Abstract: Embodiments relate to the development of accelerators, and specifically to hydrated silicate aluminate accelerators. The accelerators can be blended with cement-containing compositions to form shotcrete (e.g., sprayed concrete) mixtures. The accelerators have improved properties over conventional sodium silicate accelerators, offering early strength development of shotcrete while maintaining or improving long-term strength.

Abstract: A method and agent to induce accelerated creep deformation of shale rock formations in the annular gap between a shale formation and non-cemented sections of a casing string have been developed. A fluid containing alkali silicate or a modified alkali silicate is added to the annular space between the shale rock formation and the casing string. The alkali silicate promotes creep deformation of the shale rock, effectively closing the annulus surrounding the casing. It has been found lithium silicate provides the strongest shale-casing bond and is the presently preferred material for closing abandoned wells.