Cores are collected to obtain or confirm important data that cannot be reliably obtained remotely. Pressure cores may be initially required to collect and quantify gas and fluid content; however, they can now be used to determine permeability, consolidation and strength properties or to simply examine sedimentary core structure before expanding gases destroy the soil fabric. Geotek Coring can help achieve these goals using specialized laboratory equipment that can accept samples of core material at in situ hydrostatic pressures.
miniPCATS: Pressurized Bridge to Laboratory Equipment
Core transported from the field collection site can be transferred into miniPCATS, which fulfills the same function in the laboratory as PCATS does in the field. miniPCATS has X-ray imaging capabilities and can measure P-wave velocity to confirm core quality after storage and transport, and to aid in the selection of cut locations. Cores can be examined and cut in miniPCATS before being transferred directly to laboratory equipment under pressure for advanced analysis.
The Final Goal: Properties Under Pressure
Geotek Coring has developed sophisticated laboratory testing equipment that accepts samples from PCATS or miniPCATS. Permeability and consolidation parameters are measured in the Triaxial Permeameter. Using a direct flow technique, permeability measurements can be made over many orders of magnitude. PCATS Triaxial is a fully-featured triaxial cell with the ability to measure small strain parameters via a resonant column technique as well as standard large strain parameters and direct-flow permeability. Properties in either device can be measured as the sample is depressurized in stages, providing insights into the evolution of strength and permeability.
Custom-Designed Compatible Testing Equipment
Many measurements are currently made on repressurized samples; what if the same experiments could be run with samples before they were damaged by gas expansion? Geotek Coring can design and build customized testing equipment to allow natural, never-depressurized samples to be examined. For instance, the fine structure of undamaged core samples could be revealed using small sub-cores transferred under pressure into an X-ray-transparent microCT-compatible pressure chamber.