System and method for evaluating tracer adsorption migration law based on flowing coal reservoir water

Abstract

The present application provides a tracer adsorption migration rule evaluation system based on flowing coal reservoir water, the coal reservoir migration rule model of the system comprises a first plate body, an annular sealing layer and a second plate body connected in turn, a coal sample is laid in the first plate body, the annular sealing layer and the second plate body, a plurality of first through holes are vertically provided on the first plate body, a valve is arranged on each first through hole, a groove is vertically provided on the top surface of the second plate body, a second through hole is provided on the side wall of the second plate body and communicated with the groove; the outlet of the first piston filling device is communicated with any first through hole through a pipeline; the outlet of the second piston filling device is connected with the second through hole through a pipeline; when sampling, any first through hole not connected with the first piston filling device is selected as a sampling hole, and adsorbed water samples are sampled at intervals for a certain time length. The present application also provides a tracer adsorption migration rule evaluation method. The present application discloses the tracer fluid flow rule of the coal reservoir through the sampling concentration.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and natural gas, and in particular to a system and method for evaluating the adsorption and migration laws of tracers based on flowing coal reservoir water. Background Art

[0002] Coalbed methane (CBM) is a hydrocarbon gas primarily adsorbed on the surface of coal particles, with some remaining free within coal pores or dissolved in coal reservoir water. CBM coexists and is associated with coalbed water throughout its generation, migration, storage, and production processes. The development and utilization of CBM is a crucial component of unconventional oil and gas exploration and development, crucial for developing new energy sources and achieving a diversified energy supply. Its rational development and utilization is crucial for optimizing my country's energy structure.

[0003] Among them, the evolution law of coalbed water is closely related to the enrichment of coalbed methane. Systematic research on the evolution process and migration law of coalbed water is a necessary means to understand the occurrence characteristics and enrichment law of coalbed methane, and it is of great significance to the exploration and development of coalbed methane. For example: The patent number CN202311271575.2 applied for by the General Exploration and Research Institute of the China Coal Geology Bureau, entitled "A coal reservoir hydrodynamic field modeling method, device, equipment and storage medium", provides the following: in the preset hydrodynamic field simulation software, the coal reservoir hydrodynamic field control equation is selected to construct a three-dimensional geometric model of the coal reservoir hydrodynamic field; according to the set hydrogeological parameters of the coal reservoir hydrodynamic field, the boundary conditions of the coal reservoir hydrodynamic field model are set and the grid is divided; the hydrodynamic control equation is solved by the set solver; the three-dimensional geometric model of the hydrodynamic field is calculated through the operation mode to obtain the coal reservoir isowater level line and hydrodynamic zoning result graphics. The focus of this technology is on establishing a groundwater dynamic field model for coal reservoirs, but the description of the formation water flow field, pressure field, etc. is insufficient, and no experimental methods are used to verify the reliability of the simulation results. The patent number applied for by Sinopec is CN202211323543.8, and the patent name is "A quinoline chemical tracer for multi-stage fracturing, tracing method and fracturing fluid and use". It provides a quinoline chemical tracer with a low detection limit, which is suitable for interwell tracing technology. It can be applied to many formations with harsh conditions. The tracer has the advantages of strong temperature resistance, strong anti-adsorption ability, and no interference with each other. This technology takes into account the adsorption of tracers by the formation and does not involve coal reservoirs. However, the adsorption of tracers by coal reservoirs is much higher than that of strata. Therefore, the adsorption of coal reservoirs directly affects the actual recovery rate of coal reservoirs. Therefore, studying the adsorption of tracers by coal reservoirs is the key to affecting the accuracy of detection results. Therefore, it is very necessary to provide a tracer adsorption and migration law evaluation system and method based on flowing coal reservoir water. Summary of the Invention

[0004] In response to the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a system and method for evaluating the adsorption and migration laws of tracers based on flowing coal reservoir water. By detecting the tracer concentration in a sampled flat plate model, the adsorption of tracers by the coal reservoir can be truly reflected, providing accurate theoretical data support for the actual recovery rate of the coal reservoir.

