Concrete formulation for sealing and plugging oil or gas wells for abandonment

An oil or gas well abandoned or to be abandoned, comprising:

• a well casing;
• and;
• a concrete formulation adapted to engage and plug the well casing, the concrete formulation including (a) a cement component including a calcium sulfoaluminate cement and a Portland cement having a ratio by weight of Portland cement to calcium sulfoaluminate cement ranging from 1/19 to ⅕, and (b) an aggregate component with gradation spanning 1,200 microns to <5 microns.

An oil or gas well to be abandoned, comprising:

• an exposed well bore where at least a portion of a well casing has been removed;
• and
• (a) a concrete formulation including a calcium sulfoaluminate cement and a Portland cement having a ratio by weight of Portland cement to calcium sulfoaluminate cement ranging from 1/19 to ⅕ and (b) an aggregate component with gradation spanning 250 microns to <5 microns and (c) a foaming agent wherein the entire length of the exposed well bore is filled with the concrete formulation.

An oil or gas well to be abandoned, comprising:

• a well casing;
• and
• (a) a concrete formulation including a calcium sulfoaluminate cement and a Portland cement having a ratio by weight of Portland cement to calcium sulfoaluminate cement ranging from 1/19 to ⅕ and (b) an aggregate component with gradation spanning 250 microns to <5 microns and (c) a foaming agent wherein an entire length of the well casing is filled with the concrete formulation.