Abstract

Lost circulation occurs when mud or cement is lost to the formation while drilling. Lost circulation has been a huge problem and may cause heavy financial costs in the form of lost rig time and mud fluid and in severe cases, well blowout with serious environmental and safety consequences. Despite extensive advances in the last couple of decades, lost circulation materials used today still have disadvantages such as damaging production zones, failing to seal the fractures or just sealing the fractures without strengthening the well. Here, we propose a new class of smart expandable lost circulation material (LCM) to remotely control the expanding force and functionality of injected LCM. Our smart LCM is made out of thermoset shape memory polymers and becomes activated by formation natural heat as well as electromagnetic waves if needed, hence it can effectively seal fractures’ width without damaging production zone and strengthen the wellbore. The activation temperature of the LCMs can be adjusted based on the formation temperature. We conducted a series of experiments using a HPHT particle-plugging apparatus (PPA) to measure the sealing efficiency of the smart LCMs as a proof of concept. Various slot disc sizes were used to mimic different size fractures in the formation. The API RP 13 B-1&2 have been followed as standard test methods to evaluate fluid loss in water based muds.

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