The Energy Consulting Group

Management consultants for upstream oil and gas producers and service companies

Algerian Oil Production and Reserves (Note:  These are total liquid volumes, so are an amalgam of crude, condensate and NGL production.  According to the EIA, Algeria produces about 320 MBLPD of NGL's and about 1200 MBOPD of crude and condensate) For Larger View, Click Image	Algerian Gas Production and Reserves For Larger View, Click Image
Algerian Oil Production Segmented By Type (Crude, Condensate, and NGL) For Larger View, Click Image	Algerian Oil and Gas Fields on 3D Surface Elev. Map For Higher Resolution, Click Image
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Algerian Hydrocarbon Transport and Export Network For Larger View, Click Image	Algerian Natural Gas Export Markets-2013 For Larger View, Click Image
Algerian Oil and Gas Pipelines Relative to Oil and Gas Fields - Circa 2001 For Larger View, Click Image	Algeria Pipeline Map (high resolution) For Larger View, Click Image
Algerian New Gas-Condensate Field Development: Ain Tsila Link to 3D version of the above map.  The 3D representations shows how the terrain varies around the new field area, and how the elevation shifts as gas pipelines heads towards the domestic demand and export (LNG and pipelline) centers along the coast. 3D Map Controls: to rotate use the left mouse button, to zoom in/out use the mouse wheel, and to roam use the right mouse button.	Algiers, March 13, 2019; Ain Tsila Project Approval Announcement The Isarene Group (Incorporated by SONATRACH, Petroceltic and Enel) and PETROFAC International (UAE) LLC today signed an EPC contract for the development  of the AIN TSILA gas field located in the ISARENE perimeter, 160 km northwest of Illizi wilaya.  The development of the gas field of Ain Tsila will recover 64 billion gas with a daily output of 10.3 million m3 of sales gas and 11,500 barrel of condensate and 17,000 barrel of LPG on a plateau 14 years old.  The EPC Contract consists of: - The completion of a CPF for wet gas treatment with a capacity of 12 million m3 Day;  - The construction of a 125 MW power plant;  - The realization of utilities;  - The construction of a 110 km collection network for the connection of 30 wells planned for the First Gas;  - The completion of a 356 km long shipping system.  This EPC contract, which will come into operation within 42 months from its entry into force and amounting to 123 billion DZD, should be allow the production of  three products, namely:  - Dry gas (10.3 Million Sm3 / Day);  - Condensate (10,550 bbl / day);  - LPG (17,117 bbl / day).
Algeria: Stratigraphic Column For Larger View, Click Image Stratigraphie de la plate-forme saharienne (A- la province occidentale, B- la province triasique, C- la province orientale) Stratigraphy of the Saharan platform (A-Western Province, B-Triassic province,C-the eastern province )	Selected Geologic and Hydrocarbon Basins of Algeria (with some oil and gas fields) For Larger View, Click Image

To the left is a 3D rendering of the Algerian shaded relief map shown below.  It is rotatable, zoomable, and roamable (per the directions below).  For a full screen version of the map, go to this link. (Controls for the 3D rendering to the left and online are: to rotate use the left mouse button, to zoom in/out use the mouse wheel, and to roam use the right mouse button.)

The 3D image to the left contains an interactive 3D elevation map of most of Algeria with an overlay of oil and gas fields and pipelines.  It is intended to help provide geographic context for important oil and gas producing regions in Algeria.  It is rotatable, zoomable, and roamable (per the directions below).  For a full screen version of the map, go to this link. (Controls for the 3D rendering to the left and online are: to rotate use the left mouse button, to zoom in/out use the mouse wheel, and to roam use the right mouse button.)

Algerian Non-Conventional Oil and Gas Plays (Shale Gas and Light,Tight Oil)

Algerian Shale Gas: Ahnet Basin	It has been reported that ExxonMobil is negotiating an agreement to develop shale gas fields in the Ahnet Basin, southwestern Algeria (see exhibit to the left) with horizontal drilling and fracking technology. The shale gas zones are probably the Frasnian and Silurian, which Sonatrach tested in 2015, and which are described in more detail in the following exhibits. Reuters is reporting that ExxonMobil has temporarily suspended the above referenced negotiations due to the nascent anti-government protest movement that emerged in March 2019.
Algerian Shale Gas Overview	Play Characteristic Comparison Between Frasnian Shale and Well Known US Shales
Algerian Shale Gas Potential: Frasnian Formation	Algerian Shale Gas Potential: Silurian Formation

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GEOLOGY OF ALGERIA (ALNAFT)

1.INTRODUCTION:

The boundaries of Algeria are the Mediterranean Sea to the north (1200 km of coast), Morocco to the west, Tunisia and Libya to the east, Mauritania and Western Sahara to the south-west and finally Mali and Niger to the south (Fig. 1).

Fig.1: Geographical map of Algeria

2. GEOLOGICAL FRAMEWORK

The geological history of Algerian sedimentary basins (Fig. 2) is part of the global geodynamic process of plate tectonics that has structured Algeria in two domains:

·         in the north, alpine Algeria;

·         to the south, the Saharan Platform.

Fig. 2: Structural Map of Algeria 

2.1 ALGERIA ALGERIA:

The northern domain consists of young reliefs, modeled during the Tertiary by the Alpine movements.

Alpine Algeria is composed of the following structural-sedimentary ensembles, from north to south:

• the reduced Algerian continental shelf, with tertiary and quaternary deposits (1000 to 3500 m), is based on a metamorphic base.

