South American reserves lure E and P companies

Paul Boughton

Interest in South America continues to grow as E&P companies eye potentially huge oil and gas reserves. Sean Ottewell reports.
Colombia remains an important source of investment by exploration and production (E&P) companies working in South America. Canada-based oil and gas E&P company PetroMagdalena Energy, for example, has reported promising results from its ongoing exploration programme at Cubiro in the Llanos basin.
Luciano Biondi, ceo, commented: "We are pleased to announce the continuation of our successful exploratory and development drilling programme. The Copa 4 development well at Cubiro has extended the mapped reservoir area with higher formation tops than predicted and with positive tests of the zones identified petrophysically, this could lead to a measurable increase in oil reserves for the Copa Field."
The Copa 4 development well was spudded on 31 March and well logs were run on 13 April. The petrophysical evaluation of the C7, C5 and C3 sandstones, all productive in the Copa field, estimates the well logs to be 15-20 feet higher than predicted in the mapping done based on the seismic interpretation. Petrophysics indicate potential hydrocarbon pays of seven feet in the C7, 17 feet in C5, 13 feet in C5, and 11 feet in C3. [Page Break]
As the Copa 4 development well was drilled to the northwest, it was expected to intersect the predicted oil water contact considerably down dip from the producing Copa-1 well. With positive testing of the hydrocarbon potential in Copa-4, the oil reservoir in the Copa field will be extended to the west with an expected upward revision of the reserves for all three producing reservoir units in the Copa field.
PetroMagdalena Energy has also announced that the Alondra-1st exploration well in the Cubiro block reached total depth (TD) of 6291 feet measured depth (MD) on 12 April in the Carbonera C8 Formation. The well is in Polygon B of the Cubiro Block, where PetroMagdalena has a 70 per cent working interest. PetroMagdalena has a working interest in 19 properties in five basins in Colombia.
Gran Tierra Energy has also recently provided updates for its operations in Colombia.[Page Break]
The Ramiriqui-1 oil exploration well in the Llanos-22 block, located in the Andean foothills trend of the Llanos Basin, has reached total depth at 19,519 feet MD in basement. Gran Tierra Energy, along with its operating partner Compania Espanola de Petroleos (CEPSA), has completed initial testing on Ramiriqui-1 by collecting reservoir data and fluid samples from the Mirador formation.
The Mirador formation has 130 feet gross thickness and was perforated and tested from 17,610 feet to 17,630 feet MD in the uppermost primary reservoir interval. The interval had natural flow rates, without pumps, of up to 2525 barrels/d of oil gross over 32.5 hours with a 28/64 inch choke and a 0.12 per cent watercut with 26° API gravity oil. The Ramiriqui-1 well flowed at a restricted rate due to gas flaring limitations.
The partners are currently evaluating options for testing additional reservoir intervals, drilling of an appraisal well, and implementation of an early production programme.
"We are extremely pleased with the early success of Gran Tierra Energy's 2012 exploration drilling programme, building on our growing reserves and production base in the Llanos Basin," said Dana Coffield, president and ceo of Gran Tierra Energy. "This is the first of four exploration wells planned for this year in Colombia, with two in the Llanos Basin and two in the Putumayo Basin. In addition, one exploration well in Peru, two exploration wells in Brazil and three exploration wells in Argentina are planned through the balance of the year."
Also in Colombia, Amerisur Resources announced that it has spudded the well Platanillo-3 in the Platanillo Field, the first of a planned six well drilling campaign.
The Serinco D-10 drilling rig was recently mobilised to the Platform 9 location and was rigged up and tested before beginning operations on 5 April. Drilling began through a pre-set 13.3/8" conductor pipe. The well has currently reached approximately 914 metres and operations are continuing according to plan.
The total planned depth of the well is 2523 metres and the company expects to have electric log and test results from the well shortly.
Amerisur ceo John Wardle commented: "I am very pleased we have begun our exciting drilling programme, which has been designed on the basis of our 3D/3C seismic analysis and aims to substantially increase our reserve base and deliver our 5000 BOPD target by the end of this year."[Page Break]
Drilling in Brazil

