When people tell the story of Vaca Muerta, they list milestones: the first horizontal well, the longest lateral, the most stages in a day. This article looks at something else: how the well changed year by year, what is still changing, and what has already been optimized as far as it can go.
The curve that changed everything
In August 2016, Vaca Muerta produced about 32,000 barrels of oil per day. Brent was around $46, and activity was propped up by a domestic price of about $67.5 for Medanito, Argentina's benchmark crude. That year 112 wells were brought online, fewer than in 2015, and YPF drilled almost nine out of ten.
But 2016 was the turning point: for the first time, most new wells were horizontal (81%, up from 24% in 2015). In April that year, Vaca Muerta reached its first 100 horizontal wells on production. A few months later, in January 2017, the unions, companies and government signed a special labor agreement for unconventional work. That was the start of mass development.
Before the switch, about 500 vertical and directional wells were drilled. The first horizontals were already being tested: 120 between 2011 and 2015.
Measured by spud year, the jump is even clearer: in 2015, 41% of the wells drilled were horizontal. In 2016, 94%. Vertical wells all but disappeared in a single year.
The title of this article has a double meaning. From 2016 on, Vaca Muerta's wells took the curve: they go straight down to the rock, turn, and run sideways through the formation, with a horizontal lateral more than 3,000 ft long. That changed everything.
The numbers showed it right away. The typical 2016 horizontal well (a 4,600 ft lateral and 18 stages) against the typical 2014 vertical:
- After three months it had already produced 27,000 barrels: 3.2 times as much as the vertical (8,600).
- In the first year, 109,000 barrels against 27,000: four times as much.
- After five years, 261,000 against 52,000: five times as much.
Per ton of sand they delivered about the same (29 and 27 barrels in the first year). The horizontal was not more efficient per ton: it reached much more rock from a single wellbore and a single pad. The first three months showed it was the right call.
Ten years later, Vaca Muerta produces 670,000 barrels per day, 21 times as much, with more than 2,800 horizontal wells and a dozen operators.
Sources for the 2016 context: INSEE, Brent in August 2016 · Hydrocarbon Engineering, domestic Medanito price · Ámbito, Vaca Muerta labor agreement
Three eras
To see how the curve played out, we took Vaca Muerta's horizontal oil wells and tracked ten variables, year by year, since 2015. We used the data operators report to Argentina's Energy Secretariat: the detail of every frac job (the official equivalent of a FracFocus disclosure) and every well's monthly production. Each value is the median of the wells that started producing that year.
2011–2016: learning. Vaca Muerta's first wells were vertical, like conventional wells. In 2015, only one in four new wells was horizontal. In 2016 it was 81%, and in 2017, 96%. That year settled the debate.
2017–2022: stretch and tighten. Laterals grew from 4,850 to 8,460 ft. Stages got closer together: from one every 257 ft to one every 213 ft. Water intensity rose from 31 to 43 bbl per foot. In 2015, 68% of the sand was imported. By 2021, imports were practically zero.
Since 2023: the recipe. One stage every ~200 ft, about 2,600 lb of sand and 45 bbl of water per foot. The per-foot design has not moved since. What changes is how many feet the well has.
The ten variables
Fit for basin: adapting the well to the rock
At first, Vaca Muerta copied the US recipe: vertical wells, imported ceramic proppant, long stages. Almost everything that changed afterwards has a geological reason. The industry calls this fit for basin: not doing what works in Texas, but what works for this rock.
The learning curve is not over. Sand is one example: between 2019 and 2024, local sand from Neuquén and Río Negro came to cover about 40% of demand. In 2025, YPF went back to favoring sand from Entre Ríos. The argument is that, with Vaca Muerta's overpressure and stress regime, the stress on the grains rises as the well produces, and a weaker sand crushes. The same rock that lets wells flow on their own forces a better choice of proppant.
Fit for basin also explains what was not copied. So far, Vaca Muerta has no "cube" developments like the Permian, with many wells stacked across several zones at once. Fracturing is still almost all plug-and-perf. And simul-frac, used on more than half of Permian wells, only arrived here in 2021 (YPF, Rincón del Mangrullo).
Geology sources: AAPG Memoir 121, Loma Campana · AAPG Wiki, Vaca Muerta · Andean Geology, "beef" · YPF, landing zones (Conexplo 2018) · OGJ, Phoenix and Pan American pilots · Río Negro, frac sand 2026 · LM Neuquén, YPF's first ESP · LM Neuquén, first simul-frac · World Oil, Permian produced water
What no longer changes
The most striking number is proppant per stage: 520,000 lb, the same as in 2016. In ten years, the size of each stage has not changed. What changed was the number of stages per foot. By moving them closer, from 257 to 198 ft, proppant intensity rose from about 1,970 to 2,630 lb per foot.
