Rubber cylinder having higher hardness in upper end portion, packer, and bridge plug

Abstract

A hardness of an upper end portion of a rubber cylinder is greater than a hardness of a middle portion, so that when the upper end portion bears a first axial pressure, the deformation of the middle portion in a radial direction is greater than the deformation of the upper end portion in the radial direction. A packer and a bridge plug include the rubber cylinder. The hardness of the upper end portion is greater than the hardness of the middle portion. When the upper end portion is subject to the first axial pressure, the upper end portion more likely transfers the first axial pressure to the middle portion and a lower end portion instead of deforming radially itself. A relatively small first axial pressure can be used to enable the middle portion and the lower end portion to deform radially, thereby achieving an overall seal of the rubber cylinder.

1 : A rubber cylinder comprising:
 a through hole located at the center, an inner surface located at the through hole ( 103 ), an outer surface corresponding to the inner surface, an upper end portion and a lower end portion respectively located at two ends of the rubber cylinder ( 10 ), and a middle portion located between the upper end portion and the lower end portion, the upper end portion being used to bear a first axial pressure in an axial direction, and the lower end portion being used to bear a second axial pressure opposite to the first axial pressure in the axial direction; when the first axial pressure is applied to the upper end portion, the upper end portion, the middle portion, and the lower end portion all deforming in a radial direction; and when the second axial pressure is applied to the lower end portion, the upper end portion, the middle portion, and the lower end portion ( 105 ) all deforming in the radial direction, wherein,   a hardness of the upper end portion ( 104 ) is greater than a hardness of the middle portion, so that when the upper end portion bears the first axial pressure, the deformation of the middle portion in the radial direction is greater than the deformation of the upper end portion in the radial direction.   
     
     
         2 : The rubber cylinder according to  claim 1 , wherein,
 a hardness of the lower end portion is greater than the hardness of the middle portion, so that when the lower end portion bears the second axial pressure, the deformation of the middle portion in the radial direction is greater than the deformation of the lower end portion in the radial direction.   
     
     
         3 : The rubber cylinder according to  claim 1 , wherein,
 the hardness of the upper end portion is basically the same as a hardness of the lower end portion, so that when the upper end portion bears the first axial pressure, the deformation of the middle portion in the radial direction is greater than the deformation of the upper end portion in the radial direction and the deformation of the lower end portion in the radial direction, and when the lower end portion bears the second axial pressure, the deformation of the middle portion in the radial direction is greater than the deformation of the upper end portion in the radial direction and the deformation of the lower end portion in the radial direction.   
     
     
         4 : The rubber cylinder according to  claim 1 , wherein,
 the rubber cylinder is formed of more than two seal rings arranged in the axial direction.   
     
     
         5 : The rubber cylinder according to  claim 4 , wherein,
 the rubber cylinder is formed of two seal rings arranged in the axial direction, one seal ring is used as the upper end portion, and the other seal ring is used as the lower end portion and the middle portion; or   the rubber cylinder is formed of three seal rings arranged in the axial direction, the three seal rings are respectively used as the upper end portion, the middle portion, and the lower end portion; or   the rubber cylinder is formed of more than three seal rings arranged in the axial direction, two seal rings distributed on the two ends in the axial direction are respectively used as the upper end portion and the lower end portion, and the remaining seal ring is used as the middle portion.   
     
     
         6 : The rubber cylinder according to  claim 5 , wherein,
 each of the seal rings has a colloid and an annular base body, the base body is formed of a plurality of high-temperature high-pressure resistant filaments intersecting each other, the colloid bonds all the filaments, and the colloid is distributed on surfaces of the base bodies, so that the inner surface and the outer surface are respectively formed on the inside and outside of the plurality of seal rings arranged in the axial direction.   
     
     
         7 : The rubber cylinder according to  claim 6 , wherein,
 the base body is a graphite packing or a carbon fibre packing; and   preferably, an angle β is formed between each of the seal rings and the radial direction of the rubber cylinder, wherein 5°≤β≤45°.   
     
     
         8 : The rubber cylinder according to  claim 1 , further comprising:
 a constraining casing, wherein the constraining casing generally has a flaring form, a flaring end of the constraining casing is sleeved over the upper end portion or the lower end portion, a necking end of the constraining casing is far away from the upper end portion or the lower end portion that is sleeved over by the flaring end and used to bear the first axial pressure or the second axial pressure;   preferably, the necking end has an inward chamfer; and   preferably, the upper end portion or the lower end portion sleeved over by the flaring end has a necking form to fit the flaring end; preferably, the constraining casing is made of copper, and a maximum thickness of the flaring end is less than or equal to 2 mm; preferably, a quantity of the constraining casings is 2, wherein the flaring end of one constraining casing is sleeved over the upper end portion, and the flaring end of the other constraining casing is sleeved over the lower end portion.   
     
     
         9 : A packer, comprising:
 a rubber cylinder, wherein the rubber cylinder has a through hole located at the center;   an inner surface located at the through hole;   an outer surface corresponding to the inner surface;   an upper end portion and a lower end portion respectively located at two ends of the rubber cylinder, and a middle portion located between the upper end portion and the lower end portion, the upper end portion is used to bear a first axial pressure in an axial direction, and the lower end portion is used to bear a second axial pressure opposite to the first axial pressure in the axial direction; when the first axial pressure is applied to the upper end portion, the upper end portion, the middle portion, and the lower end portion all deform in a radial direction; and when the second axial pressure is applied to the lower end portion, the upper end portion, the middle portion, and the lower end portion all deform in the radial direction; and   wherein a hardness of the upper end portion is greater than a hardness of the middle portion, wherein, when the upper end portion bears the first axial pressure, the deformation of the middle portion in the radial direction is greater than the deformation of the upper end portion in the radial direction.   
     
     
         10 : A bridge plug, comprising:
 a rubber cylinder, wherein the rubber cylinder has a through hole located at the center;   an inner surface located at the through hole;   an outer surface corresponding to the inner surface;   an upper end portion and a lower end portion respectively located at two ends of the rubber cylinder, and a middle portion located between the upper end portion and the lower end portion, the upper end portion is used to bear a first axial pressure in an axial direction, and the lower end portion is used to bear a second axial pressure opposite to the first axial pressure in the axial direction; when the first axial pressure is applied to the upper end portion, the upper end portion, the middle portion, and the lower end portion all deform in a radial direction; and when the second axial pressure is applied to the lower end portion, the upper end portion, the middle portion, and the lower end portion all deform in the radial direction; and   wherein a hardness of the upper end portion is greater than a hardness of the middle portion, so that when the upper end portion bears the first axial pressure, the deformation of the middle portion in the radial direction is greater than the deformation of the upper end portion in the radial direction.