A horizontal well staged tracer monitoring string

Abstract

The application discloses a horizontal well segmented tracer monitoring pipe column, relates to the oil field production technology field, and comprises a main body oil pipe, tracer short sections are arranged at intervals on the main body oil pipe, guide shoes and circulating stop valves are arranged at two ends of the main body oil pipe, sand blasting through holes and assembling holes are arranged on the outside of the tracer short sections, slidable adjusting sliding sleeves are embedded in the inside of the tracer short sections, the adjusting sliding sleeves are positioned through shear pins, the tracer piece adopts a stepped double-cavity capsule, the inner capsule is filled with water-soluble tracers, the outer capsule is made of degradable polymer, a buffer cavity is reserved in the middle of the outer capsule and is filled with silicone oil, during work, the adjusting sliding sleeves switch modes according to pressure differences, uniform injection of fracturing fluid and accurate release of tracers are realized, the problems of poor pressure adaptability and inaccurate monitoring in the prior art are overcome, and the monitoring efficiency and reliability of the segmented liquid production of the horizontal well are remarkably improved.

Description

Technical Field

[0001] This utility model relates to the field of oilfield production technology, and in particular to a horizontal well segmented tracer monitoring string. Background Technology

[0002] In the field of oilfield production, horizontal well segmented monitoring technology faces many challenges. In existing technologies, the tracer release mechanism often cannot adapt to the complex pressure changes downhole, resulting in inaccurate or delayed monitoring data. For example, during fracturing and oil production, formation pressure fluctuations can interfere with the stable release of tracers, causing errors in segmented production assessment. In addition, traditional tubing structures lack effective fluid guidance and mixing designs, which can easily lead to uneven tracer diffusion or excessively high local concentrations, affecting monitoring accuracy. These shortcomings limit the need for efficient development of horizontal wells, and there is an urgent need for an improved solution that can achieve pressure self-adaptation and accurate segmented monitoring. Utility Model Content

[0003] This application provides a horizontal well segmented tracer monitoring string, which solves the technical problems of unstable tracer release and inability to adapt to pressure changes in the prior art. By adopting a sliding adjustable sleeve and a stepped double-cavity bladder structure, it achieves the technical effects of segmented precise monitoring and pressure adaptive release.

[0004] This application provides a horizontal well segmented tracer monitoring string, including a main tubing with tracer subsections spaced apart on the main tubing. Guide shoes and circulation shut-off valves are respectively installed at both ends of the main tubing. Sealing packers are correspondingly installed at both ends of the tracer subsections. Sandblasting through-holes and mounting holes for embedding tracer components are formed on the outer wall of the tracer subsections. An axially sliding adjusting sleeve is embedded inside the tracer subsection. A primary ball seat is fixed on the adjusting sleeve and positioned against the inner wall of the tracer subsection by shear pins. A flow-guiding gradient channel is formed on the adjusting sleeve corresponding to the sandblasting through-holes. The maximum sliding stroke is consistent with the spacing between the assembly hole and the sandblasting through hole; a central channel is opened at the center of the adjusting sleeve; the circulation shut-off valve includes an injection port and a sampling port, and a secondary ball seat is set at the injection port, the inner diameter of the secondary ball seat is larger than that of the primary ball seat; the tracer is a stepped double-cavity capsule, which consists of an inner capsule and an outer capsule. The inner capsule is filled with a highly soluble water-soluble tracer, and the outer capsule is made of a gradient thickness biodegradable polymer. An annular buffer cavity is reserved between the inner capsule and the outer capsule, and the annular buffer cavity is filled with low viscosity damping silicone oil.

[0005] The flow guiding gradient channel extends through the side wall of the adjusting sleeve along the axial direction of the adjusting sleeve and is divided into a fine diameter section, a conical transition section and a coarse diameter section in sequence; the fine diameter section has a hole diameter of 8mm and the coarse diameter section has a hole diameter of 12mm; the inner wall of the flow guiding gradient channel is machined with a continuous spiral flow guiding groove.

[0006] The narrow section of the flow-guiding gradient channel has a gap of 0.1-0.2 mm with the opening end of the inner bladder; the wide section is adapted to the inner port of the sandblasting through hole; the taper of the conical transition section is 1:5.

