Development and performance evaluation of a novel anti-leakage cement slurry system

Abstract:

To address the technical challenge of cement slurry lost circulation and low return during cementing operations， this study focuses on enhancing the self-sealing capability of the cement slurry itself. A novel anti-leakage cement slurry system was developed in this work. Initially， a fully sealed leakage evaluation apparatus was developed based on the modification of the API fluid loss tester， and a corresponding evaluation methodology was established. Guided by a synergistic anti-leakage mechanism of "rigid bridging， elastic filling， and fiber network capturing"， a novel lost circulation material， ZJY-1， was optimized through systematic material selection and orthogonal experiments. ZJY-1 is a composite of rigid particles， temperature-sensitive deformable particles， and composite fibers. Laboratory evaluations demonstrate that ZJY-1 exhibits excellent compatibility with both conventional and high-temperature cement slurry systems. While effectively maintaining key engineering properties such as rheology， free fluid， and compressive strength of the set cement， this material enhances the sealing pressure-bearing capacity for 1 mm pores and fractures to 7 MPa. Its thickening time can be flexibly adjusted by using retarders， and its overall performance surpasses that of the commercial materials used for comparison. This research provides effective technical support for achieving dynamic leak sealing during cementing， simplifying the cementing process， and improving cementing quality in complex formations.