Rock stratum fracture net fracturing device based on variable-viscosity fracturing fluid

Abstract

The utility model belongs to the technical field of unconventional oil and gas development, and particularly relates to a rock stratum fracture net fracturing device based on variable-viscosity fracturing fluid. Comprising a stirring tank body, a water injection pipe, a liquid reagent conveying pipe and a solid reagent conveying pipe are arranged on the stirring tank body, a funnel section is arranged on the lower portion of the stirring tank body and connected with an output pipe, a stirring rod is rotationally arranged in the stirring tank body, and a driving assembly used for driving the stirring rod to rotate is arranged on the stirring tank body; the upper part of the water injection pipe is connected with a water source through a water injection pump, and the water injection pump is controlled by a computer; the liquid reagent conveying pipe is used for conveying a chemical reagent required for preparing the fracturing fluid into the stirring tank body; the output pipe is used for outputting the prepared fracturing fluid in the stirring tank body; and the solid reagent conveying pipe is connected with a blast feeding assembly. The utility model provides a novel device which can inject fracturing fluid with different viscosities more conveniently and efficiently to form a crisscrossed rock stratum seam net.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the development technical field of unconventional oil and gas, specifically is a kind of rock formation fracture network fracturing device based on variable viscosity fracturing fluid. BACKGROUND

[0002] In recent years, coal mine underground uses clear water as fracturing fluid and obtains certain coal seam permeability improvement effect, but clear water viscosity is low, filtration rate is fast, and clear water consumption is large in fracturing process, so high viscosity fracturing fluid using viscoelastic surfactant as main agent is used to improve fracturing efficiency.Single viscosity fracturing fluid is pressed into coal rock and can only form one kind of fracture, assuming that fracture height is fixed, with the increase of fracturing fluid viscosity, fracturing fracture length reduces, and width continuously increases, which is not conducive to expanding the influence range of fracturing fluid, and fracture form is related to fracturing fluid injection rate.Therefore, the injection effect of traditional fracturing fluid cannot achieve good coal seam permeability improvement effect, and consumption is large and cost is high.Therefore, a new fracturing fluid preparation device and method capable of changing viscosity are urgently needed to realize rock formation fracture network. SUMMARY

[0003] The utility model discloses to solve the problem that single viscosity fracturing fluid cannot achieve good coal seam permeability improvement effect, provide a kind of rock formation fracture network fracturing device based on variable viscosity fracturing fluid.

[0004] The utility model discloses the following technical scheme: a kind of rock formation fracture network fracturing device based on variable viscosity fracturing fluid, including:

[0005] Mixing tank body is set up water injection pipe, liquid reagent delivery pipe and solid reagent delivery pipe on mixing tank body, funnel section connection output pipe is set in the lower part of mixing tank body, rotatingly set with stirring rod in mixing tank body, and driving assembly for driving stirring rod rotation is set on mixing tank body;

[0006] The upper portion of water injection pipe is connected with water source by water injection pump, and the water injection pump is controlled by computer, and water injection pipe transports clear water into mixing tank body;

[0007] The liquid reagent delivery pipe transports the chemical reagent required for preparing fracturing fluid into mixing tank body;

[0008] The output pipe outputs the prepared fracturing fluid in mixing tank body, and is used for rock fracturing fracture formation;

[0009] Blowing material adding assembly is connected on the solid reagent delivery pipe, for material adding.

[0010] In some embodiments, viscosity sensor is arranged inside output pipe, and viscosity sensor transmits measured viscosity data to computer through circuit.

[0011] In some embodiments, a scraper is arranged to rotate in the stirring tank body, the scraper abuts against the sidewall of the funnel section at the lower part of the stirring tank body, and the scraper is connected to the driving assembly through a connecting member.

[0012] In some embodiments, the driving assembly comprises a rotating shaft arranged to rotate on the stirring tank body, the rotating line of the rotating shaft is parallel to the central axis of the stirring tank body, a motor B is arranged on the stirring tank body to drive the rotating shaft to rotate, and a stirring rod and a connecting member for connecting the scraper are arranged on the rotating shaft.