[0007] The outer bladder is further divided into an outer bladder layer and an inner bladder layer. The outer bladder layer has a thickness of 0.8 mm on the side closest to the inner wall of the main tubing, and the inner bladder layer has a thickness of 1.2 mm on the side closest to the formation. The width of the annular buffer cavity is 0.2-0.5 mm. The inner bladder has a cylindrical structure with an open end at one end and a hemispherical closed end at the other end. The diameter of the open end is 8 mm.

[0008] The sandblasting through holes are conical through holes, evenly distributed along the circumference of the tracer short circuit, with an outer port diameter of 10mm and an inner port diameter of 6mm.

[0009] The inner capsules of the stepped double-lumen capsules on multiple tracer segments are loaded with different types of water-soluble tracers.

[0010] The assembly hole is divided into an outer section and an inner section from the outside to the inside. The outer bladder is fixed to the outer section of the assembly hole with an interference fit, and the inner bladder is fixed to the inner section with a clearance fit.

[0011] One or more technical solutions provided in this application have at least the following technical effects or advantages: By adjusting the switching design of the sliding sleeve, seamless switching between sandblasting mode and tracer mode is achieved, improving operational efficiency; the stepped dual-chamber capsule utilizes an annular buffer chamber and silicone oil filling to effectively buffer pressure fluctuations and ensure that the tracer release rate adapts to formation pressure; the spiral guide groove of the flow-guiding gradient channel promotes uniform fluid mixing and prevents local concentration deviations; the overall structure simplifies the monitoring process and improves the accuracy and reliability of horizontal well segmented production assessment. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of a horizontal well segmented tracer monitoring string according to the present invention; Figure 2 This is a half-section structural diagram of the tracer section of a horizontal well segmented tracer monitoring string according to the present invention; Figure 3 This is a schematic diagram of the flow-guiding gradient channel structure of a horizontal well segmented tracer monitoring string according to the present invention; Figure 4 This is an enlarged view of position A of a horizontal well segmented tracer monitoring string according to this utility model.

[0013] In the picture: 100. Main oil pipe; 101. Guide shoe; 102. Circulation shut-off valve; 103. Sealing packer; 104. Secondary ball seat; 200. Tracer sub; 210. Sandblasted through hole; 211. Shear pin; 212. Primary ball seat; 220. Assembly hole; 230. Stepped double-chamber bladder; 231. Outer layer of outer bladder; 232. Inner layer of outer bladder; 233. Annular buffer chamber; 234. Inner bladder; 240. Adjusting sleeve; 241. Flow guide gradient channel; 2411. Narrow diameter section; 2412. Conical transition section; 2413. Large diameter section. Detailed Implementation

[0014] To facilitate understanding of this utility model, a more comprehensive description of this application will be given below with reference to the accompanying drawings, which show preferred embodiments of the utility model. However, the utility model can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to enable a more thorough and complete understanding of the disclosure of this utility model.

[0015] It should be noted that the terms "vertical," "horizontal," "up," "down," "left," "right," and similar expressions used in this article are for illustrative purposes only and do not represent the only possible implementation.

[0016] 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 this invention pertains; the terminology used herein in the description of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention; the term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0017] Example 1: As Figures 1 to 4As shown, this application discloses a horizontal well segmented tracer monitoring string, including a main tubing 100, with tracer subsections 200 spaced apart on the main tubing 100, and guide shoes 101 and circulation shut-off valves 102 respectively installed at both ends; sealing spacers 103 are correspondingly installed at both ends of the tracer subsections 200; sandblasting through holes 210 and assembly holes 220 for embedding tracer components are opened on the outer wall of the tracer subsections 200; an axially sliding adjusting sleeve 240 is embedded inside the tracer subsections 200, a primary ball seat 212 is fixed on the adjusting sleeve 240 and positioned with the inner wall of the tracer subsections 200 by shear pins 211, and a flow guide is opened on the adjusting sleeve 240 corresponding to the sandblasting through holes 210. The gradient channel 241 has a maximum sliding stroke that is consistent with the spacing between the assembly hole 220 and the sandblasting through hole 210; the adjusting sleeve 240 has a central channel at its center; the circulation shut-off valve 102 includes an injection port and a sampling port, and a secondary ball seat 104 is provided at the injection port, the inner diameter of the secondary ball seat 104 being larger than that of the primary ball seat 212; the tracer is a stepped double-cavity capsule 230, which consists of an inner capsule 234 and an outer capsule, the inner capsule 234 being filled with a highly soluble water-soluble tracer, the outer capsule being made of a gradient thickness biodegradable polymer, and an annular buffer cavity 233 being reserved between the inner capsule 234 and the outer capsule, the annular buffer cavity 233 being filled with low viscosity damping silicone oil.

