CN-121976770-A - Split type suction pile for ultra-deep water drilling and lowering method thereof

CN121976770ACN 121976770 ACN121976770 ACN 121976770ACN-121976770-A

Abstract

The invention relates to a split suction pile for ultra-deep water drilling, which comprises an upper half part and a lower half part, wherein the top of the upper half part is in a sealing design, the bottom of the upper half part is in an opening design, a suction pump butt joint port and an exhaust port are arranged on the top of the upper half part, a reserved wellhead is arranged in the center of the interior of the upper half part, the top of the lower half part is an open horn mouth, the bottom of the lower half part is in an opening design, a butt joint step and an anti-rotation structure are arranged in the interior of the lower half part, the bottom of the upper half part can enter the lower half part and is clamped through the butt joint step and the anti-rotation structure, and hoisting structures are respectively arranged on the outer walls of the upper half part and the lower half part. The invention can realize the establishment of the underwater wellhead with excellent stability on the surface layer of the ultra-deep water soft soil body, and is convenient for the subsequent installation of equipment such as the Christmas tree, and the like.

Inventors

YIN QISHUAI
ZHANG JUYAN
ZHAI YUQI
YANG JIN
ZHU GUOJING
ZHANG XINYUE
Rui Zhenhua

Assignees

中国石油大学(北京)

Dates

Publication Date: 20260505
Application Date: 20260202
Priority Date: 20250710

Claims (8)

1. The utility model provides a split type suction stake for ultra-deep water well drilling, its characterized in that, including first half and lower half, the top of first half is the design of sealing, the bottom of first half is the opening design, be equipped with suction pump butt joint mouth and gas vent on the top of first half, the inside center of first half is equipped with reserves the well head, the top of second half is open horn mouth, the bottom of second half is the opening design, the inside of second half is equipped with butt joint step and anti-rotation structure, the bottom of first half can get into the second half and pass through butt joint step and anti-rotation structure block, first half with be equipped with hoisting structure on the outer wall of second half respectively.
2. The split suction pile for ultra-deep water drilling according to claim 1, wherein a second reinforcing rib plate is arranged in the upper half part, and the outer side of the reserved wellhead is connected with the cylinder wall on the inner side of the upper half part through the second reinforcing rib plate.
3. The split suction pile for ultra-deep water drilling according to claim 2, wherein the upper and lower halves are each of cylindrical configuration.
4. A split suction pile for ultra-deep water drilling according to claim 3, wherein a sealing structure is provided on the outer wall of the bottom of the upper half.
5. The split suction pile for ultra-deep water drilling according to claim 4, wherein a first reinforcing rib plate is further arranged in the lower half portion, the butt joint step and the anti-rotation structure are arranged above the first reinforcing rib plate, and the first reinforcing rib plate is connected with the butt joint step and the anti-rotation structure in a crossing manner and the bottom of the lower half portion.
6. A method of lowering a split suction pile according to any one of claims 1 to 5, comprising the steps of: the prepared split suction pile and the matched equipment are transported to a preset lowering position; The lower half part of the drilling ship is lifted to slowly enter the sea, dead weight sinking through is completed by the lower half part, a lifting mechanism of the drilling ship is kept in a half-tension bearing state, a barrel of the lower half part is kept still, the barrel posture of the lower half part is continuously monitored, the stable state is confirmed to be reached, lifting connection is released, and the seabed positioning of the lower half part is completed; Lifting the upper half part after exhausting by using a drilling ship, slowly entering the sea until the upper half part is in butt joint with a horn mouth of the lower half part, forming a sealed suction pile whole by the upper half part and the lower half part after the bottom of the upper half part is in contact with a butt joint step of the lower half part and an anti-rotation structure, stopping sinking after the gravity of the suction pile whole is balanced with mud entering resistance, keeping a lifting mechanism in a half-tension bearing state, enabling a cylinder body of the lower half part to stand, confirming that the stable state is achieved, releasing lifting connection, and completing the whole sinking and penetrating work of the suction pile; Closing an exhaust port at the upper half part through an ROV operation arm, connecting a suction pump, forming a closed negative pressure cavity in the whole suction pile, stopping sinking after the whole dead weight of the suction pile is balanced with mud entering resistance, stopping the pump for standing for 3-5 hours, ensuring that the suction pile is separated from the suction pump after the whole suction pile is stable, and completing the lowering of the split type suction pile; and according to the later drilling requirement, a conduit or other tubular column structure is put into the reserved wellhead, and well cementation or non-well cementation is selected according to the actual construction condition.
7. The method of lowering a split suction pile according to claim 6, wherein the condition for determining that the stable state is reached is that the inclination angle of the lower half fluctuates by <0.1 ° for 30 minutes.
8. The method of lowering a split suction pile according to claim 7, wherein the tension value of the "half tension bearing state" is 5-10kN.