[0005] To solve the above technical problems, the present invention provides a first technical solution: a system for evaluating the adsorption and migration patterns of tracers in flowing coal reservoir water, comprising a detection device for detecting adsorbed water samples containing tracers. The adsorbed water samples containing tracers are obtained by a coal reservoir adsorbed water sampling device, wherein the coal reservoir adsorbed water sampling device comprises:

[0006] A coal reservoir migration law model includes a first plate, an annular sealing layer, and a second plate that are detachably stacked from top to bottom. A coal sample is laid flat in a space formed by the first plate, the annular sealing layer, and the second plate. The first plate has a plurality of first through holes vertically extending therethrough, each of the first through holes being provided with a valve. A groove is formed on the top surface of the second plate, perpendicular to the plate surface. A second through hole communicating with the groove is formed on a side wall of the second plate.

[0007] a first piston filling device, the liquid outlet of which is connected to any of the first through holes via a pipeline, for delivering water into the coal sample so that the water treats the coal sample;

[0008] a second piston filling device, the liquid outlet of which is connected to the second through hole via a pipeline, and is used to deliver the tracer into the second through hole so that the tracer is adsorbed by the coal sample after the water treatment;

[0009] When sampling, any first through hole that is not connected to the first piston filling device is selected as the sampling hole, and the adsorbed water sample containing the tracer is sampled at a certain interval.

[0010] Preferably, the first plate body and the second plate body are both visual plates, and a plurality of the first through hole matrices are arranged on the first plate body.

[0011] Preferably, the first piston filling device includes a water syringe, a first pressure pump and a first water storage device, the liquid outlet of the water syringe is connected to any one of the first through holes through a pipeline, and the injection end of the water syringe is connected to the first water storage device through a pipeline and the first pressure pump;

[0012] The second piston filling device includes a tracer syringe, a second pressure pump and a second water storage device. The liquid outlet of the tracer syringe is connected to the second through hole through a pipeline, and the injection end of the tracer syringe is connected to the second water storage device through the pipeline and the second pressure pump.

[0013] The second solution provided by the present invention is to provide an evaluation method for a tracer adsorption and migration law evaluation system based on flowing coal reservoir water, characterized by comprising the following steps:

[0014] Selected and spare dry coal sample particles of different particle sizes are spread flatly in the space formed by the first plate, the annular sealing layer, and the second plate. The first plate, the annular sealing layer, and the second plate are then assembled and connected. A first through hole on the first plate is connected to a water injector via a pipeline, and a second through hole on the second plate is connected to a tracer injector via a pipeline.

[0015] The first pressure pump is started, the second pressure pump is shut down, water in the water injector is injected from a first through hole, and the valves connected to the other first through holes are opened until water flows out of the other first through holes, so that the coal reservoir is in a water-saturated state, and then the valves connected to the first pushing device and the other first through holes are closed;

[0016] When sampling, the second pressure pump is started, a first through hole is selected as the sampling hole, the valve on the first through hole is opened until liquid is discharged, and multiple samplings are performed at intervals of a certain length;

[0017] The samples were tested using an adsorption water sample detection device, the data obtained were summarized, and a tracer concentration profile image was drawn. Based on the obtained images and data, the tracer adsorption and migration laws under the influence of coal reservoir water flow were analyzed. The adsorption water sample detection device was an inductively coupled plasma mass spectrometer.

[0018] Preferably, a first through hole connected to the water injector is selected as the injection hole, and any other first through hole is selected as the sampling hole. The water flow direction is taken as the starting point and the sampling hole as the end point. By changing the sampling position of the sampling hole, the angle between the water flow direction and the tracer injection direction is adjusted to study the flow law of the tracer fluid in the coal reservoir.

[0019] Preferably, the sampling interval of the samples is 20 minutes, 30 minutes, 40 minutes, or 60 minutes.

[0020] Preferably, the tracer is injected at a concentration of 50 mg / L and an injection rate of 3 mL / min.

[0021] Preferably, the tracer is samarium chloride hexahydrate or lanthanum chloride hexahydrate.

