Large-drift-diameter sand-filling multi-layer yield-increasing and injection-increasing process pipe column suitable for offshore oilfield

Abstract

The utility model discloses a large-drift-diameter sand-filling multi-layer yield-increasing and injection-increasing process pipe column suitable for an offshore oilfield. The large-drift-diameter sand-filling multi-layer yield-increasing and injection-increasing process pipe column comprises an oil pipe, a depth correction short section, a shearing connector, a differential pressure type well washing valve, a gravity setting packer and a guiding shoe which are sequentially connected from top to bottom. The gravity setting packer is connected with the guiding shoe through a tubing nipple; the depth correction short section is connected with the shear joint through an R2 oil pipe; and the oil pipe is connected to a wellhead. By means of the multi-layer fracturing device, layer-by-layer fracturing from bottom to top can be achieved, the purpose of achieving multi-layer fracturing operation through one pipe column is achieved, the offshore fracturing operation time efficiency is greatly improved, safety and high efficiency are achieved, the construction cost is reduced, the fracturing fluid flowback time is shortened, damage to a reservoir is reduced, and the fracturing operation effect is improved.

Description

Technical Field

[0001] The utility model belongs to the field of petroleum mining equipment, and in particular relates to a large-diameter sand-filled multi-layer production and injection enhancement process pipe column suitable for offshore oil fields. Background Art

[0002] China National Offshore Oil Corporation has large-scale low-permeability reservoirs with low utilization rates, and is in urgent need of effective development methods. When developing such reservoirs, fracturing technology is often used to obtain industrial oil flow to achieve economic and effective development. Therefore, fracturing tools are crucial to the development of my country's offshore low-permeability reservoirs.

[0003] Fracturing technology is to inject fluid into the formation to fracture the formation and form an efficient flow channel connecting the formation and the wellbore, converting the conventional radial flow into a bilinear flow, reducing the production pressure difference, expanding the oil leakage range, and achieving the purpose of transforming the reservoir and increasing production capacity.

[0004] Due to the high construction cost and great operation risk of offshore platforms, if the fracturing operation adopts a single-trip single-layer operation mode, the operation time will be long, resulting in high cost and low construction efficiency. The fracturing fluid is not returned in time, causing various problems such as reservoir damage, which reduces the fracturing effect. Utility Model Content

[0005] The utility model is proposed to solve the problems of low efficiency, high cost and long flowback time in low-permeability fracturing operations on existing offshore platforms, and aims to provide a large-diameter sand-filled multi-layer production and injection enhancement process string suitable for offshore oil fields.

[0006] The utility model is realized by the following technical solutions:

[0007] A large-diameter sand-filled multi-layer production and injection enhancement process string suitable for offshore oil fields, comprising an oil pipe, a depth-calibration short joint, a shear joint, a differential pressure well-washing valve, a gravity-set packer and a guide shoe connected in sequence from top to bottom; the gravity-set packer and the guide shoe are connected via an oil pipe short joint; the depth-calibration short joint and the shear joint are connected via an R2 oil pipe; and the oil pipe is connected to a wellhead.

[0008] In the above technical solution, the gravity-set packer is arranged at a position 6 meters above the first fracturing operation section.

[0009] In the above technical solution, the shear joint has two release modes: lifting shearing and throwing shearing.

[0010] In the above technical solution, the differential pressure well flushing valve is a differential pressure opening structure.

[0011] In the above technical solution, the gravity-set packer is a non-rotating gravity-set mechanical packer.

[0012] In the above technical solution, the guide shoe is a beveled guide shoe.