Description

Split type suction pile for ultra-deep water drilling and lowering method thereof Technical Field The invention relates to the technical field of ultra-deep water drilling, in particular to a split suction pile for ultra-deep water drilling and a lowering method thereof. Background Currently, a jet pipe tripping process is generally adopted in deep water surface layer well construction operation, the mud tripping depth of a pipe is generally 70-100 meters, however, the method has a remarkable limitation that the bearing capacity of a wellhead system is difficult to meet the increasingly improved requirement of deep water oil and gas field development on structural stability. The bottleneck of the prior art is concentrated in: (1) The traditional integral suction pile has low transportation and lowering efficiency in ultra-deep water scenes; (2) The single large-size suction pile is difficult to adapt to the complicated sea bed landform; (3) The rigid connection structure of the wellhead system and the suction pile restricts the ocean current impact resistance. Thus, there is a need for a split suction pile for ultra-deep water drilling. Disclosure of Invention The invention aims to provide a split suction pile for ultra-deep water drilling, which solves the problems of sinking, tilting or wellhead instability of a conduit caused by extremely low bearing capacity of a seabed surface layer which is mostly soft sediment (such as muddy and sandy) due to severe ultra-deep water environment conditions. Another object of the present invention is to provide a method of lowering a split suction pile. The first aspect of the invention provides a split suction pile for ultra-deep water drilling, which comprises an upper half part and a lower half part, wherein the top of the upper half part is in a sealing design, the bottom of the upper half part is in an opening design, a suction pump butt joint port and an exhaust port are arranged on the top of the upper half part, a reserved wellhead is arranged in the center of the interior of the upper half part, the top of the lower half part is in an open horn mouth, the bottom of the lower half part is in an opening design, a butt joint step and an anti-rotation structure are arranged in the lower half part, the bottom of the upper half part can enter the lower half part and is clamped through the butt joint step and the anti-rotation structure, and hoisting structures are respectively arranged on the outer walls of the upper half part and the lower half part. The split suction pile for ultra-deep water drilling is characterized in that a second reinforcing rib plate is arranged in the upper half part, and the outer side of the reserved wellhead is connected with the cylinder wall at the inner side of the upper half part through the second reinforcing rib plate. The split suction pile for ultra-deep water drilling is preferably cylindrical in both the upper half and the lower half. The split suction pile for ultra-deep water drilling is preferably provided with a sealing structure on the outer wall of the bottom of the upper half. The split type suction pile for ultra-deep water drilling is characterized in that preferably, a first reinforcing rib plate is further arranged in the lower half part, the butt joint step and the anti-rotation structure are arranged above the first reinforcing rib plate, and the butt joint step and the anti-rotation structure are connected with the bottom of the lower half part in a crossing manner through the first reinforcing rib plate. The second aspect of the invention provides a method for lowering a split suction pile, which specifically comprises the following steps: the prepared split suction pile and the matched equipment are transported to a preset lowering position; The lower half part of the drilling ship is lifted to slowly enter the sea, dead weight sinking through is completed by the lower half part, a lifting mechanism of the drilling ship is kept in a half-tension bearing state, a barrel of the lower half part is kept still, the barrel posture of the lower half part is continuously monitored, the stable state is confirmed to be reached, lifting connection is released, and the seabed positioning of the lower half part is completed; Lifting the upper half part after exhausting by using a drilling ship, slowly entering the sea until the upper half part is in butt joint with a horn mouth of the lower half part, forming a sealed suction pile whole by the upper half part and the lower half part after the bottom of the upper half part is in contact with a butt joint step of the lower half part and an anti-rotation structure, stopping sinking after the gravity of the suction pile whole is balanced with mud entering resistance, keeping a lifting mechanism in a half-tension bearing state, enabling a cylinder body of the lower half part to stand, confirming that the stable state is achieved, releasing lifting connection, and completing the w