OGX Petróleo e Gás, the Brazilian oil and gas company responsible for the largest private-sector exploratory campaign in Brazil, has identified the presence of light oil in the Natal accumulation in the Santos basin.
The company announced that well 3-OGX-74-SPS, the first extension well of the Natal accumulation (1-OGX-11D-SPS), adjacent to the wildcat well, in block BM-S-59, demonstrated the continuity of the sandstone reservoirs of the Santonian age. In the drill-stem test for fluid identification conducted in the well, the company has verified the presence of light oil of 38° API, while in well OGX-11D the company had previously confirmed the presence of gas and condensate.
"The discovery of light oil in the sandstone reservoirs of the Santonian age corroborates our initial expectations regarding the significant potential of oil accumulations in our Santos Basin blocks," commented Paulo Mendonça, general executive and exploration officer of OGX.
OGX-74 was drilled to a depth of 4439 metres and, together with wildcat wells OGX-11D and OGX-47, will be part of a discovery evaluation plan which will appraise the sandstones of the Santonian age accumulations in block BM-S-59.
The OGX-74 well, an extension of the Natal accumulation, is located 115 km off the coast of São Paulo, in water depths of approximately 196 metres and was drilled approximately 4 km away from well OGX-11D.
Meanwhile Petrobras has completed drilling extension exploratory well 3-BRSA-1032-RJS (3-RJS-697), located in the Iara evaluation area, in the pre-salt of Santos Basin. The well is 223 km off the coast of Rio de Janeiro, 9 km from the discovery well, at a water depth of 2150 metres.
The well, informally known as Iara Oeste, is the third well drilled in the discovery evaluation plan 1-BRSA-618 (Iara) and reached the total depth of 6050 metres.

Petrobras is the operator of the consortium (65 per cent), in partnership with BG Group (25 per cent) and Galp Energia (10 per cent). The consortium will advance the activities set forth in the Evaluation Plan approved by the Brazilian National Petroleum, Natural Gas and Biofuels Agency (ANP), including formation tests to evaluate the productivity of the reservoir (Fig 1).[Page Break]
In Ecuador, state-run company Petroecuador says it plans to establish an alliance with its Venezuelan counterpart Petroleos de Venezuela (PdVSA), to explore for oil and gas in Venezuela. According to Petroecuador general manager Marco Calvopina, PdVSA has been invited to do the same in Ecuador.
Calvopina said that Petroecuador will have a 14 per cent stake in Venezuela's Dobokubi oil field, in the heavy-crude rich Orinoco belt.
"We want to internationalise our operations. Dobokubi can reach a production of 50,000 barrels/d in about two years and we have agreed to work in that field," Calvopina said.
Dobokubi is a Venezuelan oil field, operated by a joint venture between PdVSA and Iran's Petropars Oil and Gas.
Petroecuador's investment in the field hasn't yet been defined nor have the fields that PDVSA could explore in Ecuador.
Calvopina said Venezuela has also offered to Petroecuador a stake in a block for gas exploration, but he declined to provide further details.
Currently, Petroecuador and PdVSA operate together the Sacha oil field in Ecuador, through the Rio Napo joint venture, in which Petroecuador has 70 per cent of shares and the Venezuelan company the remainder.[Page Break]
Wintershall lands Argentina Licence
Wintershall Energía, a wholly owned subsidiary of Kassel-based Wintershall, has been awarded the exploration permit for the area Cuenca Neuquina V (CN-V) by the Mendoza Province. The area is located in the southernmost region of the Province and covers 956 km2.
Since 2004 Wintershall has performed field and lab-work over the whole surface, including geology mapping, geochemical analysis, geological modelling as well as 2D seismic reprocessing and interpretation. Recent evaluations indicate that the CN-V Block has an important potential to explore and develop conventional and unconventional reservoirs (shale gas and shale oil) in two different sedimentary levels.
Wintershall has been active in Argentina since 1978, especially in the production of natural gas. The company has working interests in 15 oil and gas fields and is one of the largest natural producers in the country with an annual production of 27 million barrels of oil equivalent.
This exploration commitment underlines that Wintershall Energía is determined to continue investing in Argentina on a long-term basis. As the country's fourth largest gas producer, Wintershall plays a prominent role in oil and gas exploration and production in Argentina.
"The award of the CN-V exploration permit establishes Wintershall as operator. It represents an excellent opportunity to deploy the company's technical experience in unconventional reservoirs in the promising and fast growing shale projects in the Neuquen Basin, one of the most prospective shale oil and gas regions in the world," said Gustavo Albrecht, md of Wintershall Energía.

Fig. 1. Petrobras is working to meet the activities set out in the evaluation plan approved by the Brazilian National Petroleum, Natural Gas and Biofuels Agency.

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