The main oil objective is the Mio-Pliocene;

• The Tell Atlas is the domain of aquifers, with basins of intramontane type (eg Chélif basin), whose sedimentary series extends from Jurassic to Miocene. Several deposits of variable interest are known there: Ain Zeft, Tliouanet, Oued Guettirini. The main oil objectives are middle Cretaceous, Miocene and allochthonous Eocene;

• The Hodna is a pre-pit basin whose filling sequence begins with continental deposits of Eocene and Oligocene age and continues with a marine Miocene.

The main oil target is the Eocene;

• the highlands, alpine foreland, with reduced sedimentary cover, where local processes of distension have allowed the formation of intramontane basins such as those of Telagh and Tiaret. The main oil goal is the Lias;

• The Saharan Atlas was born from a long subsident furrow pinched between the highlands and the Saharan Platform. In the Mesozoic, this furrow was filled by a powerful sedimentary series (7000 to 9000 m). During the Tertiary, a compressive tectonics reactivates the previous extensive structures in faults and inverse structures resulting in the formation of this mountain range. The main oil objective is Jurassic.

• the Chott Melrhir basins in the Constantine SE, structured in the Cretaceous Tertiary Tertiary (5000 m), generated and accumulated hydrocarbons mainly in the Cretaceous (Djebel Onk, Rass Toumb, Guerguet North El Kihal).

2.2 THE SAHARIAN PLATFORM:

It is located in the south of alpine Algeria and belongs to the North African craton. It includes a Precambrian basement on which rests a powerful sedimentary cover, structured in the Paleozoic in several basins separated by high zones. We distinguish from west to east:

• the Tindouf and Reggane basins located on the northern and northeastern borders of the Reguibat Shield. The sedimentary cover would reach 8000m in the Tindouf basin and 6500m in the Reggane basin. In this little explored zone, Paleozoic formations could be found in liquid and gaseous hydrocarbons;

• the Béchar basin bounded on the north by the High Atlas, to the south and west by the Ougarta range. Its sedimentary cover would reach 8000m. The reservoirs are found in lower Paleozoic detritic and Carboniferous reefs;

• the Ahnet-Timimoun basin bounded on the north by the Oued Namous highland, on the west by the Ougarta range, on the south by the Touareg shield and on the east by the Idjerane-Mzab ridge . Coverage would average 4000 m. In the south, the lower Ordovician and Devonian reservoirs are gasiferous. To the north, in the Sbaa basin, oil has been found throughout the Paleozoic;

• the Mouydir and Aguemour-Oued Mya basins are bounded on the west by the Idjerane-Mzab Ridge and on the east by the Amguid-El Biod Ridge. In the south, Paleozoic sediments are exposed in Mouydir. To the north, in the Aguemour-Oued Mya depression, filled by a powerful Paleozoic and Meso-Cenozoic series (5000m at Oued Mya), significant deposits have been found in the Cambrian (Hassi Messaoud) and Triassic ( Hassi Rmel);

• The Illizi-Berkine syncline is bounded on the west by the Amguid-El Biod ridge and on the east by the Tihemboka mole and the Tunisian-Libyan borders. In the Ghadames basin, the sedimentary cover (greater than 6000 m) contains hydrocarbon deposits in the Paleozoic and Triassic.

3. GEODYNAMIC EVOLUTION

The formation of the Mediterranean alpine chains including the Algerian section of this chain is linked to the rotation of Africa in relation to Eurasia. This rotation is a slow drift of the two continents towards each other. The initial stages of this convergence, detected as early as the Early Jurassic, did not manifest themselves until after the Upper Jurassic (150 Ma).

The tectonics is that of the Africa-Europe collision. The Algerian alpine chain, which leans against the northern fringe of the southern block, was born of this collision.

Although the beginning of Africa's drifting movements from Europe is only clear from the Malm, the initialization of the phenomena dates from the Lias (180 Ma). They are associated with the opening of the North Atlantic.

Schematically, this opening takes place from south to north and generates a number of phenomena whose effects on Algeria can be summarized as follows:

During the Jurassic period (180-140 Ma), south of the current Azores-Gibraltar fracture zone, Africa and the continental blocks attached to it separate from the North America-Europe block (Fig. 5a). The general direction of the Atlantic is NS while the future Mediterranean alpine zone takes an EO direction. This direction is determined by the relative movement of Africa relative to Europe. This movement, of sliding component sinister, persists until the superior Cretaceous.

In the lower Cretaceous, Spain, acting as a corner opposite the slide, separates from the America-Europe bloc. The drift of Spain is responsible for the finite Jurassic-Eocretacea compression phase, as shown by the folds encountered in the Middle Atlas. During the Cretaceous, as a result of the opening of the North Atlantic basin (Fig. 5b), there is a decrease in the sinister slide.

The opening would have caused the cancellation of the sinister component of the movement and even its "inversion". The convergence component of the two continents, which remained in the background during the Cretaceous period, became dominant during the cancellation of late Cretaceous slides.

During the Tertiary, a number of remissions and convergences are recorded, alternating with more or less distensive phases.

From the Eocene, most of Western Europe is stabilized in a form close to the current one. There is no active subduction zone in the western Mediterranean, and the collision front extends from the west from the Pyrenees all the way to the east. It is the zones of lithospheric weakness, mainly areas of Cretaceous deformations, which absorb the effects of the collision. This generalized compression provokes deformations on the European bloc and on North-Continental Africa.

