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Abstract
The importance of obtaining a perfect core of a petroleum reservoir is undisputed. Despite tremendous advances in coring techniques, some basic problems remain as challenging as ever. One of these is the coring of unconsolidated formations. Most side-wall cores result in partially damaged cores, totally damaged cores or no core at all, especially in unconsolidated formations. This proposed technique promises to greatly improve the recovery, quality and longevity of the core, thereby resulting in a much better interpretation.

Freezing has long been used to preserve cores on the surface, but never before used in-situ. Here in this technique, part of the formation is frozen before being drilled out. Freeze coring promises to be highly beneficial in percussion side-wall coring, as it increases localised formation strength thus increasing impact resistance. Hence, the chances of recovering the core intact increase significantly.

This paper discusses the science of the proposed process, explains the mechanism and puts forward a new design for coring, which will help bring back virgin cores to the surface. Changes in the current techniques are proposed which is backed by experimental work.

Overall, this work will help determine petrophysical properties of the reservoir to a much higher accuracy while drilling, thus helping in identifying prolific reservoirs.