Pacific Stratus was awarded three blocks (135, 137, and 138) in the Perupetro 2007 Bidding Round. Blocks 135 and 137 are located in the Maranon Basin, while Block 138 is located to the south in the Ucayali Basin.
The contracts include both exploration and production phases and run for 30 years for oil and 40 years for gas, with exploration phases of seven years, which are extendable for an additional three years. The contract can be terminated at the end of each phase, depending on the exploration results.
The Maranon Basin is the southern extension of the Putumayo and Oriente Basins of Colombia and Ecuador, respectively. The Putumayo-Oriente-Maranon Basin has produced 2.88 billion bbl and 660 Bcf from Cretaceous and Tertiary sandstones. The Maranon Basin is the largest Basin in Peru and it is divided into the northeast area, the western area, and the southeast area.
Two petroleum systems have been proved in the Basin, the Cretaceous and the Triassic-Jurassic. The Cretaceous system features clastic reservoirs in the Chonta and Vivian formations, the generation and migration of which took place in the Oligocene-Miocene. The Jurassic system has oil generation from the Early Cretaceous to the Oligocene, with migration occurring from the west and toward the Iquitos High to the east. The main reservoir in this system is the Pucara Formation of Jurassic age.
Blocks 135 and 137 are located to the southeast of the Basin, and the main targets are the Cretaceous Vivian, Chonta, and Cushabatay sandstones. The main seals are the carbonates of the Copacabana Formation, which are on top of the Tarme Green Reservoir. The Raya Formation is a potential seal for the Cushabatay Formation, and the Chonta reservoirs have pair's seals-reservoirs.
Petrotech Engineering Ltd. (2007) estimated a mean of the undiscovered resources for Block 135 of 301.0 MMbbl and 164.9 MMbbl for the Vivian and Chonta Formations, respectively.
The first phase exploration obligation for Block 135 includes the acquisition, processing, and interpretation of aeromagnetic and gravimetric surveys, remote sensing and satellite imaging interpretation, and the analysis and integration of all available data on the block.
The second phase includes the acquisition, processing and interpretation of 400 km of 2D seismic and the drilling of an exploratory well. The first and second phases are each 18 months long, and the third and fourth phases have durations of 24 months each, with each consisting of drilling an exploratory well.
Block 137 has regular seismic coverage and four of these lines cross a potential cretaceous structural trap consisting of east-west four-way closures related to a north-south trending fault. No wells have ever been drilled in Block 137, but the Breta�a 1X well, which tested positive for heavy oil, is located in the neighbouring Block 95.
Petrotech Engineering Ltd. (2007) estimated a mean of the undiscovered resources for the Vivian and Chonta Formations of 339.3 MMbbl and 187.2 Mmbbl, respectively.
The first phase exploration obligation includes compiling a report on the remote sensing and interpretation of satellite images, the integration of available technical information, and the acquisition, processing, and interpretation of 200 km of 2D seismic. The second phase, which like the first has a duration of 18 months, includes the drilling of an exploratory well. The third and fourth phases also last 18 months and each requires the drilling of an exploratory well.
Block 138 has good seismic coverage and there are four regional lines extending inside the block from blocks 114 and 126. Several north-south trending faults, as well as southwest dipping stratigraphy, have been identified from the seismic. This indicates the presence of tectonic-stratigraphic traps, involving the Cretaceous Vivian Formation and the Permian Ene Formation.
Petrotech Engineering Ltd. (2007) estimated a mean of undiscovered resources from the Vivian and Ene formations of 330.6 MMbbl and 82.3 Mmbbl, respectively.
Exploration commitments for this block consists of compiling a technical report of all the existing data during the first phase and the acquisition, processing, and interpretation of 300 km of 2D seismic during the second phase. The first and second phases have durations of 12 and 18 months, respectively, while the third and fourth phases each last 18 months and require the drilling of an exploratory well in each phase.
