A frac hit rarely announces itself. One month a mature producer is drifting down a clean hyperbolic decline; the next, its oil rate jumps 40%, its water cut climbs, or it goes quiet for three weeks and comes back a different well. Somewhere within a few thousand feet, an operator just completed a new lateral, and the pressure front reached your wellbore.
The question every operator and asset manager asks after the fact — or wants to catch in real time — is simple: did the offset frac hit my well, and did it help or hurt? The record can answer that, and you don't need to go pull individual well files to do it.
The two signatures that matter
Interference shows up in production as a break from an established trend. There are two flavors, and they look very different on the curve.
The positive hit (energizing). A depleted well sitting at a low, flat rate suddenly re-pressurizes because the offset completion pushed fluid and energy into the shared rock. You see a step-up in oil rate, sometimes doubling off a low base, often with a bump in gas. It fades over weeks to months, but the well may settle at a higher plateau than before.
The negative hit (damage or robbery). The offset draws down shared pressure or pushes water and proppant into your wellbore. The signature is a rate drop that doesn't recover, a spike in water cut, or a total shut-in during the offset's completion window — often followed by a lower post-restart rate than the pre-frac trend would have predicted.
Both are, by definition, outliers against the well's own history. That's the key: you're not comparing to a county average, you're comparing the well to itself.
Step one: establish the well's own trend
Before you can call something an anomaly, you need the baseline. Pull the full production history for the target well and fit its decline — the record already carries the month-by-month oil, gas, and water. A well eight months into a b-factor decline has a very predictable trajectory. Ask for the expected rate given that trend, and you have the counterfactual: what this well should be producing absent any outside event.
Outlier detection does the flagging automatically. Any month where actual production breaks meaningfully from the fitted trend — up or down — gets surfaced. A 40% jump on a well that should be gently declining is not noise; it's a signal that something changed downhole.
Step two: find the offset completion
A production break is only half the story. To call it a frac hit you need the cause, and the cause is a nearby well being completed around the same time.
This is where permits near a location earn their keep. Query drilling permits and wellbores within your radius of interest — a mile is a reasonable starting screen, tighter in stacked-pay areas — and line up their timing. A permit filed and spud a few months before your production break, with a completion date that lands right in the anomaly window, is your prime suspect. The offset's own first-production date is the tell: interference usually coincides with the neighbor's completion and early flowback, not months later.
When the anomaly month and the offset's completion window overlap, you've connected effect to cause without leaving the data.
Step three: quantify the impact
Once you've identified the hit, the useful number is the delta against the counterfactual decline.
- For a positive hit: how many incremental barrels did the well make above its projected trend, and where did the new plateau settle? That's uplift you can bank — or, if it's your own new well doing the energizing, evidence your spacing is capturing offset reserves rather than just draining a shared tank twice.
- For a negative hit: how many barrels below trend, and did the well recover its slope or reset permanently lower? A permanent loss is a real impairment to that well's remaining value, and it's the kind of thing that belongs in a lease-level economic review.
Because the record holds both wells, you can also look at the offset's own performance. If your well got robbed and the neighbor is a strong producer, that's parent-child interference doing exactly what tight spacing does. If both wells underperform, the completion may have simply been poor.
Why this is worth catching early
Most operators discover frac hits weeks or months after the fact, buried in a quarterly reconciliation. Set up alerts on the wells that matter and the sequence flips: a production change on a target well fires a flag, you check for a fresh nearby permit or completion, and you're evaluating the interference while it's still developing — in time to adjust artificial lift, manage water handling, or document damage for a lease dispute.
For a buyer running diligence on a package, the same workflow is a red-flag screen. A well with a suspicious step-down that lines up with a third-party completion next door isn't declining naturally — it's been hit, and its type curve going forward is not what the trailing history suggests.
The short version
Interference is a story told in two datasets: your well's own production trend and the permit-and-completion timeline of everything around it. Fit the decline, flag the break, find the offset, measure the delta. The record has both halves — the trick is asking for them together, which is exactly the kind of question you can put to the Wellsite data lake in plain language.