[0022] Preferably, the coal sample particles are 16-60 meshes, and the coal sample particles need to be cleaned and removed of impurities before the experiment, and then dried for use.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The present invention provides an evaluation system for the adsorption and migration laws of tracers based on the study of coal reservoirs. A coal reservoir model is constructed by spreading a coal sample flat in a coal reservoir migration law model composed of a first plate, an annular sealing layer, and a second plate. Water is injected into the coal sample of the coal reservoir through a water injector to saturate the coal sample. Then, a tracer is injected into the water-saturated coal sample of the coal reservoir through the tracer injector. At regular intervals, any first through hole other than the first through hole serving as the water injection point is selected as a sampling point to sample adsorbed water containing the tracer, and the adsorption of the coal sample of the coal reservoir is studied. The adsorption of the tracer-containing water sample is sent to a detection device for measurement to obtain tracer data for different time periods. Based on the study of the adsorption of the tracer by the coal reservoir, the recovery rate of the coal reservoir can be truly reflected, providing accurate theoretical data support for the actual recovery rate of the coal reservoir.

[0025] 2. The present invention is used to study the effect of the heterogeneity of coal samples in coal reservoirs on tracer adsorption by changing the particle size of coal sample particles, and is used to study the permeability of coal samples in coal reservoirs by changing the water injection rate and the tracer injection rate. The present invention can also change the angle between the groundwater flow direction and the tracer injection direction by changing the position of groundwater injection and extraction, and then conduct injection experiments at different angles to study the effect of the angle between the groundwater flow direction and the tracer flow direction on the flow pattern of the injected fluid in the coal reservoir.

[0026] 3. The present invention uses a detection device to obtain concentration data for tracer-adsorbed water samples. Since each data point corresponds to a tracer-adsorbed water sampling point, the flow of the tracer in the coal reservoir can be deduced, further clarifying the impact of the coal reservoir and groundwater on the flow of the tracer fluid in the coal reservoir. This allows for experimental simulation of the impact of groundwater flow on the flow of the tracer fluid in the coal reservoir. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The present invention provides a tracer adsorption and migration law evaluation system based on flowing coal reservoir water.

[0028] Figure 2 This is an exploded diagram of the coal reservoir migration law model of the tracer adsorption migration law evaluation system based on flowing coal reservoir water of the present invention.

[0029] Figure 3 This is the assembled structure of the coal reservoir migration law model of the tracer adsorption migration law evaluation system based on flowing coal reservoir water of the present invention.

[0030] Figure 4 It is a structure after groundwater injection of a coal reservoir migration law model of a tracer adsorption migration law evaluation system based on flowing coal reservoir water of the present invention;

[0031] Figure 5This is a block diagram of the evaluation method of the tracer adsorption and migration law evaluation system based on flowing coal reservoir water of the present invention.

[0032] Figure 6 This is an inductively coupled plasma mass spectrometer test diagram of samples taken in Examples 1 to 3 of the present invention.

[0033] Description of reference numerals:

[0034] 1. First plate, 2. Second plate, 3. Annular sealing layer, 4. Threaded hole, 5. Water injection hole, 6. Sampling hole, 7. Groove, 8. Water syringe, 9. Tracer syringe, 10. First pressure pump, 11. First water storage device, 12. Second pressure pump, 13. Second water storage device. DETAILED DESCRIPTION

[0035] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention are described clearly and completely below. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0036] It should be noted that when the present invention involves a numerical range, it should be understood that the two endpoints of each numerical range and any numerical value between the two endpoints can be selected. Since the steps and methods used are the same as those in Examples 1-3, in order to avoid redundancy, the present invention describes a preferred embodiment, but the present invention is not limited thereto, but can also be specifically implemented in other ways within the scope of the technical solution defined in the attached claims.

[0037] like Figures 1 to 4 , a tracer adsorption and migration law evaluation system based on flowing coal reservoir water, including a detection device for detecting adsorbed water samples containing tracers, the adsorbed water samples containing tracers are obtained through a coal reservoir adsorption water sampling device, and the coal reservoir adsorption water sampling device includes: a coal reservoir migration law model, including a first plate body 1, an annular sealing layer 3 and a second plate body 2 stacked in sequence from top to bottom and detachably connected, the coal sample is laid flat in a space formed by the first plate body 1, the annular sealing layer 3 and the second plate body 2, a plurality of first through holes are vertically opened on the first plate body 1 and penetrate the plate body, each of the first through holes is provided with a valve, a groove 7 is opened on the top surface of the second plate body 2 and is perpendicular to the plate surface, a second through hole connected to the groove 7 is opened on the side wall of the second plate body 2, the depth and width of the groove 7 are both 0.5 cm, and the length of the groove 7 is 30 cm;

