Unlocking Precise Subsurface Stress Measurements with Sigra’s IST 3D

IST 3D Tool in Core

Why Choose IST 3D?

✅ PROVEN TECHNOLOGY – Evolved from Sigra’s IST 2D system, with over 2000 successful stress measurements since 1996
✅ ERROR ELIMINATION – Equipped with 21 strain gauges. This ensures reliable stress tensor calculations with redundancy
✅ ROCK PROPERTY DETERMINATION – Young’s moduli and Poisson’s ratios for nonlinear and anisotropic rock, including the onset of plastic behaviour
✅ FIELD-TESTED RELIABILITY – Achieves a high rate, contingent on suitable rock conditions and good drilling practice

The IST 3D Overcoring Process

Using a step-by-step wireline coring technique, IST 3D captures stress relief strains, enabling precise subsurface stress analysis

Technical Requirements

PQ, HQ and NQ wireline coring system
Precise drilling control, including stable mud pressure (50–140 L/min, up to 6 MPa)
Non-magnetic rock for accurate orientation measurements, though there are alternatives where the rock is magnetic
Straight drill rods & core barrel
Adequate rock quality

Testing time is controlled by glue setting time, depth and environmental factors. Typically, a test takes 12–24 hours, though quicker options are becoming available