Harbour Energy, the U.K.-based E&P company, has formalized in its April 2026 Investor Meet what its Argentina country manager, Martín Rueda, had previewed at last year's Argentina Oil & Gas Expo: Argentina is one of the company's five core countries.
The institutional document, signed by chief executive Linda Z. Cook and presented after closing the $3.2 billion acquisition of U.S. independent LLOG Exploration in the Gulf of Mexico, places Argentina alongside Norway, the United Kingdom, the United States and Mexico as the five jurisdictions that account for nearly 90% of Harbour's portfolio. For the first time in a public corporate document, the company set a date for a key Vaca Muerta milestone: the first phase of shale oil development at the San Roque block is targeted for late 2026.
The country designation and the LLOG-proforma reserves base are confirmed; the late-2026 San Roque date and the 1,000-location drilling potential outlined by Cook are corporate projections still contingent on Neuquén province granting unconventional certification for a block currently held under conventional terms.
Argentina Among the Five Core Countries Post-LLOG
The repositioning is explicit on slide 6 of the document. Argentina sits among the five countries that account for 90% of forecast 2026 production (475,000 to 500,000 boe/d), of 1.4 billion boe in reserves and of 1.9 billion boe in resources at year-end 2025 on a proforma basis.
Pan American Energy (PAE), Argentina's largest private oil producer; YPF, Argentina's state-controlled oil and gas company; and Pampa Energía, a diversified Argentine energy company, are Harbour's central partners in the Southern Energy consortium, while TotalEnergies, the French energy major, operates three of the company's four producing assets.
Harbour's Argentine weight had already been previewed by Rueda at the 2025 Argentina Oil & Gas Expo, when the executive said 21% of the company's reserves and 40% of its resources with global development potential sit in the country.
The April 2026 presentation confirms that reading proportionally and crystallizes it in a document signed by the global CEO after the U.S. pivot via LLOG. The Gulf of Mexico entry, in other words, has not displaced Argentina from Harbour's strategic board.
The asset-by-asset breakdown is as follows.
CMA-1 (Cuenca Marina Austral, Tierra del Fuego province, offshore). Harbour holds 37.5%, partnered with TotalEnergies Austral, the French major's Argentine subsidiary (37.5%, operator) and Pan American Energy (25%). The block contributed 52,000 boe/d of gas in 2025 and now has nearly a full year of production from Fénix, whose unmanned platform was completed in January 2025. CMA-1 is the backbone of Harbour's current Argentine output, around 71% of the local total; the presentation flags Fénix as a potential tieback hub for new satellite developments.
Aguada Pichana Este (APE, Neuquén province, unconventional). Harbour holds 23% in the gas window, with TotalEnergies as operator and YPF and PAE as partners. The block sustains a plateau of 14 million cubic meters per day (MMm³/d) of natural gas and, according to Rueda, has headroom to scale to 16 MMm³/d. Within Harbour's portfolio, APE is the largest unconventional gas asset by volume.
San Roque (Neuquén province, conventional concession with shale upside). Harbour holds 25%, with the same partnership structure as APE and Total Austral as operator. Conventional output declined to 2,500 boe/d in 2025, but the block has four exploration and appraisal wells plus four pilot wells already drilled. The first phase of shale oil development is scheduled for late 2026, contingent on Neuquén province granting unconventional certification. The company sized the potential at 1,000 drilling locations, with one rig targeted to be working at the block by year-end. The initial pilot would total 16 wells.
Southern Energy S.A. (SESA, Río Negro province). Harbour holds 15% in the consortium led by PAE alongside YPF, Pampa Energía and Golar LNG, the Norway-based LNG infrastructure company. The final investment decision was confirmed in 2025 for a phased floating LNG project covering two ships and combined capacity of around 6 million tonnes per annum (MTPA), equivalent to roughly 27 MMm³/d or 1.0 billion cubic feet per day (Bcf/d).
The first ship, the Hilli Episeyo, is targeting startup in late 2027 and the second, the MK II, in late 2028. Harbour's capex contribution through commercial operation runs to about $100 million. In December 2025 the consortium signed a non-binding preliminary agreement with SEFE Securing Energy for Europe to place approximately 80% of the first ship's volume.
Why Argentina Outweighs Its Output Share: Economics, Fiscal Regime, Oil Window
The hierarchy rests on three layers.
The first is economic. Rystad Energy, the energy research and consultancy firm, projects that Vaca Muerta could reach one million barrels per day (bbl/d) by 2030, a trajectory that Radhika Bansal, the consultancy's vice president of upstream research, has described as a central pillar of Argentina's long-term energy strategy.
Within that framing, the 1,000 drilling locations identified at San Roque, with development integrated with operator Total Austral, offer marginal scale at high return. Harbour's presentation anchors the block's breakevens within the Vaca Muerta range, which Rystad puts on parity with the best Permian hubs in the United States once lifting costs of new horizontal wells are included.
The second layer is fiscal-regulatory. The RIGI granted to Southern Energy, secured export permits, and SEFE's recognition of Argentine LNG as an alternative to Russian supply form a framework that compares favorably with the U.K. fiscal regime, where taxes can total up to 75% and contributed to the $4.25 billion fiscal loss Harbour booked on its Waldorf acquisition. The effective corporate tax rate Harbour projects for the end of the decade declines materially as production shifts toward lower-burden jurisdictions.
The third is geological and strategic. CMA-1 provides stable long-cycle cash with satellite tiebacks; APE offers scalable gas volumes with secured offtake, both domestic and international via SESA; San Roque opens an oil window inside a portfolio historically heavy on gas. The presentation positions that intra-basin diversification as a competitive edge over independents with single-product exposures.
Layered Sequencing as Harbour's Distinguishing Feature
Harbour's sequencing in Vaca Muerta follows a pattern that sets the company apart within the foreign independent peer group: the gas window is concessioned and in mass development (APE); the oil window still requires provincial authorization before its pilot (San Roque); and access to international markets depends on a fourth, midstream-and-downstream asset (SESA). Each phase has a different operator, a different timeline and a different regulatory risk. That layered articulation, uncommon among majors operating a single block, is why Harbour can size 40% of its global 2C resources in a country accounting for just 15% of current production: what is left to develop is disproportionately larger than what is already producing.
The corporate guidance for 2026 envisages capital expenditure (capex) of $2.2 billion to $2.4 billion in aggregate. In a portfolio that recycled more than $3.6 billion of capital in the past year — LLOG to enter the United States, Waldorf to consolidate the United Kingdom, the Indonesia divestment to exit Southeast Asia — Argentina aligns with the company's central thesis: long-life assets, competitive breakevens, and room for organic growth.