Sergipe-Alagoas Basin

Location

Brazil’s northeastern
continental margin

- It is located in Sergipe and Alagoas States,

- It shows an elongated NE-SW shape with 350 km of extension and 35 km mean width onshore


- Total area: 44,370 km², where 12,620 km² in the onshore portion





















Infrastructure
















Exploratory History

1935 - Geophysical surveys and drilling of the 2-AL-1 well by the“Conselho Nacional do Petróleo” .Boreholes in northern Alagoas State.

1957 - First commercial oil discovery in the TM-1-AL well.Exploratory History1963 - Discovery of the Carmópolis Field in the Sergipe Sub-Basin,the greatest field, with original oil in place of 268 million m³(ANP, 2008).

60´s - First commercial oil discovery in the Brazilian continental margin,(Guaricema Field), by the wildcat well 1-SES-1A.

Wells: 996 exploratory and 3,582 development (total of 4,578);

Seismic: 39,927 km 2D onshore, 82,642 km 2D
offshore, 4,523 km² 3D onshore and 27,930 km²
3D offshore.

Fields: 44 under development/production/evaluation and
13 turned ones.

Geology









Tectonic reconstruction map of the pre-drift
configuration of the sedimentary basins
(Bizzi et al. 2003)
















Pre-drift reconstruction
(Matos, 1999, 2000)


Tectonic Evolution



Diachronism between:
- Tucano-Jatobá Basin
- Sergipe-Alagoas Basin
- Potiguar Onshore Basin








Origin: Jurassic-Cretaceous rifting between South America and
African plates;
Tectonic Styles:
. Pre-Rift and Rift sequences: Diastrophic tectonics;
. Post-Rift sequence: halokinesis;
Structural Context: asymetric elongated rift with 350 km of
extension in the NE-SW direction. It is divided
into two sub-basins (Sergipe and Alagoas);
Main structures: vertical faults in the N45°E direction (Hingeline
Alagoas) with maximum displacement of 5 km;
elongated horsts limited by normal faults (Penedo
High); anticlines and listric faults associated to
halokinesis.

Petroleum Systems
Main Petroleum Systems:
• (Muribeca) Maceió/Aptian: Muribeca Fm./Carmópolis Mb.- reservoirs
(Muribeca) Maceió Fm. shales - oil generation
Main Fields: Carmópolis, Siririzinho, Camorim and Riachuelo;

• Penedo-Barra de Itiúba/Neocomian-Barremian: oil is generated in
lacustrine shales of the Neocomian section, in the Barra de Itiúba Fm.
Main fields: Pilar and São Miguel dos Campos;

• Calumbi/Neocretaceous-Tertiary: reservoirs in the Calumbi Fm.
turbidites. Syn-rift generation, during Late Aptian in the Muribeca (Maceió)
Fm. Main fields: Guaricema and Dourado.

Source Rocks:
. Barra de Itiúba Fm. (Neocomian/Barremian): lacustrine shales
from pre-rift and rift phases;

. Coqueiro Seco Fm. (Barremian/Eoaptian): lacustrine shales
from rift phase;

. Maceió Fm. (Neoaptian): main source rocks – black shales, marls
and calcilutites. TOC =3.5%<12%;> 9 mg HC/g rock; IH=300
mg HC/g TOC; Kerogen Type II; mean thickness=200m, at
maximum of 700m ;

Riachuelo and Cotinguiba Fm. (Albian-Turonian shales and
calcilutites) could generate at great depth.

Generation and Migration:
• The main source rocks are mature in deep water at lower portions of
Alagoas hingeline.
• Shallow accumulations (onshore and shallow water): generation
from Maceió Formation. Lateral and long distance migration along
faults to the accumulations in paleogeomorphic traps. (Ex.
Carmópolis Field).
• Normal faults, listric faults and unconformity act as pathways for
hydrocarbon migration.
Reservoirs: distributed from basement to Tertiary formations.
Alagoas Sub-Basin:
Onshore: sandstones from Serraria, Barra de Itiúba, Penedo,
Coqueiro Seco e Maceió formations;
Deep water: Cretaceous and Tertiary turbidites from Calumbi
Formation; clastic rocks from Maceió Formation.
Sergipe Sub-Basin: onshore and offshore: clastic rocks from Carmópolis
Mb. (Fm. Muribeca) and Cretaceous turbidites from Calumbi Fm.,
sandstones from Serraria Fm., fractured basement, rift phase
sandstones, Riachuelo/Cotinguiba formations carbonates;
- Deep water: Cretaceous and Tertiary turbidites from Calumbi
Fm. - transitional sequence.

Traps:
- Pre-rift and rift sequences: structural traps (domes), such as Pilar and
São Miguel dos Campos fields or faulted blocks, such as Atalaia Sul and
Coqueiro Seco Fields.
- Transitional sequence: paleogeomorphic traps, as: Muribeca Fm./
Carmópolis Mb. - faulted blocks or traps associated with halokinesis.
- Upper sequence: mixed and stratigraphic traps, associated with
halokinesis or channel infill.

Seal Rocks:
- Carmópolis Mb. reservoirs and fractured basement: shales and
evaporites from Ibura Formation;
- Sandstones from Serraria Formation: basal shales from Barra de
Itiúba Fm., sandstones from Penedo Fm., basal shales from
Coqueiro Seco Formation.
- Barra de Itiúba, Coqueiro Seco and Maceió formations:
intraformational shales.
- Turbidites from Calumbi Fm.: deep water shales.
- Fractured carbonate reservoirs from Muribeca, Riachuelo and
Cotinguiba Fm.: interbedded shales.

Reserve Data

RESERVES* Oil Reserves(Million Barrels) Gas Reserves(Million Cubic Meters)
Proven Reserves 240.47 3,770.09
Total Reserves 358.53 5,661.77


*Data until December, 2007



















Current Situation
Sergipe - Alagoas
• 52 producing fields (oil / gas)
• 13 returned fields

SE-AL onshore production 2008:
• 8,661,055 bbl
• 1,337 km 2D seismic
• 408 km² 3D seismic
• 219 drilled wells
• 04 fields under development
• 01 exploratory block
• 11 fields
Alagoas Basin – Onshore