Device for building up down-pressure on well face during drilling

Claim 2

The combination with a drill string constituted by a plurality of interconnected pipes and a bit operably associated with the lower end of the drill string, of a device located in the drill string for building-up a down pressure on the well face during drilling, said device comprising: a cylinder, a rod provided with a piston located in said cylinder, said piston rod being provided with a through axial bore for the passage of a drilling fluid, and said piston being defined by coaxial alternating outer and inner rings, with each of said inner rings constituting a wedge between the two adjacent outer rings whereby under the influence of a compression pulse, the movable rings enter into contact with one another partially passing and partially dissipating the compression pulse while an extension pulse causes the rings to disengage from one another and define a boundary free surface from which the extension pulse is reflected and returns to the bit, subjecting the bit to a dynamic load, the drill string including a pipe adjacent the cylinder, said pipe having an extension, said outer and inner rings being installed movably on the extension, said extension having a lower end entering the axial bore of said rod with a provision for moving therein, said rod having an upper end and an end plate on the upper end of the cylinder, said rings being located between the upper end of said rod and the end plate of said cylinder.

Claim 3

The combination with a drill string constituted by a plurality of interconnected pipes and a rotary bit operably associated with the lower end of the drill string, of a device located in the drill string for controlling a dynamic load on the rotary bit, said device comprising a hollow cylinder mounted coaxially between two adjacent pipes of said drill string, said cylinder having upper and lower end plates, said upper end plate rigidly connecting the cylinder with an upper adjacent pipe of said drill string, said upper end plate having an axial through opening, said lower end plate of said cylinder having an axial through opening, a hollow cylindrical rod coaxially mounted in said cylinder with a possibility of axial movements, a circular flange on the upper end of said rod, the lower end of the rod passing through the opening in said lower end plate and being rigidly connected with a lower adjacent pipe of said drill string, outer rings mounted with a possibility of axial movements on said rod between said circular flange and said lower end plate of said cylinder, inner rings each of which is mounted with a possibility of axial movements on said rod between two adjacent outer rings, each of said outer rings being provided on its inner side with a wedge-shaped projection defined by two conical surfaces, each of said inner rings being provided on its outer side with a wedge-shaped projection defined by two conical surfaces which, during the bit''s operation, periodically contact with the corresponding conical surfaces on the inner sides of said adjacent outer rings thereby resulting in suppressing the stretching pulses and during periodic intervals between contacts of said conical surfaces, stretching impulses reflect from the free end of the rod and return to the bit.

Claim 4

The combination with a drill string constituted by a plurality of interconnected pipes and a rotary bit operably associated with the lower end of the drill string, of a device located in the drill string for controlling a dynamic load on the rotary bit, said device comprising a hollow cylinder mounted coaxially between two adjacent pipes of said drill string, said cylinder having upper and lower end plates, said upper end plate rigidly connecting the cylinder with an upper adjacent pipe of said drill string, said upper end plate having an axial through opening, said lower end plate of said cylinder having an axial through opening, a hollow cylindrical rod coaxially mounted in said cylinder with a possibility of axial movements, a circular flange on the upper end of said rod, the lower end of the rod passing through the opening in said lower end plate and being rigidly connected with a lower adjacent pipe of said drill string, outer rings mounted with a possibility of axial movements on said rod between said circular flange and said lower end plate of said cylinder, inner rings each of which is mounted with a possibility of axial movements on said rod between two adjacent outer rings, each of said outer rings being provided on its inner side with a wedge-shaped projection defined by two conical surfaces, each of said inner rings being provided on its outer side with a wedge-shaped projection defined by two conical surfaces which, during the bit''s operation, periodically contact with the corresponding conical surfaces on the inner sides of said adjacent outer rings thereby resulting in suppressing the stretching pulses and during periodic intervals between contacts of said conical surfaces, stretching impulses reflect from the free end of the rod and return to the bit.

Claim 5

The combination with a drill string constituted by a plurality of interconnected pipes and a rotary bit operably associated with the lower end of the drill string, of a device located in the drill string for controlling a dynamic load on the rotary bit, said device comprising a hollow cylinder mounted coaxially between two adjacent pipes of said drill string, said cylinder having upper and lower end plates, each of said end plates having a through opening, said upper end plate rigidly connecting the cylinder with an upper adjacent pipe of said drill string, a hollow cylindrical rod mounted coaxially in the cylinder with a possibility of axial movements, a circular flange on the upper end of the rod, the lower end of the rod passing through the opening in the lower end plate and being rigidly connected with a lower adjacent pipe of the drill string, a branch pipe mounted within said rod and rigidly connected at its upper end with said upper adjacent pipe of the drill string, outer rings mounted with a possibility of axial movements on the branch pipe between the circular flange on the rod and the upper end plate of the cylinder, inner rings each of which is mounted with a possibility of axial movements on the branch pipe between two adjacent outer rings, each of said outer rings being provided on its inner side with a wedge-shaPed projection defined by two conical surfaces which, during the bit''s operation, periodically contact with corresponding conical surfaces on the inner sides of said adjacent outer rings thereby resulting in suppressing the stretching pulses and during perodic intervals between contacts of said conical surfaces, stretching pulses reflect from the free end of the rod and return to the bit.

Claim 6

The combination with a drill string constituted by a plurality of interconnected pipes and a rotary bit operably associated with the lower end of the drill string, of a device located in the drill string for controlling a dynamic load on the rotary bit, said device comprising a hollow cylinder mounted coaxially between two adjacent pipes of said drill string, said cylinder having upper and lower end plates, each of said end plates having a through opening, said upper end plate rigidly connecting the cylinder with an upper adjacent pipe of said drill string, a hollow cylindrical rod mounted coaxially in the cylinder with a possibility of axial movements, a circular flange on the upper end of the rod, the lower end of the rod passing through the opening in the lower end plate and being rigidly connected with a lower adjacent pipe of the drill string, a branch pipe mounted within said rod and rigidly connected at its upper end with said upper adjacent pipe of the drill string, outer rings mounted with a possibility of axial movements on the branch pipe between the circular flange on the rod and the upper end plate of the cylinder, inner rings each of which is mounted with a possibility of axial movements on the branch pipe between two adjacent outer rings, each of said outer rings being provided on its inner side with a wedge-shaPed projection defined by two conical surfaces which, during the bit''s operation, periodically contact with corresponding conical surfaces on the inner sides of said adjacent outer rings thereby resulting in suppressing the stretching pulses and during perodic intervals between contacts of said conical surfaces, stretching pulses reflect from the free end of the rod and return to the bit.