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VoltaianProjectUnit

4/14/2012. VoltaianProjectUnit. 2. Presentation outline. ABOUT THE VOLTAIAN SEDIMENTARY BASINREGIONAL GEOLOGY AND STRATIGRAPHYGEOPHYSICAL AND GEOLOGICAL DATABASEHISTORICAL REVIEW OF OIL

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VoltaianProjectUnit

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    1. 4/14/2012 VoltaianProjectUnit 1 HYDROCARBON POTENTIAL OF THE VOLTAIAN (VOLTA) SEDIMENTARY BASIN GNPC – TEMA; 7TH FEBRUARY, 2007.

    2. 4/14/2012 VoltaianProjectUnit 2 Presentation outline ABOUT THE VOLTAIAN SEDIMENTARY BASIN REGIONAL GEOLOGY AND STRATIGRAPHY GEOPHYSICAL AND GEOLOGICAL DATABASE HISTORICAL REVIEW OF OIL & GAS EXPLORATION IN THE VOLTAIAN BASIN EFFORTS SO FAR AT GNPC REGULATORY FRAMEWORK HYDROCARBON POTENTIAL DEDUCTIONS AND CONCLUSION.

    3. 4/14/2012 VoltaianProjectUnit 3 GHANA’S SEDIMENTARY BASINS

    4. 4/14/2012 VoltaianProjectUnit 4 ABOUT THE VOLTAIAN SEDIMENTARY BASIN The Voltaian (or Volta) Basin is the single largest sedimentary basin in Ghana. It occupies about 40% of the total landmass of Ghana, covering about 103,600km2. Basin stretches from Ghana into Togo, Benin, Burkina Faso and Niger. Basin is believed to have a petroleum system in place, with favourable conditions for generation and accumulation of commercial quantities of hydrocarbon.

    5. 4/14/2012 VoltaianProjectUnit 5 COMPARATIVE SIZE OF VOLTA BASIN WITH REST OF GHANA’S SEDIMENTARY COVER

    6. 4/14/2012 VoltaianProjectUnit 6 REGIONAL GEOLOGY Offshore sedimentary basins - formed as a result of the separation of the African and South American continents. The Voltaian Basin is an epicontinental interior sag basin associated with the Pan-African Orogeny of ~ 600 million years ago and was formed as a result of the collision of the West African Shield (of the Birrimian System) with the Benin-Nigerian Shield (of the Dahomeyan System).

    7. 4/14/2012 VoltaianProjectUnit 7 LITHOSTRATIGRAPHIC SUCCESSION

    8. 4/14/2012 VoltaianProjectUnit 8 STRATIGRAPHY The basin is an asymmetrical depression filled with thick sediments of Late Precambrian (Proterozoic/Infra-Cambrian) to Early Paleozoic era. Age differentiation so far difficult due to rarity of diagnostic fossils. Oldest Voltaian sediments overlie unconformably on Lower (“Birrimian”) - Middle (“Tarkwaian”) Proterozoic basement rocks. Sediment thickness is estimated to exceed 6,000m in the deepest portions in the east and south-east. Some sediments are considered as young as Devonian-Carboniferous in age.

    9. 4/14/2012 VoltaianProjectUnit 9 STRATIGRAPHY (CONTD.) Depositional environment is shallow-marine to continental. Sedimentation is mainly clastic, with some carbonates. The lithology comprises sandstones, siltstones, shales, mudstones and limestones. The sandstones are massive and conglomeratic in places. Sediments, especially lower (older) members, are gently folded and with normal block-faulting. Dips recorded in Premuase #1 wildcat measured 1 - 4 deg.

    10. 4/14/2012 VoltaianProjectUnit 10 GEOPHYSICAL & GEOLOGICAL DATABASE Aeromagnetic data over the entire the basin, shot between 1960 and 2006 (currently as part of EU project): 1960 and 1961 surveys by Hunting Geology & Geophysics Ltd for GSD; 1969 surveys by Prakla-Seismos Ag for Uranerzbergbau Gmbh; 1971 survey by CGG for Shell International Petroleum. 2006 (ongoing EU-funded airborne surveys being coordinated by GSD). Ground Gravity data covering parts of the basin. Limited seismic data (208km of 2-D data). Shallow Premuase-1 well (1,167m or 3,830 feet) data. Limited data on ten (10) hydrodynamic wells drilled to ~700m in the 1960s by the Soviets. Diverse documentations on various aspects of the basin’s geology and geophysics, particularly the ff:

