Oil & Gas
YPF, Argentina's state-controlled oil and gas company, drilled a 4,770-meter lateral in a single run on a slim well, then repeated the feat on three wells in ten days.
The company said the lateral, about 15,650 feet, is the longest it has recorded for the design, known in the Vaca Muerta formation (one of the world's largest shale plays, in Argentina's Neuquen Basin) as a "slim" well because it is built with smaller-diameter casing. YPF Chairman and CEO Horacio Marín announced the mark on LinkedIn, adding that it was matched on three wells in just ten days, with three different drilling rigs and different service companies.
Drilling in a single run means the horizontal section was drilled continuously, without pulling the bottomhole assembly to surface and tripping back in. On long laterals, each of those trips adds rig hours, and therefore cost, to every well.
The repetition changes what the figure means. A mark on a single well can reflect a finely tuned rig, a seasoned crew or cooperative geology. Hitting it three times with different rigs and contractors suggests the result rests on a procedure that travels from one location to the next. YPF framed that as the goal: "The challenge is to turn records into standard practice."
Slim Laterals Have Grown 1,370 Meters Since 2021
YPF's annual reports to the U.S. Securities and Exchange Commission (SEC) define the design precisely: wells with 6¾-inch production casing. In its 2021 report, the company said it had tested the technical limit of that design and reached a lateral of 3,400 meters.
The 2022 report logged two advances. At Loma Campana, YPF's flagship shale oil block, location 295 exceeded 3,900 meters. At Rincon del Mangrullo, a YPF-operated gas block in Neuquen province, the company drilled its longest slim well to that point, with a 4,253-meter horizontal section. The same year, YPF reached more than 4,400 meters on a conventional-design well.
Against that Rincon del Mangrullo mark, the new 4,770 meters add 517 meters. Against the 2021 starting point, the gain is 1,370 meters. The longest lateral the company has announced for any design is 5,114 meters, drilled at Loma Campana in May 2025, leaving the slim well 344 meters short of that figure.
YPF's Standard Design for Large-Scale Development
YPF has already given the slim design a central place in its plan. In its first-quarter 2026 results, filed with the SEC in May, the company recalculated its drilling and fracturing efficiency metrics on a new basis, limiting them to slim wells, which it described as the most representative of the standard well configuration planned for large-scale development in Vaca Muerta.
On that basis, the quarter closed with an average of 364 meters drilled per day in YPF's core shale oil blocks and 11.2 frac stages per set per day. The average lateral per well drilled in the period was 3,437 meters, up 8% year-on-year. The new mark exceeds that average by 1,333 meters.
The rationale is cost. A smaller diameter means less steel per well and a lighter build, and the company linked these operations to cost reductions, with the trade-off that laterals of this length demand very precise execution. In Shale24's analysis of the LLL Oil project YPF filed under Argentina's Large Investment Incentive Regime (RIGI), the reference cost of a single well in Argentine shale was put at $9 million to $11 million.
The three wells were monitored from YPF's Real Time Intelligence Center (RTIC), where each stage is tracked and decisions are made as the well advances. The same center oversaw 203 consecutive hours of fracturing at Bandurria Sur, a YPF-operated shale oil block, in July, an operation YPF reported to the SEC with its second-quarter results as fully remote and completed without incidents. In the second quarter, the company drilled 56 horizontal unconventional oil wells in blocks it operates, 22% more than in the previous three months.
The long-run trend matches official data. Between January and November 2025, YPF averaged 5,592 meters drilled per completed well, the highest figure in a series from Argentina's Secretariat of Energy that begins in 2009, according to a Shale24 calculation published alongside YPF's contract with Baker Hughes, the U.S. oilfield services company, to drill longer wells in a single run.
Scale does the rest. Once the conventional-asset sales agreed in August close, 95% of YPF's production will come from Vaca Muerta, according to the company. With three wells in ten days, the next slim lateral will be measured against 4,770 meters.