[0038] a first piston filling device, the liquid outlet of which is connected to any of the first through holes via a pipeline, for delivering water into the coal sample so that the water treats the coal sample;

[0039] a second piston filling device, the liquid outlet of which is connected to the second through hole via a pipeline, and is used to deliver the tracer into the second through hole so that the tracer is adsorbed by the coal sample after the water treatment;

[0040] When sampling, any first through hole that is not connected to the first piston filling device is selected as the sampling hole, and the adsorbed water sample containing the tracer is sampled at a certain interval.

[0041] Specifically, the first plate body 1 and the second plate body 2 are both visual plates, and a plurality of the first through-hole matrices are provided on the first plate body 1 .

[0042] Specifically, the first piston filling device includes a water injector 8, a first pressure pump 10 and a first water storage device 11, the liquid outlet of the water injector 8 is connected to any first through hole through a pipeline, and the injection end of the water injector 8 is connected to the first water storage device 11 through a pipeline and the first pressure pump 10;

[0043] The second piston filling device includes a tracer syringe 9, a second pressure pump 12 and a second water storage device 13. The liquid outlet of the tracer syringe 9 is connected to the second through hole through a pipeline, and the injection end of the tracer syringe 9 is connected to the second water storage device 13 through a pipeline and the second pressure pump 12.

[0044] The evaluation method of the tracer adsorption and migration law evaluation system based on flowing coal reservoir water includes the following steps:

[0045] The selected dry coal sample particles of different particle sizes are spread flat in the space formed by the first plate 1, the annular sealing layer 3 and the second plate 2. The first plate 1, the annular sealing layer 3 and the second plate 2 are then assembled and connected. A first through hole on the first plate 1 is connected to the water injector 8 through a pipeline, and a second through hole on the second plate 2 is connected to the tracer injector 9 through a pipeline.

[0046] The first pressure pump 10 is started, the second pressure pump 12 is closed, the water in the water injector 8 is injected from a first through hole, and the valves connected to the other first through holes are opened until water flows out of the other first through holes, so that the coal reservoir is in a water-saturated state, and then the first pressure pump 10 and the valves connected to the other first through holes are closed;

[0047] When sampling, the second pressure pump 12 is started, a first through hole is selected as the sampling hole, the valve on the first through hole is opened until the liquid is discharged, and multiple samples are taken at intervals of a certain length;

[0048] The samples were tested using an inductively coupled plasma mass spectrometer, the data obtained were summarized, and a tracer concentration profile image was drawn. Based on the obtained images and data, the tracer adsorption and migration laws under the influence of coal reservoir water flow were analyzed.

[0049] Specifically, a first through hole connected to the water injector 8 is selected as the injection hole, and any other first through hole is selected as the sampling hole. The injection hole is used as the starting point and the sampling hole is used as the end point as the water flow direction. By changing the sampling position of the sampling hole, the angle between the water flow direction and the tracer injection direction is adjusted to study the flow law of the tracer fluid in the coal reservoir.

[0050] Specifically, the sampling intervals of the samples are 20 minutes, 30 minutes, 40 minutes, and 60 minutes.

[0051] Specifically, the tracer was injected at a concentration of 50 mg / L and an injection rate of 3 mL / min.

[0052] Specifically, the tracer is samarium chloride hexahydrate or lanthanum chloride hexahydrate.

[0053] Specifically, the coal sample particles are 16-60 meshes, and the coal sample particles need to be cleaned and removed of impurities before the experiment, and then dried for use.

[0054] The inventors discovered that coal seams come into contact with water during storage. CBM extraction involves dewatering and reducing pressure. Clarifying the flow patterns of water in coal reservoirs can facilitate efficient CBM extraction. However, existing techniques only consider tracer adsorption by the formation, but not coal reservoirs. Coal reservoirs have strong adsorption properties, so when applied to coal reservoirs, this invention may be ineffective due to excessive adsorption.

[0055] The technical solution of the present invention is further illustrated below in the form of specific examples.

