Exploration History

 

Although some exploration work has been carried out over the years in the Portuguese sedimentary basins, it can be considered that these are underestimated. Even the Lusitanian Basin, the most researched of the Portuguese basins, is a good example.

 

The first exploration surveys were carried out at the beginning of the last century. These were, for the most part, shallow and located near the occurrence of oil-impregnated rocks on the surface (seeps), onshore, north and south of the Lusitanian Basin.

 

Year 1844 can be placed as the historical starting point of petroleum exploration activities through the concession for the asphalt mine of “Canto do Azeche”, located next to the beach in Nossa Senhora da Vitória, in the municipality of Alcobaça. This mine was active until 1861, with the asphalt being used in public works linked to the railways and paving of some streets in Lisbon.

 

Source GPEP: Example of one of the entrances of “Canto do Azeche” mine

 

In 1936, a public tender was opened to allocate the captive area, with approximately 23 650 km², for the exploration and exploitation of hydrocarbons on an exclusive basis. As a result of this competition, the long period of exploration begins under the concession license nº 2138, approved by Decree 28575, of April 7, 1938. Was initially attributed to two English citizens who, a year later, would transmit their rights and obligations to the Anglo Portuguese Oil Company Ltd., which developed systematic activity in the area until the beginning of 1941, when it was interrupted until the beginning of 1946, due to the Second World War. The rights of this concession were transferred several times, which remained active until 1968.

 

During this first phase, exploration work focused on the Torres Vedras region, culminating with the carrying out of the country's first exploration wells in 1940, TV-1 and TV-2, whose oil shows admitted the possibility of a commercial reserve. However, the inexistence of adequate equipment did not allow the execution of production tests, leaving this hypothesis to be scientifically and technically unproven.

 

Source: Macieira, 1948: Planificação histórico-cronológica das pesquisas de petróleo em Portugal. Separata do fasc. II do Vol. IV de Estudos, Notas e Trabalhos do Serviço de Fomento Mineiro

 

The second phase of the exploration activity is much longer, taking place from 1946 to 1969, the year of the extinction of the Companhia dos Petróleos de Portugal (“CPP”), created in 1947 to transfer all the rights and obligations arising from this permit. During this period, the first seismic survey campaigns were carried out in the regions of Abadia, Torres Vedras and Arruda dos Vinhos and, until 1947, about 4000 km of reflection seismic were collected, mostly single-channel, as well as gravimetric surveys, a small magnetic survey near Lisbon, dozens of small survey surveys, of which the 9 surveys in Varatojo and the 2 surveys in Matacães. The CPP gave a new dynamic to oil research in the country, with exploration activities having been greatly increased and the areas for investigation being diversified, highlighting the several thousand linear kilometers of seismic profiles acquired between 1954 and 1962 and the around 80 exploration wells, between 1946 and 1969, with a total footage of rock cores of the order of 67 km, of which the deepest to date, the Barreiro-1 well, drilled in 1956, reached a depth of 3611 meters. In many of these wells, good oil shows were found, such as the cases of Verride-1 at a depth of 1494 meters, Vermoil-1 at a depth of 2309 meters, S. Pedro de Muel-2 at 1507 meters and the de Montalegre-1 at a depth of 1750 meters, this also with good evidence of gas in addition to oil, having even been carried out several production tests, but none of them showed quantities of commercial value.

 

The balance of this phase of petroleum activity in the country, in addition to a more in-depth investigation of the discovered petroleum system, allowed the geological configuration of the main sedimentary basins in the national territory, with a special focus on the onshore part of the Lusitanian Basin.

 

After the abandonment of this concession, new petroleum legislation, introduced with Decree No. 47973, of September 30, 1967, specified by DL 49360, of November 11, 1969, DL 625/71, of December 31, and DL 151/ 72, of May 6, opened the activity to free competition from all areas of the national territory with ptroleum potential, including for the first time the continental shelf, ie, the area offshore, being the areas for petroleum exploration, onshore and offshore, divided into blocks, based on a regular network and put up for international tender.

 

In this context, the first international oil companies arrive to develop a large number of geophysical exploration surveys by air or by sophisticated ships, having collected 13730 km of seismic profiles on the Portuguese continental shelf and 30455 of aeromagnetic profiles, whose results were the basis, allied to the new specific legislation for petroleum, for the intense petroleum activity that would follow.

