CN107724995A - A kind of mechanical-set half dissolving bridging device and its fracturing process - Google Patents

Abstract

A mechanically set semi-dissolved bridge plug device and its fracturing method, including an insoluble central pipe part and a dissolvable outer layer part. The mechanically set semi-dissolved bridge plug device can be run alone or form a pipe string When the semi-dissolved bridge plug that can be mechanically set is set at the predetermined position, the pipe string is upper first, and then the rotating pipe string is lowered. After the semi-dissolved bridge plug is completely set, sand fracturing is performed, and the fracturing is completed. Finally, drop in dissolving agent to dissolve the outer layer of the bridge plug, and only keep the central pipe part. The inner and outer diameters of the central pipe and the oil pipe are the same. After the operation is completed, the central pipe is directly used as the oil pipe for oil (gas) production. There is a restriction that the soluble bridge plug must be lowered into a special setting tool, and the set fracturing is completed in one trip. After the fracturing is completed, the outer layer of the bridge plug is dissolved, and the center pipe of the bridge plug is directly used as a tubing for oil (gas) production .

Description

A mechanically set semi-dissolving bridge plug device and its fracturing method

technical field

The invention relates to the technical field of oil and gas field development, in particular to a mechanically set semi-dissolving bridge plug device and a fracturing method thereof.

Background technique

Fracturing is an important link in the development of oil and gas fields. At present, conventional oil and gas field development fracturing strings mainly include mechanical staged fracturing, hydraulic jet fracturing and pumping bridge plug fracturing. Among them, the pumped bridge plug is mainly used in the development of unconventional oil and gas fields, such as oil and gas exploitation in tight shale formations. The early pumping bridge plugs were mainly fast-drilling composite bridge plugs. The process was to pump the composite bridge plugs to the lower end of the target layer first, and then drill and mill the composite bridge plugs after fracturing was completed. This method requires drilling and milling pipe string once, and it needs to flow back the debris left at the bottom of the well. When the debris is flowed back, some large debris often flow back out of the wellhead, causing these debris to remain at the bottom of the well . In order to solve this problem, a dissolvable bridge plug was developed. After the fracturing was completed, a dissolving agent was dropped to dissolve the bridge plug. This kind of bridge plug eliminates the process of drilling and milling the bridge plug, flowback of debris, etc., which greatly reduces labor costs and reduces the risk of debris to the wellbore. However, whether it is a fast-drilling composite bridge plug or a soluble bridge plug, the cable is used to send the bridge plug into the target layer, and then it is lowered into the oil and gas production string again, which still causes an increase in labor costs.

Contents of the invention

Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a mechanically set semi-dissolving bridge plug device and a fracturing method thereof, which can be used to complete fracturing and oil production by completing a trip of the pipe string with the mechanically set semi-dissolving bridge plug (gas) and other processes.

In order to achieve the above object, the technical solution of the present invention is:

A mechanically set semi-dissolvable bridge plug device, comprising an insoluble central tube 1, on which a dissolvable setting ring 3, a setting outer cylinder 4, slips 5, and a cone 6 are sequentially sleeved , gear ring 7, side rubber tube 9, middle rubber tube 10, inner sleeve 11, support ring 12, friction block outer cylinder 13; the gear ring 7 is between the cone 6 and the central tube 1, and the inner side of the gear ring 7 is stuck in the center On the tube 1, the outer side of the retaining ring 7 is embedded in the cone 6, the setting pin 8 is fastened on the center tube 1 through the cone 6, and the sealing ball 2 is placed in the center tube. The central tube 1 is provided with lugs 14 , and the lugs 14 are slidably connected with the J-shaped groove of the outer cylinder 13 of the friction block.

The setting ring 3 is a "C-shaped ring" with a variable diameter, wherein the outer side 3-1 of the setting ring 3 is composed of a "large upper and lower small" ring body, and the inner side 3-2 of the setting ring 3 is a The conical surface of "upper big and lower small" is formed.

The hardness of the material selected for the middle rubber tube 10, the side rubber tube 9, the inner sleeve 11 and the support ring 12 increases sequentially.

A fracturing method for a mechanically set semi-dissolving bridge plug device, comprising the following steps:

1 Tubing connection tool goes down to the designed position

2. Set and seal the semi-dissolved bridge plug; lift up the pipe string for more than 1 meter, and lift the lug of the center pipe 1 to position A. Rotate clockwise for more than three times, lower the lug of center tube 1 to position B while rotating, cut off the setting pin 8, and then rotate and set until the side rubber tube 9 and middle rubber tube 10 are completely set, and the slips 5 fully open;

3 Fracturing the target layer: add sand from the casing, and perform fracturing sequentially from top to bottom.

(4) Dissolving and semi-dissolving the outer layer of the bridge plug: the setting ring fixes the setting state so that the rubber tube cannot be unsealed. After the first layer of fracturing is completed, a dissolving agent is dropped to dissolve the outside of the semi-dissolved bridge plug, leaving only the part of the inner layer that is the same as the inner and outer diameters of the tubing.

