CN105298461B - The unlimited solvable ball fracturing sliding bush of full-bore - Google Patents

Abstract

The invention discloses a full-diameter unlimited-times soluble ball type fracturing sliding sleeve, which solves the problems of processing and delamination control of the existing sliding sleeve. Specifically, it is composed of several levels of sliding sleeve components and several soluble balls. Each level of sliding sleeve components includes a main body, split ball seats, springs, rotating sliding sleeves and bearings. The diameters of sliding sleeve components at all levels increase sequentially from bottom to top. Large, each level of sliding sleeve assembly is equipped with at least one soluble ball of corresponding outer diameter; the use of split ball seat can ensure the effective flow area; the split ball seat can combine the shaft Rotational motion is converted into rotary motion, and the torque of the split ball seat is transmitted through the connecting rod on the rotating sliding sleeve, which realizes the rotation of the rotating sliding sleeve and controls the opening and closing of the fracturing port; the use of soluble balls can realize the channel the repeat switch.

Description

Full Bore Unlimited Times Dissolvable Ball Fracturing Sleeve

technical field

The invention relates to a fracturing sliding sleeve, in particular to a ball-pitching fracturing sliding sleeve.

Background technique

With the progress of oil exploration and development, oil and gas well testing process is constantly updated. The domestic multi-layer and multi-stage fracturing methods mostly use sliding sleeve tools, and the sliding sleeves at all levels are designed with a differential design, and some sealing balls corresponding to the sliding sleeves of the level need to be put in order to complete the sliding sleeves of each stage. After opening and isolation from the modified section, the sealing ball that blocks the ball seat is discharged through blowout and flowback after pressure, and the sliding sleeve and ball seat are left in the downhole, and the final diameter in the wellbore is small. Due to the influence of the inner diameter of the ball seat, the displacement of the construction will also be limited.

Chinese patent announcement number: 102345452A, provides a "self-forming ball seat type sliding sleeve", which is applied to oil well layered fracturing. The invention is a sliding sleeve that forms a ball seat after sensing pressure downhole, including an upper joint, a split ring, a retaining ring, a plug-type sliding key, a shear pin, an outer cylinder, a sliding sleeve, a cone seat, a Locking sleeves, retaining sleeves, sliding mandrels, shear pins and lower joints. The invention adopts the pressure transmission hole of the lower joint to receive the pressure, and the pressure acts on the bearing pressure step of the sliding core, the pin between the fixed sleeve and the sliding mandrel is cut off, the sliding mandrel slides upward, and the inverted "V" shaped opening groove is on the ball seat The inner diameter is gradually closed to form a ring with an inner diameter of 57mm. At this time, the pawl or lock ring of the self-locking sleeve has been engaged with the pawl or the open groove of the ball seat, and the fixed connection between the sliding mandrel and the sliding sleeve is completed. Only the same ball needs to be thrown, and the reconstruction construction of all horizontal sections can be completed under the premise that the construction displacement is no longer affected by the inner diameter of the ball seat.

However, there are still many problems in this patent. Specifically, the pressure conduction hole of this patent is difficult to process. When working, it is necessary to use a capillary to press down on the small hole in the joint, and the patent does not explain how to achieve layering control. Press down on the specified layer to realize the contraction of the ball seat.

Contents of the invention

In order to solve the problems in the background technology, the present invention provides a full-diameter infinitely soluble ball-type fracturing sleeve. The fracturing sleeve can not only guarantee the construction displacement, but also greatly increase the number of times the sliding sleeve can be opened. Realize hierarchical control, repeatable switch, convenient flowback, and can also open the sliding sleeve at any position according to needs.

