Geotek’s pressure coring tools seal the core at full in situ pressure which provides not only complete capture of all solids, liquids and gasses but also reduces formation damage during recovery. Damage from gas expansion can disturb core samples from shale gas formations, gas-hydrate-bearing sections, and gassy marine sediments during recovery. Geotek Coring’s pressure core tools prevent this gas expansion damage by retaining in situ pressure while retrieving the core material.
Geotek works closely with the drilling contractor to provide a seamless drilling/coring operation in the target zone. Pressure coring tools are run in the borehole by Geotek Coring engineers in cooperation with the drilling engineer to provide the best quality core material. Primary analysis in the field is tailored to customer requirements. This can range from simple gas collection directly from the sealed core to a more detailed analysis using non-destructive testing and imaging at pressure in the field as well as subsampling for further laboratory testing. This more advanced analysis maximises the return from the pressure core investment by providing detailed data that cannot be obtained in any other way.
Geotek Coring’s current wireline pressure coring tools, the G-PCS family (previously PTCS and HPTC), are optimized for harder formations, such as shale, indurated formations, or gas-hydrate-cemented sediments. They also provide good “total capture” in softer formations with some core disturbance. Techniques to further minimize disturbance in softer and interbedded formations are in development. Variants of these tools run in 5″ to 5 1/2″ and 6 5/8″ OD drill pipe. All interfaces with the drilling rig (custom bottom-hole assemblies, crossover subs, connections to wireline or slickline) are provided as part of the coring package.