In the Oligocene, as a consequence of the conjugation of the north Atlantic opening, in the west, and the East-Africa collision, in the east, the western Mediterranean regions are subjected to a general tectonic regime of distension. It is responsible for the large intracontinental grabens systems affecting all of Europe from Spain to the North Sea.

The Mio-Pliocene sees the resumption of Africa-Europe convergence, implying the resumption of tectonic deformations in the western Mediterranean.

At the level of the Azores-Gibraltar line, the convergence has a sinister component which manifests on the one hand by activating local points of subduction and on the other hand, by generating an intracontinental tectonics at the level of the Pyrenees, the Iberian Chain and of the High Atlas. At the end of the cycle, the crushing constraints generate the large sheets like the south vergence of the Atlas Tellien especially developed between El Asnam and Annaba.

4. THE PETROLEUM PROVINCES

From the oil point of view, we distinguish, across the entire mining sector of Algeria, four more or less mature provinces:

·         The Eastern Sahara, with known deposits of oil and gas, still has good potential for discoveries;

·         The Central Sahara, considered as gas (deposits of varying importance) but where recent discoveries of oil can hope for further developments;

·         Western Sahara is mainly considered globally gas with the exception of the oil discoveries highlighted in the reservoir of Tournaisien basin Sbaa, its resources remain virtually unknown;

·         In northern Algeria, integrating offshore basins, which despite small oil and gas discoveries, the oil potential has not yet been revealed due to a complex geology.

5.STRATIGRAPHIE 

It is organized into two distinct areas as those already mentioned.

On the one hand, the Saharan Platform is a very large and stable region that has been modeled since the Paleozoic and subdivided into three oil provinces.

On the other hand, the north of Algeria, modeled during the Tertiary by the Alpine movements, has several different sets of stratigraphic characters.

5.1 THE SAHARIAN PLATFORM

The thicknesses of the series (1000 to 8000 m), their nature, the tectonic deformations and the subsidence, shaped the Saharan Platform in a number of basins distributed in the western province, the eastern province and the triasic province.

 Fig. 3: Stratigraphic section of the provinces of the Saharan platform

  a) THE WESTERN PROVINCE

The western province includes the basins of Bechar, Tindouf, Reggane, Ahnet, Mouydir, Timimoun and Sbaa. These depressions are Paleozoic, Cambrian to Namurian. The Meso-Cenozoic is poorly developed. The power of the series varies from 3500 to 8000m. The Tindouf and Reggane basins are dissymmetrical depressions located on the N and NE borders of the Eglab massif.

Paleozoic sediments would reach 8000m in the Tindouf basin and 6000m in the Reggane basin. The Bechar basin is bounded on the north by the High Atlas, on the south and west by the Ougarta range and on the east by the Meharez highland. The power of the series is of the order of 8000m.

The Ahnet-Timimoun basin is bounded on the north by the Oued Namous highland, on the west by the Ougarta range, on the south by the Touareg shield and on the east by the Foum Belrem ridges and Mzab. The Mouydir basin is bounded on the west by the Foum Belrem Ridge and on the east by the Amguid-El Biod Ridge. The sedimentary series can reach more than 3000m.

b) THE TRIAL PROVINCE

Located in the northern part of the Saharan Platform, the Triassic Province is an EO-direction anticlinorium where the following major elements have been individualized:

·         the vault of Tilrhemt and the high ground of Talemzane;

·         the structural system of Djemâa-Touggourt;

·         the El Agreb-Messaoud dislocation system;

·         the pier of Dahar.

These elements are separated by depressions (Oued Mya) where one meets the typical series of the triasic province. (Fig.9b) Paleozoic deposits are often highly eroded, as deep as the Ordovician or Cambrian.

The Mesozoic, discordant on the Paleozoic, is present from the Triassic to the Cretaceous. The Cenozoic is represented by a detrital series of Mio-Pliocene.

c) THE EASTERN PROVINCE

This province, called Synéclise East Algeria, consists of the basins of Illizi and Ghadames separated by the pier of Ahara.

The typical Precambrian sedimentary series (Fig. 9c) presents all the terms, from the Cambrian to the Present. A sandy series of Mio-Pliocene age locally covers the terminal formations of the Mesozoic.

Finally, the discontinuous Quaternary, of small thickness, constitutes the last element of the stratigraphic series.

• Illizi Basin

Paleozoic sediments (about 3000m) rise to the outcrop to the south where they form the Tassilis. As for the Mesozoic formations, they are only in the center of the basin.

Tertiary deposits are well represented in the northwest

• Berkine Basin

This depression is an intracratonic basin that has retained a sedimentary filling of over 6000m from the Paleozoic to the Present. The Mesozoic deposits are characterized by a salt series located in the north and northeast of the basin.

5.2 NORTHERN ALGERIA

Northern Algeria is part of the geological evolution of the Mesogean basin. The foreland has four paleogeographic or structural sets (Fig. 2):

·         the Oran Meseta;

·         the Saharan Atlas at large;

·         southeastern Constantine;

·         the tellian domain.

The stratigraphy (Figs 4 and 5) of northern Algeria has been defined in these areas from field and survey data.

a) THE PALEOZOIC

It is mainly restricted to the northern part (Ghar-Rouban Mountains, Tiffrit, Traras, Chenoua and Kabylie).

