Hydraulic centralizer for hydraulic jet fracturing

Abstract

A plurality of body radial holes are formed in the middle section of a centralizer body, a sealing piston is arranged in each body radial hole, a rectangular spring is embedded in a counter bore in the center of the outer end face of each sealing piston, and the outer end of each rectangular spring abuts against the inner wall of the middle of a gland. The periphery of the gland is screwed in an outer port screw hole of the radial hole of the body; a soluble supporting rod is embedded in a central through hole of the gland, and the inner end of the soluble supporting rod is screwed in a screw hole in the center of the outer end face of the sealing piston; an outer sleeve is embedded in the body center hole, an inner sleeve is embedded in the outer sleeve, the upper end and the lower end of the inner sleeve respectively exceed ports of the outer sleeve, a body upper sealing ring is embedded at the upper end of the body center hole and sealed with the outer wall of the upper portion of the outer sleeve, and a body lower sealing ring is embedded at the lower end of the body center hole and sealed with the outer wall of the lower portion of the inner sleeve. The centralizer can ensure that the hydraulic ejector is centered, the sand prevention effect is reliable, and recovery of the centralizer can be ensured when abnormal conditions occur.

Description

TECHNICAL FIELD

[0001] The utility model relates to a centralizer, especially to a hydraulic jet fracturing hydraulic centralizer, belongs to oil and gas well hydraulic fracturing tool technical field. BACKGROUND

[0002] Hydraulic jetting separate layer fracturing is a new type of stimulation measure which integrates perforation, fracturing and isolation. The technology uses special jetting tools to generate high-speed fluid to penetrate the casing and rock and form a hole. The jet stream forms a pressure boost in the jetting channel, and the annulus fluid is pumped to increase the annulus pressure. The superposition of jetting fluid pressure and annulus pressure exceeds the formation fracture pressure, thereby fracturing the formation. The technical principle is based on Bernoulli equation. When the fluid passes through the jetting tool, the pressure energy is converted into kinetic energy. The high-speed fluid impacts to form a perforation channel, and hydraulic perforation is completed. After the crack is formed, the high-speed fluid is injected into the hole and the crack. The hole is equivalent to a "jet pump". The annulus fluid enters the formation under the action of the jet stream, maintains the extension of the crack, and controls the annulus pressure to be lower than the extension pressure of the formation. The whole process realizes hydraulic isolation based on hydrodynamics, without the need for other mechanical isolation measures.

[0003] The advantages of this technology are: no mechanical isolation is needed, and it can automatically isolate, which is suitable for horizontal well staged fracturing that cannot be sealed by packers for open hole, screen pipe and out-of-pipe flow; no separate perforation operation is needed, and perforation and fracturing are completed at one time, and one trip string can be used for multi-stage fracturing, saving operation procedures compared with traditional fracturing process; directional jetting fracturing can be carried out to accurately form cracks; the construction safety is high, and one trip string can be used to quickly and accurately fracture multiple cracks in the horizontal well, the hydraulic jetting tool can be connected with the conventional oil pipe into the well, and it can also be combined with the large-diameter coiled tubing to make the construction more efficient.

[0004] However, in the construction process of hydraulic jetting separate layer fracturing, the centering degree of the hydraulic jetting device directly affects the jetting effect. Because hydraulic jetting fracturing construction requires high pressure, when the hydraulic jetting device perforates the sand around the pipe column, the pipe column shakes or vibrates seriously under the double action of high pressure and jet flow, the frequency is high, and in severe cases, it even leads to pipe column fracture, thereby causing construction failure.

[0005] The utility model discloses a hydraulic fracturing pipe column, the hydraulic jet is connected with the centralizer, and the centralizer is rigid centralizer, and the outer diameter of horizontal well centralizer is about 112mm, and the inner diameter of 5 1 / 2 '' casing is 124mm, and the centralizing effect is not ideal, so that the traditional centralizer does not effectively solve the centering problem of hydraulic jet. In addition, in the construction process, the fracturing sand is blocked by the casing and reflected to the jet body and the adjacent upper and lower connecting pipes. Because the hydraulic jet is not centered, the reflection force of the fracturing sand blocked by the casing is uneven, which may cause partial perforation and even pipe column breakage, causing complex downhole accidents.

