Progressively expanded packing element for a bridge plug

Claim 1

AS A SUB-COMBINATION, A PACKING ELEMENT ADAPTED FOR EXPANSION INTO SEALING ENGAGEMENT WITH A WELL BORE, SAID PACKING ELEMENT CONSISTING OF: A PLURALITY OF ELASTOMERIC ELONGATED ANNULAR PLIES BONDED TOGETHER TO FORM A UNITARY TUBULAR HAVING A WALL OF UNIFORM THICKNESS, EACH OF SAID PLIES BEING OF AN ELASTOMERIC MATERIAL HAVING AT LEAST A DIFFERENT MODULUS OF ELASTICITY THAN THAT OF AT LEAST ANOTHER ONE OF SAID PLIES WITH EACH BEING UNIFORMLY TAPERED FROM A FIRST THICKNESS AT EACH END THEREOF TO A SECOND THICKNESS AT THE CENTRAL PORTION THEREOF, SAID PLIES BEING COOPERATIVELY PROPORTIONED AND ARRANGED IN SUCH A MANNER THAT THE COMPOSITE MODULUS OF ELASTICITY AT ANY TRANSVERSE SECTION OF SAID TUBULAR MEMBER PROGRESSIVELY INCREASES FROM THE CENTRAL PORTION THEREOF TOWARD EACH END OF SAID TUBULAR MEMBER.