PRELIMINARY REPORT ON OFFERED BLOCKS OF SONANGOL

REPUBLIC OF ANGOLA

PREPARED BY

ABDUL QAYYUM ( MANAGER EXPLORATION, OVERSEAS)KHALID JAVED ( DY.CHIEF GEOLOGIST , OVERSEAS)

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Introduction:

Angola is world 23rd largest country and second largest country in Sub-

Saharan Africa. It came into existence on November 11, 1975 and has an

area of 1.2467 million square kilometer and population of about 15.941

million people. In general 75% of the population is Agriculture dependent

and has main export of coffee. National Currency name is Kwanzaa and

official language is Portuguese.

Geographic position:

Republic of Angola is bordered by Democratic Republic of Congo in the north

(NE), Namibia in the south and Zambia in the east and Atlantic Ocean in the

west.

Fig-1: Location map of the Republic of Angola.

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History of Hydrocarbon Exploration:

Hydrocarbon exploration activity dates back to 1910 but first onshore well

was drilled in 1955 in Kwanzaa Basin (Benfica Field). The country first

shallow water offshore commercial discovery was made in 1960 in lower

Congo basin (limba Field). This triggered deep water exploration in 1993

which resulted in another commercial discovery in 1996 in lower Congo basin

(Girrasol Field) . The country moved to ultra deep-water exploration in 1999

and it made commercial discovery in lower Congo basin at Plutao Field in

2002. Since 1996 till 2003, total 55 deep-water commercial discoveries have

been made. The country total oil output is one Million barrels and associated

gas production is 1.20 BCF/day. About 200 exploratory and appraisal wells

have been drilled in the country since

1990 and some thirty companies are

operating in 29 offshore and offshore

blocks out of which 14 are Operators.

Sedimentary Basins of Angola:

Sedimentary Basins of Angola can be

broadly divided into two;

01: Offshore Basin

02:Onshore Basin

Offshore Basin includes; Congo Basin, Kwanzaa Basin , Benguela and Namibe

Basin (Frontier Basin), Whereas, onshore basins include; Kassanje and

Okawango Fig-2: Map showing location of

onshore basins of Angola.

and inner Kwanzaa Basin.

Kwanzaa Basin:

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Kwanzaa Basin has an aerial volume of 25,000 square kilometers and

extends into offshore. On onshore it consists of 23 blocks, each one about a

thousand square kilometer.

Fig-3: Location Map of offshore basins of

Angola.

M/S Sonangol has offered three blocks in

the Kwanzaa Basin namely Cabinda

Centro, KON-11, KON-12. The blocks have

been imaged by Vibroseis and dynamite

source and have poor line spacing.

Therefore, additional data will be required

to technically evaluate the block as

evident from scattered data in each block.

For quick look, please refer to Summary of

three on-shore blocks

Fig-4: Map showing location of Kon-

11,Kon-12 and Cabinda Centro in

regional perspective.

Stratigraphy of Kwanzaa Basin,

Block-KON-11,KON-12:

Sediments from early Cretaceous to

Pliocene were deposited in the basin with

key reservoirs;

Binga Logoon Carbonates

Catembula

Lacustrine sands and carbonates

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The basin has proven source rock of Binga and Pre-salt (Albian).

Fig-5: Stratigraphic section of blocks Kon-11,Kon-12.

Seismic Coverage Block Kon-11 and Kon-12:

As evident from blocks layout that

they are contiguous and has poor

seismic coverage. Kon-11 has

32.00 and Kon-12 has about 100

L.km 2D which for a block size of

1000 sq.km is not sufficient to

reasonably evaluate its existing

potential. Aero -magnetic data is

available and its professional

interpretation will be required before envisaging work programme.

Fig-6 : Map showing seismic profiles in blocks Kon-11,Kon-12

Cabinda Centro block:

Cabinda Centro has seismic

coverage of 238 l.km and history of

33 wells with minor oil shows.

Aeromagnetic survey is available

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and its ingenious interpretation will be required in addition to re-visiting the

old seismic and well histories.

Fig-7 : Map showing seismic profiles in Cabinda Centro block

TECHNICAL SUMMARY /QUICK LOOK INFORMATIONS ABOUT OFFERED

BLOCKS:

Summary and comparison of three onshore blocks is given below in a tabulated form;

CABINDA CENTRO BLOCK-KON-11 BLOCK- KON-12.

Title Cabinda Centro KON-11 KON-12Area sq.km

1425 1020 1024

Wells 33 dry holes 03 expl and appraisal

04 expl and appraisal

Target Fm

Basement cherty L.st. LuculaLacusturine TurbiditeMavumaVermelha

Binga FmCatumbelaLacusturine Sand, carbonates

Binga FmCatumbelaLacusturine Sand, carbonates

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Source Rock

Bucomazi Binga Fm & Pre-salt Binga Fm & Pre-salt

2D survey 238.50 32.84 99.68Aero Magnetic

Yes Yes yes

Structures

Pre and post Salt Horst structures

Salt induced Salt induced

Oil Fields Nil, only oil shows Galinda &Tobais Pitchy ShowsPotential 250 mm bbls 100 mm bbls 100 mm bblsData Cost US $ 270,000 US $ 140,000 US $ 115,000

BLOCK-KON-11: Key information’s about Galinda &Tobais Oil Fields:

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Tobais Oil Field:

Wells drilled: 12Datum level: 710 m ssOil wells : 8OOIP: 94 mmblOriginal oil water contact: 850 m ssOil recovery factor: 31%Cumulative oil production: 29 mmbblCumulative gas production: 10 b scfCumulative water production: 3 mmbblOil gravity: 30º APIOil volume factor: 1.129 bbl/stb;Oil viscosity cpo: 3.250Initial reservoir pressure: 946 psia;Saturation pressure: 775 psiaReservoir temperature: 120ºF

Galinda Oil Field

Wells drilled: 8Datum level: 1,901 m ssOil wells: 6OOIP: 21 mmblOriginal oil water contact: 1,970 m ssOil recovery factor: 11%Cumulative oil production: 2 mmbblCumulative gas production: 777 mm scfCumulative water production: 113 m bblOil gravity: 28º APIOil volume factor: 1.180 bbl/stb;Oil viscosity cpo: 2.000Initial reservoir pressure: 5,100 psia;Saturation pressure: 2,058 psiaReservoir temperature: 230ºF

GEOSEISMIC SECTION ALONG TOBAIS AND GALINDA OIL FILED

CONCLUSIONS:

M/s Sonangol has offered onshore and offshore blocks and we have

reviewed the available web data for three onshore blocks, Cabinda

Centro, and KON-11, KON-12.

Cabinda Centro has seismic data of 238 L.km and 33 wells with oil

shows.

Kon-11 and Kon-12 are adjacent blocks, has seismic coverage of 32

and 100 L.km with history of 03 exploratory and 04 exploratory dry

wells.

Three blocks have salt induced tested extensional structures out of

which Kon-11 and Kon-12 has Galinda and Tobais oil Field.

Aeromagnetic data is available for all three blocks.

Basic petroleum system exists in the blocks as proved by the

commercial discoveries; however dry wells history will be required for

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review as 33 wells in a block like Cabinda Centro must portray solid

technical reasons.

The data shows remaining potential of 100 Million Barrels in block-

KON-11 and KON-12 each.

On the basis of anticipated thick salt in the blocks, seismic imaging is

major technical issue.

RECOMMENDATIONS:

On the basis of very limited available information’s it is extremely

difficult to recommend a block and its data purchase, However,

among two blocks; KON-11 and KON-12, data for either may be

purchased so that could evaluate the block and move forward.

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