Multilayer-section fracturing technique pipe column and construction method thereof

Abstract

The invention discloses a multilayer-section fracturing technique pipe column comprising an oil pipe, a safe releasing sub, an ejector, a ball seat, an oscillator, a sand-oil blender, an oil pipe, a packer and a blank plug which are sequentially connected from top to bottom. A construction method of the multilayer-section fracturing technique pipe column comprises the following steps: putting the pipe column into a well, aligning the ejector with a target segment, feeding a seal ball through an opening of the well, positioning the seal ball on the ball seat so as to seal a liquid flow passage below the ball seat immediately, and performing abrasive perforating by use of the ejector; after abrasive perforating is finished, repeatedly leaching out the seal ball, lifting up the pipe column to seal the packer, injecting sand-laden fluid with a high sand ratio into the oil pipe in a low-displacement manner, and annularly ejecting pure liquid into an oil sleeve; performing a repeated 'lifting-descending' annular displacement step so as to form pulse cycles so as to control down-hole sand concentration in real time, so that temporary blockage of a proppant in a seam is realized, the static pressure in the seam is instantaneously improved, the crack complexity is further improved, and the purpose of improving the well yield through complicated seam-net fracturing is achieved; and after the construction is finished, lifting the pipe column to a next target segment, and repeating the construction process.

Description

technical field

[0001] The invention relates to the technical field of multi-layer and multi-stage fracturing in oil and gas fields, and relates to a multi-layer (stage) fracturing process string and method for implementing complex fracture network fracturing in low-permeability oil and gas fields to improve single well production. Background technique

[0002] In recent years, studies at home and abroad have shown that increasing the complexity of fractures during fracturing operations can effectively increase the production of single wells in low-permeability oil and gas fields. At present, volume fracturing is the main technical method for constructing complex fracture networks. In the process of hydraulic fracturing, large displacement, large sand volume, large liquid volume, and low sand ratio are used to inject natural fractures and generate shear in brittle rocks. Cutting and sliding, forming a fracture network in which natural fractures and artificial fractures are i...

Examples

Embodiment 1

[0035] Such as figure 1 As shown, a multi-stage fracturing process string includes an upper oil pipe 1, a safety hand 2, an injector 3, a ball seat 4, an oscillator 5, a sand mixer 6, and a lower oil pipe connected sequentially from top to bottom. Tubing 7, packer 8 and plug 9.

[0036] In this embodiment, the upper oil pipe 1, the hand 2, the injector 3, the ball seat 4, the oscillator 5, the sand mixer 6, the lower oil pipe 7, the packer 8 and the plug 9 are sequentially arranged from top to bottom The connected pipe string is lowered into the predetermined reconstruction position in the well; the injector hole 10 is aimed at the target section; the sealing ball 11 corresponding to the ball seat 4 at the lower end of the injector 3 is put in from the wellhead, and when the sealing ball 11 is located on the injector 3 When the ball seat 4 at the lower end is on, the liquid flow channel below the ball seat is blocked; sandblasting and perforation are carried out through the h...

Embodiment 2

[0038] On the basis of Example 1, the injector 3 is provided with holes 10 ; the sand mixer 6 is provided with pressure-guiding sandblasting holes 15 . The multi-stage fracturing process string also includes a sealing ball 11, and the sealing ball 11 is put into the ball seat 4 and returned to the ball seat 4 to realize the opening and closing of the channel of the sand mixer 6.

[0039] The multi-stage fracturing process string described in the present invention is an integrated string for sandblasting and perforating fracturing. The liquid outlet channel is changed by casting sealing balls, and different liquid outlet channels are used in different construction stages: sandblasting and perforating In the first stage, a hydraulic sand blaster is used for sand blasting and perforation; in the fracturing stage, a bottom hole sand mixer is used to quickly and evenly mix the high-sand ratio sand-carrying fluid injected into the tubing with the liquid injected into the annulus form...

