An intelligent tracer full-contact flow-bypass downhole control system

Abstract

The present invention discloses an intelligent tracer full-contact flow-around downhole control system. The downhole control system comprises a hollow cylinder formed by a base pipe and an outer pipe; a circular tracer mounting plate is provided in the annulus of the hollow cylinder, and oil-soluble tracers and water-soluble tracers are arranged on the tracer mounting plate, and the oil-soluble tracers and water-soluble tracers are alternately arranged along the axial direction of the hollow cylinder; a plurality of circumferential and axial slit holes are provided on the wall of the outer pipe; an inflow through hole is provided at one end of the base pipe. When the downhole control system of the present invention is applied, the tracer is installed in the production tubing, and the tracer is gradually released along with the production fluid. The production of the monitoring well or different production layers is determined by detecting the tracer content. The intelligent tracer full-contact flow-around downhole control system of the present invention can realize tracer monitoring of oil and gas wells or production monitoring of different outputs or different well sections, dynamic monitoring of oil reservoir production, and evaluation of reservoir transformation effects.

Description

Technical Field

[0001] The present invention relates to an intelligent tracer full-contact flow-bypass type downhole control system, belonging to the technical field of key production parameter monitoring in the process of oil and natural gas extraction. Background Art

[0002] The production profile, liquid production rate, water breakthrough time, and water production rate of oil and gas reservoirs and wells are crucial to the efficient development of oil and gas fields. To overcome the limitations of traditional production logging tools (PLTs) and enable long-term online monitoring of oil and gas well production, an intelligent tracer production profile online testing technology has been developed. Its core features include two aspects: first, intelligent tracer encapsulation and slow release, detection and interpretation technology; second, a downhole intelligent tracer tethering and control device.

[0003] Smart chemical tracers are an emerging technology that eliminates the need for major changes to the completion or production string of an oil and gas well and enables the acquisition of critical information such as reservoir and well fluid profiles, fluid production rates, water breakthrough time, and water production without disrupting production. A key element of this intelligent tracer technology lies in encapsulating water-soluble or oil-soluble tracers with water-soluble polymers and oil-soluble polymers, respectively. Due to the differences in solubility of the tracers, oil-soluble tracers in polymers are slowly released upon contact with crude oil but become inert and unable to release upon contact with water. Conversely, water-soluble tracers in polymers are slowly released upon contact with water but become inert upon contact with crude oil. Currently, intelligent tracer encapsulation and release technologies primarily utilize polyethylene, polypropylene, ethylene glycol, or polyurethane for encapsulation, resulting in strips, ropes, and other forms. However, the limited material used for tracer encapsulation and the shape of the tracers result in a relatively short effective release period. The downhole intelligent tracer binding control device mainly adopts direct grooving on the surface of the base pipe or welding the groove plate to the surface of the base pipe, and simultaneously controls the oil-soluble tracer and water-soluble tracer in different grooves. Figure 1 Due to the influence of slotting and the spacing control method of oil-soluble tracer materials and water-soluble tracer materials, it is impossible to ensure that the oil phase and water phase in the wellbore are in contact with the corresponding tracer materials during the production process. Therefore, the release of tracers during the production process is somewhat accidental, and the test results cannot fully reflect the actual situation downhole. Figure 4 shown. Summary of the Invention

[0004] The purpose of the present invention is to provide an intelligent tracer full-contact flow-bypass downhole control system, which can realize comprehensive, accurate and intelligent slow release of tracers and long-term monitoring of oil and liquid production profiles in various sections of oil and water wells.

[0005] The intelligent tracer full-contact flow-around downhole control system provided by the present invention comprises a hollow cylinder formed by a base pipe and an outer pipe;

[0006] A circular tracer mounting plate is provided in the annulus of the hollow cylinder, and oil-soluble tracers and water-soluble tracers are arranged on the tracer mounting plate. The oil-soluble tracers and the water-soluble tracers are arranged alternately along the axial direction of the hollow cylinder.

