| dc.description.abstract | Lost circulation continues to be one of the most troublesome problems encountered during drilling.
The financial cost of lost circulation in geothermal drilling can rise to 15% of the total drilling
cost. A corrective approach to preventing lost circulation is using lost circulation materials (LCMs)
to plug the fractures in the wellbore, minimizing fluid loss and strengthening the wellbore. The
overall objective of this research is to test potential LCMs for sealing fractures under high-temperature conditions.
This research assessed the concept of recreating complex and drilling-induced fractures using 3D
printing. This study aims to generate fractures that look closer to the ones present downhole in
geothermal wells. Two LCMs, shape memory polymer (SMP) and crosslinked polymer, were
investigated for their potential to reduce fluid loss and seal complex fractures. Experimental
investigations, such as particle size distribution, rheology, gelation kinetics, alkalinity control, and
fracture sealing tests, were conducted to optimize the concentration of LCMs in drilling mud. The
experiments were conducted at temperatures between 93.3°C(200°F) to 150°C(302°F).
The results included the optimum concentration of SMP that can seal complex fracture zones.
Compared to walnuts, a conventional LCM, SMP significantly reduced mud loss. Additionally,
the importance of particle size distribution in the performance of granular LCMs is highlighted.
Rheology and gelation kinetics are essential for the settable crosslinked polymer in any successful
field application. This study's novelty is using a 3D-printed fracture disc for testing and optimizing
SMP and crosslinked polymer, which should reduce lost circulation in high-temperature
environments. | en_US |