    11. 4/14/2012 VoltaianProjectUnit 11 GEOPHYSICAL & GEOLOGICAL DATABASE (CONTD.) Data currently available at GNPC: 11 individual reports (including on Premuase – 1 well) 16 maps and sections (incl 3 of 4 seismic sections) 7 suites of well logs on sole wildcat, Premuase – 1 Field/Borehole samples including: Washed & dried drill cuttings from 2 locations: Buipe - SGST #7 and Premuase #1; Core chips from 4 locations: Nasia - SGST #5, Tamale – SGST #2, Tibagona – SGST #1 and Yendi – SGST #6. Other field geological/outcrop samples. Other data not yet in GNPC domain: Some ~ 31 individual published and unpublished reports. Data believed to be in domain of Prof N.A. Bozhko/Zarubezhgeologia of Russia: Unspecified reports, sections, maps and other data.

    12. 4/14/2012 VoltaianProjectUnit 12 GEOLOGICAL MAP (AFTER N.A. BOZHKO, 1964, AND J.E. CUDJOE, 1971 – GSD)

    13. 4/14/2012 VoltaianProjectUnit 13

    14. 4/14/2012 VoltaianProjectUnit 14 HISTORICAL REVIEW Phase I: Up to 1961- Geological Survey Department (GSD) efforts, including P. Davis’ Gravity Survey of 1957 – 58 and early Soviet Geological Team’s exploration efforts to determine hydrodynamics of the basin. Phase II: 1962 - 70 – Soviet Team efforts (till 1965), and later Romanian Team’s oil prospecting efforts. Continuation of GSD geophysical (mainly gravity) data acquisition. Phase III: 1971 - 77 - Efforts by Shell International in magnetic, then seismic data acquisitions. Eventual wildcat drilling of Premuase #1 well. Fallow period : 1978 - ~1996 – No significant activity (for ~ 18 yrs.) Phase IV (Current): 1996 – Date - Exploration promotion and re-evaluation of Basin’s potential by GNPC in cooperation with prospective partners, notably Ghana Geological Survey and the Mining Sector.

    15. 4/14/2012 VoltaianProjectUnit 15 HISTORICAL REVIEW (CONTD.) Reconnaissance geological mapping by Geological Survey Dept (GSD) with detailed mapping in isolated areas. 10 hydrogeological wells drilled in the 1960s by the Soviets (SGST wells) to average depth of 700m, with some of them encountering traces of bitumen, heavy oil and gas indications. Ground Gravity data acquisition by Geological Survey Dept in the 1970s. Wide grid aero magnetic survey by CGG in the 1970s, totaling 18,000 line-kilometers made up of groups of 4 flight lines at 4km spacing and 11 tie lines at 45km spacing. Only 208 line kilometers of 2D seismic survey by Shell. 1 wildcat – Premuase-1 well by Shell in 1977 with results: dry, plugged and abandoned.

    16. 4/14/2012 VoltaianProjectUnit 16 HISTORICAL REVIEW (CONTD.) Indications of heavy oil and gas in Soviet (SGST) wells of the 1960s. Saline waters (of Cl – Na – Ca type mineralization), usually associated with petroliferous sediments, were also found in the wells. Bitumen was also found impregnated in limestone, shale and sandstone sequences, of the Middle Voltaian formation. Early attempts at evaluating hydrocarbon potential have not been successful. Further attempts between 1996 and early 2000s were also not sustained.

    17. 4/14/2012 VoltaianProjectUnit 17 EFFORTS SO FAR AT GNPC In May 2005, GNPC established the Voltaian Project Unit (VPU) and charged it with the major objective of accelerating and coordinating programmes to promote the Voltaian Basin to a marketable status. In particular, the VPU was charged to: Develop strategies of opening up the Voltaian Basin to vigorous exploration; Develop strategies for raising funds for reconnaissance survey; Collaborate with the Ghana Geological Survey to obtain applicable set of data from the EU Airborne Surveys; Develop and implement complementary reconnaissance exploration programmes to bring the Basin to a marketable status.

    18. 4/14/2012 VoltaianProjectUnit 18 EFFORTS SO FAR (CONTD) VPU WORK PROGRAMME The VPU of GNPC proposed a Work Program and Budget for the Basin’s Geoscientific Study and Evaluation. It outlines GNPC’s plan to undertake a systematic geologic and geophysical study of the Basin within a 4˝-year, three-phase Study Program. Essentially, the Study involves Geological-Geophysical Reconnaissance in the initial phase, to be followed by a High-grade Evaluation in the second. It will culminate in a Drilling/Evaluation programme in the final phase. This Study is expected to generate a catalogue of leads, prospects, maps, reports and other important technical documentation within a broad spectrum of a well-defined Petroleum System. Its results are targeted at the international petroleum industry and are expected to raise the Basin’s status to an attractive and marketable level.