In order to achieve the purpose of the above invention, the technical solution adopted by the present invention is: a full-diameter unlimited number of soluble ball fracturing sleeves, which are composed of several levels of sliding sleeve components and several soluble balls, and the sliding sleeve components of each level The diameter increases sequentially from bottom to top, and each level of sliding sleeve assembly is equipped with at least one soluble ball with a corresponding outer diameter. Each level of sliding sleeve assembly includes a main body, a split ball seat, a spring, a rotating sliding sleeve and a bearing, among which:

The main body is cylindrical, and the upper half of the inner wall of the main body is provided with a diameter-reducing section, which is divided into an expanding section and a diameter-reducing section from top to bottom. Zigzag slideway, each unit of this kind of zigzag slideway includes an upper inflection point, a lower inflection point, an upward slideway and a downward slideway, a number of external fracturing holes are arranged at the bottom of the main body along the circumferential direction, and steps are set at the lower end of the inner cavity of the main body , there is a rotating bearing in interference fit with the main body on the step.

The base of the split ball seat is in the shape of a ring sleeve and placed in the main body. The base of the split ball seat is extended upward along the circumference with a number of ball claws, and the inside of each ball claw is provided with a lock for receiving a soluble ball. The ball step, the pitching pressure is suppressed, the split ball seat goes down along the main body, when passing through the expanding section of the variable diameter section, the radial expansion of the ball claw gradually increases, and when it reaches the shrinking section, the soluble ball falls from the locking ball step ; The lower part of the split ball seat is provided with a plurality of strip-shaped longitudinal slots along the circumferential direction and a plurality of pins are evenly distributed, and the pins are inserted into the serrated slideway on the main body.

The base body of the rotating sliding sleeve is in the shape of a circular ring and sits on the rotating bearing in the main body. The rotating sliding sleeve extends upwards along the circumference and is provided with a number of strip-shaped connecting rods. The strip-shaped connecting rods are inserted into the split valves In the longitudinal slot of the ball seat, a spring is fixed between the upper end surface of the rotating sliding sleeve at the root of the connecting rod and the lower end surface of the split ball seat. When the spring is in a natural state, the height of the spring supports the pin on the split ball seat. At the upper inflection point of the serrated slideway, and the insertion depth of the connecting rod is less than the depth of the longitudinal slot; the number of inner fracturing holes equal to the number of outer fracturing holes is arranged under the rotating sliding sleeve along the circumference, and the inner fracturing holes are connected with the outer fracturing holes. The centers of the holes are on the same horizontal plane, and when the fracturing channel is closed, the phase difference angle between the inner fracturing hole and the outer fracturing hole is equal to the phase difference angle between the two adjacent upper inflection points of the serrated slideway.

Preferably, the number of inner fracturing holes and outer fracturing holes is 2, the phase difference between inner fracturing holes and outer fracturing holes is 90°, and the number of sawtooth-like slideway units is 4.

Beneficial effects of the present invention:

1. Compared with the ordinary ball seat, the split ball seat is designed so that even the lowest layer with the smallest diameter can ensure a larger displacement, increase the effective flow area of the liquid, and maximize the flow rate of the ball seat. Reduced energy loss;

2. The improved rotating sliding sleeve is used with soluble balls or self-destruction balls (explosive self-destruction), which can realize the cycle switch of the channel, and can repeat fracturing when the pressed layer does not achieve the effect of increasing production;

3. When the soluble ball is designed with a 2mm step difference, this sliding sleeve fracturing tool can fracture 20 sections of oil layers. The maximum outer diameter of the tool is 110mm, and the diameter is 68mm; soluble ball (27~67mm);

4. The split ball seat can convert the axial movement into the rotary motion through the combination of the pin and the serrated slideway, and the torque of the split ball seat is transmitted through the connecting rod on the rotating sliding sleeve to realize the rotation of the rotating sliding sleeve And then control the opening and closing of fracturing ports;

5. When the normal ball-drop fracturing process completes the fracturing construction of the target layer, the steel balls in the pressed layer directly interact with the formation pressure, which is prone to reverse discharge or formation pressure release. This patent overcomes this shortcoming. For the pressed section where the soluble ball is closed, the formation pressure directly acts on the inner wall of the split ball seat, and its pressure will not enter the inner cavity of the tool to interact with the soluble ball, and no soluble ball will appear. The phenomenon of ball reverse row and bottom layer spit out pressure.

