| CPC E21B 33/128 (2013.01) [E21B 34/063 (2013.01); E21B 43/27 (2020.05)] | 18 Claims |
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1. An acidizing plug assembly, comprising:
a mandrel comprising a body having an outer cylindrical surface and an inner surface, the inner surface forming an opening in the mandrel body approximately parallel to the outer cylindrical surface's axis, the mandrel having an axis that extends in the same direction of the outer cylindrical surface's axis;
a sealing element comprising a flexible material having a cylindrical inner surface, installed along the outer cylindrical surface of the mandrel, and configured to seal the mandrel against a casing when force is applied to the sealing element in the direction of the mandrel's axis;
at least one backup ring comprising a semi-rigid or rigid material configured to having a cylindrical inner surface, each of the at least one backup rings installed along the outer cylindrical surface of the mandrel such that the backup ring is in contact with a surface of the sealing element;
at least one cone comprising a rigid material, each of the at least one cones having a cylindrical inner surface and installed along the outer cylindrical surface of the mandrel such that the cone is in in contact with the backup ring, each of the at least one cones comprising a ramp portion angled between five and forty degrees from the mandrel's axis;
at least one slip comprising a semi-rigid or rigid material, each of the at least one slips having a cylindrical inner surface and installed along the outer cylindrical surface of the mandrel such that the slip is adjacent to and in contact with the ramp portion of the cone, each of the at least one slips further comprising a plurality of teeth configured to bite into a casing when the slip is forced outward from the mandrel's axis, each slip operable to expand and be forced outward from the mandrel's axis when forced against the ramp portion of the adjacent cone;
a shoe configured to capture one or more of the sealing element, backup ring, cone, and slip on the mandrel; and
at least one breakable plug located within the mandrel and blocking fluid flow into at least an acid-vulnerable portion of the opening in the mandrel body that is more vulnerable to acid than another portion of the mandrel body; wherein:
the at least one breakable plug comprises an upper breakable plug positioned adjacent a first end of the mandrel and spaced apart from a lower breakable plug positioned adjacent a second end of the mandrel, the upper and lower breakable plugs configured to shield the acid-vulnerable portion of the opening in the mandrel body therebetween,
the acid-vulnerable portion of the opening in the mandrel body includes the inner surface of the mandrel between the upper breakable plug and the lower breakable plug, and
the at least one breakable plug is selectively breakable to enable an acid to flow through the opening in the mandrel to dissolve the acid-vulnerable portion thereof.
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