    19. 4/14/2012 VoltaianProjectUnit 19 EFFORTS SO FAR (CONTD) Notable efforts currently at GNPC are devoted to accomplishing Phase I of the Program. However, they also include: Technical contacts, data reviews, etc between GNPC and interested investor partners and service companies; Compilation and study/review of the basin’s data inventory, useful data exchanges with GSD, our reliable and dependable partner.

    20. 4/14/2012 VoltaianProjectUnit 20 EFFORTS SO FAR (CONTD) Technical liaison with GSD and by extension, with GEUS (of Denmark) through its Technical Advisor (TA) to foster familiarization and participation in the Voltaian Study/EDF Project, and to identify further channels of technical cooperation. Projections have also been made for a joint GNPC - GSD geological fieldwork over the basin as a collaborative effort. GNPC/GSD Geotraverse Project in 2Q-2006 over the Buem and Voltaian geological provinces of Ghana Conducted in collaboration with Prof. Pascal Affaton of CEREGE in France. Objective: to collect fresh rock samples for dating to know more about the geology of the Voltaian Basin as part of efforts toward further investigation. GNPC participation in Geosciences workshops, as on the Stratigraphy & Water Quality of the Voltaian Basin, organized jointly by GSD, HAP (Hydrogeological Assessment Project), GEUS and others.

    21. 4/14/2012 VoltaianProjectUnit 21 EDF AIRBORNE SURVEYS The EDF (European Development Fund) through its “8 ACP GH 027” project has provided financial and technical support to fund a 36-month €40m project for Ghana’s Mining Sector Support Programme. GNPC is keenly interested in the results of these surveys. Under the Terms of Reference for Airborne Geophysical Surveys, the total area to be surveyed includes the Volta River Basin (93,000 km˛) and the Keta Basin (5,000 km˛) totaling 98,000 km˛. The works are being conducted in 5 phases, with Phases 1 and 2 together taking ~12 months: Phase 1: Geological outline through Radar and Optical Satellite imageries; Phase 2: Airborne Geophysical Survey for Magnetics, Gamma-Ray Spectrometry (and Gravity?); Phase 3: Airborne Electromagnetic and Magnetic Geophysical Survey of specific areas, following the completion and interpretation of phase 2, using fixed wing Time Domain technology – 12 months; Phase 4: Interpretation of the combined Geology and Geophysics – 9 months; Phase 5: Production of factual and interpretation maps – 3 months.

    22. 4/14/2012 VoltaianProjectUnit 22 EDF AIRBORNE SURVEY LOCATIONS

    23. 4/14/2012 VoltaianProjectUnit 23 REGULATORY FRAMEWORK The following Laws govern petroleum E & P operations in Ghana: GNPC Law (PNDCL 64); Exploration & Production Law (PNDCL 84); Petroleum Income Tax Law (PNDCL 188). The above have been conveniently packaged into a Model Petroleum Exploration and Production Agreement. The elements of the existing fiscal regime are contained in PNDC Laws 84 and 188. The fiscal elements are: Royalty, Carried Interest, Additional Interest (Pay Interest), Petroleum Income Tax, and Additional Oil Entitlement.

    24. 4/14/2012 VoltaianProjectUnit 24 REGULATORY FRAMEWORK (CONTD) Ghana National Petroleum Corporation recommends a downward revision of some fiscal elements and an increase in exploration period for Voltaian Basin and Deep Water operations, and the fixing of same in the Laws. These proposals are currently receiving Cabinet attention.

    25. 4/14/2012 VoltaianProjectUnit 25 HYDROCARBON POTENTIAL OF THE VOLTAIAN BASIN

    26. 4/14/2012 VoltaianProjectUnit 26 KEY PLAY ELEMENTS Primary Objective: Middle Voltaian: Upp Grnsh Gry Sandstone series; Conglomeratic series; possibly Variegated Argillaceous Carbonates. Secondary Obj: Lower Voltaian Oti beds (if fractured). Porosity: Fair, about 10-15% av; Maximum ~ 20%, if fractured. Permeability: Fair.

    27. 4/14/2012 VoltaianProjectUnit 27 KEY PLAY ELEMENTS (CONTD) Source: Middle Voltaian - Variegated Shale series. Type II, possibly Type III kerogen. Seal: Variegated Shale/Argillaceous Carbonate series. Traps: Structural: Horsts and fault blocks, possibly anticlines. Stratigraphic: possibly pinchouts.

