Updated methodology for evaluating lost circulation control of cement slurry for double lost channels

This paper presents an evaluation method for evaluating the sealing capacity of cement slurry with lost circulation control for effective lost channel sealing during cementing operations. The method was developed based on a lost device and an evaluation model that we developed ourselves. This evaluation model includes three critical evaluation indexes: the loss time, loss weight, and maximum sealing pressure. In addition, it can be used to quantitatively evaluate the effective sealing capability of cement slurry with lost circulation control. This method is aimed at evaluating the sealing capacity of cement slurry as a way to investigate its applicability in designing effective treatments for the sealing of multiple lost channels. The results suggest the particle lost circulation materials (LCM) can improve the bridging capacity of fiber cement slurry. The loss capacity of a fracture-pore double lost channel is not equal to that of a fracture and a channel superposition. Moreover, the lost channel method can avoid an excessive or overly low evaluation of the sealing capacity of the cement slurry.