[0007] The outer tube is provided with a plurality of slot holes evenly distributed along the circumference and axis.

[0008] An inflow through hole is provided at one end of the base pipe, and the tracer released during the oil production process flows into the oil pipe together with the produced liquid through the inflow through hole.

[0009] In the above-mentioned downhole control system, the tracer mounting plate is a rubber plate fixed on the base pipe.

[0010] In the above-mentioned downhole control system, the tracer installation plate is provided with evenly arranged tracer installation holes.

[0011] In the above-mentioned downhole control system, the outer tube includes two symmetrical parts, both ends of which are provided with countersunk threaded holes.

[0012] The present invention further provides a method for using the downhole control system, comprising the following steps:

[0013] S1. Installing an oil-soluble tracer and a water-soluble tracer on the tracer installation plate in the downhole monitoring system;

[0014] S2. Installing the tracer mounting plate on the base pipe and fixing it;

[0015] S3, sleeve the outer pipe onto the base pipe to assemble the downhole control system;

[0016] S4, connecting the downhole control system to the production string of the oil and gas well and lowering it into the corresponding production layer;

[0017] S5. During the production process, the produced fluid flows into the annulus of the hollow cylinder through the slotted holes on the outer pipe and contacts the oil-soluble tracer and the water-soluble tracer. The corresponding oil-soluble tracer and the water-phase tracer are intelligently and selectively released according to the contacted oil phase or water phase, and then flows into the oil pipe through the inflow hole on the base pipe. The production of the monitoring well or different production layer sections is determined by detecting the content of the oil-soluble tracer and the water-phase tracer.

[0018] The oil-soluble tracer and the water-phase tracer are both cylindrical, with a diameter of 10-15 mm and a height of 6-10 mm.

[0019] The packaging material used for the oil-soluble tracer is polylactic acid, polymethyl methacrylate, polystyrene, nylon 66, polyethylene terephthalate, polyethylene or polypropylene. After packaging, the mass content of the oil-soluble tracer is 10% to 30%.

[0020] The packaging materials used for the water-phase tracer are liquid resin and curing agent, the liquid resin is epoxy resin, phenolic resin or furfuryl alcohol resin, and the curing agent is ethylenediamine or weak organic acid. After packaging, the mass content of the water-soluble tracer is 10% to 30%.

[0021] The intelligent tracer full-contact flow-bypass downhole control system provided by the present invention can achieve comprehensive, precise, and intelligent slow-release of tracers. The intelligent slow-release tracers include water-soluble and oil-soluble tracers, which are evenly spaced and distributed on the tracer mounting plate. Fluid flows through the space where the tracers are evenly distributed, and the fluid and tracers are fully and comprehensively contacted. The water-soluble intelligent slow-release tracer releases the tracer evenly when it comes into contact with water, but not when it comes into contact with oil; the oil-soluble intelligent slow-release tracer releases the tracer when it comes into contact with oil, but not when it comes into contact with water. The release rate is uniform and controllable, and the release period is as long as 10 years. The tracer monitoring technology of the present invention is used to monitor the oil and liquid production profiles of various sections of oil and water wells over the long term.

[0022] The intelligent tracer full-contact flow-by-flow downhole control system of the present invention can realize tracer monitoring of oil and gas wells or production monitoring of different outputs or different well sections, dynamic monitoring of oil reservoir production, and evaluation of reservoir transformation effects.

[0023] When the downhole control system of the present invention is used, a tracer is installed in the production string, and the tracer is gradually released along with the produced fluid. The production of the monitoring well or different production layer sections is determined by detecting the tracer content.

[0024] The tracer monitoring technology of the present invention is used to monitor the oil production and liquid production profiles of various sections of oil and water wells over a long period of time. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a photo of tracer deployment for a conventional intelligent tracer system.

[0026] Figure 2 This is a schematic structural diagram of the intelligent tracer full-contact flow-bypass downhole control system of the present invention.

[0027] Figure 3 The figure is a schematic diagram of the control mode of water-soluble tracers and oil-soluble tracers in the intelligent tracer full-contact flow-bypass downhole control system of the present invention.

