Facies definitions naturally vary from field to field (and between different operators drilling in the same field). Thus, the examples below are provided to support our most abundant facies interpretation scheme that is applied by default in the Western Canadian Oilsands region.
Oilsands Common Lithology Cutoffs:
Massive sand
• Sand is very clean, cutoff of <10%
• VSH near zero
• Indistinct bed boundaries and few laminations
Planar-tabular cross-bedded sand
• Very clean sand, cutoff of <10%
• >10 deg flow cross-beds, often alternating direction
• Flat scour surfaces (<5 deg)
Trough cross-bedded sand
• Very clean sand, cutoff of <10%
• >10 deg cross-beds
• Incline scour surfaces
Laminated sand
• <10 deg beds, cutoff of <10%
• No truncations or scour surfaces
• Can be parallel to overlying IHS sequences
Sand with clasts
• Any of the above sands
• Matrix supported mud clasts
• VSH cutoff of 20%
Sandy IHS
• VSH cutoff between 10% and 40%
• Inclined beds of alternating mud and sand with consistent dip direction and magnitude (lateral
accretion)
Muddy IHS
• VSH cutoff between 40% and 80%
• Inclined beds of alternating mud and sand with consistent dip direction and magnitude (lateral
accretion)
• Image also used to confirm the percentage of mud
Mudstone
• VSH cutoff of 80%
• Boundary between Mudstone and IHS Mud occurs where neutron porosity is 15% higher than
density porosity
• Image, GR, PE secondary indicators
• >90% mud
• Usually highly bioturbated
• Bedding almost always flat
Mud Breccia
• VSH cutoff between 20% - 80%
• Sandy matrix with angular mud clasts
(Siderite) Cemented Sand
• Image generally very light-coloured
• Usually a few cm's thick
• May be discontinuous or nodular in appearance
• Most commonly occur above McMurray
• PE spikes
• GR, neutron and density decrease
Silty Mud
• Reserved for above the McMurray Formation
• Equivalent to IHS Sand (40-80% VSH), but without the IHS bedding
Silty Sand
• Reserved for above the McMurray Formation
• Equivalent to IHS Sand (10-40% VSH), but without the IHS bedding
Interactive bioturbation interpretation with following designations:
• Heavy bioturbation
• Moderate bioturbation
• No bioturbation