It consists of gneisses, micaschists, sandstones and quartzites, locally dated (Ordovician, Devonian, Carboniferous, Permian).

b) THE MESOZOIC

• Trias

It is known in situ only in a few boreholes where it consists of a sandstone series at the base followed by a powerful evaporitic series comprising calcareo-dolomitic past and basic volcanic intercalations at the summit.

In Greater Kabylia, the lower Triassic, probably in part Permian, is represented by red sandstones followed by Muschelkalk limestones, in thick banks or platelets, themselves followed by red sandstones sometimes interspersed with doleritic rocks.

Further south, in the Babors region, the Muschelkalk is surmounted by the salt and gypsiferous formations of Keuper. The lagoon regime of the Babors extends throughout the Tellian zone.

In the east, the lagoonal Triassic clay-detrital region, however, includes carbonate-dominated top sequences attributed to Muschelkak. In Hodna and Constantine, variegated clays are interposed in these same sequences.

At the end of the Triassic, with the exception of a few stable zones (Doui Zaccar, Beni Snassene, etc.), the evaporitic facies are generalized.

• Jurassic

In most of northern Algeria, it begins with a transgressive Lias.

• Lias:

After the Evaporitic episode of the Upper Triassic, the marine character increases during the Lias. The calcareodolomitic facies evolves gradually towards the marls of the higher Lias. The marine character of the Lias is confirmed by the appearance of dolomitic and oolitic limestones indicating an open environment with pelagic influences without being very deep.

The Lias begins with a carbonate level that caps the evaporitic sequences of Keuper. In various points of the Saharan Atlas, this level is Rhétien age. In the southern parts of the chain, Hodna and Bousaada, the essentially carbonaceous deposits fill the atlasic trench. The western Tellian zone and the Saharan Platform see the carbonate sedimentation continue with a Hettangien-Sinémurien limestone which reaches, in places, 200m. In the Hettangien-Pliensbachien, the transgression reached its maximum with flint limestones, red limestones with Ammonites, limestones with polyps, algae and finally calcareous dolomites (200m). At Domérien, Algeria is entirely under marine environment. The ammonitico-rosso facies appear in the Djurdjura.

• Dogger:

It is distributed, from north to south, in different paleogeographic domains. The kabyle domain with reduced carbonate deposits, followed by the relatively thick clay-carbonate sedimentary zone, by the high plateaus and the Constantine mole with mainly carbonated deposits, and finally by the atlasic pit, with clay-sandstone facies often exceeding 2000m. thickness. In the southern part of the Oran highlands and the western Saharan Atlas, the upper Bajocian is marked by traces of detrital sedimentation, reflecting the proximity of fluvio-deltaic activity.

• Malm:

The extension of sandstone facies towards the north shows that the regression, initiated in the Atlas fossa at the end of the Dogger, is accentuated. During this period, marine areas in the north and continental or deltaic domains in the south are opposed. In the latter, however, we find in the highlands and the Atlas fossa, facies of marine influence in the form of sand and sandstone, clay and limestone. East of the meridian passing through Sedrata-Laghouat, a free marine environment without detrital input persists throughout the Upper Jurassic.

• Cretaceous

It is outcropping in the Saharan Atlas. Its detrital and siliceous sediments know their greatest development in the Western Saharan Atlas with thicknesses of 1200m.

• Neocomial-Barremian:

This period is characterized by a maximum regression to the Barremian with a retreat of the sea from the Tell Atlas, the Constantine mole and the NE of the Atlas fossa. The facies are most often alternating between clay-sandstone episodes and carbonate levels.

• Aptian:

In the region of Hodna and Aurès, it is represented by a brief transgressive marine episode with carbonates and reefs. To the south and west, sandstone facies dominate and reflect a fluvio-deltaic regime.

However, in the Atlas fossa, there is nothing to distinguish the Aptian from the Albian, except in the region of Laghouat where calcareous deposits have been found.

• Albian:

Two lithological sets are distinguished. In the Saharan Atlas, the sandstone Albian at the base, evolves towards flysch facies towards the south. In the Tell, it is represented by a clay-sandstone facies and finally in the south-east Constantine, where the transgression is already initiated, the Albian is carbonated.

In the upper Albian, deposits of marl and limestone succeeding the sandstone facies of Tell and Hodna, announce the major transgression of the Upper Cretaceous.

• Cenomanian:

After the Albian transgression, the sea stabilizes.

In the south, a decrease in the water slice causes evaporitic sedimentation. Elsewhere, the trend is clearly marine. In the Tell Atlas, the deposits are marl (1000m) with pelagic fauna. The Cenomanian is neritic in the Telagh and Tiaret regions and carbonated (300 to 400m) in the Hodna Mountains.

• Turonian:

With the exception of some areas of the highlands and Constantine, the sea covers all of northern Algeria and the Sahara. Cenomanian facies are replaced by lamellibranch and echinoderm marl.

• Senonian:

It is a marl-limestone sedimentation with lumachelles.

The previous paleogeography persists until the Upper Senonian, with a slight deepening of the sea and, again, an abundant pelagic microfauna.

c) THE CENOZOIC

• Eocene

In Algeria, the Eocene formations are very important both in terms of their surfaces and their thickness. In the Tell, the Eocene includes marls rich in microfauna, limestones and clays. Lutetian and Thanetian are represented by the classical nummulite levels in these regions. South of the Hodna, the lower Eocene is composed of gypsum marls, phosphated limestones and flint limestones. The Lutetian comes under a facies of oyster marl.

