Iraq: Vast Exploration updates operations on the Qara Dagh Block in Kurdistan
07 Apr 2011
Vast Exploration has provided an update on the Niko Resources operated Qara Dagh Block in Kurdistan, where preliminary analysis indicates prospective pay in the Shiranish formation - the first primary reservoir to be penetrated.
Qara Dagh-1 Well
The well has been drilled to a depth of 3,558 meters and a 7 inch, 35 lb/ft, L-80 liner has been successfully set to this depth. The previous casing point for the 9 5/8 inch casing was 2,522 meters. During drilling of this interval, increased fluorescence and gas readings were observed. The interval has been logged and preliminary analysis by Niko Resources indicates possible prospective pay of up to 143 meters in the lower Tanjero and upper Shiranish formations. The Shiranish formation is the first primary reservoir to be penetrated. The top of this formation has been interpreted to be at 3,420 meters.
The current plan is to continue drilling deeper to a maximum depth of 4,200 meters with a 6 inch hole to continue evaluating the prospectivity of the Shiranish formation and, in the event we encounter encouraging results, the underlying formations. Niko Resources projects that the revised completion date for drilling, completing and testing of the current well is estimated to be June, 2011.
Extension of Exploration Period
The operator, Niko Resources, on behalf of the consortium partners, has applied to the Kurdistan Regional Government for a one year extension to the first exploration sub-period of the Production Sharing Contract to allow for the completion of drilling operations and the subsequent evaluation of results. Upon approval, the first exploration sub-period, including the one year extension, will continue until May 14, 2012.
Qara Dagh-1 well
- The primary prospective reservoirs have been identified as the main carbonate sequences in the Cretaceous as well as underlying Jurassic and Triassic sections.
- Well location was selected to test 7 prospective reservoirs on the crestal position of the Qara Dagh Dome
- A large thrust fault bounds the structure to the south-west and cuts the Cretaceous to Permian section
- The exploration well will be drilled to 4000 meters and expected to encounter up to 7 potential reservoir targets
- Qara Dagh Block
Qara Dagh Block
The Qara Dagh Block is located in the prolific Zagros foldbelt which extends from southern Turkey across northern Iraq and into southwest Iran. Large anticlinal structures, which formed during collision and formation of the Zagros Mountains, contain giant and supergiant accumulations of oil. The large surface structure on the block is known as Qara Dagh Mountain (Black Mountain in Kurdish) and is a prominent anticline which rises as high as 600 meters above adjacent valley floors. This 65 kilometer by 5 kilometer feature has steeply dipping limbs and an exhumed central valley which exposes progressively older stratigraphy towards the anticlinal core. The Eocene and Paleocene Pila Spi, Gercus and Sinjar formations of lower Tertiary age extend along the interior slopes of the mountain and the central valley is covered by the Paleocene Kolosh shale.
The subsurface structure is characterized by a large thrust fault, which extends along the length of the southern limb of the surface anticline, and a large fault bend fold in the overthrust section which is comprised of Cretaceous, Jurassic and Triassic strata.
There has been no prior oil exploration on the Qara Dagh Block and the entire Kurdish area of northern Iraq was virtually unexplored until the Kurdish Regional Government issued new exploration contracts in 2007. To the southwest, the supergiant Kirkuk Field was among the first discoveries in Iraq. Kirkuk and other major fields such as Bai Hassn, Jambur and Kor Mor produce mainly from Tertiary reservoirs; however, to the northeast these formations lose prospectivity as intense deformation has caused the Tertiary formations to be exposed on the land surface. This deformation has resulted in highly fractureds subsurface structures formed by the deeper Mesozoic formations. As a result, the main reservoirs at TaqTaq and Miran are formed by the Cretaceous Shiranish, Kometan and Qamchuqa Formations.
Extrapolation from nearby oil fields, recent discoveries and the seismic interpretations indicate seven potential reservoirs on the Qara Dagh structure. Fractured carbonates in the Cretaceous Shiranish, Kometan and Qamchuqa/Balambo Formations are prospective under the Kolosh shale seal and above a rich oil source rock in the Sarmord Formation. The Jurassic Alan, Mus and Butmah Formations are sealed by upper Jurassic anhydrite and charged by the Sargelu Shale which forms a regional oil source rock. Few wells have been drilled into the Triassic; however, the Kurra Chine is productive elsewhere in Iraq and could contain oil or liquids-rich gas at Qara Dagh.
The Company believes that proximity of the Qara Dagh Block to recent discoveries at TaqTaq and Miran and the presence of oil seepages on the block make the Qara Dagh structure a low risk prospect with the potential for the discovery of large oil reserves.
Source: Vast Exploration / energy-pedia