Jupiter’s Block 31 shown on Figure 1 is amongst the producingfields of the basin. The 1st well on the Contract Area (NWZ2) was drilled by the Soviets in 1969. Jupiter has since drillednine new wells since purchasing the licence in 2008. The firsteight wells - J-50 (2009), J-52 (2010), J-51 (2011), J-53(2012), J-55 (2012), J-58 (2012), J-59 (2013) and Well 19 (2014)all discovered oil. The most recent well (J-57) was not successfulin identifying hydrocarbons.
Block 31 field is a large anticlinal structure that produces from six pay zones. The first miscible gas-injection enhanced oil recovery project has been operated by ARCO since 1952 in the middle Devonian reservoir, which is the main producing interval in the field. BP's exploration success in deepwater Block 31, offshore Angola, has been driven by conventional narrow-azimuth 3D seismic data coupled with the latest available imaging algorithms. However limitations in these data are now apparent and the data is deemed insufficient for the appraisal and development of the subsalt discoveries in the western part of the block. 3D acoustic finite-difference. Sociedade Nacional de Combustiveis de Angola (Sonangol) and BP Exploration (Angola) Limited announced the 'Tebe' oil discovery in ultra-deepwater Block 31, offshore Angola. This is the nineteenth discovery made by BP in Block 31 and is located in the southern portion of Block 31 some 350 kilometres northwest of Luanda and about 12 kilometres to.
The J-55, J-58 and J-59 wells are all located inthe new West Zhetybai field to the south of the alreadydiscovered Akkar East field. The Akkar East field has beendelineated by the J-51, J-52, J-53 and #19 wells. The J-50well is located on Akkar North (East Block) (see Fig 4 below). Piccure 2 0 0 271.
Independently verified reserves have, to date, beenencountered in the Mid Triassic Carbonates.
The Kazakhstan reserves classification system, which has beendeveloped from the Russian classifications, divides geological(in-place) and recoverable reserves into various categoriesincluding C1 and C2. The basis for the evaluation, andcategorisation, is the geological data set, the C1/C2classification system does not take into consideration thecommercial factors impacting the development of the identified C1and C2 reserves. Current State approved preliminary C1/C2 estimatesfor Block 31 are:
- C1+C2: ~58 mmbbls
- C1: ~24 mmbbls
- C2: ~34 mmbbls
Under the SPE’s Petroleum Resources Management System (PRMS)reserves are defined as those quantities of oil (and gas) which areestimated to be commercially recovered from a known accumulationfrom a given date forward, i.e. determined on the geologicaland commercial data set. The commercial nature ofPRMS reserves is relevant in relation to the Jupiter Energy reportsin that these estimates included only a small quantity of reservesfor the two areas covered by wells J-53 and J-55; further drillingwork needs to be carried out to establish commercial productionfrom these separate areas. Current 1P/2P/3P estimates for Block 31are:
- Proved Reserves: 1P 9.7 mmbbls
- Proved plus Probable Reserves: 2P 19.2 mmbbls
- Proved plus Probable plus Possible: 3P 28.7mmbbls
Block 31 Oil Field
Fig 4 – Mid Triassic Northeast Akkar OilField Hydra 4 3.
J-50 and J-52 penetrated a 100-120m Mid Triassic Carbonatesection which was wholely oil saturated. J-51 penetrated a160m section. J-53 confirmed approximately 87m of gross and 56m ofnet pay at the Middle Triassic carbonate reservoir unit. Core,wireline logs and flow testing suggests about half the section isproductive in all wells. The field is mapped to extend over anarea of ~14 sq km.
Fig 5 – Mid Triassic Northeast Akkar Oil Field with lineof section
Fig 6 – J-50 Dip Section
J-52 encountered the Lower Jurassic which flowed oil in NWZ#2 inan updip position. This 25m sand was oil saturated on logsand core but when flow tested it was shown that it may not beviable for commercial production. It is expected that there will befurther testing of this reservoir during future drillingprograms.
Block 31 Oil & Gas Field Development
Fig 7 – NWZ#2 to J-52 Dip Section
Block 31 Oil Fields
Sociedade Nacional de Combustiveis de Angola (Sonangol) and BP Exploration (Angola) Limited announced the 'Tebe' oil discovery in ultra-deepwater Block 31, offshore Angola.
This is the nineteenth discovery made by BP in Block 31 and is located in the southern portion of Block 31 some 350 kilometres northwest of Luanda and about 12 kilometres to the south east of the Hebe discovery.
Tebe was drilled in a water depth of 1752 metres and reached a total depth of 3325 metres below sea level. The well results confirmed the capacity of the reservoir to flow in excess of 5,000 barrels a day under production conditions.
Sonangol is the concessionaire of Block 31. BP Exploration (Angola) Limited as operator holds 26.67 per cent. The other interest owners in Block 31 are Esso Exploration and Production Angola (Block 31) Limited (25 per cent), Sonangol P&P (20 per cent), Statoil Angola A.S. (a subsidiary of StatoilHydro ASA) (13.33 per cent), Marathon International Petroleum Angola Block 31 Limited (10 per cent) and TEPA (BLOCK 31) Limited, (a subsidiary of the Total Group) (5 per cent).
This is the nineteenth discovery made by BP in Block 31 and is located in the southern portion of Block 31 some 350 kilometres northwest of Luanda and about 12 kilometres to the south east of the Hebe discovery.
Tebe was drilled in a water depth of 1752 metres and reached a total depth of 3325 metres below sea level. The well results confirmed the capacity of the reservoir to flow in excess of 5,000 barrels a day under production conditions.
Sonangol is the concessionaire of Block 31. BP Exploration (Angola) Limited as operator holds 26.67 per cent. The other interest owners in Block 31 are Esso Exploration and Production Angola (Block 31) Limited (25 per cent), Sonangol P&P (20 per cent), Statoil Angola A.S. (a subsidiary of StatoilHydro ASA) (13.33 per cent), Marathon International Petroleum Angola Block 31 Limited (10 per cent) and TEPA (BLOCK 31) Limited, (a subsidiary of the Total Group) (5 per cent).