The rig site handling of unconsolidated core is a risky process that might hamper core integrity if inappropriate procedures are utilised. Using freezing in the stabilization of unconsolidated core has become an accepted practice in specific circumstances for many oil field operators despite the logistical challenges and high cost implications.

Freezing method

The freezing technique has been subject to numerous studies over the last decade and it is well known that repeated freezing and thawing is a main cause of core damage. Despite improvements in the freezing procedures in the last few years no proper solution has been found for the problems associated with logistics and unwanted freezing/thawing cycles. The Kirk Petrophysics™ Lithofreeze™ technique presents a new technology to guarantee constant core freezing thus offering a perfect long-term stabilization.

The technique involves
 

• The pre-conditioning of the core using a full length core basket with multi-chanel sensors where the core is first frozen at the right temperature for the right amount of time
• Core is processed using adpated and standard coring equipment
• The core is packed into specially designed core containers which are monitored from the moment the core is in the thaw cycle

Chilling method

This technique is used to chill the fluid inside the rock sample and prevent its migration during transportation. Also for preserving unconsolidated rocks, this method remain less controversial and probably more suitable when combined with a pre injection using the Lithotarge® stabilisation technique.