Embodiment 3

[0041] On the basis of Embodiment 1, the oscillator 5 is a Helmholtz oscillator, which consists of an upstream nozzle 12 , a vibrating chamber 13 and a downstream nozzle 14 sequentially connected from top to bottom. When the fluid flows through the vibrating chamber 13, hydraulic pulsation is generated under the modulation of the vibrating chamber 13, so the water flow ejected from the nozzle forms a fluctuating pressure with large and small pressures. Collision with the downstream collision wall can generate pressure disturbance to form pulse vibration, and the fluid forms a self-excited pulse jet with strong vibration. The invention uses the self-excited pulse vibration principle generated by the oscillator and the swirl mixing principle of the sand mixer to fully and uniformly mix the sand-carrying liquid and the pure liquid in the annular space in a short period of time, which can further improve the sand mixing effect and achieve complex fracture network pressure. The pur...

technical field

[0001] The invention relates to the technical field of multi-layer and multi-stage fracturing in oil and gas fields, and relates to a multi-layer (stage) fracturing process string and method for implementing complex fracture network fracturing in low-permeability oil and gas fields to improve single well production. Background technique

[0002] In recent years, studies at home and abroad have shown that increasing the complexity of fractures during fracturing operations can effectively increase the production of single wells in low-permeability oil and gas fields. At present, volume fracturing is the main technical method for constructing complex fracture networks. In the process of hydraulic fracturing, large displacement, large sand volume, large liquid volume, and low sand ratio are used to inject natural fractures and generate shear in brittle rocks. Cutting and sliding, forming a fracture network in which natural fractures and artificial fractures are i...

Examples

Embodiment 1

[0035] Such as figure 1 As shown, a multi-stage fracturing process string includes an upper oil pipe 1, a safety hand 2, an injector 3, a ball seat 4, an oscillator 5, a sand mixer 6, and a lower oil pipe connected sequentially from top to bottom. Tubing 7, packer 8 and plug 9.

[0036] In this embodiment, the upper oil pipe 1, the hand 2, the injector 3, the ball seat 4, the oscillator 5, the sand mixer 6, the lower oil pipe 7, the packer 8 and the plug 9 are sequentially arranged from top to bottom The connected pipe string is lowered into the predetermined reconstruction position in the well; the injector hole 10 is aimed at the target section; the sealing ball 11 corresponding to the ball seat 4 at the lower end of the injector 3 is put in from the wellhead, and when the sealing ball 11 is located on the injector 3 When the ball seat 4 at the lower end is on, the liquid flow channel below the ball seat is blocked; sandblasting and perforation are carried out through the h...

Embodiment 2

[0038] On the basis of Example 1, the injector 3 is provided with holes 10 ; the sand mixer 6 is provided with pressure-guiding sandblasting holes 15 . The multi-stage fracturing process string also includes a sealing ball 11, and the sealing ball 11 is put into the ball seat 4 and returned to the ball seat 4 to realize the opening and closing of the channel of the sand mixer 6.

[0039] The multi-stage fracturing process string described in the present invention is an integrated string for sandblasting and perforating fracturing. The liquid outlet channel is changed by casting sealing balls, and different liquid outlet channels are used in different construction stages: sandblasting and perforating In the first stage, a hydraulic sand blaster is used for sand blasting and perforation; in the fracturing stage, a bottom hole sand mixer is used to quickly and evenly mix the high-sand ratio sand-carrying fluid injected into the tubing with the liquid injected into the annulus form...

Embodiment 3

[0041] On the basis of Embodiment 1, the oscillator 5 is a Helmholtz oscillator, which consists of an upstream nozzle 12 , a vibrating chamber 13 and a downstream nozzle 14 sequentially connected from top to bottom. When the fluid flows through the vibrating chamber 13, hydraulic pulsation is generated under the modulation of the vibrating chamber 13, so the water flow ejected from the nozzle forms a fluctuating pressure with large and small pressures. Collision with the downstream collision wall can generate pressure disturbance to form pulse vibration, and the fluid forms a self-excited pulse jet with strong vibration. The invention uses the self-excited pulse vibration principle generated by the oscillator and the swirl mixing principle of the sand mixer to fully and uniformly mix the sand-carrying liquid and the pure liquid in the annular space in a short period of time, which can further improve the sand mixing effect and achieve complex fracture network pressure. The pur...

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