System for hoisting a load on a drilling rig
A system for hoisting a load on a drilling rig includes: a hoisting means having an elongated hoisting member and an elongated hoisting member drive means; a drill string rotation means suspended from an end of the elongated hoisting member; a support structure having a first side and a second side and being adapted to support at least a portion of the weight the drill string rotation means; a first elongated hoisting member guiding means connected to the support structure; and a counterweight connected to the elongated hoisting member at the second side of the support structure. The elongated hoisting member is reeved over the first elongated hoisting member guiding means from the first to the second side of the support structure. The drill string rotation means is suspended from the elongated hoisting member at the first side of the support structure.
1. System for hoisting load on a drilling rig, the system comprising:
a hoisting means including an elongated hoisting member and an elongated hoisting member drive means;
a drill string rotation means suspended from an end of said elongated hoisting member;
a support structure having a first side and a second side, the support structure configured to support at least a portion of the weight of said drill string rotation means; and
a first elongated hoisting member guiding means connected to said support structure, said elongated hoisting member being reeved over said first elongated hoisting member guiding means from said first side to said second side of the support structure;
a counterweight connected to said elongated hoisting member at said second side of the support structure;
wherein said drill string rotation means is suspended from said elongated hoisting member at said first side of the support structure.
2. System according to claim 1 , wherein the weight of said counterweight is less than the weight of said drill string rotation means.
3. System according to claim 2 , wherein said elongated hoisting member comprises two separate portions; a first portion reeved over said first elongated hoisting member guiding means directly connecting the drill string rotation means and the counterweight, and a second portion connecting the counterweight and the elongated hoisting member drive means.
4. System according to claim 3 , wherein said second portion of the elongated hoisting member is reeved directly from the elongated hoisting member drive means over the counterweight and to an anchor.
5. System according to claim 3 , wherein said second portion of the elongated hoisting member connects said elongated hoisting member drive means to said counterweight via a second elongated hoisting member guiding means.
6. System according to claim 1 , wherein the weight of said counterweight is greater than the weight of said drill string rotation means.
7. System according to claim 1 , wherein said elongated hosting member drive means is a winch adapted to accommodate only a single layer of elongated hoisting member.
8. System according to claim 7 , wherein said winch is adapted to accommodate a plurality of parallel elongated hoisting members connecting said winch to said drill string rotation means.
9. System according to claim 7 , wherein a ratio between a diameter of a winch drum of said winch and a diameter of said second portion of said elongated hoisting member is larger than 30.
10. System according to claim 7 , wherein a ratio between a diameter of said first elongated hoisting member guiding means and said first portion of said elongated hoisting member is larger than 30.
11. System according to claim 9 wherein the ratio between the diameter of the winch drum of said winch and the diameter of said second portion of said elongated hoisting member is larger than 60.
12. System according to claim 1 , wherein said first elongated hoisting member guiding means is a crown block provided at top of the support structure, the support structure being a derrick.
13. System according to claim 12 , wherein the crown block is connected to the derrick via motion compensation means.
14. System according to claim 1 wherein the counterweight comprises a travelling block.
15. System for hoisting load on a drilling rig, the system comprising:
a hoist including an elongated hoisting member and a winch;
a top drive suspended from an end of said elongated hoisting member;
a support structure having a first side and a second side, the support structure configured to support at least a portion of the weight of said top drive; and
a first sheave connected to said support structure, said elongated hoisting member being reeved over said first sheave from said first side to said second side of the support structure;
a counterweight connected to said elongated hoisting member at said second side of the support structure;
wherein said top drive is suspended from said elongated hoisting member at said first side of the support structure.
16. System according to claim 15 , wherein the weight of said counterweight is greater than the weight of said top drive.
17. System according to claim 15 , wherein the weight of said counterweight is less than the weight of said top drive.
18. System according to claim 17 , wherein said elongated hoisting member comprises two separate portions; a first portion reeved over said first sheave directly connecting the top drive and the counterweight, and a second portion connecting the counterweight and the winch.
19. System according to claim 18 , wherein said second portion of the elongated hoisting member is reeved directly from the winch over the counterweight and to an anchor.
20. System according to claim 18 , wherein said second portion of the elongated hoisting member connects said winch to said counterweight via a second sheave.