pads too. Based on his experiences in Canada and in south Texas, the question is no longer if a frac hit will happen, but how bad will it be.
“You usually have two scenarios,” he said. “One may be that you have a temporary loss of production, but you will recover to the trend that you had before. The other will be really bad for your production and reserves.”

He is alluding to the fact that some wells impacted by frac hits never fully recover and, in the worst cases, permanently stop producing after taking frac hits. The frequency of these outcomes are unknown as there are no publicly available statistics. In a small minority of cases, and in select formation types, frac hits have been known to increase production in the impacted well, but this is unusual.