[0018] The flow guiding gradient channel 241 extends axially through the side wall of the adjusting sleeve 240 and is divided into a narrow diameter section 2411, a conical transition section 2412, and a coarse diameter section 2413. The diameter of the narrow diameter section 2411 is 8 mm, and the diameter of the coarse diameter section 2413 is 12 mm. The inner wall of the flow guiding gradient channel 241 is machined with continuous spiral flow guiding grooves.

[0019] The narrow section 2411 of the flow-guiding gradient channel 241 has a gap of 0.1-0.2 mm with the opening end of the inner bladder 234; the wide section 2413 is adapted to the inner port of the sandblasting through hole 210; the taper of the conical transition section 2412 is 1:5.

[0020] The outer capsule is further divided into an outer layer 231 and an inner layer 232. The outer layer 231 has a thickness of 0.8 mm on the side near the inner wall of the main tubing 100, and the inner layer 232 has a thickness of 1.2 mm on the side near the formation. The width of the annular buffer cavity 233 is 0.2-0.5 mm to ensure that the silicone oil can effectively buffer pressure fluctuations and prevent the inner capsule 234 from being directly compressed (e.g., when the pressure rises to 18 MPa, the buffer cavity is compressed to slow down the release of the tracer). The inner capsule 234 has a cylindrical structure with an open end and a hemispherical closed end on the other end. The diameter of the open end is 8 mm.

[0021] The sandblasting through-hole 210 is a conical through-hole, evenly distributed along the circumferential direction of the tracer short circuit, with an outer port diameter of 10mm and an inner port diameter of 6mm.

[0022] The inner capsules 234 of the stepped double-lumen capsules 230 on the multiple tracer segments 200 are loaded with different types of water-soluble tracers.

[0023] The assembly hole 220 is divided into an outer section and an inner section from the outside to the inside. The outer bladder is fixed to the outer section of the assembly hole 220 with an interference fit, and the inner bladder 234 is fitted with the inner section with a clearance fit.

[0024] Specific implementation: The stepped double-lumen capsule 230 is embedded into the assembly hole 220 of the tracer sub 200 (the outer capsule is fixed with an interference fit to the outer section of the assembly hole 220, and the inner capsule 234 is clearance-fitted with the inner section), and silicone oil is filled in the annular buffer cavity 233; the adjusting sleeve 240 is fixed inside the tracer sub 200 by multiple shear pins 211, at which time the flow guiding gradient channel 241 of the adjusting sleeve 240 (the diameter of the coarse diameter section 2413 is 12mm) is aligned with the sandblasting through hole 210 (inner diameter 6mm) of the tracer sub 200, and the spiral flow guiding groove of the flow guiding gradient channel 241 forms line contact with the inner wall of the sandblasting through hole 210; the entire tubing string is lowered into the horizontal well, the guide shoe 101 guides the tubing string to the predetermined well section, and the sealing packer 103 sets and seals to separate each section.

[0025] The first soluble ball (10mm in diameter, matching the taper of the first-stage ball seat 212) is inserted into the tubing string. The soluble ball flows with the fluid to the first-stage ball seat 212 of the regulating sleeve 240. The soluble ball fits tightly against the inner wall of the ball seat, sealing the internal channel of the regulating sleeve 240. In sandblasting mode, the fracturing fluid needs to flow from the central channel of the regulating sleeve 240 into the guide gradient channel 241, and after being guided by the spiral guide groove, it is sprayed into the formation. The diameter of the coarse section 2413 is 12mm, which is 6mm larger than the inner port of the sandblasting through hole 210, forming an "expansion cavity". After the fracturing fluid enters the coarse-diameter section 2413 from the central channel (high flow velocity), the flow area increases and the flow velocity decreases (for example, from 1-2 m / s to 0.5-0.8 m / s), avoiding high-speed fluid scouring the well wall. The spiral guide channel of the coarse-diameter section 2413 makes the fracturing fluid form a rotating flow state. When the rotating fluid passes through the inner port (6 mm) of the sandblasting through hole 210, due to the uniform distribution of centrifugal force, it is evenly sprayed along the conical channel (outer 10 mm) of the sandblasting through hole 210, avoiding localized injection pressure concentration.

