Thick Wall Cylinder (TWC) Test
Incremental costs associated with sand production remains to be a challenge for hydrocarbon producers in unconsolidated/poorly consolidated/weak intergranular cementation reservoir rock.
The incremental costs include managing produced sand, damage to surface facilities, field equipment corrosion, reduction in productivity, and in some cases, plugging of the wellbore.
Analytical/numerical models are available to analyze the geomechanics of sand production; the models can be verified by thick wall cylinder (TWC) collapse test, using a sample bored along the axis to replicate a wellbore/perforation cavity.
The sample may/ may not be saturated with brine/oil (mimicking pore fluid). The sample is subjected to gradually increasing isostatic stress till the sample collapses, and the collapse strength is recorded.
In a modified version, the experimental setup is equipped with a load cell monitoring the amount of sand being produced real time and permits detecting the onset of sanding.
Recommended Sample Dimensions:
Length: 3” Diameter: 1.5”
Length: 2” Diameter: 1”
For both the sizes, the ratio between OD to ID is 3:1.