[0006] The utility model discloses a hydraulic centralizer suitable for multistage hydraulic jet fracturing, although its principle can achieve certain centralizing effect, but in actual application, the sand prevention performance is unreliable, and the fracturing sand is easy to enter between the elastic sand prevention pipe and the centralizing block. After the construction is finished, the centralizing block lacks spring forced recovery force, and cannot restore, so that the operation pipe column cannot be normally tripped out, and even the oil and water well may be overhauled. Utility model content

[0007] This part is to summarize some aspects of the embodiments of the utility model and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this part and the abstract of the specification and the utility model name, and such simplifications or omissions cannot be used to limit the scope of the utility model.

[0008] The utility model discloses a hydraulic centralizer for hydraulic jet fracturing, which can effectively solve the centering problem of the hydraulic jet, and the sand prevention effect is reliable, and the centralizer can be recovered in abnormal conditions, ensuring that the pipe column can be tripped out smoothly.

[0009] To solve the above technical problems, the utility model discloses a hydraulic centralizer for hydraulic jet fracturing, which comprises a centralizer body, a plurality of body radial holes are arranged in the middle section of the centralizer body and communicated with the body center hole, a sealing piston is arranged in each body radial hole, a rectangular spring is embedded in the center hole of the outer end surface of the sealing piston, the outer end head of the rectangular spring abuts against the middle inner wall of the gland, and the outer peripheral of the gland is screwed in the outer end port screw hole of the body radial hole;A soluble support rod is embedded in the center through hole of the gland, and the inner end head of the soluble support rod is screwed in the screw hole in the center of the outer end surface of the sealing piston;An outer sleeve is embedded in the body center hole, an inner sleeve is nested in the outer sleeve, the upper and lower ends of the inner sleeve respectively exceed the ports of the outer sleeve, the upper end of the body center hole is embedded with a body upper sealing ring and the upper outer wall of the outer sleeve is sealed, and the lower end of the body center hole is embedded with a body lower sealing ring and the lower outer wall of the inner sleeve is sealed.

[0010] The upper part of the inner sleeve is uniformly provided with a plurality of inner sleeve wire cutting slits which are communicated with the inner wall gap of the outer sleeve, and the lower part of the outer sleeve is uniformly provided with a plurality of outer sleeve wire cutting slits which are communicated with the inner wall gap of the body central hole.

[0011] The lower end of the inner sleeve abuts on the inner step of the body central hole, the outer wall of the upper end of the inner sleeve is expanded in diameter to form an inner sleeve large end, the lower part of the inner sleeve large end is provided with an inner sleeve large end outer taper surface, the inner sleeve large end outer taper surface is pressed on the trumpet mouth of the upper end of the body central hole, and each inner sleeve wire cutting slit extends to the top of the inner sleeve large end.

[0012] The top of the inner sleeve large end is a plane and is provided with a circlip thereon, and the circlip is embedded in the inner wall ring groove of the body central hole.

[0013] The upper part of the outer sleeve abuts below the root of the inner sleeve large end, and the lower end of the outer sleeve abuts on the inner step of the body central hole.

[0014] The cooperation gap between the inner sleeve and the outer sleeve and the cooperation gap between the outer sleeve and the body central hole are all H10 / d10 or H10 / c10.

[0015] The wall thicknesses of the inner sleeve and the outer sleeve are both 2 mm.

[0016] The slit widths of the inner sleeve wire cutting slits and the outer sleeve wire cutting slits are both 0.2-0.3 mm.

