Atterberg Limit Tests Indicate Physical Properties in Caprock: A Low Cost Screening Tool for Caprock Integrity Evaluation Michelle Uwiera‐Gartner Gartner Works Ltd. Mike R. Carlson Applied Reservoir Enterprises Ming Lui & Peter Cooper Big Guns Energy Services Inc. 1
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Atterberg Limit Tests Indicate Physical Properties in Caprock:A Low Cost Screening Tool for Caprock Integrity Evaluation
Michelle Uwiera‐Gartner Gartner Works Ltd.Mike R. Carlson Applied Reservoir EnterprisesMing Lui & Peter Cooper Big Guns Energy Services Inc.
• What are Atterberg Limits?» History» How are they done
• Do they work?• What do they identify?
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Basic objective – Strength characterization
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$$$$$
Screening tool – test where it matters
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$Triaxial test critical area
* Approximately one tenth the cost
Screen with cheap test
Atterberg Limits: Background• HISTORIC:
– Developed early 1900s Swedish soil scientist• Originally ceramic industry• Describes plasticity of clay for bricks • Avoid shrinkage and cracking when fired
– Only 2 parameters needed:» Upper and lower plasticity limits
• TODAY:– Behavior of clay– Classifying soils– Correlate engineering properties
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Transition in Soil Behavior• Measure of critical water
contents in a fine‐grained, soil. – Impacts shear strength
• Shrink Limit (SL)– Water content between the
solid and semi‐solid states.• Liquid Limit (LL)
– Water content between semi‐liquid and plastic state
• Plastic Limit (PL)– Water Content between plastic
and semi‐solid state• Calculated: Plasticity Index (PI)
– Range of water content where a soil behaves plastically.
– PI = LL ‐ PL
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Water Contents where the soil behaviour changes
Core Preparation, Logging, Testing
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Everything you need to know you learned in Kindergarten ….
8(after Practical caprock analysis Carlson et al.)
• Atterberg Limit tests are fast & cost effective for assessing caprock properties:– Long history of use in other engineering fields– Screening method for selecting triaxial sample locations
– Identify potential weaker areas– Insight into possible clay type
• Used with other index tests.• Assist with developing site‐specific, correlations for evaluating delineation wells.