• Oligocene-Miocene

·         Oligocene: it is characterized by important contributions of essentially sandstone material

·         Lower Miocene: it is the seat of a vast transgression taking in sling, following a line substantially EO, all the Algerian domain of the region of Tlemcen to the Saharan depression of Biskra. It consists of a thick series of blue marls (more than 1000m) passing laterally to marine clayey sandstones. Within this immense submerged zone, individual basins, the Tafna, the low and the medium Chelif, the Hodna, the Sébaou, etc., are individualized.

·         Upper Miocene: the regression of the Burdigalian is followed by a progressive transgression on the Chelif scale. The upper Miocene includes various facies (black or blue marl, sand, sandstone, limestone, diatomite and gypsum).

d) THE PLIOCENE AND THE QUATERNARY

At the Pliocene, in Chelif and Mitidja the sea deposits blue marls with sandstone intercalations (1000m). In the rest of Algeria, the Pliocene is lagoonal and passes upward to continental quaternary formations.

6 . THE MERIE ROCKS:

The sedimentary cover of Algeria includes a number of parent rock levels distributed from Paleozoic to Cenozoic.

The main source rock levels likely to be the source of the hydrocarbons highlighted in the different reservoirs of the sedimentary cover are:

- The Silurian:

This bedrock includes radioactive clays made of gray-black to black clays, radioactive at the base. This source rock settled over the entire Saharan platform. Some regions are devoid of it as a result of Hercynian erosion.

The state of cooking of kerogen is dry gas and condensate in the center and north of the basins of Reggane and Tindouf, in the center of the basin of Ghadames and Oued Mya, in the center and the North West of the furrow of Sbaa and finally in the basins of Timimoun, Ahnet, Bechar, Mouydir.

On the other hand, this same kerogen is in oil phase in the rest of the Triassic province, in the Illizi basin, in the southern part of the Reggane and Tindouf basins, in the eastern part of the Reggane basin around the Uganda and finally in the South East of Sbaa furrow. The kerogen is often immature as is the case for the South East of the Sbaa furrow, near the vault of Azzene.

- The Frasnian:

The Frasnian consists of black radioactive organic clays. The distribution of clays shows that in the basins of Ghadames, Illizi, Mouydir, Ahnet, Timimoun, Benoud furrow, this level is rich in organic matter (Fig. 6).

However, the kerogen is immature to the South East of the Sbaa furrow. It is in oil phase in the basins of Illizi, Ghadames (except in the center), the furrow of Sbaa (except the SE) and the southern border of the basins of Tindouf and Reggane. On the other hand, in the basins of Timimoun, Ahnet, in the center of the basins of Tindouf, Reggane and Ghadames, the kerogen is in gas phase (dry gas condensate).

Fig. 6: Isopach, maturation and TOC in the radioactive clays of Frasnien.

 -The Cenomanian-Turonian passage:

The main Mesozoic bedrock is located at the Cenomanian-Turonian Passage. The latter shows the persistence of the marine transgression initiated from the Albian. The mother rock is limited (Fig. 7) to the east by the Tunisian border, to the north by the front of the Tellian aquifers, to the west by the meridian of Algiers and to the south by the parallel 32 ° 50 '.

 Fig. 7: Isopach and ripening of Cenomano-Turonian radioactive clays.

7. THE PETROLEUM TANKS:

As a rule, the reservoirs of the Saharan Platform are related to the Paleozoic and Mesozoic whereas for the North of Algeria they are reservoirs of the Mesozoic and Cenozoic.

THE RESERVOIRS OF THE SAHARIAN PLATFORM:

  THE PALEOZOIC RESERVOIRS

                      The Paleozoic includes mostly well-developed and regularly distributed reservoirs in all the basins of the Saharan Platform (Fig 8). It constitutes an important part of the reserves of the Algerian Sahara.

- THE CAMBRIAN:

It is productive in the fields of the Triassic province and in the basins of Illizi and Timimoun.

The main production comes from the Ra and R2 lithozones and to a lesser extent R3. Productive reservoirs are mainly related to fracking.

- THE ORDOVICIAN:

The relatively numerous Ordovician reservoirs are located in the following formations:

·         the clayey sandstone of Oued Mya and the sandstone of El Atchane;

·         the quartzites of Hamra;

·         the sandstone of Ouargla;

·         the sandstone of Oued Saret;

·         the sandstone of Ramade or the slab of Mkratta.

The sandstones come from a wide variety of environments, ranging from marine to glaciofluvial, resulting in a great diversity of reservoir geometry as well as some disparity in the distribution of most facies.

Fig. 8: Generalized geological section for the whole area of ​​Algeria.

 - THE SILURIAN:

On the entire Saharan Platform, the Silurian is known for its rock-mother qualities. In the Illizi basin and the Triassic province, it has in its upper part potential reservoir zones where the thicknesses often important make it a good oil objective.

- THE DEVONIEN:

In general, the Devonian is a producer wherever he exists. Reservoir levels are medium to coarse sandstones with good petrophysical characteristics. It exists in three stratigraphic sets (F6, F5 and F4).

- THE CARBONIFERE:

 The reservoirs are divided into three sectors. To the west of the platform in the basins of Tindouf, Ahnet and Timimoun, the matrix characteristics of sandstone can be good reservoirs.

