Drillable bridge plug for high pressure and high temperature environments

A method of setting a drillable bridge plug comprising:

• applying an upward axial force to a mandrel;
• transferring the upward axial force to a lower cone and an upper cone;
• compressing a sealing element between the upper cone and the lower cone;
• radially expanding the sealing element into contact with a casing;
• creating a seal between the sealing element and the casing;
• deforming an upper ring assembly and a lower ring assembly radially outwardly into contact with the casing;
• exceeding a predetermined pressure of an upper slip assembly and a lower slip assembly;
• and
• radially expanding the upper slip assembly and the lower slip assembly to engage the casing,
• wherein the seal is fluid-tight under pressure up to approximately 15,000 pounds per square inch and under temperatures up to approximately 400° Fahrenheit.

A method of removing a drillable bridge plug comprising:

• milling through a top portion of a first drillable bridge plug, the top portion of the first drillable bridge plug comprising:
• a first mandrel having an upper end and a lower end, wherein the lower end comprises external splines disposed on an outer surface of the mandrel;
• a sealing element disposed around the mandrel;
• an upper cone disposed around the mandrel proximate an upper end of the sealing element;
• a lower cone disposed around the mandrel proximate the lower end of the sealing element, wherein an inner surface of the lower cone comprises internal splines configured to engage the external splines;
• an upper slip assembly disposed around the mandrel adjacent a sloped surface of the upper cone;
• a lower slip assembly disposed around the mandrel adjacent a sloped surface of the lower cone;
• an upper ring assembly comprising a first upper segmented barrier ring, a second upper segmented barrier ring, and an upper back-up ring disposed proximate the upper end of the sealing element, wherein a plurality of segments disposed in the first upper segmented barrier ring are radially offset with respect to a plurality of segments disposed in the second upper segmented barrier ring;
• a lower ring assembly comprising a first lower segmented barrier ring, a second lower segmented barrier ring, and a lower back-up ring disposed proximate the lower end of the sealing element, wherein a plurality of segments disposed in the first lower segmented barrier ring are radially offset with respect to a plurality of segments disposed in the second lower segmented barrier ring;
• and
• a bottom sub connected to the lower end of the first mandrel using a connector;
• milling through the connector disposed between the lower sub and the lower end of the first mandrel;
• releasing a lower portion of the lower sub such that the lower portion of the lower sub falls onto a top portion of a second drillable bridge plug,
• wherein the lower portion of the lower sub comprises an inner thread, and
• wherein the top portion of the second drillable bridge plug comprises an outer thread configured to engage the inner thread of the lower portion of the lower sub.