[0056] Example 1

[0057] The evaluation method of the tracer adsorption and migration law evaluation system based on flowing coal reservoir water includes the following steps:

[0058] Step 1: Crush the coal rock samples in the target area, screen out 40-60 mesh coal sample particles, clean and remove impurities from the screened coal sample particles, dry them and set aside.

[0059] Step 2: Stack the first plate 1 as a visible acrylic glass plate 1, the second plate 2 as a visible acrylic glass plate 2, and the annular sealing layer 3 as an annular silicone gasket 3 vertically, and form a storage space in the annular space of the annular silicone gasket 3 for filling coal sample particles to simulate a coal reservoir; drill threaded holes 4 evenly on the edges of the visible acrylic glass plate 1, the visible acrylic glass plate 2, and the annular silicone gasket 3, and pass bolts through the holes to fix the vertically stacked visible acrylic glass plate 1, the visible acrylic glass plate 2, and the annular silicone gasket 3. The annular silicone gasket 3 can be used to seal the edge of the device to ensure the sealing of the device; a plurality of first through holes are opened inside the visible acrylic glass plate 1, one of the first through holes can be used as a water injection hole 5, and the other plurality of first through holes can be used as sampling holes 6; a groove 7 is hollowed out on the visible acrylic glass plate 2 as a horizontal well, and a second through hole is drilled on the side of the groove. The second through hole is a threaded hole used to connect to the groove and serve as an injection end.

[0060] Step 3: Apply a layer of double-sided tape to the inside of acrylic glass plates 1 and 2. Evenly spread the coal sample particles prepared in Step 1 on the tape, ensuring a single layer. Stack visible acrylic glass plates 1 and 2, and annular silicone gasket 3 vertically and secure with bolts.

[0061] Step 4: Connect the second through hole to the tracer syringe 9 through a pipeline, and the tracer syringe 9 is connected to the second water storage tank 13 through a pipeline and a second pressure pump 12.

[0062] Step 5: Connect the water injection hole 5 to the water injector 8 through a pipeline, and the water injector 8 is connected to the first water storage tank 11 through a pipeline and a first pressure pump 10.

[0063] Step 6: Start the experiment, open all valves on the other first through holes except the water injection hole 5, start the first pressure pump 10, and close the second pressure pump 12. When all valves are discharging water, the coal reservoir coal seam is saturated with water, and then close the first pressure pump 10 and the valves connected to the other first through holes.

[0064] Start the second booster pump 12, close the valves on the water injection holes 6 except for the sampling hole 5, and inject samarium chloride hexahydrate at a concentration of 50 mg / L and a rate of 3 mL / min. Starting from the first discharge of liquid from the sampling hole 5, extract water samples from the sampling hole 5 at intervals of 20 minutes, 30 minutes, 40 minutes, and 60 minutes, and monitor the tracer concentration.

[0065] Step 7: The obtained samples are tested using an inductively coupled plasma mass spectrometer, the obtained data are summarized, and the tracer concentration profile of the well group is drawn. Based on the obtained images and data, the tracer adsorption and migration patterns under the influence of coal reservoir water flow are analyzed.

[0066] Example 2

[0067] The evaluation method of the tracer adsorption and migration law evaluation system based on flowing coal reservoir water includes the following steps:

[0068] Step 1: Crush the coal rock samples in the target block and select coal sample particles with mesh sizes of 16 to 30. Wash and remove impurities from the selected coal sample particles, dry them and set them aside.

[0069] Step 2: Stack the first plate 1 as a visible acrylic glass plate 1, the second plate 2 as a visible acrylic glass plate 2, and the annular sealing layer 3 as an annular silicone gasket 3 vertically, and form a storage space in the annular space of the annular silicone gasket 3 for filling coal sample particles to simulate a coal reservoir; drill threaded holes 4 evenly on the edges of the visible acrylic glass plate 1, the visible acrylic glass plate 2, and the annular silicone gasket 3, and pass bolts through the holes to fix the vertically stacked visible acrylic glass plate 1, the visible acrylic glass plate 2, and the annular silicone gasket 3. The annular silicone gasket 3 can be used to seal the edge of the device to ensure the sealing of the device; a plurality of first through holes are opened inside the visible acrylic glass plate 1, one of the first through holes can be used as a water injection hole 5, and the other plurality of first through holes can be used as sampling holes 6; a groove 7 is hollowed out on the visible acrylic glass plate 2 as a horizontal well, and a second through hole is drilled on the side of the groove. The second through hole is a threaded hole used to connect to the groove and serve as an injection end.