In the triassic province, the good reservoirs are located in the south-west in the Viséen and in the north-west in the Moscovian.

Deposits are known in the Viséen of Ghadames and the Moscovian of Bordj Nili. In the Illizi Basin, well-developed levels (D8 to D0 and B14 to B10) produce in the Viseen to Zarzaïtine, Tiguentourine, Edjeleh and Adeb Larache. Oil occurrences have been encountered in the Viséen region of Hassi Messaoud. Namurian (B8, B6, B4 and B0) produced only in Zarzaïtine.

  MESOZOIC RESERVOIRS:

In the northwestern part of the Saharan Platform, the Mesozoic in general and the Triassic in particular harbor significant oil and gas resources.

The Triassic is divided into a clay-sandstone base sequence (TAGI), a median carbonate Triassic and a clay-sandstone upper sequence (TAGS).

- TRIAS ARGILO-GRESEUX INFERIEUR (TAGI)

The main discoveries were made in the Rhourde Nouss, Gassi Touil, Nezla, El Borma, Keskessa, Wad-Teh, Haoud Berkaoui and recently Bir Rebaa-North and Rhourde El Khrouf regions.

- TRIAS CARBONATE AND ITS EQUIVALENTS:

Located at the top of the sequence (TAGI), it is formed by clay series and brown-red dolomite with some limestone levels.

It should be noted, however, that the South West part of the Saharan Platform has given good results in the regions of Rhourde Nouss, Hassi Chergui and Sif Fatima.

Similarly, in the northwest of the triassic province, the fluvial sandstones have good potential, as in the southeast of the Ghadames Basin (Zarzaaitin series).

- TRIAS ALGILO-GRESEUX SUPERIEUR (TAGS):

It is one of the main reservoirs of the Saharan Platform, however it has produced in Hassi Rmel, Rhourde Nouss, Hassi Chergui, Rhourde Adra, Hamra, Rhourde Chouf, Brides and recently Rhourde Messaoud and Rhourde El Khrouf.

The Triassic province has well-developed reservoirs.

·            THE RESERVOIRS OF NORTHERN ALGERIA:

Although northern Algeria is only partially known, its oil potential may be limited to sandstone or carbonate reservoirs of Jurassic to Miocene age (Fig. 8).

- THE JURASSIQUE:

The reservoirs are carbonated with bioclastic buildings and dolomites. They are found mostly in the Saharan Atlas. Despite indications, no commercial deposits were discovered.

- CRETACE:

The best-known reservoirs are located in the Cenomano- Turonian. Intergranular porosity has been improved by dolomitization and fracturing.

Some barremian reservoirs have porosities of 30%. Despite some clues, these levels have not delivered commercial discoveries.

- THE TERTIARY:

The historical discovery of oil exploration in Algeria goes back to the Miocene sandstone of Ain Zeft in the Chélif basin at the end of the last century.

Similar discoveries took place at the beginning of the century in the Tliouanet post-nappe Tortonian sandstones.

The reservoirs are the Eocene Nummulites of the Hodna basin and the Miocene sandstones of the Chélif basin. The first commercial discovery took place in 1949 in the facies of high energy platform of Oued Gueterini.

9. ROCHES COVERINGS

9.1 THE SAHARIAN PLATFORM:

The basins of the Saharan Platform include levels of Paleozoic and Mesozoic-aged rock, and are argilo-evaporitic deposits.

  THE PALEOZOIC:

- THE ORDOVICIAN

The Ordovician age covered rocks are present on almost the entire Saharan Platform

- THE LOWER ORDOVICIAN - ARGILES OF EL GASSI

They are gray-black to black clays and cover the Cambrian tanks. This facies is distributed throughout the Sahara (Ain Romana in the Ghadames Basin).

- THE ORDOVICIAN MEDIUM - ARGILES OF AZZEL AND TIFEROUINE

These gray-black silty-micaceous clays ensure the sealing of Hamra quartzites and Ouargla sandstones.

- THE ORDOVICIAN SUP. - MICRO-CONGLOMERATIC CLAYS

These are black and gray clays with rolled quartz grains of periglacial origin. This level may lie unconformably on several Cambrian and Ordovician reservoirs.

- THE SILURIAN

The Silurian formations of the Saharan Platform are considered on the one hand as source rocks composed of clay horizons and on the other hand as covered rocks for reservoirs of the Upper Ordovician.

They are found in Moukhag El Kebach and in the Oued Mya Basin or in Guaret El Gueffoul and Hssi Msari in the Ahnet Basin.

- THE DEVONIEN

These are mainly Frasnian and Famennian clays, located in the western Sahara (Teguentour basin and In Salah basin) and in the basins of south-eastern Sahara.

For its part, the clayey Praguian constitutes the lower Devonian cover of the southeastern Saharan basins, as in Bir Berkine and Bir Rebaa.

- THE CARBONIFERE

The cover of the Tournaisian reservoirs, like those of the localities of Krechba and Zarafa, is ensured by clays dated from the Viséen.

  THE MESOZOIC:

The Mesozoic cover corresponds to the Triassic and Lias clays and evaporites. In the Triassic basin, they cover the sandstone reservoirs of the Triassic and, sometimes unconformably, that of the Paleozoic reservoirs.

9.2 NORTHERN ALGERIA

The north of Algeria has been little explored, the distribution of the cover corresponds to reservoir facies.

- THE JURASSIQUE

The Jurassic cover includes clays and marls of the Upper Lias or Lower Malm.

