Instituto Superior Técnico Master Degree in Petroleum Engineering Brazil s Pre-Salt Oil & Gas Exploration (Santos and Campos sedimentary basins) Petroleum Engineering Seminars Presentation by: André Pereira N.º 49108 8th May 2014
Index 1. South Atlantic sedimentary basins 2. Pre-salt Oil & Gas 3. Brazil pre-salt region (Santos & Campos basins) 4. Pre-salt E&P 5. Pre-salt challenges 2
1. South Atlantic sedimentary basins Brazil pre-salt region South Atlantic conjugate margin basins. (Source: Getech) 3
Geological setting Ancient supercontinent of Gondwana. Around 120 million years ago, Africa and South America continents were part of a super continent called Gondwana, which was split by the Atlantic Ocean rifting, leaving very similar coastal sediments on both sides of the ocean. Reactivation of zonal weaknesses in the Precambrian basement during the Permian, Triassic and Jurassic resulted in the formation of localized sag basins. Palaeogeographic maps of the Cretaceous break up of Africa and South America, (modified after Tissot et al., 1980; Brownfield & Charpentier, 2006). 4
Geodynamic phase model (Cainelli & Mohriak, 1999) Phase I (Pre-rift): (Fig.2.a) - Lithospheric extension. - Small degree of asthenospheric uplift and a regional thinning of the continental crust and upper mantle. - Incipient faults in the upper crust controlling local depocentres. Phase II (Syn-rift): (Fig.2.b) - Increased lithostratigraphic stretching and asthenospheric uplift. - Large faults affecting the continental crust, formation of half grabens and extrusion of continental flood basalts. - Main episode of intra-continental rifting. Schematic geodynamic model of the South Atlantic evolution, showing the sequence of events during the break up of Gondwana and the formation of the passive margin sedimentary basins. (Cainelli & Mohriak, 1999; Mohriak et al., 2008). 5
Geodynamic phase model Phase III (Syn-rift): (Fig.2.c) - Last phase of syn-rift extension, characterized by continued lithospheric extension. - Large faulting setting, the rift blocks and the syn-rift sediments rotated. Phase IV (Transitional) : (Fig.2.d) - Development of oceanic crust. - Lithospheric extension, becomes focused on the mid-ocean ridge. This cycle is most important for its evaporites, which, controlled the facies distribution of the overlying post-rift and severely deformed it by halokinesis. Schematic geodynamic model of the South Atlantic evolution, showing the sequence of events during the break up of Gondwana and the formation of the passive margin sedimentary basins. (Cainelli & Mohriak, 1999; Mohriak et al., 2008). 6
Geodynamic phase model Phase V (Post-rift) : (Fig. 2.e) - Development of a marginal sag basin architecture. - Progressive increase in bathymetry. - Halokinetic movements, dominated this phase, deforming post-rift strata and determining patterns of deposition. (Salt tectonics). Summary: All South Atlantic basins commenced as interior rift basins, and during the opening of the South Atlantic ocean, evolved into post-rift passive margins. Schematic geodynamic model of the South Atlantic evolution, showing the sequence of events during the break up of Gondwana and the formation of the passive margin sedimentary basins. (Cainelli & Mohriak, 1999; Mohriak et al., 2008). 7
Cycles of Basin Evolution Generalized geoseismic section in the Campos basin, showing the different mega-sequences, as well as the tectonic compartments associated with halokinesis (Mohriak, 2003). 8
2. Pre-salt oil & gas Pre-salt explorations depths: - Deep waters (depths> 600 m ) - Ultra-deep waters: (depths> 2000 m) Main reasons for pre-salt exploration: Decrease in reserves and production onshore. Political instability in major exporting regions (Middle East). Greater productivity of offshore wells. Pre-salt oil & gas exploration (www.petrobras.com.br/ website). 9
What s the pre-salt? The pre-salt is the range of rocks deposited before the salt and comprises the steps of rift and sag. The total depth of these rocks can reach more than 7.000 m. In some areas of the coast, the salt layer reaches thicknesses up to 2.000 m. Source: WesternGeco 10
3. Brazil pre-salt region Brazil pre-salt region (Financial Times website) 11
Campos Basin - Location, Geological Limits, Bathymetry and E&P history Main sedimentary area already explored off the Brazilian coast. It ranges from the Alto do Cabo Frio (state of Rio de Janeiro) to Alto de Vitória (state of Espirito Santo). Total area 100.000 square kilometers. Bathymetry up to 3.000 meters. The off-shore oil exploration in the Campos Basin began in 1968. The first exploratory well was drilled in 1971. The first field to be discovered was Garoupa in 1974 at a shallow depth of 120 m. Campos Basin (source: ANP). The first oil production started in 1977 from Enchova field at the depth of 124 m. 12
