Extended reach plug having degradable elements

A settable isolation tool sized and configured to be capable of being used in fracing past at least one casing patch within 4½ inch to 5½ inch outer diameter (O.D.) casing in a horizontal leg of a hydrocarbon well, the tool comprising:

• a mandrel with a longitudinal axis;
• first and second expanders around the mandrel, each expander having an outer surface which is not parallel to the mandrel's axis section and having a first end with a first outer diameter and a second end having a second outer diameter, the first outer diameter being larger than the second outer diameter;
• first and second annular slips around the mandrel, the first expander and the first slip being a first expander/slip pair and the second expander and the second slip being a second expander/slip pair, each slip having an inner surface complementary to its paired expander's outer surface section and a slip outer surface having outer teeth or inclusions for setting into the casing;
• the slips and expanders are sized and configured so each slip, in a retracted slip position, has a slip outer diameter of 3 inches to 3.8 inches, and the slip's outer diameter is smaller than the first outer diameter of the slip's associated expander and small enough so the slip may be moved past the casing patch in the horizontal leg while being inserted into the well;
• the retracted tool has an outer diameter of 3.25 inches to 4.18 inches, and the retracted tool's outer diameter is small enough so the retracted tool may be moved past the casing patch in the horizontal leg while being inserted into the well;
• the mandrel, expanders and slips are configured, sized and comprised so the retracted slips' O.D. is small enough so the tool is capable of being run through and past a 0.125 inch thick casing patch with a 4 inch to 4.892 inch inner diameter (I.D.) casing in the horizontal leg;
• each slip is movable radially outward by axial movement relative to its paired expander to an expanded slip position;
• the slips and expanders each being large enough to be located about the mandrel and large enough so axial movement of each slip over its paired expander will expand each slip to an expanded slip configuration where the slip has an outer diameter of 4.1 inches to 5.05 inches and is 15% wider than the slip's outer diameter in the retracted slip position;
• each expanded slip is capable of gripping the inner diameter of the casing and setting the outer teeth or inclusions into the casing during setting of the tool to the casing;
• the tool is configured, sized and comprised so the retracted tool is capable of being run past the casing patch in the horizontal leg, and then expanded to set into the casing, and then used in isolating and fracing in the horizontal leg;
• wherein each of the mandrel, expanders and slips is comprised of a material degradable in a natural aqueous downhole fluid in the well produced from formation flow in the well having a pH less than about 7, wherein the degradable material or materials are selected from the group comprising magnesium, or magnesium alloys or polymer acids, and the degradable materials of each of the mandrel, expanders and slips are either the same or different such degradable materials;
• the tool is configured and comprised to be interventionless, namely, within less than five days after the tool is immersed in a natural aqueous downhole fluid in the well produced from formation flow in the well having a pH less than about 7, the tool dissolves enough in the downhole fluid so the tool ceases to isolate the zone above the tool from a zone below the tool, without milling out the tool, retrieval of the tool from the well or other intervention on the tool from the surface;
• the tool is capable of degrading in the wellbore fluid enough to not obstruct production of hydrocarbons from the well without drilling out the tool;
• the tool is configured, sized and comprised so five such tools are capable of being run past the casing patch in the horizontal leg within the casing, set within the casing, and used in isolating and fracing zones in the horizontal leg past the casing patch;
• the first tool being run in, set and used in isolating and fracking, then the second tool being run in, set and used in isolating and fracking above the first tool, then the third tool being run in, set and used in isolating and fracking above the second tool, then the fourth tool being run in, set and used in isolating and fracking above the third tool, then the fifth tool being run in, set and used in isolating and fracking above the fourth tool, and
• the tool is configured, sized and comprised so production of hydrocarbons from the well can begin within less than five days after the tool is immersed in the well's downhole fluid without drilling out or retrieving the five such tools or other intervention on the 5 such tools from the surface.