    28. 4/14/2012 VoltaianProjectUnit 28 OVERVIEW OF ANALOGOUS BASINS IN ALGERIA The following clips are based on a presentation, circa 2005, “Contribution of the Exploration Activity in Renewing the Reserves – the Case of Algeria” by Rabih Lounissi of Sonatrach, Algeria’s major indigenous hydrocarbon institution.

    29. 4/14/2012 VoltaianProjectUnit 29 ALGERIA - SEDIMENTARY BASINS

    30. 4/14/2012 VoltaianProjectUnit 30 PLAY TYPES BY COMPARISON Algeria (Proved case histories) Objective zones (Reservoirs): ? (Pz) thro’ Eoc-Mio (Cz). Reservoir lithologies: Mainly Sdst and Lmst. Discoveries: Oil: Tr, D, O, C, ?, S and K. Oil & Gas: Tr, D, O and C. Gas: D, O, Tr, C, S and ?. Source rocks: O, S and D (Frasnian). Seals: Tr shales. Traps: Mainly Structural – Horst blocks, Fault traps, Anticlines; and Stratigraphic. Voltaian (Projected) Objective zones (Reservoirs): Infra-? (Vt1) Oti beds thro’ Mid-Voltaian (Vt2) Upp Grnsh Gry Sdst. Reservoir lithologies: Sdst, Congl Sdst and Carbonates. Discoveries: Nil (Not yet applicable). Source rocks: Pz Mid-Voltaian Variegated Shales. Seals: Pz Mid-Voltaian Variegated Argillaceous Carbonates. Traps: Structural – Horst blocks, Fault traps, possibly Anticlines. Stratigraphic: Possibly pinchouts.

    31. 4/14/2012 VoltaianProjectUnit 31 ALGERIA – EXPLORATION SUMMARY Earliest exploration activities in the Cheliff Basin in the 1890s. First commercial discovery in Oued Gueterini Basin in 1948. Discovery of Hassi Messaoud and Hassi R’Mel giant fields in 1956. Between 1953 and 2004 in Algeria, the following advances were made in petroleum E & P: ~ 530,000 km of 2D seismic acquisition – i.e. 0.4 km per km˛ surface area; ~ 6,000 km˛ of 3D seismic acquisition; and ~ 1,400 wildcats and appraisal wells - i.e. 9 wells per 10,000 km˛.

    32. 4/14/2012 VoltaianProjectUnit 32 DEDUCTIONS On the basis of investigations conducted so far on the Voltaian Basin, and based on experience from analogous basins that are petroliferous in North Africa, South America, and elsewhere, what is the outlook for hydrocarbon prospectivity of the Volta Basin? Clearly, there is a bright and challenging outlook for the hydrocarbon prospectivity and future exploration potential of the Volta Basin. These stem from fact that: There really exists a thick sedimentary cover in the basin of at least 6km thick in the deepest sections.

    33. 4/14/2012 VoltaianProjectUnit 33 DEDUCTIONS (CONTD.) Structural as well as stratigraphic traps are likely to occur in various subsurface locations. The occurrence of sandstones and limestones in the succession may serve as suitable reservoir rocks. On account of the indications of heavy oil and gas, bituminous and other hydrocarbon indications that were encountered in the 10 SGST wells, this Basin most probably harbours favourable conditions for the generation and accumulation of commercial quantities of hydrocarbon. Known oil and gas discoveries already exist in analogous basins in North Africa, Brazil and elsewhere.

    34. 4/14/2012 VoltaianProjectUnit 34 CONCLUDING REMARKS The Voltaian Sedimentary Basin has a very bright outlook for its hydrocarbon exploration. There really exists a thick sedimentary cover of at least 6km in its deepest sections. There must certainly be oil + gas in the Voltaian Basin waiting to be tapped. On account of the thickness of its sedimentary cover and the bituminous and other hydrocarbon indications encountered in the Soviet wells of the 1960s, this Basin is deemed to possibly harbour favourable conditions for generation and accumulation of commercial quantities of hydrocarbon. There are possible structural and stratigraphic leads that could provide favourable architecture for generation and accumulation of commercial quantities of hydrocarbon. The occurrence of sandstones and limestones in the succession, may serve as suitable reservoir rocks. Known oil and gas discoveries and production already exist in analogous basins in North Africa and elsewhere in the world. A very large domestic market for gas and oil in Ghana waits impatiently to be fed from discoveries and production from the Volta Basin. Political, fiscal and legal environments in Ghana provide a lot of incentives for attracting and sustaining investments in hydrocarbon exploration in the Volta Basin.

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