[0028] Figure 4 This is a three-dimensional diagram of the tracer deployment of a conventional intelligent tracer system.

[0029] Figure 5 Schematic diagram of tracer explanation for a certain well.

[0030] Figure 6 Schematic diagram of the tracer release device installation in a well.

[0031] The marks in the figure are as follows:

[0032] 1. Base tube; 2. Countersunk screw; 3. Inflow hole; 4. Tracer mounting plate; 5. Slit hole; 6. Outer tube; 7. Water-soluble tracer; 8. Oil-soluble tracer; 9. Tracer retaining ring; 10. Circlip; DETAILED DESCRIPTION

[0033] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0034] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0035] like Figure 2 The figure shows the structure of the intelligent tracer full-contact flow-around downhole control system provided by the present invention, which includes a hollow cylinder formed by a base pipe 1 and an outer pipe 6. A circular tracer mounting plate 4 is provided in the annulus of the hollow cylinder, which can be a rubber plate. A tracer retaining ring 9 is used to limit the axial movement of the tracer mounting plate 4, which is fixed by a retaining spring 10. Several cylindrical tracer mounting holes are evenly arranged on the tracer mounting plate 4 for installing oil-soluble tracers 8 and water-soluble tracers 7. Along the axial direction of the hollow cylinder, the oil-soluble tracers 8 and the water-soluble tracers 7 are evenly and alternately arranged, as shown in FIG. Figure 3 shown.

[0036] like Figure 2 As shown, the outer tube 6 has a plurality of slot holes 5 uniformly distributed along the circumference and the axial direction on its wall; an inflow hole 3 is provided at one end of the base tube, and the tracer released during the oil production process flows into the oil pipe through the inflow hole 3 together with the produced liquid.

[0037] In the downhole control system of the present invention, the outer pipe 6 includes two symmetrical parts, and both ends are engaged with the base pipe 1 through countersunk screws 2.

[0038] When using the intelligent tracer full-contact flow-bypass downhole control system of the present invention, the following steps are followed:

[0039] 1. Packaging of cylindrical intelligent tracers

[0040] Method 1: Prepare polymer particles, such as polylactic acid, polymethyl methacrylate, polystyrene, nylon 66, polyethylene terephthalate (PET), polyethylene, and polypropylene. Mix these polymer particles with a trace tracer, such as a rare earth element, a fluorinated carboxylic acid, a perfluoroalkane, or a fluorescent quantum dot, with the tracer comprising between 10% and 30%. Finally, use an extruder to extrude the mixture into a mold with a diameter of 10-15 mm and a height of 6-10 mm. The tracers are rare earth elements, fluorinated carboxylic acids, perfluoroalkanes, and fluorescent quantum dots.

[0041] Method 2: The liquid resins are epoxy resins E44 and E51, phenolic resin, or furfuryl alcohol resin, and the curing agent is ethylenediamine or a weak organic acid. A tracer is added to the resin solution under high-speed stirring to uniformly disperse the tracer. The corresponding curing agent is then added and stirred. After mixing thoroughly, the mixture is poured into a mold and cured to form a cylinder with a diameter of 10-15 mm and a height of 6-10 mm. The tracers include rare earth element tracers, fluorinated carboxylic acids, perfluoroalkane tracers, and fluorescent quantum dot tracers.

[0042] 2. Implementation of underground intelligent tracer restraint device and control

[0043] 1) Mounting the prepared cylindrical tracer on the tracer mounting plate 4;

[0044] 2) Install the tracer mounting plate 4 loaded with the tracer on the base pipe 1, use the tracer retaining ring 9 to limit the axial movement of the tracer mounting plate 4, and fix it with the retaining spring 10;

[0045] 3) Install the two-piece outer tube 6 on the base tube 1 using the countersunk screws 2. The tracer slow release device is now installed.