Since 2023, all four variables have held steady. A 2025 well is a 2023 well with 1,300 more feet of lateral.
For a service company, that gives a simple rule: every 1,000 ft of lateral takes about 5 stages, 1,300 tons of sand and 45,000 bbl of water. If you know how many feet of lateral will be fracked next year, you know how much sand, water and frac hours will be needed.
Still changing: length
Laterals grew from 4,180 ft in 2015 to 10,160 ft in 2025, and stages followed: from 16 to 51. In 2025, 29% of wells had laterals over 11,500 ft, up from 6% in 2023, and the record reached 16,780 ft.
In 2026 the median is holding at about 10,000 ft. It is too early to tell whether this is a pause or a ceiling.
And here is the uncomfortable part. First-year oil per well has not grown since 2021: it hovers around 245,000 barrels. Wells are 1,870 ft longer and have 14 more stages, but they produce the same. That is why oil per 1,000 ft of lateral fell from 32,600 barrels in 2019 to 24,400 in 2025: back to the 2015 level.
It is the same effect we saw in Frack or crash: each ton of sand yields less. Early rates are still rising (from 1,040 to 1,257 barrels per day between 2019 and 2025). The first-year decline, however, has not changed: between 60% and 67%. The well starts stronger, but over the year it delivers the same.
Flowing wells, for less and less time
One way Vaca Muerta differs from almost every other shale play in the world is pressure. The rock is overpressured and wells flow on their own, without a pump, for two or three years. That period is getting shorter.
Of the wells that came online between 2020 and 2022, half were still flowing at 36 months. For the 2023–2025 wells, it was 29. At two years, 62% are still flowing, against 78% for the previous group.
When they stop flowing, seven out of ten go straight to rod pump and one in four to gas lift. ESPs are barely used: under 3% of lift changes since 2023.
There are several possible explanations, and probably all of them play a part:
- More child wells, drilled next to parent wells that have already depleted the pressure.
- More water: water rose from 20% to 28% of the liquids produced in the first year.
- Operators that install the pump earlier so as not to lose rate.
Against the Permian
People in the industry keep saying Vaca Muerta is "the new Permian". This is how the two compare side by side on what can be compared:
In design, Vaca Muerta has already caught up with the Permian. Lateral length is almost the same, so is stage spacing, and both basins have settled on their recipe: the Permian in 2017 and Vaca Muerta in 2023. Both have the same problem: wells are longer, but each foot delivers less.
The differences lie elsewhere.
Vaca Muerta did not copy, it adapted. It pumps more sand per foot (2,630 vs about 2,200 lb), produces far less water and takes advantage of the rock's pressure: a Permian well usually needs an ESP from its first months, which lasts up to eight months and then has to be replaced (switching to a rod pump costs about $300,000 per well). A Vaca Muerta well skips that stage and goes straight from natural flow to rod pump.
The remaining gap is about speed and scale, not design. A Permian frac fleet completes roughly twice as many stages per day. More than 6,800 wells are completed there every year. Here, about 470.
What it means
The technical frontier of well design has been reached: stage spacing, proppant per stage and water per foot have not moved in years. Length can still grow, but each new foot delivers less than the one before.
So what will define Vaca Muerta's next years is not a better well but drilling the same well faster and cheaper: more stages per day, fewer days per well, moving sand with fewer trucks. That is where the gap with the Permian still lies. And it is a race that will be won by service companies as much as by operators.
How we measured it
Horizontal oil wells in the Vaca Muerta formation (Argentina Energy Secretariat: monthly production per unconventional well and frac job reports, data through August 2026). Each value is the median of the wells that started producing that year. First-year oil is only calculated for wells with 12 months of history, so 2025 includes wells that came online through August. Wells drilled per year: official well registry (Chapter IV), by spud date. Flowing wells are estimated from the lift type each operator reports month by month (Kaplan-Meier method). Metric data were converted to US units (1 m = 3.28 ft, 1 m³ = 6.29 bbl, tons are US short tons). There is no complete public annual series for the Permian, so some values are for specific years or are estimates, and we say so in each case.
Permian sources: EIA, laterals 2015–2025 · API, simul-frac and wells 2025 · Novi Labs, proppant intensity · E&P / Rystad, Delaware 2018 · E&P / Hart, stage spacing 2016 · JPT, spud to production · PB Oil & Gas, the ESP cycle · Diamondback, SEC filing · Bloomberg NEF, productivity 2022 · LM Neuquén, YPF frac speed
Keep reading
- Frack or crash: how many wells and how much sand are needed
- Fracs in Vaca Muerta, month by month and by field
- Hydraulic fracturing · Frac sand · Drilling
- Rod pumping · Gas lift · Electric submersible pumps (ESP)
Lautaro Maggi · Chemical Engineer (ITBA) · Specialist in Oil and Natural Gas Production (ITBA)
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