- CRETACE

The Cretaceous reservoirs are covered by the Santonian and Campanian clay-marly facies (Rass Toumb, Guerguitt El Kihal and Djebel Foua).

- THE TERTIARY

Tertiary cover is provided by the Lutetian evaporitic clays or the clays and marl of the Mio-Pliocene outer platform and basin.

10. HYDROCARBON TRAPS:

Until the last few years, exploration was mainly focused on the structural pitfalls from which most of the current production comes. New tools and concepts now provide a better understanding of other types of traps, taking into account their respective geological contexts.

10.1 THE SAHARIAN PLATFORM

10.1.1 STRUCTURAL TRAPS:

These are anticlinal folds formed during the different tectonic phases. Indeed, there are many anticlines created by tectonic inversion in the Triassic Basin. In the Illizi basin, the anticlines are associated with steeply dipping reverse faults and setbacks. The anticlines developed on low-dip reverse fault are known in some areas such as Sbaa Bowl.

Fig. 9: trap of structural type.

10.1.2 OTHER TRAPS:

With the exception of diapirs, the Saharan Platform contains all known traps. However, no major discovery has been made outside the structural domain.

 Fig. 10: The different types of stratigraphic traps.

 a) Stratigraphic traps

The tanks are generally sandstone bodies closed by lateral bevelling. Among the best studied basins are the Illizi Basin with the Devonian erosion bevels (tanks F3, F4 and F6) around the Ahara mole or the regressive sandstone units of the Tihemboka mole (reservoir Devonian F6).

The same is true of Devonian erosion bevels of the Allal and Wadi Namous vaults. In the furrow of Benoud, we note the same type of bevel in place in both the Devonian and the Carboniferous. Finally, at Wadi Mya, it is the sizzling lenses of the Triassic that serve as a reservoir.

b) Reef traps

They are mainly known in the Carboniferous limestones of the Bechar basin and the Benoud furrow.

c) Hydrodynamic traps

The F6 reservoir of the Tin Fouyé deposit in the Illizi basin is a good example.

d) permeability barrier

This type of trap characterizes mainly the sandstone reservoirs of the Ordovician basin Illizi and Ahnet (Fig. 10).

10.2 NORTHERN ALGERIA:

10.2.1 STRUCTURAL TRAPS:

These are structures formed during the atlas phase. The Finite-Lutetian and Miocene periods were the most active.

10.2.2 OTHER TRAPS:

Although little explored, the alpine domain potentially includes most of the known traps.

a) Stratigraphic traps:

The known examples are the carbonated Ypresian bevel or the erosion bevel under the Miocene (Barremian-Senonian) mismatch of the Hodna basin. Elsewhere, as on the southern flank of the Chotts basin (Upper Cretaceous) and the northern flank of the Western Atlas (Jurassic) furrow, there are good traps in accretion bevels.

b) Reef traps (Fig. 10):

They are known in a number of points as in the southeastern Constantine with the Albo-Aptian reefs. In the north of this basin, they are often related to diapirs.

We find in the Cenomanian, Turonian and Coniacien south of the basin of Chotts. Finally, the reefs of the Portlandian and Kimmeridgian central Atlas or those of the Lias of the Western Atlas are also good potential targets.

c) Diapirism (Fig. 11):

Apart from the reefs associated with diapirism that have just been mentioned, the salinity traps are likely to exist both in the highlands, in the western Hodna basin, in the Chelif basin and finally in the Ain Beïda region east of Constantine.

Fig. 11: Traps associated with diapirism.

 d) lateral variations of facies

This type of trap is illustrated by the carbonate-anhydrite passage of the regions of Rass-Toumb and Hassi-Bouras (Cretaceous) or even by the variation of sandstone clay in the Miocene reservoirs of the Cheliff basin.

X. DESCRIPTION OF SOME FIELDS

The hydrocarbon deposits of the Algerian Sahara are distributed in the Illizi basin, the Ghadames basin, the Triassic basin and in the Central West basin.

In the same way deposits are dated from Cambrian to Triassic. All types of traps, structural, stratigraphic, hydrodynamic or mixed traps, are represented.

The nature of the fluids varies from undersaturated, saturated oils to volatile oils as well as condensate gas or dry gas.

THE MAIN FIELDS:

a) ALRAR FIELD:

It is located in the northern part of the Illizi Basin, this deposit was discovered in 1961 by the drilling of Alrar East-1.

Significant gas-condensate accumulation was found in Middle Devonian (F3) sandstones.

An oil ring about ten meters thick was encountered three years later on the wells Nord Alrar 103 and Nord Alrar 106.

(b) ZARZAITINE FIELD:

It is located south-east of Algiers near the Libyan border. This field was discovered in 1957 and was put into production in 1960.

It is an oil deposit surmounted by a gas-cap and subjected to an active aquifer.

The main F4 reservoir is of lower Devonian age, this field also produces smaller reservoirs, some of Carboniferous age and others of higher Devonian age (F2).

c) FIELD OF TIN FOUYE TABANKORT (TFT):

This field is located south-east of Hassi Messaoud and north of In-Amenas. The reservoir is Ordovician age impregnated with oil.

The gas-cap of Tin Fouyé Tabankort was discovered in 1961 by the TFE-1 survey. The oil was only encountered in 1965 in the TFEZ drilling.

d) FIELD OF RHOURDE EL BAGUEL:

This deposit is located on the western edge of the Ghadames Basin, it was discovered in 1961. The Cambrian constitutes the productive level of the Rhourde El Baguel field.