[0013] The beneficial effects of the utility model are:

[0014] The utility model provides a large-diameter sand-filled multi-layer production and injection enhancement process string suitable for offshore oil fields. The large inner diameter design enables sand filling through the process string; a gravity-set packer that can be repeatedly sealed and unsealed is adopted to achieve a one-trip multi-layer dragging fracturing operation; matched reverse circulation well washing and hand-dropping tools make the operation safer; the utility model can achieve layer-by-layer fracturing from bottom to top, so as to achieve the purpose of multi-layer fracturing operation in one trip of the string, greatly improve the timeliness of offshore fracturing operations, be safe and efficient, reduce construction costs, reduce the time for fracturing fluid return, reduce damage to reservoirs, and improve the effect of fracturing operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of the utility model.

[0016] in:

[0017] 1. Tubing; 2. Depth-calibration nipple; 3. Shear joint; 4. Pressure differential well-washing valve; 5. Gravity-set packer; 6. Guide shoe; B. First fracturing stage; A. Second fracturing stage.

[0018] For ordinary technicians in this field, other relevant drawings can be obtained based on the above drawings without any creative work. DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to better understand the technical solution of the present utility model, the technical solution of the present utility model will be further described below in conjunction with the accompanying drawings and through specific implementation methods.

[0020] like Figure 1 As shown, a large-diameter sand-filled multi-layer production and injection enhancement process string suitable for offshore oil fields comprises an oil pipe 1, a depth calibration nipple 2, a shear joint 3, a differential pressure well flushing valve 4, a gravity-set packer 5 and a guide shoe 6 which are threadedly connected in sequence from top to bottom;

[0021] The gravity-set packer 5 and the guide shoe 6 are connected via a tubing nipple;

[0022] The depth calibration nipple 2 and the shear joint 3 are connected via the R2 oil pipe;

[0023] The oil pipe 1 is connected to the wellhead;

[0024] The gravity-set packer 5 is arranged about 6 meters above the first fracturing operation section, and the setting position avoids the casing collar;

[0025] The depth calibration nipple 2 is used to calibrate the depth of the fracturing string, so as to accurately locate the position of the gravity-set packer 5;

[0026] The shear joint 3 has two release modes: lifting shear and ball shear. The shear joint 3 can realize the release of the fracturing pipe string when sand is stuck. The shear joint 3 is a conventional commercial product in this field.

[0027] The differential pressure well-washing valve 4 is a differential pressure opening structure. When the annular pressure is greater than the pressure in the oil pipe, it can be opened to connect the annular space with the oil pipe. The differential pressure well-washing valve 4 is opened by differential pressure. If sand blockage or sand jam occurs, reverse circulation well-washing can be immediately realized to timely remove sand in the oil pipe or on the upper part of the gravity-sealed packer. The differential pressure well-washing valve 4 is a conventional commercial product in the field.

[0028] The gravity-set packer 5 is a non-rotating gravity-set mechanical packer, which can achieve repeated setting and unsealing. The gravity-set packer 5 has a hydraulic anchor, which can anchor the fracturing string during the fracturing operation to prevent the string from moving. The gravity-set packer 5 is a conventional commercial product in this field.

[0029] The guide shoe 6 is an oblique guide shoe, which is convenient for lowering the fracturing string; in this embodiment, the length of the tubing short section between the guide shoe 6 and the gravity-set packer 5 is 3 meters. The guide shoe 6 is a conventional oblique guide shoe commercially available in the art.

[0030] The use of the utility model:

[0031] (I) Fracturing string is lowered into the wellhead

[0032] The guide shoe, gravity-set packer, differential pressure well-washing valve, shear joint, depth-calibration nipple, and tubing are lowered into the wellhead from bottom to top;

[0033] (II) Gravity-set packer:

[0034] After the fracturing string is lowered into place, the string is seated at the wellhead, and the depth is calibrated by cable to check the depth position of the depth calibration nipple 2, so as to accurately determine the setting depth position of the gravity setting packer 5.