[0070] Step 3: Apply a layer of double-sided tape to the inside of acrylic glass plates 1 and 2. Evenly spread the coal sample particles prepared in step 1 on the tape, ensuring a single layer. Stack visible acrylic glass plates 1 and 2, and annular silicone gasket 3 vertically and secure with bolts.

[0071] Step 4: Connect the second through hole to the tracer syringe 9 through a pipeline, and the tracer syringe is connected to the second water storage tank 13 through a pipeline and a second pressure pump 12.

[0072] Step 5: Connect the water injection hole 5 to the water injector 8 through a pipeline, and the water injector 8 is connected to the first water storage tank 11 through a pipeline and a first pressure pump 10.

[0073] Step 6: Start the experiment, open all valves on the other first through holes except the water injection hole 5, start the first pressure pump 10, and close the second pressure pump 12. When all valves are discharging water, the coal reservoir coal seam is saturated with water, and then close the first pressure pump 10 and the valves connected to the other first through holes.

[0074] Start the second booster pump 12, close the valves on the water injection holes 6 except for the sampling hole 5, and inject samarium chloride hexahydrate at a concentration of 50 mg / L and an injection rate of 3 mL / min. Starting from the first discharge of liquid from the sampling hole 5, sample each sampling well at intervals of 20 minutes, 30 minutes, 40 minutes, and 60 minutes to monitor the tracer concentration;

[0075] Step 7: The obtained samples are tested using an inductively coupled plasma mass spectrometer, the obtained data are summarized, and the tracer concentration profile of the well group is drawn. Based on the obtained images and data, the tracer adsorption and migration patterns under the influence of coal reservoir water flow are analyzed.

[0076] Example 3

[0077] The evaluation method of the tracer adsorption and migration law evaluation system based on flowing coal reservoir water includes the following steps:

[0078] Step 1: Crush the coal rock samples in the target block and select coal sample particles with mesh sizes of 16 to 30. Wash and remove impurities from the selected coal sample particles, dry them and set them aside.

[0079] Step 2: Stack the first plate 1 as a visible acrylic glass plate 1, the second plate 2 as a visible acrylic glass plate 2, and the annular sealing layer 3 as an annular silicone gasket 3 vertically, and form a storage space in the annular space of the annular silicone gasket 3 for filling coal sample particles to simulate a coal reservoir; drill threaded holes 4 evenly on the edges of the visible acrylic glass plate 1, the visible acrylic glass plate 2, and the annular silicone gasket 3, and pass bolts through the holes to fix the vertically stacked visible acrylic glass plate 1, the visible acrylic glass plate 2, and the annular silicone gasket 3. The annular silicone gasket 3 can be used to seal the edge of the device to ensure the sealing of the device; a plurality of first through holes are opened inside the visible acrylic glass plate 1, one of the first through holes can be used as a water injection hole 5, and the other plurality of first through holes can be used as sampling holes 6; a groove 7 is hollowed out on the visible acrylic glass plate 2 as a horizontal well, and a second through hole is drilled on the side of the groove. The second through hole is a threaded hole used to connect to the groove and serve as an injection end.

[0080] Step 3: Apply a layer of double-sided tape to the inside of acrylic glass plates 1 and 2. Evenly spread the coal sample particles prepared in Step 1 on the tape, ensuring a single layer. Stack visible acrylic glass plates 1 and 2, and annular silicone gasket 3 vertically and secure with bolts.

[0081] Step 4: Connect the second through hole to the tracer injector 9 through a pipeline. The tracer injector 9 is connected to the second water storage tank 13 through a pipeline and a second pressure pump 12. The tracer storage device 9 is filled with a tracer solution.

[0082] Step 5: Connect the water injection hole 5 to the water injector 8 through a pipeline. The water injector 8 is connected to the first water storage tank 11 through a pipeline and a first pressure pump 10. Set the water injection rate to 1 mL / min to simulate groundwater flow. The simulated groundwater flow here is mainly used to study the flow law of the tracer in the coal reservoir under the influence of groundwater.