(5) Fracturing the second interval: Repeat steps (3) and (4) until all target intervals are fractured.

(6) After the fracturing is completed, the blowout and swabbing process is carried out, and gas production is carried out.

The present invention can be run alone, and can also be composed of string strings. When the predetermined position of the present invention is available, the pipe string is lifted up first, and then the rotating pipe string is lowered. After the present invention is completely set, sand fracturing is carried out. After the fracturing is completed, a dissolving agent is dropped to dissolve the outer layer of the bridge plug, leaving only the central tube. The inner and outer diameters of the center pipe and the oil pipe are the same. After the operation is completed, the center pipe is directly used as the oil pipe for oil (gas) recovery. The invention can avoid the link of the oil pipe during the gas recovery of the traditional soluble bridge plug, and saves the production cost. The setting method of the present invention can effectively avoid phenomena such as failure of normal construction due to incomplete setting.

Description of drawings

Figure 1 is a schematic diagram of the overall structure of the device.

Figure 2 is a schematic diagram of the J-shaped groove of the friction outer cylinder.

Fig. 3 is a schematic diagram of a setting ring; Fig. 3A is a side view, and Fig. 3B is a front view.

Figure 4 is a schematic diagram of the combination of the inner sleeve and the support ring.

Figure 5 is a schematic diagram of the device after the soluble part is dissolved.

Fig. 6 is a schematic diagram of the initial state of the fracturing string composed of the device when it goes downhole.

Fig. 7 is a schematic diagram of the fracturing string composed of the device after the first bridge plug is dissolved.

Fig. 8 is a schematic diagram after the second bridge plug of the fracturing string composed of the device is dissolved.

Figure 9 is a schematic diagram of the combined connection of the semi-dissolved bridge plug at the bottom of the device and the negative pressure sand dredging tool.

In the figure: 1. Central tube, 2. Sealing ball, 3. Setting ring, 4. Setting outer cylinder, 5. Slips, 6. Cone, 7. Stop ring, 8. Setting pin, 9. Side Rubber cartridge, 10, middle rubber cartridge, 11, inner sleeve, 12, support ring, 13, friction block outer cylinder, 14, lug.

detailed description

The present invention will be discussed in detail below in conjunction with the accompanying drawings.

Referring to Figure 1, a mechanically set semi-dissolving bridge plug device includes an insoluble central tube 1, referring to Figure 5, a dissolvable setting ring 3 and a setting outer cylinder 4 are sequentially sleeved on the central tube 1 , slips 5, cone 6, gear ring 7, side rubber tube 9, middle rubber tube 10, inner sleeve 11, support ring 12, friction block outer cylinder 13; gear ring 7 is between cone 6 and center tube 1 The inner side of the retaining ring 7 is stuck on the central tube 1, the outer side of the retaining ring 7 is embedded in the cone 6, the setting pin 8 is fastened on the central tube 1 through the cone 6, and the sealing ball 2 is placed in the central tube. Referring to FIG. 2 , lugs 14 are provided on the central tube 1 , and the lugs 14 are slidably connected to the J-shaped grooves of the outer cylinder 13 of the friction block.

Referring to Fig. 3A and Fig. 3B, the setting ring 3 is a "C-shaped ring" with a variable diameter, wherein the outer side 3-1 of the setting ring 3 is composed of a ring body with "large upper part and smaller lower part". 3. The inner side 3-2 is constituted by a conical surface with "large upper part and smaller lower part". When the present invention is setting, the setting ring 3 is gradually opened; when the setting is completed, it can just be inserted into the setting outer cylinder 4 .

Referring to FIG. 4 , the hardness of the materials selected for the middle rubber tube 10 , the side rubber tube 9 , the inner sleeve 11 and the support ring 12 increases sequentially, so that the auxiliary sealing side rubber tubes can be effectively protected from being torn.