[0035] (III) According to the depth calibration result, pipes are arranged, the pipe string is lifted up to change the track, and the fracturing string is lowered to set the gravity-set packer. The gravity-set packer is set by pressing the pipe string down by 15 tons, and the suspension force of the gravity-set packer is tested;

[0036] (IV) Fracturing operations:

[0037] Keep the pipe string under 15T pressure and carry out the first stage of fracturing operation according to the fracturing pumping procedure. At this time, the hydraulic anchor of the gravity-sealed packer 5 will bite the casing to prevent the pipe string from moving;

[0038] (V) Sand filling operation

[0039] After the first stage of fracturing operation is completed, the pipe string is lifted, the gravity-set packer 5 is unsealed, and the pipe string is lifted to a safe position. Sand filling operation is performed in the oil pipe through the fracturing process pipe string. The sand filling depth needs to cover the first stage of fracturing by at least 5 meters.

[0040] (VI) lifting the fracturing string to the designed setting position of the second fracturing stage, setting the gravity setting packer 5, and performing fracturing construction according to the second stage fracturing pumping procedure; completing the fracturing operation layer by layer from bottom to top;

[0041] (VII) After all the fracturing operations are completed, the upper fracturing string is pulled out, and the sand flushing string is lowered to perform sand flushing operations, so that all the ceramsite in the wellbore is circulated out of the wellbore;

[0042] (VIII) Plan for complex situations:

[0043] If sand plugging or sand jam occurs during fracturing, the annulus is pressurized to 15 MPa, and the differential pressure well-washing valve 4 is opened for reverse circulation well-washing. If the tubing string cannot be pulled out, a ball is dropped into the tubing 1 to shear the shear joint 3 to achieve emergency release of the tubing string.

[0044] If after the fracturing operation is completed, if there is resistance when lifting the tubing string, the annulus is pressurized and the circulating well washing valve is opened to carry out the wellbore back-circulation well washing to release the stuck fracturing string. If it continues to be stuck, the fracturing string is lifted, the shear joint is sheared, the tubing string above the gravity-sealed packer is lifted out of the wellbore, and the remaining tubing string in the wellbore is salvaged.

[0045] In the description of the present utility model, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present utility model, unless otherwise specified, "multiple" means two or more.

[0046] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0047] The applicant declares that the above is only a specific implementation method of the present utility model, but the protection scope of the present utility model is not limited thereto. The technicians in the relevant technical field should understand that any changes or substitutions that can be easily thought of by the technicians in the relevant technical field within the technical scope disclosed in the present utility model fall within the protection scope and disclosure scope of the present utility model.

Claims

1. A large-diameter sand-filled multi-layer production and injection enhancement process string suitable for offshore oil fields, characterized by: The invention comprises an oil pipe (1), a depth adjustment short joint (2), a shear joint (3), a differential pressure well flushing valve (4), a gravity-set packer (5) and a guide shoe (6) which are connected in sequence from top to bottom; the gravity-set packer (5) and the guide shoe (6) are connected via an oil pipe short joint; the depth adjustment short joint (2) and the shear joint (3) are connected via an R2 oil pipe; and the oil pipe (1) is connected to a wellhead.

2. The large-diameter sand-filled multi-layer production and injection enhancement process string suitable for offshore oil fields according to claim 1 is characterized in that: The gravity-set packer (5) is arranged at a position 6 meters above the first fracturing operation section.

3. The large-diameter sand-filled multi-layer production and injection enhancement process string suitable for offshore oil fields according to claim 1 is characterized in that: The shear joint (3) has two release modes: lifting shearing and ball throwing shearing.

4. The large-diameter sand-filled multi-layer production and injection enhancement process string suitable for offshore oil fields according to claim 1, characterized in that: The differential pressure well flushing valve (4) is a differential pressure opening structure.

5. The large-diameter sand-filled multi-layer production and injection enhancement process string suitable for offshore oil fields according to claim 1 is characterized in that: The gravity-set packer (5) is a non-rotating gravity-set mechanical packer.

6. The large-diameter sand-filled multi-layer production and injection enhancement process string suitable for offshore oil fields according to claim 1, characterized in that: The guide shoe (6) is a beveled guide shoe.

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