A few weeks after being declared commercial, Petrobras’ recently named Mero Field—part of the Libra Block—is set for a 3-D seismic survey using ocean-bottom node (OBN) acquisition systems.

OBN systems provide the best seismic data quality and clearest reservoir image to inform E&P strategies throughout the development of the production of the Mero Field, according to Brazilian Geophysical Society Institutional Secretary Ricardo Augusto Rosa Fernandes.

“Seismic surveys of this nature are usually associated with the tracking of the displacement of the oil front with 4-D seismic (time variants),” the geologist said. “In this sense, we understand that the investment in seismic sensors with background sensors indicates that the company and partners plan the use of 4-D seismic to monitor the reservoirs.

Also, the geologist believes that other prolific fields in the Libra presalt block have potential to be declared commercial soon.

“There are exploratory areas recently tendered by the Brazil’s oil regulator ANP in this same northern portion of the Santos Basin, which also indicate excellent geological potential,” he said. The “Mero Field is located in a retention area defined by Petrobras [‘ring fence’] of about 320 sq km [124 sq miles]. The total area of ​​the Libra block is 1,550 sq km [598 sq miles].”

Mero is located in the northwestern part of the Libra Block of the presalt Santos Basin offshore Brazil. The field, which is within Brazil’s largest oil area, was deemed commercial in late November after a three-year campaign. The field is located about 180 km (112 miles) off the coast of Rio de Janeiro.

Mero entered production through a long-duration output test carried out by the Pioneiro Libra FPSO unit. The field holds roughly 3.3 Bbbl of recoverable oil. According to Petrobras, eight extension wells were drilled in the PAD area during the exploratory and evaluation stage of the Libra block to identify reservoirs with good-quality oil with high commercial value. In fact, the declaration of commerciality of Mero field represents a very important achievement by Petrobras.

“This is our first unit equipped to inject all the gas produced during the tests. To date, 12 wells have been drilled in the Libra Block. Due to its magnitude, production potential, good oil quality and high commercial value, Libra opens up a new business opportunity in the offshore industry,” Petrobras said in an official statement. “With an expected duration of one year, the long-duration output test has the goal of evaluating the behavior of the oil reservoir and increasing the knowledge of the characteristics of the deposit.”

Libra is Brazil’s biggest oil field to date and is expected to produce 1.4 MMbbl/d by 2021, and it holds between 8 Bbbl to 12 Bbbl of recoverable oil, according to ANP. It was the first presalt area that was acquired under the 35-year production-sharing agreement contract by the consortium formed by Petrobras (40%,operator), Shell (20%), Total (20%), CNPC (10%) and CNOOC (10%) in 2013.

—Brunno Braga