Skirt type well mouth suction anchor for building and cementing horizontal well in oil and gas exploitation

Abstract

The invention discloses a skirt type wellhead suction anchor for building and cementing a horizontal well in oil and gas exploitation. The skirt type wellhead suction anchor consists of a steel wellhead, an internal steel guide pipe and an outer skirt structure, the steel well mouth is of a steel cylindrical structure with the top closed and the bottom open. The internal steel guide pipe is of a slender tubular structure and is mounted in the center of a steel wellhead; the outer skirt structure is an annular steel pipe and is installed at the outer end of the upper side of the steel wellhead. The structure can improve the vertical load resistance of well building and cementation so as to bear larger weight of a blowout preventer group, increase the coupling area with a soil body and the structure and reduce the drop shaft risk, and has higher horizontal overturning or torsion resistance compared with a traditional wellhead suction anchor.

Description

Technical Field

[0001] The invention belongs to the technical field of deep-water drilling and is a surface cementing device suitable for deep-sea oil and gas exploitation. Background Art

[0002] In the field of oil and gas extraction, the traditional well construction method is mainly to inject the lower pipe to build the well, which has high geological requirements and limited bearing capacity after well construction, and there is a risk of well slipping. With the development of oil and gas extraction in the deep sea, larger blowout preventer groups and unavoidable dynamic loads such as seawater pipes and seawater currents have put forward higher requirements on the stability of the wellhead, so it is urgent to propose a new type of cementing technology. The present invention provides a new type of skirt-type wellhead suction anchor for horizontal cementing, which is of great significance to the development of deep-sea oil and gas extraction in my country. Summary of the invention

[0003] The present invention proposes a skirt-type wellhead suction anchor for cementing horizontal wells for oil and gas production, which combines suction anchor technology with traditional conduits, takes into account the wellhead oil production function while providing greater vertical and horizontal bearing capacity, can resist the dynamic loads brought by oil production pipelines and ocean currents, reduce the risk of wellhead sinking, and provide a convenient installation method to greatly reduce the construction process and shorten the construction period.

[0004] The present invention adopts the following technical solutions:

[0005] A skirt-type wellhead suction anchor for cementing horizontal wells for oil and gas production comprises three parts: a steel wellhead, an internal steel conduit, and an external skirt structure; the steel wellhead is a steel cylindrical structure with a closed top and an open bottom; the internal steel conduit is a slender tubular structure and is installed at the center of the steel wellhead; the external skirt structure is an annular steel pipe and is installed at the upper outer end of the steel wellhead.

[0006] In the present invention, the steel wellhead has a conical steel thickened area inside, and the upper end of the internal steel pipe is embedded in the thickened area. The thickened area can increase the rigidity of the wellhead end and avoid excessive vertical deviation during the sinking process.

[0007] In the present invention, the steel wellhead, the internal steel conduit and the tip of the outer skirt structure are all sharpened to reduce the penetration resistance during the penetration process.

[0008] In the present invention, the installation method of the invention is to sink it into the designated position by applying suction.

[0009] The advantages of the present invention are: 1. It can sink to the designated position only by suction; 2. It saves the jet grouting well construction process and adopts an integrated wellhead casing (internal steel conduit and steel wellhead) installation method to eliminate the pollution caused by grouting; 3. It greatly increases the vertical bearing capacity and horizontal bearing capacity, can bear a heavier blowout preventer group, and reduce the risk of wellhead sinking. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is the overall schematic diagram of the skirt-type wellhead suction anchor;

[0011] Figure 2 This is the cross-section of the skirt-type wellhead suction anchor

[0012] In the figure: 1-internal steel conduit; 2-external skirt structure; 3-steel wellhead; 4-conical steel thickening area DETAILED DESCRIPTION

[0013] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0014] Combination Figure 1 as well as Figure 2 The skirt-type wellhead suction anchor for cementing horizontal wells for oil and gas production comprises three parts: a steel wellhead, an internal steel conduit, and an outer skirt structure; the steel wellhead is a steel cylindrical structure with a closed top and an open bottom; the internal steel conduit is a slender tubular structure and is installed at the center of the steel wellhead; the outer skirt structure is an annular steel pipe and is installed at the upper outer end of the steel wellhead.

[0015] Furthermore, there is a conical steel thickened area inside the steel wellhead, and the upper end of the internal steel pipe is embedded in the thickened area. The thickened area can increase the rigidity of the wellhead end and avoid excessive vertical deviation during the sinking process.

[0016] Furthermore, the steel wellhead, the internal steel conduit and the tip of the outer skirt structure are sharpened to reduce the penetration resistance during the penetration process.

[0017] Furthermore, the installation method of the invention is to sink it into the designated position by applying suction.

[0018] The above embodiments further illustrate the purpose, technical solutions and advantages of the present invention in detail. It should be understood that the above is only an embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A skirt-type wellhead suction anchor for cementing horizontal wells for oil and gas production, comprising a steel wellhead, an internal steel conduit, and an outer skirt structure; the steel wellhead is a steel cylindrical structure with a closed top and an open bottom; the internal steel conduit is a slender tubular structure and is installed at the center of the steel wellhead; the outer skirt structure is an annular steel pipe and is installed at the upper outer end of the steel wellhead.

2. According to claim 1, a skirt-type wellhead suction anchor for cementing horizontal wells for oil and gas production, the steel wellhead has a conical steel thickened area inside, and the upper end of the internal steel pipe is embedded in the thickened area.

3. According to the skirt-type wellhead suction anchor for cementing horizontal wells for oil and gas production in claim 1, the steel wellhead, the internal steel conduit, and the tip of the outer skirt structure are all sharpened.

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