Description of drawings

Fig. 1 is a schematic diagram of the overall structure of the full-bore unlimited-times soluble ball fracturing sleeve of the present invention.

Fig. 2 is a structural schematic diagram of the main body.

Fig. 3 is a structural schematic diagram of a split ball seat.

FIG. 3A is a partially enlarged view of part I in FIG. 3 .

Fig. 4 is a schematic diagram of the structure of the rotating sliding sleeve.

Fig. 5 is an expanded view of the quasi-sawtooth slideway.

Fig. 6a is a diagram of the initial contact state of the soluble ball and the split ball seat and a diagram of the running track of the pin at this time.

Fig. 6b is a state diagram of the soluble ball moving down to the step of the ball seat and a diagram of the running track of the pin at this time.

Fig. 6c is a state diagram of the soluble ball falling from the step of the split ball seat and a diagram of the running track of the pin at this time.

detailed description

Below in conjunction with accompanying drawing and specific embodiment, the present invention will be further described:

Example 1

A full-bore unlimited number of dissolvable ball fracturing sleeves, composed of several stages of sliding sleeve components and several soluble balls, the diameters of the sliding sleeve components of each level increase sequentially from bottom to top, in this embodiment The difference between the upper and lower diameters of the sliding sleeve assembly is 2mm, and the outer diameter of the above-mentioned soluble balls also differs by 2mm in turn, as shown in Figure 1: each level of sliding sleeve assembly includes a main body 1, a split ball seat 2, a spring 3, and a rotating sliding sleeve 4 and bearing 5, wherein:

As shown in Figure 2 in conjunction with Figure 1: the main body 1 is cylindrical, and the upper half of the inner wall of the main body is provided with a diameter-reducing section, which is divided into a diameter-expanding section 1-1 and a diameter-reducing section from top to bottom. Section 1-2, the lower half of the inner wall of the main body is provided with a serrated slideway along the circumference. This type of sawtooth slideway has 4 sawtooth units, as shown in Figure 5: each unit of the serrated slideway includes The upper inflection point 1-3, the lower inflection point 1-6, the upward chute 1-5 and the downward chute 1-4, two outer fracturing holes 1-7 are arranged on the lower part of the main body along the circumferential direction, and the two outer fracturing holes 1- 7. The phase difference is 180°. A step is provided at the lower end of the inner cavity of the main body 1, and a rotating bearing 5 is provided on the step in an interference fit with the main body 1.

As shown in Fig. 3 in conjunction with Fig. 3A: the base of the split ball seat 2 is in the shape of a ring sleeve, placed in the main body 1, and the base body of the split ball seat is provided with several ball claws 2-1 extending upward along the circumference. The inner side of each ball claw 2-1 is provided with a ball locking step 2-3 for receiving the soluble ball 6, and the ball seat 2 goes down along the main body 1 and passes through the expanding section 1-1 of the variable diameter section. , the radial expansion of the ball claw 2-1 gradually increases, and when it reaches the diameter-reducing section 1-2, the soluble ball 6 falls from the ball locking step 2-3; a guide surface 2-1 is set above the ball claw 2-1 2. A number of strip-shaped longitudinal slots 2-4 are arranged on the lower side of the split ball seat along the circumference, and a number of pins 2-5 are evenly distributed, and the pins 2-5 are inserted into the serrated slideway on the main body 1.