It was put into production in August 1963 with the RB-1 test, which produced, from a large accumulation of oil, in the Cambrian quartzites.

e) GASSI TOUIL FIELD:

This field is located in the triassic basin south of Hassi Messaoud. The first well established in July 1960 proved the presence of oil in the Triassic clay-upper sandstone (TAGS), in the Triassic carbonate (Triassic intermediate) and in the lower clay-sandstone Triassic (TAGI).

LEGAL FRAMEWORK FOR CARRYING OUT HYDROCARBON RESEARCH AND / OR EXPLOITATION ACTIVITIES

Algerian Oil and Gas Acreage Blocks For Larger View, Click Image

Law No. 05-07 of 19 Rabie El Aouel 1426 corresponding to April 28, 2005 relating to hydrocarbons. Ordinance No. 06-10 of 3 Rajab 1427 corresponding to July 29, 2006 amending and supplementing the law n ° 05-07 of 19 Rabie El Aouel 1426 corresponding to April 28, 2005 relating to hydrocarbons. The completion of the new institutional building of the energy sector, which was crowned by the promulgation of the law 05-07 of April 28, 2005 on hydrocarbons and the ordinance n ° 06-10 of July 29, 2006, which l supplemented, provided the appropriate legal framework, which takes into account both developments in the hydrocarbon sector within the country and changes in the world economy. On the other hand, the important energy reforms, and the resulting new legal framework, allow for better development of the hydrocarbon sector; they provide the instruments necessary to evolve effectively to better integrate into the international arena and prepare for the major challenges brought about by globalization.

Algeria: Country Overview

(source:  EIA)

Link to EIA article

EIA Overview

Algeria is the leading natural gas producer in Africa, the second-largest natural gas supplier to Europe, and is among the top three oil producers in Africa. Algeria is estimated to hold the third-largest amount of shale gas resources in the world. However, gross natural gas and crude oil production have gradually declined in recent years, mainly because new production and infrastructure projects have repeatedly been delayed.

Source: U.S. Department of State

Oil and natural gas sector management

Algeria's national oil and natural gas company, Sonatrach, dominates the country's hydrocarbon sector, owning roughly 80% of all hydrocarbon production. By law, Sonatrach is given majority ownership of oil and natural gas projects in Algeria.

Security risks

Militant groups operating in North Africa and the Sahel have presented security risks to oil and natural gas installations in the region. In January 2013, a militant group stormed Algeria's In Amenas gas facility, resulting in several causalities and a temporary suspension of gas production at the facility.

The In Amenas gas facility in Algeria

Source: BP

Oil sector

Reserves and exploration

Algeria holds the third-largest amount of proved crude oil reserves in Africa, all of which are located onshore because there has been limited offshore exploration. According to Sonatrach, about two-thirds of Algerian territory remains largely underexplored or unexplored.

Production and development

The country produced almost 1.8 million bbl/d of total petroleum and other liquids in 2013, which includes crude oil, condensate, natural gas plant liquids, and refinery processing gain. The largest and oldest oil field, Hassi Messaoud, contributed more than 40% of total crude oil production, which averaged 1.2 million bbl/d in 2013.

Crude oil exports

The vast majority (about 72%) of Algerian crude oil exports are sent to Europe. The United States was the single largest destination until 2013 when U.S. imports fell to 29,000 bbl/d, or by more than 75%, compared with 2012.

Petroleum products

Algeria has five oil refineries with a total nameplate capacity of 652,500 bbl/d. The vast majority of Algeria's domestic petroleum consumption, which averaged 380,000 bbl/d in 2013, derives from domestically refined products. Algeria's petroleum consumption has increased by an annual average of 5% over the past decade.

Oil pipelines and export terminals

Natural gas

Reserves and exploration

Algeria holds the world's tenth-largest amount of proved natural gas reserves and the third-largest technically recoverable shale gas resources. In May 2014, Algeria's Council of Ministers gave formal approval to allow shale oil and gas development.

Production and development

Algeria's gross natural gas production was 6.4 Tcf in 2012, a 4% decline from the previous year. Production has steadily declined over the past decade as output from the country's large, mature fields is depleting. There are several new projects planned to come online, but they have repeatedly been delayed.

Midstream and downstream infrastructure

Algeria exports natural gas via pipelines and on tankers in the form of liquefied natural gas (LNG). It has three transcontinental export gas pipelines: two transport natural gas to Spain and one to Italy. Algeria's LNG plants are located in the coastal cities of Arzew and Skikda. Algeria was the first country in the world to export LNG in 1964.

Natural gas exports

Algeria exported more than 1.7 Tcf of natural gas in 2012, although preliminary 2013 data show that Algeria's natural gas exports fell by more than 10% to 1.5 Tcf in 2013. Approximately 90% of Algeria's natural gas exports were sent to Europe in 2012 and 2013, making it the region's second-largest natural gas supplier.

Electricity sector

Algeria's public utility, Sonelgaz, is pursuing a large-scale investment program to almost double electricity generation capacity in the next three to four years. The company has already made notable strides, as capacity increased by about one-third from 2011 to 2013. However, Sonelgaz faces some challenges as energy subsidies continue to affect its finances and as natural gas output has declined. Most of Algeria's planned capacity additions are from natural gas-fired plants.

Notes

Sources

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