The Orinoco Belt is located in Guárico and south of the Anzoátegui, Monagas, and Delta Amacuro states, and it follows the line of the river.

[1] Petróleos de Venezuela S.A. has estimated that the producible reserves of the Orinoco Belt are up to 235 billion barrels (3.74×1010 m3) which would make it the largest petroleum reserve in the world, slightly ahead of the similar unconventional oil source in the Athabasca oil sands, and above Saudi Arabia.

[2] In 2009, the US Geological Survey increased the estimated reserves to 513 billion barrels (8.16×1010 m3) of oil which is "technically recoverable (producible using currently available technology and industry practices)."

These are: Boyacá (formerly Machete), Junín (formerly Zuata), Ayacucho (formerly Hamaca), and Carabobo (formerly Cerro Negro).

In 1938, the first well discovering hydrocarbons was drilled with the name "Zuata 1" Source:The data in this section are taken directly from the official PDVSA web page.

Oil Sowing Plan 2005–2012 includes six fundamental axes: Production blocks will be developed by PDVSA in cooperation with foreign partners.

Junin block 6 is developed in cooperation with a consortium of Russian oil companies, including Rosneft, Gazprom Neft, Lukoil, TNK-BP and Surgutneftegaz.

[9] The same year, PDVSA and Sinopec signed an agreement to collaborate on the development of the block,[10] whose future production was estimated to be 200,000 barrels per day (32,000 m3/d).

[5] Carabobo 2 will be developed in cooperation with Rosneft and Corporation Venezolana del Petroleo (CVP) - a subsidiary of Venezuela's state oil and gas company PDVSA.

The agreement, signed by Rosneft CEO Igor Sechin and Venezuelan Oil Minister, PDVSA chief Rafael Ramirez in the presence of President Hugo Chávez, establishes a joint venture to develop the Carabobo 2 bloc in the southern Orinoco extra-heavy crude belt in Venezuela.

To develop the Carabobo 2 bloc Rosneft will invest a total of $16 billion, according to CEO Igor Sechin.

Rosneft, along with several Russian oil companies (Gazprom Neft, Lukoil, TNK-BP and Surgutneftegaz), have formed a consortium to develop the Junin bloc 6 of the Orinoco belt in Venezuela.

[citation needed] The formation waters from the boreholes show a main Na-Cl level (TDS up to 30g/L) with a dilution trend toward Na-HCO3 composition (down to 1g/L).

[13] The hypothetical presence of flood by a meteoric paleo-water also offers new hints to explain the low API gravity (<10°API biodegraded, extra heavy oil) and composition of the local crude.