[0013] In some embodiments, the connecting member is a plurality of telescopic rods arranged on the rotating shaft, one end of each telescopic rod is connected to the rotating shaft, and the other end of each telescopic rod is connected to the scraper.

[0014] In some embodiments, the air-blowing and material-adding assembly comprises an air-blowing assembly and a material-adding assembly, the air-blowing assembly and the material-adding assembly are connected to a computer, the material-adding assembly comprises a material-adding tank and a material-adding valve, the material-adding tank is connected to a solid reagent conveying pipe, and the material-adding valve is arranged at the connection position; and the air-blowing assembly is connected to the solid reagent conveying pipe.

[0015] In some embodiments, the air-blowing assembly comprises a funnel wide-mouth section, a front cover, a fan blade, and a bracket, the fan blade is controlled by a motor A, the motor A is attached to the bracket and is connected to a power supply through a power supply lead, and the bracket is connected to the funnel wide-mouth section through threaded nails.

[0016] Compared with the prior art, the device has the following beneficial effects:

[0017] The device provided by the present application can inject fracturing fluid with different viscosities more conveniently and efficiently, and form a crisscross rock seam network. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 A rock seam network fracturing device based on variable-viscosity fracturing fluid is provided in the present application.

[0019] Figure 2 An air-blowing assembly is provided in the present application.

[0020] Figure 3 A material-adding assembly is provided in the present application.

[0021] Figure 4 A main trunk cross-sectional view of a rock seam network fracturing device based on variable-viscosity fracturing fluid is provided in the present application.

[0022] Figure 5 A telescopic rod structure is provided in the present application.

[0023] Figure 6A schematic diagram of a method for using a rock formation fracture network fracturing device based on a variable viscosity fracturing fluid provided by the present invention;

[0024] In the figure, 1-mixing tank body, 2-water injection pipe, 3-liquid reagent delivery pipe, 4-output pipe, 5-solid reagent delivery pipe, 6-water injection pump, 7-air blasting and feeding assembly, 7.1-feeding tank, 7.2-feeding valve, 7.3-funnel wide mouth section, 7.4-front cover, 7.5-fan blade, 7.6-threaded nail, 7.7-bracket, 7.8-motor A, 7.9-power lead, 8-viscosity sensor, 9-motor B, 10-computer, 11-rotating shaft, 12-stirring rod, 13-scraper, 14-telescopic rod, 15-fracturing hole. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments; based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0026] The technical solutions adopted in this utility model are as follows:

[0027] First, drill a fracturing hole and a fracturing well in the rock formation and place the device in the appropriate location. This utility model uses coal seam fracturing as an example. The fracturing fluid formula listed is suitable for coal seams. If this device and method are used to fracture other rock formations (such as oil and gas formations, shale, etc.), the fracturing fluid formula must be adjusted.

[0028] like Figure 1 As shown, a rock formation fracture network fracturing device based on variable viscosity fracturing fluid includes a stirring tank body 1, on which a water injection pipe 2, a liquid reagent delivery pipe 3 and a solid reagent delivery pipe 5 are provided, a funnel section is provided at the lower part of the stirring tank body 1 to connect to the output pipe 4, a stirring rod 12 is rotatably provided in the stirring tank body 1, the stirring rod 12 is perpendicular to the side wall of the stirring tank body 1, a scraper 13 is rotatably provided in the stirring tank body 1, the scraper 13 is abutted against the side wall of the funnel section at the lower part of the stirring tank body 1, and a driving assembly for driving the stirring rod 12 and the scraper 13 to rotate simultaneously is provided on the stirring tank body 1.

[0029] Furthermore, it also includes a water injection pipe 2, the upper part of the water injection pipe 2 is connected to the water source through a water injection pump 6, the water injection pump 6 is controlled by a computer 10, and the water injection pipe 2 transports clean water into the mixing tank body 1; the liquid reagent delivery pipe 3 transports the chemical reagents required for preparing the fracturing fluid into the mixing tank body 1; the output pipe 4 outputs the prepared fracturing fluid in the mixing tank body 1 for rock formation fracturing and seaming; the viscosity sensor 8 transmits the measured viscosity data to the computer 10 through the line.

