Analysis and simulation of the mechanism of leakage and plugging in dynamic fractures under the comprehensive action of multiple factors

ABSTRACT: Effective plugging of formation leakage caused by drilling and cementing is an effective way to reduce the economic loss of oil and gas well drilling and development and ensure normal operation. A large number of laboratory tests and numerical simulations have been conducted to study the leakage formation mechanism, plugging processes, plugging materials, and plugging methods. However, these studies often focus on plugging test of static crack simulation devices, which reduces the success rate of indoor formulation in field. Based on the above problems, this paper comprehensively analyzes the relationship between drilling fluid leakage, plugging material plugging and dynamic fracture propagation. The fracture model with rough tortuous surface is simulated by 3D printing technology, the variation of the crack width during in situ stress generation is simulated by the compressibility of the deformation block and liquid. The migration and plugging of plugging materials in fractures are monitored in real time by CT on-line scanning technology, displacement sensing technology and injection data analysis. Finally, a systematic evaluation method of plugging effect was developed, which synthesized the formation time, location, compactness, pressure bearing capacity and stability of plugging layer. It is of guiding significance for the analysis and simulation of the mechanism of leakage and plugging in dynamic fractures under the comprehensive action of multiple factors.