Wireline coring recovery system of a seafloor drilling rig and method of using same

Patent metadata

Field	Value
Publication number	US-11041344-B1
Application number	US-202016988702-A
Country	US
Kind code	B1
Filing date	Aug 9, 2020
Priority date	Dec 3, 2019
Publication date	Jun 22, 2021
Grant date	Jun 22, 2021

Abstract

There is provided a wireline coring recovery system of a seafloor drilling rig, including: a winch, a rope, a submersible tension sensor, a cover, a main shaft and a catcher. One end of the rope is wound on the winch, and the other end of the rope is connected to an upper end of the catcher after the rope passes over a first pulley provided below the submersible tension sensor and then through a tapered hole on the cover. The catcher is provided in a center hole of the main shaft. The present application further provides a method of using the wireline coring recovery system. By the cooperation of the compression rod skewed teeth, the first rotating core skewed teeth, the second rotating core skewed teeth and the compression spring, the inner core barrel is readily recovered or released.

First claim

What is claimed is:

1. A wireline coring recovery system of a seafloor drilling rig, comprising: a winch, a rope, a submersible tension sensor, a cover, a main shaft and a catcher;
wherein the cover is provided on a drilling power head; a center hole of the cover is communicated with a center hole of the main shaft which is provided on the drilling power head; a first bracket is provided on the cover to support the submersible tension sensor; the first bracket is connected to a first pulley via a connecting rod; the submersible tension sensor is provided on the connecting rod; one end of the rope is wound on the winch, and the other end of the rope is connected to an upper end of the catcher after the rope passes over the first pulley and then through a top hole on the cover; and the catcher is located in the center hole of the main shaft;
the catcher comprises a mechanism to prevent being stuck, a weight rod, a compression rod, a fixed guide tube, a rotatable ferrule, a compression spring, a steel ball seat and a plurality of steel balls; wherein the mechanism to prevent being stuck further comprises: a seal plug, an anti-stuck spring, a connecting pipe, a second sealing ring and a saddle, and is provided at an upper end of the weight rod and connected to the other end of the rope; the compression rod is fixed at a lower end of the weight rod and inserted into an inner cavity of the fixed guide tube; a plurality of compression rod skewed teeth are provided at a lower end of the compression rod; a guide groove is provided on a side of the compression rod along an axis of the compression rod; a guide key is provided on a side wall of the inner cavity of the fixed guide tube along an axis of the fixed guide tube; the guide groove and the guide key fit with each other;
the rotatable ferrule is located in the fixed guide tube; a plurality of first rotating core skewed teeth and a plurality of second rotating core skewed teeth are alternately provided at an upper end of the rotatable ferrule to match with the plurality of compression rod skewed teeth; a U-shaped groove is provided on each second rotating core skewed tooth; a compression spring seat is provided in an inner cavity of the rotatable ferrule; and the rotatable ferrule has a trumpet-shaped lower part; and
the steel ball seat is fixed at a bottom of the fixed guide tube and provided with an annular column; the compression spring is provided between the compression spring seat and a top of the annular column; a plurality of steel ball holes are provided at a side wall of the annular column; each steel ball hole is provided with one steel ball; a downward movement of the rotatable ferrule forces the steel balls to move towards a center of the annular column and then snap into an annular groove of a spearhead of an inner core barrel.

2. The wireline coring recovery system of claim 1 , wherein
the saddle is fixed on the upper end of the weight rod and connected to the other end of the rope and a lower end of the connecting pipe; a lower end of the seal plug is inserted in the connecting pipe and is provided with a flange; a diameter of the flange is larger than that of a through hole at a top of the connecting pipe; and a part of the seal plug that protrudes from the connecting pipe has a conical top;
a bottom of the top hole on the cover through which the rope passes has a negative taper; the conical top of the seal plug and the bottom of the top hole form a seal; the anti-stuck spring is placed in the connecting tube; and two ends of the anti-stuck spring are respectively connected to the saddle and the seal plug.

