Development of a Cement Slurry System Suitable for Plugging Oil-Based Drilling Fluid
Cement slurry plugging is one of the effective measures to solve malignant leakage, but it is difficult for cement slurry to solidify in oil-based drilling fluid, so its use is limited. Based on the mechanism of oil-based drilling fluid polluting cement slurry, oil-water displacement agent was developed, the gelling system was researched and selected, matching fluid loss reducer and retarder, oil-based drilling fluid plugging mud system was developed, and the performance of cement slurry system was evaluated. The research showed that oil-water displacement agent was prepared by micro lotion copolymerization (i.e. simultaneous initiation of polymerization of oil phase and water phase). After oil-water displacement agent was added to oil well cement, the compatibility between drilling fluid and cement slurry was good. The slurry system with a volume ratio of 50:50 between cement slurry and oil-based drilling fluid was cured for 24 h at 50 ℃, and the strength could reach about 2 MPa. The oil-water displacement agent had good universal performance, aiming at different types of oil-based drilling fluids taken from different areas of the site, the strength developed. The matching fluid loss agent BXF-200LL and retarder GH-9 were studied and selected, and a cement slurry system suitable for plugging of oil-based drilling fluid was developed. The oil-water displacement agent had no adverse effect on the thickening of cement slurry, and the temperature resistance reached 120 ℃.
Malignant leakageOil based drilling fluidCement slurry pluggingOil-water displacement agent
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