Oil & Gas resources

Petroleum Resources

The United States Geological Survey (USGS) and the Afghanistan Geological Survey (AGS) jointly assessed the oil and gas resources in northern as well as in Western and Southern Afghanistan. The estimated mean volumes of    petroleum in the Northern assessment area were 1.6 billion barrels of crude oil,  16 trillion cubic feet of natural gas, and 0.50 billion of natural gas liquids, (USGS FS-3031, 2006). Most of the undiscovered  crude oil occurs in the Afghan-Tajik basin and most of the undiscovered  natural gas is located in the Amu Darya basin. These two basins within the Afghanistan encompass area of approximately 515,000 square kilometers.


Basins in Afghanistan

Afghanistan has five (5) major and 1 minor sedimentary basins (figure1), all of which are underexplored. 

Almost all of the petroleum exploration and development activities were confined to northern

Figure 1 shows general location of the 6 sedimentary basins in Afghanistan

Afghanistan within the Armu Darya and Afghan-Tajik basins. During the Soviet era (1957-1989), a total of seven (6) oil and eight (8) gas fields were discovered. 

Limited exploration in the Tirpul basin (Herat Province) confirmed the presence of oil whilst Katawaz and Helmand basins have no reported shows, owing to negligible or no work at all. 

 

Northern Afghanistan Basins

The Afghan –Tajik, Amu Darya, and Kushka basins represent a total petroleum system, (figure 2). The Kushka Basin is an extension of the highly prolific Amu Darya Basin. This basin has giant and supergiant fields in Turkmenistan and Uzbekistan including the South Yolotan field in Turkmenistan which is one of the largest gas fields in the world.

The Afghan-Tajik basin offers similar geology and reservoirs making it a prized prospect for development. Lack of investment in post-Soviet times has precluded any active exploration programs to date within Afghanistan.

Figure 2    Satellite image of northern Afghanistan showing locations of the Amu Darya and Afghan-Tajik basins, as well as the Total Petroleum Systems, (After USGS, 2006).


Source rocks - The Lower to Middle Jurassic continental to marine clastics and coals and Upper Jurassic (primarily Oxfordian) anoxic basinal black mudstone, contain up to 2.5 weight % of total organic carbon with Type III kerogen and thin coal layers.

  • Two identified Reservoirs were: (i) Hauterivian Kyziltash Formation sandstone, several tens of meters thick, high porosity and permeability and contains most of the oil and gas reserves. (ii) The second important reservoir is Upper Jurassic (Callovian to Oxfordian) shallow-shelf carbonates that contain sour gas, (see figure 3 for typical stratigraphic column).
  • Geothermal gradient of producing wells of the North Afghan high is about 34.6 degrees C/km.  The Jurassic beds are in the thermal gas window in all the basin areas. Cretaceous beds are partly in the thermal gas window (deeper parts) and in the oil window (basin perimeter and in part of the Turanian platform area). Paleogene and some Neogene beds are in the oil window on the basin perimeter.
  • Traps -All known fields are in structural traps, most of the discovered productive traps are in anticlinal uplifts. Undiscovered fields are expected in structural traps, in reefs, or combination of the two.
  • The principal regional seal is the Kimmeridgian to Tithonian Gaurdak Formation composed of salt and anhydrite with local carbonate beds.
  • Plays - over 500 structures are discovered in the Amu Darya Basin. Five
    Figure 3  Typical stratigraphic column in the northern Afghanistan basins
    important plays are recognized in the North Afghanistan basins that together are assumed to contain more than 95 %of the hydrocarbons.


 

 

 

 

 

 

 

 

 

 


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