Definition - What does 10-Second Gel mean?
10 second gel strength indicates the initial gel as per API, and is the shear stress measured at low shear rate after the mud is allowed to set for 10 seconds. Gel strength is time dependent and is usually done in the 10 second or 10 minute range. The gel strength is an important rheological parameter to understand drilling fluid properties for directional drilling projects in trenchless technology.
Trenchlesspedia explains 10-Second Gel
The 10 second gel strength is measured by slowly rotating the hand wheel at slow and steady motion of 3 rpm till the gel breaks. Before testing, the mud slurry is rotated at 600 rounds per minute (rpm) and allowed to rest for 10 seconds. Gel strength indicates the gelling that will take place once circulation of drilling fluid is stopped. It measure the inter-particle forces that will prevent the cuttings from settling in the borehole.
To break circulation in a high gel mud, high pump pressure is required.