As shown in Fig. 4 in conjunction with Fig. 1: the rotating sliding sleeve 4 has a base body in the shape of a ring sleeve and is seated on the rotating bearing 5 in the main body 1. Rod 4-1, the strip-shaped connecting rod 4-1 is inserted in the longitudinal slot 2-4 of the split ball seat, and the upper end surface of the rotating sliding sleeve at the root of the connecting rod and the lower end surface of the split ball seat are also fixed Spring 3, when the spring 3 is in the natural state, the height of the spring 3 supports the pin 2-5 on the split ball seat just at the upper inflection point 1-3 of the serrated slideway, and the insertion depth of the connecting rod 4-1 at this time Less than the depth of the longitudinal slots 2-4. There are two inner fracturing holes 4-2 along the circumference below the rotating sliding sleeve. The centers of the inner fracturing holes 4-2 and the outer fracturing holes 1-5 are on the same horizontal plane. When the fracturing channel is closed, the inner fracturing holes and the outer fracturing holes 1-5 The phase difference angle of the external fracturing holes is equal to the phase difference angle of two adjacent upper or lower inflection points of the serrated slideway, both of which are 90°.

The soluble ball 6 can adopt the soluble fracturing ball disclosed in the prior art. For example, the exposed strips of soluble materials are all 5-gallium-aluminum soluble alloys, composed of 85% aluminum by weight, 5% Gallium-aluminum alloy, 5% Bi and 5% Cr composition. The material is insoluble in oil but soluble in water. In water at 70°C, it can guarantee pressure bearing and fracturing requirements within 5 hours, and completely dissolve within 15 days.

The working process of the fracturing sliding sleeve of the present invention is specifically described below:

1. When the soluble ball matching the first layer (lowest layer) is put in, the working process of the fracturing sleeve

Put the soluble ball 6 into the wellhead, pump the soluble ball 6 to the target position with a small displacement, as shown in Fig. Displacement, the soluble ball produces an axial downward thrust due to the throttling pressure difference, and the soluble ball 6 will slide down along the guide surface 2-2 of the split ball seat 2. At the initial stage of the downward sliding of the soluble ball 6, because the ball claw 2-1 of the split ball seat 2 is radially constrained by the inner wall of the main body 1, it can only move axially downward under the promotion of the soluble ball 6. When the ball claw 2-1 moves to the enlarged diameter section of the main body 1, due to the gradual expansion of the inner diameter of the main body, the ball claw 2-1, under the push of the soluble ball 6, simultaneously produces axial downward movement and radial expansion movement, as shown in the figure In the state shown in 6b, at this time, due to the radial expansion of the claw 2-1, the soluble ball 6 descends and gets stuck on the ball locking step 2-3. Continue to increase the pump pressure, the soluble ball 6 pushes the ball claw 2-1 to continue downward and continue to expand radially. When the ball claw 2-1 moves to the maximum inner diameter of the main body 1, the inner diameter surrounded by the ball claw at the lock ball step 2-3 The expansion will be equal to the outer diameter of the soluble ball 6, and the soluble ball 6 will fall out of the constraint of the ball claw 2-1, and the axial movement of the ball claw 2-1 will stop. At this time, the state is shown in Figure 6c.

As shown in Figures 6a~6c: when the soluble ball 6 pushes the split ball seat 2 to move downward, the pins 2-5 on the split ball seat 2 will move downward from the upper inflection point 1-3 in the initial state The slideway 1-4 moves downward at the inflection point 1-6, and the split ball seat 2 will make a downward right-handed movement under the guidance of the downward slideway 1-4; the split ball seat 2 will compress when it is in the downstroke Spring 3, although the connecting rod 4-1 of the rotating sliding sleeve 4 is inserted in the longitudinal slot 2-4 of the split ball seat 2, but at this time the connecting rod 4-1 is not inserted into the bottom of the longitudinal slot 2-4 , so the split ball seat 2 only transmits the torque to the rotating sliding sleeve 4 when the split ball seat 2 is doing downward right-handed movement, and the axial force is controlled by the depth between the connecting rod 4-1 and the longitudinal slot 2-4 The difference is eliminated, therefore, the rotary sliding sleeve 4 can only do relative rotary motion with the main body 1. Because the phase difference between the upper inflection point 1-3 and the lower inflection point 1-6 is 45°, the split ball seat will rotate 45° during the downstroke, and the split ball seat 2 will also rotate 45° at the same time.

