| 摘要 |
A novel method and device for manipulating ferrofluids for use in cementing wells are disclosed. The cementitious fluids may comprise: (a) a hydraulic cement, (b) finely divided magnetic particles, (c) a binding agent of a surfactant, and (d) a liquid medium. The binding agent or surfactant is present in the compositions in an amount sufficient to render the compositions stable in a magnetic field. When used in cementing wells, the cementitious ferrofluids are implaced in the annulus separating a casing from the formation in a wellbore by conventional techniques and the slurry is subsequently subjected to an activating alternating magnetic field that causes movement of the slurry. The noncementitious ferrofluids comprise: (a) finely divided magnetic particles, (b) stabilizing agent, and (c) a liquid medium. The movement of the slurry results in a "scrubbing" action against the surface of the casing and formation surfaces, and a mixing of the slurry which helps displace any residual drilling mud. The net result is better bonding of the cement to the casing and formation. |