Campos Basin - Petroleum System (source rocks) Source: H.D.Rangel, 1993 / ANP 13
Campos Basin - Petroleum System (reservoir rocks) Source: H.D.Rangel, 1993 / ANP 14
Santos Basin - Location, Geological Limits, Bathymetry and E&P history The largest offshore sedimentary basin in Brazil. It ranges from Alto do Cabo Frio (state of Rio de Janeiro) to Alto de Florianopolis (state of Santa Catarina). Total area of over 350.000 square kilometers. Bathymetry up to 3.000 meters. The exploration in the Santos Basin began in 1979 with the discovery of natural gas reserves primarily in the Merluza field. Brazil Pre-salt discoveries were made by 2006. Figure 5 Santos Basin (source: ANP). 15
Santos Basin - Petroleum System (source rocks) Source: H.D.Rangel, 1993 / ANP 16
Santos Basin - Petroleum System (reservoir rocks) Source: H.D.Rangel, 1993 / ANP 17
Santos Basin Main Plays Source: H.D.Rangel, 1993 / ANP 18
Pre-salt - Petroleum System (migration and oil accumulation) Migration Listric faults associated to salt tectonics, unconformity surfaces and salt dome walls, Autochthonous conditions of migration (Pre-salt section) Traps Structural / stratigraphic control by salt tectonics effects in post-rift section. Pre-salt section prevail on structural traps Source: Guardado et al., 1989 / ANP Cap Rocks Calcilutites, marls, shales and evaporites 19
Pre-salt - Reservoir characteristics Stromatolites and other carbonates are the main reservoir in pre-salt. Due to its formation process stromatolites presents porosity and permeability superior to the remaining carbonates section. Deposited at Syn-rift phase (sag basins). 20
Pre-salt - Reservoir challenges of exploration Large lateral and vertical variability in therms of Permo-porous properties (Ø: 0 to 30%, K: than 0.1 to 1.000-5.000 md ); Deep reservoirs located at a depth ultra-deep water (in some cases with nearly two thousand meters); Presence of faults, fractures, vugs and caves (impacting on drilling operations, cementing and completion of wells); Uncertainty about efficiency in secondary recovery (water injection, gas or alternating water and gas); Presence of contaminants ( H2S and CO2 ) in the fluid produced. 21
4. Pre-salt E&P Source: Modec 22
Exploration (assessment phase) Source: ANP (Fev. 2014) 23
Exploration Operators @ Campos Basin (assessment phase) Source: ANP (Fev. 2014) 24
Exploration Operators @ Santos Basin (assessment phase) Source: ANP (Fev. 2014) 25
Production fields Source: ANP (Fev. 2014) 26
E&P Companies Source: ANP (Fev. 2014) 27
Production (Oil bbl/day) Feb.2014: 386.795 bbl/d 2008 Source: ANP (Fev. 2014) 2014 28
Production 20 biggest oil production fields in Brazil (Fev.2014) Source: ANP (Fev. 2014) 29
Well productivity Santos Basin: Lula field @ 08 wells @ CP 178 Mbbl/d Sapinhoá field @ 03 wells @ CP 40 Mbbl/d Campos Basin: Baleia Azul field @ 04 wells @ CP 56 Mbbl/d Marlim Leste field @ 04 wells @ CP 53 Mbbl/d Jubarte field @ 02 wells @ CP 45 Mbbl/d CP= Cumulative Production of total wells Source: ANP (Fev. 2014) 30
Forecasting Production By the year 2020, the production in the pre-salt region is expected to increase up to 50%. Source: ANP (Fev. 2014) 31
5. Pre-salt challenges Brazil's pre-salt environments consist of carbonates and are found below the salt layer. The total area of the pre-salt province is over 110.000 km2, with discoveries along Santos, Campos and Espírito Santo basins. Reservoirs buried below as much as 2.000 meters salt layers, the pre-salt play presents a multifaceted deepwater scenario. Reservoirs in this domain are complex heterogeneous layered carbonates. Wells drilling is proving to be extremely difficult with low penetration rates - tendency for borehole deviation. Flow assurance related to paraffin deposition, hydrate and scaling control is also a challenge. Developing Brazil's pre-salt reservoirs requires a broad scope of technologies and capabilities. 32
References Mio, E.Chang, H.K., e Corrêa, F. S. 2005 Interpretação de métodos geofísicos na modelagem crustal da Bacia de Santos Revista Brasileira de Geofísica. Cainelli & Mohriak, 1999, Rifte do Atlântico Sul. Pereira, M. J.; Feijó, F. J., 1994. Bacia de Santos, Boletim de Geociências da Petrobras. Magoon, L. B., & Dow, W. G., 1994. The Petroleum System) ANP, Agência Nacional do Petróleo, Gás Natural e Biocombustiveis Brasileira (www.anp.gov.br/) Petróleo Brasileiro S.A PETROBRAS (www.petrobras.com.br/) Pre-Salt Oil & Gas Around the World (www.presalt.com/) 33
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