3. The wireline coring recovery system of claim 1 , wherein there are an even number of the compression rod skewed teeth which are evenly and circumferentially distributed; and the first rotating core skewed teeth, the second rotating core skewed teeth and the compression rod skewed teeth are same in number.

4. The wireline coring recovery system of claim 2 , wherein the second sealing ring is provided between the seal plug and the through hole at the top of the connecting pipe.

5. The wireline coring recovery system of claim 1 , wherein a diameter of the catcher is smaller than that of the center hole of the main shaft and that of an inner cavity of the cover.

6. The wireline coring recovery system of claim 2 , wherein a first sealing ring is provided at the bottom of the top hole; a water inlet is provided at a side wall of the cover and communicated with the center hole of the cover; and a flushing water hose is connected to the water inlet.

7. The wireline coring recovery system of claim 1 , wherein the winch is fixed on the cover via a second bracket; a second pulley is fixed on the second bracket; the other end of the rope is connected to the upper end of the catcher after the rope passes over the second pulley and the first pulley; and the rope on both sides of the first pulley is parallel to the connecting rod.

8. A method of using the wireline coring recovery system of claim 1 , comprising:
1) before the seafloor drilling rig goes into the sea, manually switching the catcher to an “unlocking” mode, wherein the steel balls in the steel ball holes return to the trumpet-shaped lower part of the rotatable ferrule;
2) after the seafloor drilling rig arrives at the seafloor and before the core drilling is performed, driving the winch to reel in the rope, so as to raise the catcher to be inside the main shaft and the cover, wherein at this time, the seal plug abuts against the top hole to form a seal;
3) during the core drilling of the seafloor drilling rig, supplying flushing water into the drilling power head to allow the flushing water to arrive at a bottom of a drill bit of an outer core barrel after flowing along an annular gap between the catcher and the main shaft and passing through an inner cavity of a drill rod, so as to cool the drill bit and realize flushing water circulation;
4) after the seafloor drilling rig completes the core drilling, turning off the flushing water and starting the recovery of the inner core barrel; driving the winch to reel out the rope to lower the catcher from the cover, along the main shaft and through the drill rod to an upper end of the outer core barrel, clamping the spearhead using the steel ball seat and stopping the downward movement of the steel ball seat; forcing the compression rod to continue the downward movement due to the continued downward movement of the weight rod under self-weight; rotating the rotatable ferrule an angle of one first rotating core skewed tooth or one second rotating core skewed tooth under the cooperation of the compression rod skewed teeth, the first rotating core skewed teeth, the second rotating core skewed teeth and the compression spring, so as to make the guide key enter one of the first rotating core skewed tooth; moving the steel balls in the steel ball holes towards the center of the annular column under the force of the trumpet-shaped lower part of the rotatable ferrule, so as to make the steel balls snap into the annular groove of the spearhead to realize the clamping of the spearhead, wherein at this time, the catcher is switched to an “interlocking” mode from the “unlocking” mode;
5) driving the winch to reel in the rope to raise the catcher together with the inner core barrel for the recovery; wherein at this time, the guide key abuts one of the first rotating core skewed tooth to defeat the upward movement of the rotatable ferrule, and the trumpet-shaped lower part of the rotatable ferrule stops the outward movement of the steel balls in the annular groove of the spearhead; and
6) when the spearhead is 10-20 cm away from a lower end of the main shaft during the recovery of the inner core barrel, stopping reeling in

Assignees

• Univ Hunan Science & Technology

Inventors

• Wan Buyan
• Jin Yongping
• Huang Xiaojun

Classifications

• E21B7/122

  with submersible vertically movable guide · CPC title

• E21B21/001

  specially adapted for underwater drilling (dual gradient drilling E21B21/082) · CPC title

• E21B25/18 Primary

  the core receiver being specially adapted for operation under water · CPC title

• E21B25/02 Primary

  the core receiver being insertable into, or removable from, the borehole without withdrawing the drilling pipe · CPC title

• E21B19/002 Primary

  specially adapted for underwater drilling (E21B19/09, E21B19/143 take precedence) · CPC title