highly favourable hydrocarbon prospectivity of ... · 3. crest of trap at reservoir depth may not...
TRANSCRIPT
Baranan Block
Mountain FrontFault Zone
BarananMonocline
(Bazian extensionstructurally)
A more complex structure than Kurdamir and has fewer of the region’s reservoirs sub-surface and sealed.
Kurdamir-1 well
SW
Detachments inSilurian shales ?
Drawn by: Date:
Author:October 2011
G BanksScale: 1:100,000
Crustal thickening belowTop Basement Surface
E
Analogue for the unfavourable clay-rich Shiranish reservoir in tight Kurdistan structures(Complex folding and faulting of the Balambo Formation in Azmar Mountain, Kurdistan)
Analogue for the complex geology observed in some Kurdistan structures, and analogue for over-thickened Kolosh, Aaliji and Tanjero formations within Qara Dagh Mountain. Photo shows folding and faulting of Kolosh-like rocks in the UK (of D. Peacock)
above thrusts
Photo from D. Peacock
Analogue for structural complexity in supra-Shiranish Formation lithologies within a complex Kurdistan fold, e.g. Kurdistan Mountain Front zone (this example is Mt. Tyrwhitt, Rocky Mountains, Canada).C B
B
AA
Depth
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Line 1 Trace 1
Schematic cross section A - A’across Kurdistan, northern Iraq
WesternZagros-TLM: Kurdamir Block
- Oligceone-, Eocene- and Upper Cretaceous-aged reservoirs well-sealed - Well-imaged traps are young and unbreached - Shiranish has more carbonate and less clay (southwestwards regionally), thus more brittle and liable to fracture. - Much evidence of hydrocarbon-yielding fractures in Kurdamir-1 Shiranish Formation - Numerous, large prospects with stacked reservoirs within the PSC blocks
Traps in Garmian and Kurdamir blocks are relatively simple and follow the regional norms Qara Dagh Structure: Complex and regionally anomalous
Depth converted and interpreted seismic dipline KK-07
Highly f WesternZagros’s PSC blocks compared to other blocks in avourable hydrocarbon prospectivity of SE Kurdistan
.
WesternZagros: Garmian Block
Niko-Vast-Groundstar:Qara Dagh Block
KNOC: Sangaw South Block NE
Qara Dagh-1 well Top Shiranish = c. TD = “400m along NE flank” (Vast, 2011)
3420m
MFF
- Oligocene- and Eocene-aged reservoirs are thin, at surface, being eroded - Crest of reservoir traps not aligned below surface crest - Qara Dagh is, “An exhumed oil field: 3 seal breaching and oil dissipation events” (Dunnington, 1952) - Shiranish Formation reservoir likely more clay-rich, thus more plastic and less liable to fracture, as inferred in Vast’s press release (30.09.11)
?
Favourable Shiranish Formation envisaged in Kurdamir from well data (Shiranish Formation near Dokan, Kurdistan) D
1. Seal rocks can be much thickened by Tanjero-Aaliji-Kolosh seal in Qara Dagh.2. Top reservoir can be much deeper than prognosed if seal rock thickening is not taken into account.3. Crest of trap at reservoir depth may not be aligned below the crest of the surface structure. Unfavourably increases risks during hydrocarbon exploration and increases the time, cost and complexity of drilling.
folding and thrusting, e.g.over-thickened
MFF = Mountain Front “Fault bend fold” (Vast, 2011); Reverse-reactivated fault (several sources)
Photo C
Niko-Vast-Groundstar:Qara Dagh Block
Talisman-Murphy:Baranan Block
Notes
This cross section honours all available data and press releases.
Some geological complexity has been omitted for simplicity.
Photo D
The Foothills. Following proven plays on better quality seismic Increasing: number of reservoirs, reservoir quality, P hydrocarbon discoveries and trap preservation to SW
data. The Mountains. Some plays eroded away, others unproven. oorer quality seismic. Increasing geological complexity and risk to NE.
Sarqala-1 well
Depth converted and interpreted seismic dipline KK-19Mil Qasim-1
well
Upper Fars Units
Lower Fars and Lower Miocene Units
Oligocene and Eocene Units
Paleocene Units
Upper Cretaceous Units
Lower Cretaceous Units
Jurassic and Triassic Units
Paleozoic Units
Basement
Halocene
Bakhtiari Fm (Pliocene to Upper Miocene
Top L. Fars ( Red Beds)
Top U. Fars
Top Oligocene to Top Pila Spi
Top Aaliji
Top Shiranish (Upper Cretaceous)
Top Gulneri / Balambo (Albian)
Top Chia Gara (Jurassic)
Base Mesozoic (Speculative)
Top Basement (Speculative)
Key
Clay-rich facies (likely to have less oil-bearing fractures)
Gas condensate (contingent)
Gas condensate (prospective)
Oil (contingent)
Oil (prospective)
Oil tests and shows
Jeribe within Lower Miocene Units
10km
Light oil. Uncommercial
S Source rock
S
S
S
S
S
S
S
S
S
S
Reverse-reactivated extensional fault
Thrust fault / detachment zone
Extensional fault
G Banks
Photo B
Photo A
Oil or gas (prospective)
Oil recovered from below anticline spill point
Alyan and Alyan South Qulijan (into page) Zardi Tilako Segrdan
Upper Fars Fault Trap
The Foothills region The high mountains regionMountainFront
NE
SW
Unfavourably increases geological prognosis risks and drilling risks.
Unfavourable for predicting subsurface geology, for drilling and for recovering hydrocarbons due to fewer and more unpredictable fractures.
Lower clay content and higher carbonate content, thus more brittle and more liable to be densely fractured.Favourable for hydrocarbon prospectivity, flow rates and yields due to denser and more predictable fracturing.
A
Location of cross section relative to WZ prospects
9444 BOPD light oil produced upon testing: limited by surface equipment
Depth
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