Hydrocarbon well and technique for perforating casing toe

A hydrocarbon well having

• a well bore including a vertical leg and a horizontal leg,
• a casing string in the horizontal leg having
• a tubular wall providing a passage therethrough adjacent a casing toe of the casing string, the passage having therein a ball, a first ball seat for cooperating with the ball to prevent flow into the casing string and a second ball seat cooperating with the ball to prevent flow out of the casing string, the ball plugging the passage and being soluble in a completion liquid, and
• float equipment adjacent the casing toe and further from earth's surface than the passage, and
• a cement sheath substantially filling an annulus between the casing string and the well bore from adjacent the float equipment toward the earth's surface.

A method of completing a hydrocarbon well in a well bore extending from a location on earth's surface and having a horizontal leg, comprising

• providing a soluble element in a passage through a wall of a casing string upstream of float equipment adjacent a casing toe of the casing string;
• running the casing string into the horizontal leg and creating an annulus between the casing string and the well bore;
• pumping cement into the casing string, out through the float equipment and into the annulus from the casing toe toward a heel of the well and displacing drilling fluid from the annulus toward the surface location by pumping a liquid into the casing string that slowly dissolves the soluble element;
• after the cement sets up and after the soluble element dissolves to provide at least one passage through the wall of the casing string, propelling perforating equipment into the casing string by pumping an additional liquid into the casing string and out through the at least one passage, creating first perforations through the casing string and then fracing the well through the first perforations;
• after the first perforations are fraced, placing second wire line perforating equipment in the casing string and pumping liquid into the casing string to propel the second perforating equipment toward the casing toe to a location spaced from the first perforations, at least some additional liquid in front of the second perforating equipment exiting the well bore through the first mentioned perforations;
• creating a second set of perforations in the casing string with the second perforating equipment, placing a wire line isolation tool in the casing string at a location between the first and second perforations and setting the isolation tool to isolate the first perforations from the second perforations;
• and
• fracing the well through the second perforations.

A method of completing a hydrocarbon well in a well bore extending from a location on earth's surface and having a horizontal leg, comprising

• providing a soluble element in a passage through a wall of a casing string upstream of float equipment adjacent a casing toe of the casing string;
• running the casing string into the horizontal leg and creating an annulus between the casing string and the well bore;
• pumping cement into the casing, out through the float equipment and into the annulus, from the casing toe toward a heel of the well and displacing drilling fluid from the annulus toward the surface location by pumping a water based liquid into the casing string that slowly dissolves the soluble element;
• and
• after the cement sets up and after the soluble element dissolves to provide at least one passage through the wall of the casing string, pumping perforating equipment through the casing string to a location adjacent the casing toe and pushing the water based liquid through the at least one passage;
• creating perforations in the casing string at the location with the perforating equipment and then removing the perforating equipment from the well;
• and then
• fracing the well through the perforations.