[0046] 3. Monitoring steps

[0047] 1) Connect the corresponding intelligent tracer full-contact bypass flow downhole control system to the oil and gas well production string according to the depth of the production layer and the number of monitoring well sections;

[0048] 2) Run a series of intelligent tracer full contact flow-around downhole control systems into the oil and gas well production string, so that the intelligent tracer full contact flow-around downhole control systems are deployed in the corresponding production intervals (such as Figure 6 shown);

[0049] 3) During the production process, the produced fluid flows into the pipe through the external slotted holes and contacts the tracer. The tracer selectively releases the corresponding tracer according to the contact oil phase, water phase, etc., and flows into the oil pipe through the base pipe hole (such as Figure 5 shown).

[0050] like Figure 5 As shown, the oil and water flow channels in the intelligent tracer full-contact flow-bypass downhole control system of the present invention are not independent flow units. After the fluid passes through the screen, the oil and water phases inevitably flow around each other under the action of the columnar tracer blocks, thus ensuring that the oil and water phases are fully in contact with their respective tracer materials. Furthermore, the tracers are arranged horizontally, spaced apart along the direction of water flow, further ensuring full contact between the oil and water phases and their respective tracer materials. This overcomes the certain degree of randomness inherent in the detection process of the strip tracer pup control system, further improving the reliability and accuracy of monitoring oil well production and water breakthrough time.

[0051] like Figure 4 The figure below shows a three-dimensional diagram of tracer layout in a conventional intelligent tracer system. It can be seen that each slot in the strip tracer sub is an independent flow unit, and each flow unit is separately controlled by an oil-soluble tracer or a water-soluble tracer. After the fluid flows through the screen, it is affected by this slot and tracer layout method, and it is not possible to fully ensure that the oil phase and water phase are in contact with the corresponding tracer materials. If the following occurs: Figure 4 If the water phase flows into the oily tracer tank, or the oil phase flows into the water-soluble tracer tank, as shown in (b), neither the water-soluble nor the oil-soluble tracer can be effectively released, which in turn affects the accuracy of monitoring oil production and water breakthrough time. Therefore, when a strip tracer is short-circuited, tracer release during production is somewhat accidental, and the test results may not fully reflect the actual downhole conditions.

Claims

1. An intelligent tracer full-contact flow-around downhole control system, comprising a hollow cylinder formed by a base pipe and an outer pipe; A circular tracer mounting plate is provided in the annulus of the hollow cylinder, and oil-soluble tracers and water-soluble tracers are arranged on the tracer mounting plate. The oil-soluble tracers and the water-soluble tracers are arranged alternately along the axial direction of the hollow cylinder. The outer tube is provided with a plurality of slit holes along the circumference and the axial direction on the tube wall; One end of the base pipe is provided with an inlet through hole; The tracer installation plate is evenly arranged with a plurality of cylindrical tracer installation holes, and the oil-soluble tracer and the water-soluble tracer are evenly distributed on the tracer installation plate at intervals.

2. The downhole control system according to claim 1, characterized in that: The tracer mounting plate is a rubber plate fixed on the base pipe.

3. The downhole control system according to claim 1 or 2, characterized in that: The outer tube comprises two symmetrical parts, both ends of which are provided with countersunk threaded holes.

4. The downhole control system according to claim 1 or 2, characterized in that: The oil-soluble tracer and the water-soluble tracer are both cylindrical, with a diameter of 10 to 15 mm and a height of 6 to 10 mm.

5. The downhole control system according to claim 1 or 2, characterized in that: The packaging material used for the oil-soluble tracer is polylactic acid, polymethyl methacrylate, polystyrene, nylon 66, polyethylene terephthalate, polyethylene or polypropylene. After packaging, the mass content of the oil-soluble tracer is 10% to 30%.

6. The downhole control system according to claim 1 or 2, characterized in that: The packaging materials used for the water-soluble tracer are liquid resin and curing agent, the liquid resin is epoxy resin, phenolic resin or furfuryl alcohol resin, and the curing agent is ethylenediamine or weak organic acid. After packaging, the mass content of the water-soluble tracer is 10% to 30%.

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