[0026] Continue to pressurize the tubing (e.g., increase the pressure to 15MPa), adjust the two sides of the sliding sleeve 240 to form a pressure difference (adjust the pressure on the left side of the sliding sleeve 240 to be higher than that on the right side), the pressure difference force overcomes the shear strength of the shear pin 211 (e.g., the fracture strength of the shear pin 211 is preset to 12MPa), and multiple shear pins 211 break at the same time. Adjust the sliding sleeve 240 to slide along the axis of the tracer short section 200 toward the guide shoe 101 (with the same spacing as the assembly hole 220 and the sandblasting through hole 210) until the narrow diameter section 2411 (8mm) of the flow guiding gradient channel 241 is aligned with the opening end of the inner bladder 234, and the inner wall of the flow guiding gradient channel 241 forms a line contact with the opening end of the inner bladder 234. The soluble spheres slowly dissolve in the fluid (e.g., if the material is polylactic acid, the dissolution time is 2 hours), and the internal channels of the adjusting sleeve 240 are restored to unobstructed flow. At this time, the adjusting sleeve 240 switches to "tracer mode". In tracer mode, the tracer needs to flow from the opening end (8mm) of the inner bladder 234 into the narrow section 2411, mix through the spiral guide groove, and then enter the central channel of the adjusting sleeve 240. The diameter of the narrow section 2411 is 8mm < the inner diameter of the assembly hole 220 is 15mm, forming a "nested structure". Section 2411 is inserted into the inner space of assembly hole 220. The inner layer 232 (1.2mm thick) of the outer capsule fits against the inner wall of assembly hole 220. The narrow section 2411 is only connected to the opening end of the inner capsule 234, blocking the path of tracer leakage into the gap of assembly hole 220. The diameter of the narrow section 2411 is the same as the opening end of the inner capsule 234. After the tracer flows out, it directly enters the spiral guide groove, avoiding tracer diffusion caused by excessively large pore size, ensuring that the spiral groove can fully stir and mix, and improving concentration uniformity. The second soluble ball (the second soluble ball has a diameter of 15mm, which is larger than the inner diameter of the secondary ball seat 104 by 12mm) is inserted. The soluble ball flows to the secondary ball seat 104 of the circulation shut-off valve 102, which blocks the injection port. The tubing is switched to "oil production mode". The formation fluid (product fluid) enters the tracer section 200 through the section separated by the sealing packer 103. If the formation pressure increases (e.g., the pressure rebounds to 18 MPa after fracturing), the outer layer 231 (wall thickness 1.2 mm) of the outer bladder is slightly compressed due to the pressure, slowing down the polymer dissolution rate (the thick-walled structure delays dissolution). At the same time, the silicone oil in the annular buffer cavity 233 is squeezed by the pressure, applying a buffering force to the inner bladder 234 (avoiding direct pressure on the inner bladder 234), and the tracer release rate of the inner bladder 234 decreases (e.g., from 0.5 mg / min to 0.3 mg / min). If the formation pressure decreases (e.g., the pressure drops to 8 MPa in the later stages of oil production), the inner layer 232 (wall thickness 0.8 mm) of the outer bladder dissolves first (thin-walled structures are easily dissolved), the outer bladder expands as a whole, the silicone oil in the annular buffer cavity 233 releases its buffering force, the inner bladder 234 expands slightly under the action of fluid, and the tracer release rate increases (e.g., from 0.5 mg / min to 0.7 mg / min). The tracer enters the product liquid through the spiral guide channel 241. The spiral guide channel causes the tracer and the product liquid to form a rotating mixture (avoiding excessively high local concentrations), and finally it is produced from the oil extraction port along with the product liquid.

[0027] Periodically collect product samples from the collection port (e.g., once every 24 hours), and detect the concentration of different tracers in the samples using a chromatograph; based on the correspondence between tracer concentration and release rate, infer the product volume of each stage; calculate the proportion of product volume of each stage to the total product volume, which is the product contribution value of each stage.

