Two wells sit a mile apart in the same bench. Well A came online at 1,400 bbl/d and made the operator's press release. Well B opened at 850 bbl/d and nobody mentioned it. Eighteen months later, Well B has produced more oil.
That's not a trick. It's the difference between a peak-month number and a cumulative number — and it's the single most common way a buyer overpays for a package. IP30 measures how hard a well was flowed out of the gate. Cumulative measures what it actually delivered. When you screen and rank wells, choosing the wrong metric changes which wells look like winners.
What IP actually measures
Initial production — IP24, IP30, IP90, whatever the convention — is a snapshot of the flush period, when a fresh frac is unloading and the near-wellbore reservoir is at its highest pressure. It's real, but it's also a management decision. A well choked back to protect the reservoir posts a lower IP than an identical well flowed wide open. A well that flushes hard early often declines hard, too. So a headline IP tells you as much about the choke setting and the operator's flow strategy as it does about the rock.
The problem is that IP is easy to find, easy to compare, and easy to brag about. So it becomes the default ranking metric — in investor decks, in county rankings, and in the mental model buyers carry into a deal. Rank a county by IP30 and you get a leaderboard of the wells that were flowed hardest, not the wells that will pay you back the most.
The question to ask instead
The more useful question is blunt: which wells in this county have actually produced the most oil, and how does that list compare to the IP ranking?
That's a query you can put to the Wellsite data lake in plain language. Ask it to rank every wellbore in a county by cumulative oil to date, then pull the same set ranked by first-month or first-90-day rate. Line the two lists up side by side. The wells that appear near the top of both are genuinely strong. The wells that top the IP list but slide down the cumulative list are the flush-and-fade performers — big opening act, thin second half. And the quiet overachievers — modest IP, high cume — are exactly the wells a disciplined buyer wants to find before anyone else does.
Because the record runs from first permit to last production, cumulative isn't an estimate here — it's the sum of what the well reported, month by month, across its whole life.
Normalize before you conclude
Raw cumulative favors older wells simply because they've had more time. So the comparison has to account for age. A few ways to keep it honest, all answerable against the record:
- Cumulative at a common point. Compare oil produced in the first 12 or 24 months across wells, so a two-year-old well and a six-year-old well are measured on the same clock.
- Cumulative versus decline shape. A well with a high cume and a shallow decline still has runway. A well with a high cume built entirely in the first six months, followed by a steep fade, has already spent most of its reserves.
- Benchmark against the county average. Pull the county's average cumulative-by-month curve and see which wells sit above it — that's the type-curve context that turns a raw number into a percentile.
Ask Wellsite to combine these — rank by 24-month cumulative, then overlay each candidate's current decline rate — and the flush-and-fade wells separate cleanly from the durable ones.
Why this matters at the deal table
Value lives in the area under the decline curve, not at its peak. Two wells with identical IP can carry EURs that differ by 40% because one holds a shallow terminal decline and the other drops off a cliff. If your bid is anchored to IP, you're paying for the peak and inheriting the fade.
The same logic screens an entire package. Instead of taking a seller's IP-sorted well list at face value, re-rank every wellbore by cumulative and by remaining trend. Wells that were sold on their opening rate but have already produced most of their oil get valued for what's left — often a lot less. Wells the seller undersold because they never had a flashy month get the credit they've earned in barrels on the ground.
The takeaway
IP is the trailer. Cumulative is the movie. Both belong in your analysis — the gap between a well's IP ranking and its cumulative ranking is itself a signal, telling you whether you're looking at a flush performer, a slow burner, or a genuine top-tier well.
Ask the record both questions. Rank by peak, rank by cume, and pay attention to the wells that move. That's usually where the mispriced value is hiding.