 

The international public bidding resulted in the signing of 30 contracts for offshore areas, in 1973 and 1974.

 

Effectively, the golden years of petroleum exploration, particularly with regard to the offshore took place between 1973 and 1985.

 

Source GPEP: Concession areas granted in the 70´s and 80´s

 

The first offshore concessions were awarded in 1973 to Esso, Shell and Sun in the Lusitanian Basin. In 1974, new offshore concessions and for the first time in the Algarve and Porto Basins were awarded to Challenger and Chevron and Texaco. respectively.

About 21366 km of seismic, gravimetry and magnetometry profiles were acquired and 22 exploration wells were drilled in the Portuguese offshore, 3 in the Porto Basin and 14 in the Lusitanian Basin with a footage of rock cores of about 50 km, and 5 exploration wells , the only existing ones to date, in the Algarve Basin, with a length of about 14 km. Of these wells, 14A-1 drilled down to 2862 meters and Moreia-1 well up to 2144 meters deep in the Lusitanian Basin, produced approximately 290 liters and 525 liters of oil in tests, respectively. In the Lusitanian Basin, 3667 meter depth Dourada-1C well is also noteworthy, which also showed very good oil shows. In the Algarve basin, Ruivo-1 well, down to a depth of 2249 meters, showed traces of natural gas. In the Porto Basin, Lula-1 well, down to a depth of 4040 meters, the deepest well drilled in Portugal, showed good oil and gas shows.

 

Source GPEP: Moreia-1 exploration well

 

In the onshore of the Lusitanian Basin, concessions were granted to Petrogal, Sceptre Resources and Union Texas in the same period, with 8 exploration wells been drilled, with a length of about 18 km, highlighting Benfeito- 1, carried out by Petrogal in the Torres Vedras region, which reached 3343 meters in depth and produced, in tests, around 795 liters of oil.

 

In summary, the general results of the wells drilled in the country, there were good oil and/or gas shows in 72 of the 95 wells drilled onshore from 1938 to 1985, of which, in 17 it was possible to recover crude oil. Of the 25 wells drilled offshore, until 1985, oil shows were detected in 6 and samples were recovered in 2.

 

Source GPEP: Benfeito-1 exploration well (Petrogal, 1982)

 

In 1986, following the new multi-client geophysical data, acquired by GSI in 1984, and the reassessment of the petroleum potential prepared by Gabinete para a Pesquisa e Exploração de Petróleo (GPEP) based on existing data, which resulted in the publication of a promotional report– “The Petroleum Potential of Portugal”, the 2nd international public bidding was opened for concession areas in the entire available area, both onshore and offshore, accompanied by a promotional campaign for the oil industry.

 

The decline in petroleum activity was evident between 1988 and 1994. Despite the lure of new geophysical data and the report “The Petroleum Potential of Portugal” released to companies in the sector, interest in the Porto Basin and in the onshore Lusitanian Basin was maintained.

 

However, in 1990, a new regime for the attribution of exploration licenses was entered into, regulated by Decree-Law 141/90, of 2 May, in which three types of licenses and subsequent exploitation contracts were created. In the new legal-legal context, between 1990 and 1994, a license for exploration in onshore Lusitanian Basin and four licenses in the shallow offshore Porto Basin were granted to the companies Charles Dodge & Associados, Taurus Petroleum and, also, at the end of 1993, three more licenses were granted to the Heritage Exploration company in the onshore Lusitanian Basin, which in 1994 were transferred to the company Mohave Oil & Gas Corp.

 

In 1994, as a result of lack of interest and little investment in Portugal, a new regime for the attribution of preliminary evaluation licenses and concessions was established, by Decree-Law 109/94, of 26 April, which was based, on its establishment, either following the new European Directive 94/22/CE of 30 May, relating to petroleum activity, and a work of consultation and analysis of the rights regimes applied in Europe and in countries in a situation similar to that of Portugal, and which it remains in force until today.

 

To Mohave Oil & Gas Corp., meanwhile, in 1995 were granted new areas, under the new law, in the regions of Monte Real, Rio Maior, Figueira da Foz, Torres Vedras, Marinha Grande and Aljubarrota.

