Magallanes basin

From SEG Wiki
Jump to: navigation, search
This picture shows the location of the Austral-Magallanes basin or Magallanes basin that is discussed in this SEG Wikipedia page.


The Magallanes Basin is found in the southern tip of Patagonia, Argentina, and Chile. This basin is one of the main hydrocarbon-producing basins in South America and the reserves are proven to hold 2.4 billion barrels of oil. The sediment deposits range from off-shore to onshore and the traps consist of unconventional and conventional reservoirs.



This is a geoseismic cross section of the Magallanes basin depicting the folds, thrusts, and petroleum systems.

The Magallanes basin is located at the southern tip of Argentina and is a young earth basin dating back as far as 250 million years. The basin is bounded by the Andes mountains to the west and stops at the Rio Chico-Dungeness high on its eastern border. Originally, in the Mesozoic Period, this basin was an extensional back-arc basin but through the Cenozoic period, it transitioned into a compressional foreland basin. [1]


The first exploratory well was drilled in the Tierra del Fuego Island subsurface in 1946 by the Argentine state oil company. This first well helped to discover hydrocarbons in the Spring Hill formation. Since then, over 1,000 wells have been drilled in the Magallanes Basin mainly producing Oil and Gas. The primary field of production is The Spring Hill formation which hosts most of the proven and probable reserves at 12.5Mm of petroleum and 15,750 Mm of gas. There are primarily 6 different operators focusing on 28 different blocks. There are onshore and offshore reserves and as the oil price rises it will make it more affordable to produce these arenas.[2]

Petroleum Geology

Source Rock Migration

This is a lithology column of the Magallanes basin showing drilled proven wells in different targeted formations.

The bottom of the Magallanes Basin contains remnants of volcanic sediments that were formed at the end of the Jurassic era but above this section lies the Springhill formation. This formation contains the majority of the hydrocarbons that are produced from the basin. The shales are primarily lower ignoramus marine mudstones. The migration of the hydrocarbons began with a lateral shift following the forlorn basin and continued up the monocline into the Springhill formations. Though the Springhill makes up most of the conventional reservoir some of the oil vertically migrated into the Zona Glauconitic and some remained in the Lower Cretaceous source rocks. These make up the unconventional reservoirs of the Magallanes Basin.[3]

Trap and Seal

The majority of the hydrocarbons that are produced in the Magallanes basin were formed in the early cretaceous period. The traps were created from Triassic-Late Jurassic rift faults that follow the southwest border of the Dungeness Arch. The Spring hill formation also has faults, drapes, and folds which have caught the oil. The reservoirs are sealed by the Inoceramus and Springhill mudstones.[4]

Future Production Potential and Political Challenges

The Magallanes Basin primarily resides in Argentina and the Energy industry is at the political fate of those in power. During the 1990s the Oil and Gas industry saw much self-sufficiency but in the later 2000s to 2015 the policies that were implemented dropped production and exploration dramatically. The industry has since been affected by the COVID-19 pandemic which saw another drop in demand. The government has since been trying to coddle their industry back as Oil prices start to rise again and worldwide demand for oil recovers.[5]

Petroleum Risks and Facility Engineering

This is a map displaying the pipeline network of Argentina. As you can see, there is only one major pipeline spanning the whole area of the Magallanes basin. This makes it difficult to transport hydrocarbons from the main producing areas of the basin which are located in the heart of lower Argentina.

The coast borders different parts of the basin which makes it easy to ship large amounts of equipment from around the world. There are also two large interstates that border the outskirts of Argentina and the basin. The main issue facing the Argentinean Oil industry is the lack of stable infrastructure within the heart of the basin. This makes it more challenging to access targeted plays within the basin. As of 2018, there is only one main pipeline spanning the entire length of the basin. The majority of the major oil plays are located more centrally in Argentina.


This page is currently being authored by a student at the University of Oklahoma. This page will be completed by Dec. 15, 2021.

  1. Cuitino , Jose, et al. “(PDF) the Austral-Magallanes Basin (Southern Patagonia): A ...” Research Gate, Latin American Journal of Sedimentology and Basin Analysis, Dec. 2019,>
  2. Rossello , Eduardo, et al. “Hydrocarbons and Petroleum Geology of Tierra Del Fuego ...” Research Gate, Mar. 2008,>
  3. U.S. Department of the Interior, and U.S. Geological Survey. “National and Global Petroleum Assessment ... -” USGS , Jan. 2016,>
  4. Schenk , C.J. “Magallanes Extensional Structures Assessment Unit ... - USGS.” Magallanes Extensional Structures, United States Geological S, 5 Feb. 1999,>
  5. Alliani, Pablo, and Fernando Brunelli. “The Law Reviews: Title - the Oil and Gas Law Review.” The Law Reviews , 3 Nov. 2021,>

Additional Readings