New Sponge Liner Coring System Records Step-Change Improvement in Core Acquisition and Accurate Fluid Recovery

S. Radford¹, T. Uhlenberg¹, J. Rylance¹, A. Kvinnesland¹, L.T. Shale¹, C. Rengel¹, T. Fate², and W. Tackaberry²

Abstract

New sponge coring service and technology have been introduced to the oil and gas industry. Admittedly sponge coring has been an industry offering in some form for over twenty years but until now it has been plagued by chronic problems. The objective of sponge coring was to determine separate in-situ oil and water saturations of the formation materials. The problem with conventional coring has always been that the fluids would be expelled and lost from the core, caused by the expanding gas while bringing it to the surface. The long-time solution was to surround the core with a special oil-absorptive (oleophilic) sponge material that would capture the expelled oil and hold it in place for laboratory analysis. One author stated that his experience has shown “that trapping of the oil by the liners is efficient, with no oil loss during retrieval to surface. The oil bleeding from the core is collected in the sponge and reconstituted back into the core porosity to correct the oil saturation for bleeding.” Another author estimated that this “bleeding can be as much as 50% of the oil in the core.” Hence here is the need for a specialized coring device and service such as sponge coring. The challenge was to fit the sponge tightly enough around the core to prevent fluid migration and mud contamination in the sponge-core clearance annulus, and yet avoid core jamming and sponge damage.

AAPG Search and Discovery Article #90188 ©GEO-2014, 11th Middle East Geosciences Conference and Exhibition, 10-12 March 2014, Manama, Bahrain