[0017] Compared with the prior art, the utility model has the following beneficial effects: 1, adopt the inner sleeve and the outer sleeve to realize two layers four ways filtration and prevent sand, the inner sleeve and the outer sleeve and the cooperation gap H10 / d10 or H10 / c10 between the outer sleeve and the body, in the fracturing construction process, pressure rises, liquid from the inner sleeve wire cutting slit enters the gap between the inner sleeve and the outer sleeve, then passes through the outer sleeve wire cutting slit and enters the gap between the body inner wall and the outer sleeve, and then enters the body radial hole, and the liquid acts to push the sealing piston to push the soluble support rod to extend, so that the hydraulic jet is centered and supported. The double-layer filtration of the inner sleeve and the outer sleeve has good sand prevention effect.

[0018] 2, the soluble support rod adopts soluble metal, in the abnormal situation, the sand in the outer sleeve and the body inner wall cannot be recycled, the soluble metal of the soluble support rod is automatically dissolved, the hydraulic jet fracturing fluid pressure centralizer is not provided with the rod body of the soluble support rod, the normal outer diameter is restored, and the pipe string is smoothly lifted.

[0019] 3. The rectangular spring structure is adopted to increase the resilience of the soluble support rod and facilitate the retraction of the soluble support rod. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical scheme of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings described in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings. The drawings are provided for reference and description only, and are not intended to limit the present application. Among them:

[0021] Figure 1 Figure 1 is a structural diagram of the hydraulic jet fracturing fluid pressure centralizer of the present application;

[0022] In the figure: 1. Centralizer body; 1a. Upper sealing ring of the body; 1b. Lower sealing ring of the body;

[0023] 2. Spring clip;

[0024] 3. Outer sleeve; 3a. Outer sleeve wire cutting seam;

[0025] 4. Inner sleeve; 4a. Inner sleeve wire cutting seam;

[0026] 5. Sealing piston; 5a. Piston sealing ring;

[0027] 6. Cover; 7. Rectangular spring;

[0028] 8. Soluble support rod. DETAILED DESCRIPTION

[0029] In the following description of the present application, the terms "upper", "lower", "front", "rear", "left", "right", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not mean that the device must have a particular orientation.

[0030] In order to make the technical means, creative features, purposes and effects achieved by the present application easy to understand, the following will further describe the present application in combination with specific drawings. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0032] AsFigure 1 As shown, the hydraulic jet fracturing fluid pressure centralizer of the utility model comprises: a centralizer body 1, a clamping spring 2, an outer sleeve 3, an inner sleeve 4, a sealing piston 5, a rectangular spring 7, a soluble support rod 8 and a gland 6. The centralizer body 1 serves as the basic frame of the whole device and is used for mounting and fixing other components.

[0033] The outer sleeve 3 is located in the body center hole, and the lower end of the outer sleeve 3 abuts against the inner step of the body center hole. The upper part of the body center hole is embedded with the upper sealing ring 1a of the body and the upper outer wall of the outer sleeve 3, so as to realize the sealing between the outer wall of the outer sleeve 3 and achieve the sealing performance of the device.

[0034] The inner sleeve 4 abuts against the inner wall of the outer sleeve 3, the lower end of the inner sleeve 4 extends out of the lower end port of the outer sleeve 3 and abuts against the inner step of the body center hole, and the upper part of the body center hole is embedded with the lower sealing ring 1b of the body and the lower outer wall of the inner sleeve 4 to realize the sealing. The outer wall of the upper end of the inner sleeve 4 is expanded in diameter to form a large end of the inner sleeve, the lower part of the large end of the inner sleeve is provided with an outer taper surface of the large end of the inner sleeve, the outer taper surface of the large end of the inner sleeve is pressed on the bell mouth of the upper end of the body center hole, the top of the large end of the inner sleeve is a plane and is pressed by the clamping spring 2, the clamping spring 2 is embedded in the annular groove below the tapered female thread of the upper end of the centralizer body 1, the upper part of the outer sleeve 3 abuts below the root of the large end of the inner sleeve, so that the inner sleeve 4 and the outer sleeve 3 are prevented from moving, and the stability of the components in the working process is ensured.

