Login
  •  
  •  US
 
 
 
< BACK Home

Jebel Hammah - Block 47

SUMMARY

Block 47 is located in the interior of Oman and covers 8,524 km2. Unlike most blocks this one contains substantial outcrop belts of the major reservoirs, seals and source intervals expected within it. Likewise, some of the structural and stratigraphic trapping possibilities are present in laterally extensive outcrop belts.

The northern portion of the block contains Jabal Akhdar and Jabal Shams. Extensive erosion of these mountains has resulted in a breach of the Jabal Akhdar anticline and the creation of a series of extremely deep wadis cutting through the stratigraphic section. Because of this it is possible to view in detail the three dimensional aspects of what are the subsurface reservoirs in the portions of the block were gas and gas/condensate have been discovered.

Tight gas is the predominant play within Block 47. To date gas has been discovered in the Natih and Shuaiba formations while gas/condensate has been discovered in the Amin Formation. These discoveries have not been fully appraised. There are currently four gas and gas/condensate prospects mapped across the block.

Within the tight gas play is an unconventional sub-play for the Natih E. This unit is a source interval and also a reservoir. Development of unconventional gas is only beginning in the Sultanate and the Natih E has been recognized as a prime target.

Infrastructure within this block is exceptional. The towns of Nizwa, Bahla and Al Hamra are within the block. These are major towns within the interior so modern roads occur throughout the non-mountainous areas. Within the mountainous regions roads exist that connect the villages to the modern road infrastructure. Other infrastructure elements such as power and water exist across the block.

Concession Map with Block 47 Highlighted

BLOCK OWNERSHIP HISTORY

The current configuration of Block 47 has evolved since the area was first designated for offering to outside companies. The original area was once part of Petroleum Development Oman's (PDO) nation-wide concession. A significant portion of that concession area was relinquished, as specified in the original agreement, during the 1970s.

As of today the owners of the block in its current configuration have been the following companies.

  • PDO
  • Amoco
  • Indago Oman
  • Novus Oman
  • RAK Petroleum
  • DNO

AVAILABLE DATA

  • Block seismic base map, satellite image map and infrastructure map
  • 4,175 km 2D seismic data
  • Gravity data
  • 6 Wells

Seismic and well location base map

STRATIGRAPHY

Oman chronostratigraphic chart (GTS 2012 dates incorporated)

The stratigraphic section occurring in this block can be placed into three groups. The oldest of these ranges from Precambrian to Early Silurian in age and contains the Haima and Huqf Supergroups. The Amin Formation is part of the Haima Supergroup and so far is the deepest formation penetrated within the block.

Separated by a regional unconformity that removed well over 100 million years of geologic time is the predominant pay section. This begins with the Permian age Haushi Group and generally ends with the Fiqa Formation of the late Cretaceous age Aruma Group. Within this portion of the stratigraphic section can be found the Natih, Shuaiba and Lekhwair formations, all of which are regionally significant reservoirs.

Stratigraphy of the Khamah and Wasia Groups in Oman

Finally, overlying the previous portion of the geologic section is the Triassic through Tertiary age allochthonous section associated with the Hawasina Thrust Complex. This interval is composed of time-equivalent rocks from over 200 kilometers away. These were thrust over the block as a result of Tertiary obduction. This portion of the section covers much of the block but has been partially removed by erosion in the southern-most area.

OUTCROP AND ANALOGS

The non-Amin prospective and source intervals as well as some regional seals are found in outcrop across the northern portion of the block. These are exceptional outcrops and several of the formations found in the subsurface were first described at these outcrops. This outcrop locations include Jabal Akhdar and Jabal Shams. The wadis within the block have eroded deeply, exposing the formations in multiple, predominantly dip-oriented transects. The following formations are present in multiple outcrops and can also be viewed regionally along the modern road to Jabal Akhdar.

  • Hamrat Duru Group: Allochthonous sediments of the Hawasina Basin
  • Natih Formation: Reservoir and source
  • Nahr Umr Formation: Regional seal
  • Shuaiba Formation: Reservoir
  • Kharaib Formation: Potential reservoir
  • Lekhwair Formation: Potential reservoir

The Amin Formation is not found in outcrop within the block. The nearest outcrops are rather far away to the southeast, in the Huqf High. There are some professional papers that have been published. The Target interpretation package also contains material on this formation.

DISCOVERIES

  • Gas: Natih and Shuaiba formations
  • Gas/Condensate: Amin Formation

PROSPECTS

4 mapped prospects that target the Natih, Lekhwair or Amin formations. These are gas and gas/condensate prospects. They are distributed across the block.

Main Horizon interpreted & mapped

PLAY SUMMARY

The play for this block is Tight Gas. An active hydrocarbon system has been established for this and adjacent blocks. There are two hydrocarbon sources to which most of the stratigraphic succession found within the block have been exposed.

TRAP

Predominantly 4-way, dip-closed anticlines. Stratigraphic traps associated with progradational clinoforms and carbonate platforms exist in adjacent blocks and are expected within this block. Although not actively pursued to date imbricate thrusting and fault bend folding within the Hamrat Duru Group sediments would create traps.

SW to NE seismic line across an anticline. This structure was tested by the Hawamel-1. Pressure data indicate gas across several zones.

Top Natih Formation TWT interpretation

RESERVOIR

All potential reservoirs that have been encountered in the block are tight. The carbonate reservoirs are fractured, which is common in the blocks adjacent to this block. These can be considered unconventional reservoirs. These are listed below by Group.

  • Wasia Group
    • Natih Formation (gas already discovered)
    • Natih E is an unconventional hydrocarbon target (self-sourced)
  • Kahmah Group
    • Shuaiba Formation (gas already discovered)
    • Kharaib Formation
    • Lekhwair Formation (strong gas shows)
  • Mahatta Humaid Group
    • Amin Formation (gas/condensate already discovered)

SEAL

  • Wasia Group
    • Natih Formation's more shale-prone members
    • Nahr Umr
  • Kahmah Group
    • Low permeability carbonate mudstones and shales associated with the basal portions of its formations
  • Akhdar Group
    • Khuff Formation
  • Mahatta Humaid Group
    • Miqrat Formation

SOURCE

  • Cambrian sourced from Huqf Supergroup
  • Natih E



Page created at 18/09/2016
Last updated at 06 Sep