When the soluble ball 6 passed through the split ball seat 2 completely, the active force acting on the split ball seat 2 disappeared. It is conceivable that the pins 2-5 on the split ball seat 2 were under the rebound force of the spring 3. Will enter and crawl along the upward track 1-5, during the movement of the pin 2-5 from the lower inflection point 1-6 to the upper inflection point 1-3, the split ball seat 2 drives the rotating sliding sleeve 4 to rotate 45° again, and the ball The claw 2-1 also returns to the original position.

As can be seen from the descriptions of the above two paragraphs, from the time when the soluble ball 6 is thrown into until it completely passes through the split ball seat 2, the rotating sliding sleeve 4 is driven by the split ball seat 2 to rotate a total of 90°. At the initial position, that is, when the fracturing channel is closed, the inner fracturing hole 4-2 and the outer fracturing hole 1-7 are on the same horizontal plane with a phase difference of 90°. After the above process, the inner fracturing hole 4-2 2 will coincide with the outer fracturing holes 1-7, and at this moment, the first layer of fracturing channels is opened.

2. Put the soluble ball 6 matching the second layer (reciprocal) at the wellhead, the working process of this fracturing sleeve

The opening process of the second layer of fracturing channels is exactly the same as that of the first layer of fracturing channels, and will not be repeated here. At this time, the pump discharge rate is increased, and the second layer of soluble balls generates an axial downward thrust due to the throttling pressure difference, pushing the first layer of the sliding sleeve assembly in the first layer. The first split ball seat 2 moves downward, and the spring in the first layer of sliding sleeve assembly and the rotating sliding sleeve will be linked accordingly. When the upper port of the first split ball seat 2 moves to the enlarged diameter section 1- 1 at the junction point with the diameter-reducing section 1-2, the claws 2-1 are fully opened to wrap the second layer of soluble balls 6, but due to the structural size design, the outer diameter of the second layer of soluble balls 6 put in It is larger than the diameter of the first layer of sliding sleeve assembly, so the second layer of soluble ball 6 cannot pass through the first split ball seat, but is stuck in this position and self-locked, causing the first split ball seat 2 to fail Downward movement, can not shrink upward movement, it is not difficult to understand, during this process, the first split ball seat 2 rotated 45°, the first rotating sliding sleeve also rotated 45°, while the first layer of fracturing The channel is open, that is, the inner fracturing hole 4-2 is coincident with the outer fracturing hole 1-7, and after the first rotating sliding sleeve rotates 45°, the inner fracturing hole 4-2 and the outer fracturing hole 1- 7 The difference in phase is 45°, and the first layer of fracturing channels is closed.

Therefore, whenever the soluble ball 6 opens the fracturing channel of one layer, it will close the fracturing channel of the next layer.

3. Control between different layers:

It is not difficult to find from the above description of the working state that the key to really controlling whether the soluble ball 6 can pass through the split ball seat 2 is the minimum inner diameter of the ball claw 2-1 when the diameter is fully expanded, and this minimum inner diameter is defined as the sliding sleeve assembly When the minimum inner diameter is greater than the diameter of the input soluble ball, the soluble ball will pass through. When the minimum inner diameter is smaller than the diameter of the soluble ball passed through, the soluble ball will not pass through. Therefore, in order to control the opening and closing of fracturing channels in different intervals, the diameters of sliding sleeve assemblies at all levels should be set to increase sequentially from the bottom of the well to the wellhead. For example, if you want to close the fracturing channel in the first layer and open the fracturing channel in the adjacent second layer to be fractured, you should invest in the fracturing channel that can open the second layer to be fractured. Dissolving ball, this ball will eventually go to close the frac channels that have been fractured in the first layer. If you want to close the fracturing channel of the second layer and open the fracturing channel of the adjacent third layer to be fractured, you should put in a soluble ball that can open the fracturing channel of the third layer to be fractured. This ball will eventually go to seal off the frac channels that have been fractured in the second layer. By analogy, the opening and closing of fracturing channels in all intervals can be completed.