[0035] A plurality of inner sleeve linear cutting slits 4a are uniformly arranged on the upper part of the inner sleeve 4, the slit width of each inner sleeve linear cutting slit 4a is 0.2-0.3mm, and the inner sleeve linear cutting slit 4a extends to the top of the large end of the inner sleeve 4, which is used for guiding the liquid flow into the gap between the inner sleeve 4 and the outer sleeve 3.

[0036] The wall thicknesses of the outer sleeve 3 and the inner sleeve 4 are 2mm respectively, a plurality of outer sleeve linear cutting slits 3a are uniformly arranged on the lower part of the outer sleeve 3, the slit width of each outer sleeve linear cutting slit 3a is 0.2-0.3mm, which is used for guiding the liquid flow into the gap between the outer sleeve 3 and the inner wall of the body center hole. The inner and outer of the outer sleeve 3 are the centralizer body 1 and the inner sleeve 4 respectively, when the liquid enters, the outer sleeve 3 is limited by the inner and outer, which prevents the outer sleeve linear cutting slit 3a from expanding and limits the entry of fracturing sand.

[0037] A plurality of body radial holes are arranged on the circumference of the centralizer body 1 and communicated with the body center hole, a sealing piston 5 is embedded in each body radial hole, the circumferential wall of the sealing piston 5 is embedded with a piston sealing ring 5a and the inner wall of the body radial hole to realize the sealing, a counterbore is arranged in the center of the outer end surface of the sealing piston 5, a rectangular spring 7 is embedded in the counterbore, the outer end head of the rectangular spring 7 abuts against the middle inner wall of the gland 6, the outer circumference of the gland 6 is screwed in the outer end port screw hole of the body radial hole; the soluble support rod 8 is embedded in the center through hole of the gland 6, and the inner end head of the soluble support rod 8 is screwed in the screw hole in the center of the outer end surface of the sealing piston 5.

[0038] The cover 6 is used to press the outer end of the rectangular spring 7 and provides positioning for the soluble support rod 8; the rectangular spring 7 provides resilience for the sealing piston 5, ensuring that the soluble support rod 8 can retract in time when the pressure changes, facilitating the pulling out of the pipe string.

[0039] The hydraulic jet fracturing fluid centralizer is installed at both ends of the hydraulic jet, and is lowered together with the fracturing pipe string; after the pipe string is lowered to the designed position, fracturing is performed; when the pressure increases during the construction, the liquid pushes the sealing piston 5 to move outward; the sealing piston 5 overcomes the elastic force of the rectangular spring 7 and pushes the soluble support rod 8 to extend radially and firmly support the inner wall of the casing, thereby realizing the centralization of the hydraulic jet and ensuring the reliable centering of the hydraulic jet.

[0040] When the construction is completed and the pressure in the pipe string is less than the sealing pressure of the hydraulic anchor, the sealing piston 5 retracts under the elastic force of the rectangular spring 7, driving the soluble support rod 8 to restore, i.e., the outer end of the soluble support rod 8 is retracted into the center hole of the cover, and the pipe string can be smoothly pulled out.

[0041] The soluble support rod 8 is made of soluble metal; in the event of an abnormal situation, the sand prevention of the inner sleeve 4 and the outer sleeve 3 is unexpected, and the fracturing sand enters between the outer sleeve 3 and the inner wall of the centralizer body 1, the sealing piston 5 cannot be recovered, and the soluble support rod 8 can be automatically dissolved; the hydraulic jet fracturing fluid centralizer has no rod body of the soluble support rod 8 outside, the centralizer returns to the normal outer diameter, and the pipe string can be smoothly pulled out.

[0042] The hydraulic jet fracturing fluid centralizer is not only suitable for hydraulic jet fracturing, but also suitable for conventional fracturing sliding sleeve sand blaster + K344 packer technology, which can ensure the centering of the K344 packer and improve the pressure-bearing capacity and service life of the packer.