[0030] As shown in Figure 2 , the solid reagent conveying pipe 5 is connected with the air blowing and feeding assembly 7, the air blowing assembly is connected with the feeding assembly by a computer, the feeding assembly includes a feeding tank 7.1 and a feeding valve 7.2, the feeding tank 7.1 is connected with the solid reagent conveying pipe 5, and the feeding valve 7.2 is arranged at the connecting position;

[0031] The air blowing assembly is connected with the solid reagent conveying pipe 5, the air blowing assembly includes a funnel wide opening section 7.3, a front cover 7.4, a fan blade 7.5 and a support 7.7, the fan blade 7.5 is controlled by a motor A 7.8, the motor A 7.8 is attached to the support 7.7 and is connected with a power supply lead 7.9, and the support 7.7 is connected with the funnel wide opening section 7.3 through a threaded nail 7.6.

[0032] As shown in Figure 4 , the driving assembly includes a rotating shaft 11 arranged on the stirring tank body 1, the rotating line of the rotating shaft 11 is parallel to the central axis of the stirring tank body 1, the stirring tank body 1 is provided with a motor B 9 for driving the rotating shaft 11 to rotate, the rotating shaft 11 is provided with a stirring rod 12 and a connecting piece for connecting the scraper 13.

[0033] As shown in Figure 5 , the connecting piece includes a plurality of telescopic rods 14 arranged on the rotating shaft 11, one end of the telescopic rod 14 is connected with the rotating shaft 11, and the other end is connected with the scraper 13.

[0034] A method for using a rock stratum network fracturing device based on a variable viscosity fracturing fluid, comprising the following steps,

[0035] S100: open the motor A and the feeding valve by the computer control, convey the solid reagent to the stirring tank body, and add the liquid reagent required by the fracturing fluid to the liquid reagent conveying pipe, and then convey the liquid reagent to the stirring tank body; for example, the formula for coal seam fracturing can be selected as 0.8wt% cetyl trimethyl ammonium chloride + 0.2wt% sodium salicylate + 1wt% potassium chloride, and if the fractured rock stratum is an oil and gas layer, shale or the like, the fracturing formula needs to be reselected.

[0036] If the selected fracturing fluid formula is 0.8wt% cetyl trimethyl ammonium chloride + 0.2wt% sodium salicylate + 1wt% potassium chloride, the viscosity of the formula is 15mPa·s at a shear rate of 170s -1 , the fracturing fluid has good cross-linking property, and 1000g of the fracturing fluid requires 8g of cetyl trimethyl ammonium chloride, 2g of sodium salicylate, 10g of potassium chloride and 980g of water, and if the formula does not use liquid reagent, the liquid reagent conveying pipe is not required;

[0037] S200: open the water injection pump by the computer to inject water from the water injection pipe to the stirring tank body.

[0038] S300: After the reagent is added, the computer turns on motor B to drive the shaft to drive the stirring rod and scraper to rotate at a certain speed until the viscosity of the fracturing fluid in the stirring tank is stable;

[0039] The rotating shaft drives the stirring rod to stir the chemicals and water until the fracturing fluid viscosity stabilizes. The rotating shaft connects to the scraper through a connector, which helps stir the chemicals and water in the funnel section of the mixing tank. The fracturing fluid viscosity is transmitted back to the computer via the viscosity sensor line.

[0040] S400: Open the valve of the funnel section at the bottom of the mixing tank and output the fracturing fluid through the output pipe for fracturing. The first high-viscosity fracturing will form cracks with longer lengths and smaller widths.

[0041] S500: After completing a fracturing operation, the water injection volume of the water injection pump is adjusted by a computer; the high-viscosity fracturing fluid is diluted by water injection, and the micelles lose their rod-like shape and become spherical. They no longer entangle with each other, and the viscosity is reduced, achieving variable viscosity.

[0042] S600: After the secondary water injection is completed, the computer turns on the motor B to drive the shaft to drive the stirring rod and the scraper to rotate at a certain speed until the viscosity of the fracturing fluid in the stirring tank is stable.