[0028] Beneficial effects: By adjusting the switching design of the sliding sleeve 240, seamless switching between sandblasting mode and tracer mode is achieved, improving operational efficiency; the stepped dual-chamber capsule 230, using an annular buffer chamber 233 and silicone oil filling, effectively buffers pressure fluctuations and ensures that the tracer release rate adapts to formation pressure; the spiral guide groove of the flow-guiding gradient channel 241 promotes uniform fluid mixing and prevents local concentration deviations; the overall structure simplifies the monitoring process and improves the accuracy and reliability of horizontal well segmented production assessment.

[0029] The above description is merely a preferred embodiment of this utility model and is not intended to limit the scope of this utility model. For those skilled in the art, various modifications and variations are possible with this utility model. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A segmented tracer monitoring string for horizontal wells, characterized in that, The system includes a main oil pipe (100), on which tracer subsections (200) are spaced apart, with guide shoes (101) and circulation shut-off valves (102) installed at both ends respectively; sealing spacers (103) are installed at both ends of the tracer subsections (200); sandblasting through holes (210) and assembly holes (220) for embedding tracer components are provided on the outer wall of the tracer subsections (200); an axially sliding adjusting sleeve (240) is embedded inside the tracer subsections (200), a primary ball seat (212) is fixed on the adjusting sleeve (240) and positioned with the inner wall of the tracer subsections (200) by shear pins (211), and a flow guiding gradient channel (24) is provided on the adjusting sleeve (240) corresponding to the sandblasting through holes (210). 1) The maximum sliding stroke is consistent with the distance between the assembly hole (220) and the sandblasting through hole (210); a central channel is opened at the center of the adjusting sleeve (240); the circulation shut-off valve (102) includes an injection port and a sampling port, and a secondary ball seat (104) is set at the injection port. The inner diameter of the secondary ball seat (104) is larger than that of the primary ball seat (212); the tracer is a stepped double-cavity capsule (230), which is composed of an inner capsule (234) and an outer capsule. The inner capsule (234) is filled with a highly soluble water-soluble tracer, and the outer capsule is made of a gradient thickness biodegradable polymer. An annular buffer cavity (233) is reserved between the inner capsule (234) and the outer capsule. The annular buffer cavity (233) is filled with low viscosity damping silicone oil.

2. The horizontal well segmented tracer monitoring string as described in claim 1, characterized in that, The flow guiding gradient channel (241) extends axially through the side wall of the adjusting sleeve (240) and is divided into a fine diameter section (2411), a conical transition section (2412), and a coarse diameter section (2413). The fine diameter section (2411) has a diameter of 8 mm and the coarse diameter section (2413) has a diameter of 12 mm. The inner wall of the flow guiding gradient channel is machined with a continuous spiral flow guiding groove.

3. The horizontal well segmented tracer monitoring string as described in claim 2, characterized in that, The narrow section (2411) of the flow guide gradient channel (241) has a gap of 0.1-0.2 mm with the opening end of the inner bladder (234); the wide section (2413) is adapted to the inner port of the sandblasting through hole (210); the taper of the tapered transition section (2412) is 1:

5.

4. The horizontal well segmented tracer monitoring string as described in claim 1, characterized in that, The outer capsule is further divided into an outer capsule outer layer (231) and an outer capsule inner layer (232). The outer capsule outer layer (231) has a thickness of 0.8 mm on the side near the inner wall of the main tubing (100), and the outer capsule inner layer (232) has a thickness of 1.2 mm on the side near the formation. The width of the annular buffer cavity (233) is 0.2-0.5 mm. The inner capsule (234) is a cylindrical structure with an open end at one end and a hemispherical closed end at the other end. The diameter of the open end is 8 mm.

5. The horizontal well segmented tracer monitoring string as described in claim 1, characterized in that, The sandblasting through hole (210) is a conical through hole, evenly distributed along the circumferential direction of the tracer short circuit, with an outer port diameter of 10mm and an inner port diameter of 6mm.

6. The horizontal well segmented tracer monitoring string as described in claim 1, characterized in that, The assembly hole (220) is divided into an outer section and an inner section from the outside to the inside. The outer bladder is fixed to the outer section of the assembly hole (220) with an interference fit, and the inner bladder (234) is fitted with the inner section with a clearance fit.

7. The horizontal well segmented tracer monitoring string as described in claim 1, characterized in that, The inner capsules (234) of the stepped double-lumen capsules (230) on multiple tracer segments (200) are loaded with different types of water-soluble tracers.

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