Shearable tubular system and method

A method for accessing subterranean horizons, comprising:

• assembling a first tubular string comprising multiple sections of a first tubular material to extend only beneath a subterranean level to a horizon of interest except during placement and removal of the first tubular string;
• assembling a second tubular string comprising multiple sections of a second tubular material attached above the first tubular string, the second tubular string extending along a length that will traverse a blow out preventer during accessing of the horizon of interest;
• and
• assembling a third tubular string comprising multiple sections of the first tubular material attached above the second tubular string to extend only above the blow out preventer in a subsea environment;
• wherein the second tubular string comprises a single wall material, and the first tubular material has a ratio of yield strength to tensile strength of at most approximately 0.85 and the second tubular material has a ratio of yield strength to tensile strength of at least approximately 0.90, whereby the second tubular material is more favorable to shear by action of the blow out preventer than the first tubular material.

A tubular string comprising:

• a first tubular string comprising multiple sections of first tubular material extending only beneath a subterranean level to a horizon of interest except during placement and removal of the first tubular string;
• a second tubular string comprising multiple sections of second tubular material attached above the first tubular string, the second tubular string extending along a length that will traverse a blow out preventer during accessing of the horizon of interest;
• and
• a third tubular string comprising multiple sections of first tubular material attached above the second tubular string to extend only above the blow out preventer in a subsea environment;
• wherein the second tubular string comprises a single wall material, and the first tubular material has a ratio of yield strength to tensile strength of at most approximately 0.85 and the second tubular material has a ratio of yield strength to tensile strength of at least approximately 0.90, whereby the second tubular material is more favorable to shear by action of the blow out preventer than the first tubular material.