[0043] The valve in the lower funnel section of the mixing tank is opened again, and the fracturing fluid is discharged through the output pipe for fracturing. The second low-viscosity fracturing will form a shorter and wider fracture based on the first fracture. By controlling the delivery of solid reagents, liquid reagents, and clean water to the mixing tank, fracturing fluids of different viscosities are formed. Repeated fracturing eventually forms a network of alternating vertical and horizontal fractures in the rock formation.

[0044] like Figure 6 As shown, firstly, a fracturing device is arranged in the fracturing hole 15, and a first fracturing with a high-viscosity fracturing fluid is performed. After cracks are generated, a second fracturing with a low-viscosity fracturing fluid is performed, and the fracturing is alternately performed until the fracturing operation is completed.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A variable viscosity fracturing fluid based rock formation network fracturing apparatus, characterized by, The utility model relates to a kind of fracturing fluid preparation device, including: Stirring tank body (1), water injection pipe (2), liquid reagent delivery pipe (3) and solid reagent delivery pipe (5) are provided on stirring tank body (1), funnel section connection output pipe (4) is provided in the lower part of stirring tank body (1), stirring tank body (1) is rotatably provided with stirring rod (12), and stirring tank body (1) is provided with the drive assembly for driving stirring rod (12) to rotate; The upper portion of the water injection pipe (2) is connected to a water source by a water injection pump (6), which is controlled by a computer (10). The water injection pipe (2) delivers clean water into the stirring tank body (1). The liquid reagent delivery pipe (3) delivers chemical reagents required for preparing fracturing fluid into the stirring tank body (1). The output pipe (4) outputs the prepared fracturing fluid in the stirring tank body (1) for fracturing and seam formation of rock strata. The solid reagent delivery pipe (5) is connected to an air-blowing material adding assembly (7) for adding materials.

2. The variable viscosity frac fluid based formation network fracturing apparatus of claim 1, wherein, The output pipe (4) is provided with a viscosity sensor (8) inside. The viscosity sensor (8) transmits the measured viscosity data to the computer (10) through a circuit.

3. The variable viscosity frac fluid based formation network fracturing apparatus of claim 1, wherein, The stirring tank body (1) is rotatably provided with a scraper (13), which abuts against the sidewall of the funnel section at the lower part of the stirring tank body (1). The scraper (13) is connected to the drive assembly through a connecting member.

4. The variable viscosity frac fluid based formation network fracturing apparatus of claim 3, wherein, The drive assembly includes a rotating shaft (11) rotatably arranged on the stirring tank body (1). The rotating line of the rotating shaft (11) is parallel to the central axis of the stirring tank body (1). The stirring tank body (1) is provided with a motor B (9) for driving the rotating shaft (11) to rotate. The rotating shaft (11) is provided with the stirring rod (12) and the connecting member for connecting the scraper (13).

5. The variable viscosity frac fluid based formation network fracturing apparatus of claim 4, wherein, The connecting member is a plurality of telescopic rods (14) on the rotating shaft (11). One end of the telescopic rod (14) is connected to the rotating shaft (11), and the other end is connected to the scraper (13).

6. The variable viscosity frac fluid based formation network fracturing apparatus of Claim 1, wherein, The air-blowing material adding assembly (7) includes an air-blowing assembly and a material adding assembly. The air-blowing assembly and the material adding assembly are connected to the computer. The material adding assembly includes a material adding tank (7.1) and a material adding valve (7.2). The material adding tank (7.1) is connected to the solid reagent delivery pipe (5). The material adding valve (7.2) is arranged at the connection. The air-blowing assembly is connected to the solid reagent delivery pipe (5).

7. The variable viscosity frac fluid based formation network fracturing apparatus of claim 6, wherein, The air-blowing assembly includes a funnel wide-mouth section (7.3), a front cover (7.4), a fan blade (7.5), and a bracket (7.7). The fan blade (7.5) is controlled by a motor A (7.8). The motor A (7.8) is attached to the bracket (7.7) and connected to the power supply by a power supply lead (7.9). The bracket (7.7) is connected to the funnel wide-mouth section (7.3) by a threaded peg (7.6).

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