 

Source GPEP: Concession areas granted in the 90´s

 

Following the deep-offshore seismic and gravimetric survey carried out by TGS-NOPEC in 1999-2002, and the data and good prospectivity obtained from existing exploration wells, a new International Public Bidding was launched in 2002 for the deep offshore. The group formed by Repsol-YPF (Spain) and RWE-Dea (Germany) applied for blocks 13 and 14 in the Algarve Basin, which were awarded in 2005.

 

At the end of 2006, only one company operated in Portugal, Mohave Oil & Gas, holder of 2 concessions in the onshore Lusitanian Basin. In the Alcobaça region, Mohave found strong evidence of gas in two of the exploration wells and, in the Torres Vedras region, it carried out a set of wells, recovering oil from fractures and starting production tests. In 1996, the company had acquired 224 km of seismic onshore and, in 2000, 760 km offshore.

 

Source GPEP: Aljubarrota-2 exploration well (Mohave, 1999)

 

Given the lack of effectiveness of the 2002 International Public Bidding, an intense work was started to promote and disseminate the country's petroleum potential among companies and the oil industry, through participation in conferences and seminars in the area and, above all, in international exhibitions/exhibitions such as APPEX and PROSPEX.

 

As a result of this work, in 2007 there was a significant increase in petroleum exploration in Portugal with the signing of 12 new concession contracts: 5 concessions located in the onshore and shallow offshore of the Lusitanian Basin in the regions of S. Mamede, S. Pedro de Muel, Torres Vedras, Monte Real and Cabo Mondego, 3 concessions in the deep offshore of the Alentejo Basin and 4 concessions in the deep offshore of the Peniche Basin. For the first time, the Peniche and Alentejo Basins, considered border areas, are the target of interest and investment for the study of their petroleum potential.

 

In 2011, contracts were signed for the 2 blocks awarded in the 2002 International Public Bidding by Repsol / RWE consortium.

 

In 2013, given the prevailing positive situation, 5 preliminary evaluation licenses were awarded in the deep offshore of the Algarve Basin, with a maximum duration of 6 months, to the companies Repsol and Panoceanic. Also this year, the extinction of the company Mohave Oil & Gas resulted in the expiry of all 7 concession contracts it held in the onshore and shallow offshore of the Lusitanian Basin.

 

Finally, in 2015, the last petroleum concessions in the country were awarded, with the signing of 6 contracts, 4 of which were located onshore in the Lusitanian and Algarve Basins by the companies Australis Oil & Gas and Portfuel respectively and 2 in the deep offshore of the Algarve Basin by the Repsol / Partex consortium.

 

Source DGEG: Concession areas e 2015

 

From the work carried out, following the concessions awarded over more than 8 decades, an increase in data and information for the country was generated, embodied in important  geophysical acquisitions, whether gravimetric, aeromagnetic or seismic, in sediments sampling campaigns. from the seabed and in 27 exploration wells in the onshore Lusitanian Basin, 4 of which were very deep, giving rise to new interpretations and better assessment of the geological potential of this basin. The year 2010 is highlighted with the first 3D seismic campaigns ever carried out in Portugal, with new acquisitions of this type continuing until 2015 (See Summary Map of exploration work carried out in Portugal).

 

Source DGEG: 3D Geophysical acquisition (Mohave, 2010)

 

Source DGEG: 3D seismic vessel Polarcus Nails (Repsol, 2012)

 

As of end of 2016, both deep offshore and onshore contracts in the Algarve Basin were terminated, either by relinquishment by the State or by the concessionaires.

 

Of the 15 concessions active in 2015, only 2 of these concessions remained in force until 2020. However, due to the relinquishment of all the “Batalha” and “Pombal” areas by the concessionaire Australis Oil & Gas, the respective contracts were terminated.

 

Currently, in the country, there are no rights assigned for petroleum exploration and exploitation.

 

For more information “Livro Verde sobre a prospeção, pesquisa, desenvolvimento e produção de hidrocarbonetos em território nacional”, prepared by the former National Entity for the Fuel Market, E.P.E. (ENMC), current National Entity for the Energy Sector, E.P.E. (ENSE) (See Documentation/Disclosure - Publications).