4. Repeated switching of fracturing channels

For any fracturing layer, when the fracturing operation is completed, the fracturing channel in the layer is closed, and there is a soluble ball 6 on the split ball seat. After a period of time, the soluble ball 6 melts and disappears, and the split ball Seat 2 returns to the initial state. At this time, the re-opening of the fracturing channel can be realized by re-introducing the soluble ball 6 that matches the corresponding interval. According to this principle, the number of opening and closing of each fracturing channel is theoretically unlimited.

Claims (2)

1. A full-bore unlimited number of dissolvable ball fracturing sleeves, composed of several stages of sliding sleeve components and several soluble balls, the diameter of each level of sliding sleeve components increases from bottom to top, each stage The sliding sleeve assembly is equipped with at least one soluble ball with a corresponding outer diameter. Each level of sliding sleeve assembly includes a main body, a split ball seat, a spring, a rotating sliding sleeve and a rotating bearing. It is characterized in that: The main body is cylindrical, and the upper half of the inner wall of the main body is provided with a diameter-reducing section, which is divided into an expanding section and a diameter-reducing section from top to bottom. Zigzag slideway, each unit of this kind of zigzag slideway includes an upper inflection point, a lower inflection point, an upward slideway and a downward slideway, a number of external fracturing holes are arranged at the bottom of the main body along the circumferential direction, and steps are set at the lower end of the inner cavity of the main body , there is a rolling bearing on the step with an interference fit with the main body; The base of the split ball seat is in the shape of a ring sleeve and placed in the main body. The base of the split ball seat is extended upward along the circumference with a number of ball claws, and the inside of each ball claw is provided with a lock for receiving a soluble ball. The ball step, the pitching pressure is suppressed, the split ball seat goes down along the main body, when passing through the expanding section of the variable diameter section, the radial expansion of the ball claw gradually increases, and when it reaches the shrinking section, the soluble ball falls from the locking ball step ; A number of strip-shaped longitudinal slots are arranged on the lower side of the split ball seat along the circumference and a number of pins are evenly distributed, and the pins are inserted into the serrated slideway on the main body; The base of the rotating sliding sleeve is in the shape of a circular ring and sits on the rotating bearing in the main body. The rotating sliding sleeve extends upwards along the circumference and is provided with a number of strip-shaped connecting rods. The strip-shaped connecting rods are inserted into the split valves In the longitudinal slot of the ball seat, a spring is fixed between the upper end surface of the rotating sliding sleeve at the root of the connecting rod and the lower end surface of the split ball seat. When the spring is in a natural state, the height of the spring supports the pin on the split ball seat. At the upper inflection point of the serrated slideway, and the insertion depth of the connecting rod is less than the depth of the longitudinal slot; the number of inner fracturing holes equal to the number of outer fracturing holes is arranged under the rotating sliding sleeve along the circumference, and the inner fracturing holes are connected with the outer fracturing holes. The centers of the holes are on the same horizontal plane, and when the fracturing channel is closed, the phase difference angle between the inner fracturing hole and the outer fracturing hole is equal to the phase difference angle between the two adjacent upper inflection points of the serrated slideway. 2. The full-diameter unlimited-times soluble ball fracturing sleeve according to claim 1, characterized in that: the number of the inner fracturing hole and the outer fracturing hole are two respectively, and the number of the inner fracturing hole and the outer fracturing hole are two. The phase difference of the outer fracturing holes is 90°, and the number of quasi-serrated slideway units is four.