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Baqlah - Block 51

SUMMARY

Block 51 is a 10,134 km2 area located in the interior of Oman. Over its history Block 51 has had several owners and it has also experienced several significant configuration changes. These configuration changes mean that a few of the companies only possessed a portion of the block during their tenure. This increases the block's prospectivity.

To date gas and condensate have been discovered in the Natih Formation and gas in the Gharif Formation. Gas shows are present in other formations. Based upon them and offset fields/discoveries adjacent to the block the Shuaiba and Amin formations are prospective.

There are two plays within this block. The first is conventional oil and gas within Natih and Shuaiba formations. In portions of the block both formations possess good reservoir properties. The rocks, however, are most likely fractured.

Tight gas is the second play within Block 51. This is especially true for pre-Cretaceous reservoirs and possibly the Natih Formation based on data from some nearby blocks. 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 across northern Oman.

BLOCK OWNERSHIP HISTORY

Over its history Block 51 has had several owners and it has also experienced several significant configuration changes. These configuration changes mean that a few of the companies only possessed a portion of the block during their tenure. Below is the list of companies that have owned all or part of the current block.

  • Petroleum Development (Oman) Ltd. (PD(O)), comprised of Shell, PARTEX and eventually Compagnie Francaise de Petroles
  • Petroleum Development Oman, Ltd. (PDO) comprised of Shell, PARTEX and eventually Total and the government of Oman
  • Amoco
  • Japex
  • ARCO
  • Nimr Petroleum
  • Hunt Oil

The first well was drilled in 1966 by PD(O): the Afar-2H1. The last well on the block, the Al Naba-1H1, was drilled in 2008 by Hunt Oil.

AVAILABLE DATA

  • 2D seismic data from 37 surveys
  • Block seismic base map, satellite image map and infrastructure map
  • Gravity data
  • Data for 19 wells, including raw log data and well reports

Seismic base map

STRATIGRAPHY

Step 2: MOG raw data viewing and purchase Step 2: MOG raw data viewing and purchase

Oman chronostratigraphic chart (GTS 2012 dates incorporated)

The figure below presents the Cretaceous section within the block. This is the autochthonous section found below the allochthonous Hawasina section. The allochthonous section is not found across the block but only in the northern portion. Gas shows have been noted in the Natih and Shuaiba formations. Gas and condensate have been discovered in the Natih Formation within the block.

Stratigraphy of the Cretaceous section within Block 51

In the Permian though Jurassic section, shown in the figure below, gas has been discovered in the Gharif Formation. This portion of the stratigraphic section is one where nomenclature issues exist in several of the block's wells. This issue is dealt with in Target's evaluation package for the block.

Stratigraphy of the Permian through Jurassic section within Block 51

The stratigraphy for the Haima Supergroup also contains nomenclature issues. For example, these impact intervals within the Mahatta Humaid Group, where gas shows exist. The figure below shows the stratigraphy for the Haima Supergroup. The Amin Formation is a tight gas reservoir in an adjacent block.

Stratigraphy of the Haima Supergroup within Block 51

OUTCROP AND ANALOGS

The following formations are present in multiple outcrops in the Hajar Mountains (Jabals Akhdar and Shams being prime locations).

  • Hawasina Group: Allochthonous sediments
  • Natih Formation: Reservoir and source
  • Nahr Umr Formation: Regional seal
  • Shuaiba Formation: Reservoir
In the Huqf uplift outcrop area to the south of the block some of the older formations can be observed in outcrop. These outcrops include the Mahatta Humaid group. The distance to these outcrops, however, may diminish their use as direct analogs.

DISCOVERIES

Gas and condensate have been discovered in the Natih Formation.

Gas has been discovered in the Gharif Formation.

SHOWS

Oil shows were observed in the following formations.

  • Hawasina Allochthon, Wahrah Formation
  • Fiqa Formation
  • Shuaiba Formation
  • Sahtan Group (undifferentiated)
Gas shows were observed in the following formations.
  • Hawasina Allochthon, Wahrah Formation
  • Fiqa Formation
  • Natih Formation
  • Shuaiba Formation
  • Sahtan Group (undifferentiated)
  • Mahil Formation
  • Mahatta Humaid Group (undifferentiated)

PROSPECTS

There are currently four prospects mapped within the block.

PLAY SUMMARY

There are two plays within this block. The first is conventional oil and gas within Natih and Shuaiba formations. In portions of the block both formations possess good reservoir properties. The rocks, however, are most likely fractured.

Tight gas is the second play within Block 51. This is especially true for pre-Cretaceous reservoirs and possibly the Natih Formation based on data from some nearby blocks. 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 across northern Oman.

TRAP

Predominantly 2-way dip-closed, fault-bounded 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 Hawasina Group sediments would create traps.


North-South seismic line across Block 51 showing the major reflectors.

RESERVOIR

Wasia Group

Natih Formation (gas already discovered)

Natih E is an unconventional hydrocarbon target (self-sourced)


Kahmah Group

Shuaiba Formation


Haushi Group

Gharif Formation (gas already discovered)


Mahatta Humaid Group

Amin Formation


SEAL

Aruma Group

Shales within the Fiqa Formation


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


Safiq Group

Shale units within the Sahmah Formation


Mahatta Humaid Group

Miqrat Formation



SOURCE

The Fiqa Formation can serve as a source based on block well data.

Natih Formation.

Safiq siltstones.

Huqf Supergroup as the possible deep gas source is known in area.




Page created at 20/09/2016
Last updated at 18 Sep