Referring to Fig. 6-Fig. 9, the working principle of this device is: the lug 16 of the center pipe 1 slides on the J-shaped groove of the friction block outer cylinder 13 by the rotation of the oil pipe, so that the friction block outer cylinder 13 pushes the cone 6 to move, and the seat is cut off. After sealing 8, push the slips 5 to open, so that the middle rubber tube 10 is completely close to the inside of the wellbore, and the side rubber tube 9, support ring 12, and inner sleeve 11 mainly play an auxiliary sealing role; when the setting is complete, the setting ring 3 Expand in the setting outer cylinder 4 and be stuck on the central pipe 1. The support ring 12 and the inner sleeve 11 together form a traffic outburst prevention combination. When the conventional rubber cartridge is set and sealed, the rubber cartridge is often torn under the force of lowering, resulting in the failure of the rubber cartridge. The failure of the rubber cartridge will affect the entire fracturing effect. The combined effect of the support ring 12 and the inner cover 11 is to protect the rubber tube from tearing, and the hardness of the materials selected for the rubber tube, the inner cover, and the support ring increases sequentially, so that the rubber tube can be effectively protected from being torn.

A fracturing method for a mechanically set semi-dissolved bridge plug device, referring to Figures 6-9, comprising the following steps:

1. The tubing connection tool is lowered to the designed position;

2. Set and seal the semi-dissolved bridge plug; lift up the string for more than 1 meter, lift the lug of the central tube 1 to position A, refer to Figure 2, rotate clockwise for more than three times, and lower the lug of the central tube 1 while rotating When reaching position B, cut off the setting pin 8, and then keep rotating the setting until the side rubber tube 9 and the middle rubber tube 10 are completely set, and the slips 5 are fully opened;

(3) Fracturing target layer: add sand from the casing, and then fracture from top to bottom.

(4) Dissolving and semi-dissolving the outer layer of the bridge plug: the setting ring fixes the setting state so that the rubber tube cannot be unsealed. After the first layer of fracturing is completed, a dissolving agent is dropped to dissolve the outside of the semi-dissolved bridge plug, leaving only the part of the inner layer that is the same as the inner and outer diameters of the tubing.

(5) Fracturing the second interval: Repeat steps (3) and (4) until all target intervals are fractured.

(6) After the fracturing is completed, the blowout and swabbing process is carried out, and gas production is carried out.

Claims (4)

1. a semi-dissolution bridge plug device of mechanical setting, is characterized in that, comprises insoluble central pipe (1), is socketed with dissolvable setting ring (3), seated on central pipe (1) successively Sealing outer cylinder (4), slips (5), cone (6), retaining ring (7), side rubber cylinder (9), middle rubber cylinder (10), inner sleeve (11), support ring (12) , friction block outer cylinder (13); the retaining ring (7) is between the cone (6) and the central tube (1), the inner side of the retaining ring (7) is stuck on the central pipe (1), and the outer retaining ring (7) Embedded in the cone (6), the setting pin (8) is fastened on the central tube (1) through the cone (6), and the sealing ball (2) is placed in the central tube; the central tube (1) is provided with lugs (14), the lug (14) is slidingly connected with the J-shaped groove of the friction block outer cylinder (13). 2. The semi-dissolving bridge plug device of a kind of mechanical setting according to claim 1, characterized in that, the described setting ring (3) is a "C-shaped ring" with a reduced diameter, wherein the setting ring ( 3) The outer side (3-1) is constituted by a "large top and small bottom" ring body, and the inner side (3-2) of the setting ring (3) is constituted by a cone surface with "large top and small bottom". 3. The semi-dissolving bridge plug device of a kind of mechanical setting according to claim 1, characterized in that, the middle rubber tube (10), the side rubber tube (9), the inner sleeve (11) and the support ring (12) The hardness of the selected material increases sequentially. 4. A method for fracturing a mechanically set semi-dissolving bridge plug device, comprising the following steps: (1) The tubing connection tool is lowered to the designed position; (2) Set and seal the semi-dissolved bridge plug; lift the pipe column for more than 1 meter, and lift the lug of the central pipe (1) to position A; rotate clockwise for more than three weeks, and rotate the lug of the central pipe (1) Lower the side to position B, cut off the setting pin (8), and then keep rotating the setting until the side rubber tube (9) and the middle rubber tube (10) are completely set, and the slips (5) are fully opened; (3) Fracturing target layer: add sand from the casing, and then fracturing sequentially from top to bottom; (4) Dissolving the outer layer of the semi-dissolved bridge plug: the setting ring fixes the setting state so that the rubber tube cannot be unsealed; Keep the part of the inner layer that is the same as the inner and outer diameters of the tubing; (5) Fracturing the second interval: repeat steps (3), (4) until all the target intervals are fractured; (6) After the fracturing is completed, the blowout and swabbing process is carried out, and gas production is carried out.