| dc.description.abstract | The loss of drilling fluid is one of the main concerns of the petroleum industry, causing
excessive expenditure both for operational and increasing the non-productive drilling time
(NPT). The NPT associated with loss circulation issues cost the oil industry a lot. The
preventive and corrective methods are the main techniques to manage the loss circulation in a
wellbore. Lost circulation materials (LCM) have been widely used to prevent fluid loss into the
formation, but the use of these materials depends on the types of formation, the loss zones, and
the degree of severity of the losses.
In this thesis, a total of four experimental tests are designed to systematically investigate
the bridging performance of LCM in laboratory synthesized K- and Na-formate based drill-in
fluids. The static high pressure LCM bridge test apparatus with different artificial fracture slot
widths were used for the investigations.
The test results showed that the bridging performance of LCM materials in the K- and
Na-formate drilling fluids are almost the same, and a strong fracture bridge is obtained by
mixing very small with medium and coarse that creates an improved packing of pistachio
particles. Another observation from this work is that the LCM used in drill-in drilling fluid,
CaCO3, is mechanically weak. However, the blending of CaCO3 with Quartz increased the
bridge strength and showed positive synergy as compared with their separate performances. | |
