Experimental Study of Loss Circulation Materials Bridging Performance in K/Na-formate based Drilling Fluids

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