[0043] The test in the well of Chen XX et al. shows that the fracturing is successfully performed at a construction pressure of 60 MPa, the pipe string is smoothly pulled out, no sticking occurs, the hydraulic jet fracturing fluid centralizer is disassembled, there is a little fracturing sand between the inner sleeve 4 and the outer sleeve 3, and there is no fracturing sand between the outer sleeve 3 and the centralizer body 1, and the soluble support rod 8 has been dissolved.

[0044] The above merely describes preferred and feasible embodiments of the present application, shows and describes the basic principles, main features and advantages of the present application, and is not intended to limit the patent protection scope of the present application. Those skilled in the art should understand that the present application is not limited by the above embodiments. In addition to the above embodiments, the present application can also have other implementation manners without departing from the spirit and scope of the present application. The present application can also have various changes and improvements, and any technical solution formed by equivalent replacement or equivalent transformation falls within the protection scope of the present application. The protection scope of the present application is defined by the appended claims and their equivalents. The technical features not described in the present application can be realized by or using the prior art, and will not be described here.

Claims

1. A hydraulic jet fracturing hydraulic centralizer, comprising a centralizer body, a middle section of the centralizer body is provided with a plurality of body radial holes communicated with a body center hole, characterized in that: The sealing piston is arranged in each body radial hole, the rectangular spring is embedded in the counterbore in the center of the outer end surface of the sealing piston, the outer end head of the rectangular spring abuts against the inner wall of the middle part of the gland, and the outer periphery of the gland is screwed in the outer end port screw hole of the body radial hole; the center through hole of the gland is embedded with the soluble support rod, the inner end head of the soluble support rod is screwed in the screw hole in the center of the outer end surface of the sealing piston; the body center hole is embedded with the outer sleeve, the inner sleeve is nested in the outer sleeve, the upper and lower ends of the inner sleeve respectively exceed the ports of the outer sleeve, the upper end of the body center hole is embedded with the upper body sealing ring and the upper outer wall of the outer sleeve is sealed, and the lower end of the body center hole is embedded with the lower body sealing ring and the lower outer wall of the inner sleeve is sealed.

2. The hydraulic jetting frac fluid centralizer of claim 1, wherein: The upper periphery of the inner sleeve is uniformly provided with a plurality of inner sleeve wire cutting slits which are communicated with the inner wall gap of the outer sleeve, and the lower periphery of the outer sleeve is uniformly provided with a plurality of outer sleeve wire cutting slits which are communicated with the inner wall gap of the body center hole.

3. The hydraulic jetting frac fluid centralizer of claim 2, wherein: The lower end of the inner sleeve abuts against the inner step of the body center hole, the upper end outer wall of the inner sleeve is expanded in diameter to form an inner sleeve large end, the lower part of the inner sleeve large end is provided with an inner sleeve large end outer taper surface, the inner sleeve large end outer taper surface is pressed on the bell mouth of the upper end of the body center hole, and each inner sleeve wire cutting slit extends to the top of the inner sleeve large end.

4. The hydraulic jetting frac fluid centralizer of claim 3, wherein: The top of the inner sleeve large end is a flat surface and a circlip is pressed above the top, and the circlip is embedded in the inner wall ring groove of the body center hole.

5. The hydraulic jetting frac fluid centralizer of claim 3, wherein: The upper part of the outer sleeve abuts below the root of the inner sleeve large end, and the lower end of the outer sleeve abuts against the inner step of the body center hole.

6. The hydraulic jetting frac fluid centralizer of claim 1, wherein: The cooperation gap between the inner sleeve and the outer sleeve and the cooperation gap between the outer sleeve and the body center hole are both H10 / d10 or H10 / c10.

7. The hydraulic jetting frac fluid centralizer of claim 1, wherein: The wall thickness of the inner sleeve and the outer sleeve is 2mm respectively.

8. The hydraulic jetting frac fluid centralizer of claim 2, wherein: The slit width of the inner sleeve wire cutting slit and the outer sleeve wire cutting slit is 0.2-0.3mm respectively.

Images