[0083] Step 6: Start the experiment, open all valves on the other first through holes except the water injection hole 5, start the first pressure pump 10, and close the second pressure pump 12. When all valves are discharging water, the coal reservoir coal seam is saturated with water, and then close the first pressure pump 10 and the valves connected to the other first through holes.

[0084] Turn on the second booster pump 12, close the valves on the water injection holes 6 except the sampling hole 5, and inject samarium chloride hexahydrate at an injection concentration of 50 mg / L and an injection rate of 3 mL / min. Sampling is carried out from the sampling hole 5 at intervals of 20 min, 30 min, 40 min, and 60 min to monitor the tracer concentration in each production well.

[0085] Step 8: The obtained samples are tested using an inductively coupled plasma mass spectrometer, the obtained data are summarized, and the tracer concentration profile of the well group is drawn. Based on the obtained images and data, the tracer adsorption and migration patterns under the influence of coal reservoir water flow are analyzed.

[0086] Experimental part

[0087] The water samples obtained in Examples 1 to 3 were tested by inductively coupled plasma mass spectrometry. The test results were plotted as a tracer concentration profile of the well group, as shown in FIG. Figure 6 shown.

[0088] from Figure 6 It can be seen that the coal sample used in Example 1 is 40-60 mesh particles with small porosity, so the flow is relatively uniform, the concentration difference between each sampling point is not obvious, and the overall advancement speed is faster than that of Example 2; the coal sample particles used in Example 2 are 16-30 mesh particles with large porosity, and the concentration difference between each sampling point is obvious. It can be seen from the figure that the flow front is obvious, and the concentration difference between each sampling point is obvious. Compared with Example 1, the advancement speed is slower. There is a clear difference from the result of Example 1; the coal sample particles used in Example 3 are 16-30 mesh particles, and groundwater is added. Under the influence of groundwater flow, the flow front is irregular in shape. The result is significantly different from that of Example 2. The obvious difference here is due to the presence of groundwater flow in Example 3. The flow of groundwater causes resistance to the migration process of the tracer, resulting in a lower concentration in places where groundwater exists. Therefore, using this method can achieve the problem to be solved in this patent.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A tracer adsorption and migration law evaluation system based on flowing coal reservoir water, including a detection device for detecting adsorbed water samples containing tracers, characterized in that: The adsorption water sample containing the tracer is obtained by a coal reservoir adsorption water sampling device, and the coal reservoir adsorption water sampling device comprises: A coal reservoir migration law model comprises a first plate body (1), an annular sealing layer (3) and a second plate body (2) which are stacked in sequence from top to bottom and are detachably connected. A coal sample is laid flat in a space formed by the first plate body (1), the annular sealing layer (3) and the second plate body (2). A plurality of first through holes are vertically opened on the first plate body (1), each of which is provided with a valve. A groove (7) is opened on the top surface of the second plate body (2) and is vertical to the plate surface. A second through hole communicating with the groove (7) is opened on the side wall of the second plate body (2). a first piston filling device, the liquid outlet of which is connected to any of the first through holes via a pipeline, for delivering water into the coal sample so that the water treats the coal sample; a second piston filling device, the liquid outlet of which is connected to the second through hole via a pipeline, and is used to deliver the tracer into the second through hole so that the tracer is adsorbed by the coal sample after the water treatment; When sampling, any first through hole that is not connected to the first piston filling device is selected as the sampling hole, and the adsorbed water sample containing the tracer is sampled at a certain interval.

2. The tracer adsorption and migration law evaluation system based on flowing coal reservoir water according to claim 1, characterized in that: The first plate body (1) and the second plate body (2) are both visual plates, and a plurality of the first through-hole matrices are arranged on the first plate body (1).

3. The tracer adsorption and migration law evaluation system based on flowing coal reservoir water according to claim 1, characterized in that: The first piston filling device comprises a water injector (8), a first pressure pump (10) and a first water storage device (11); the liquid outlet of the water injector (8) is connected to any first through hole via a pipeline, and the injection end of the water injector (8) is connected to the first water storage device (11) via a pipeline and the first pressure pump (10); The second piston filling device comprises a tracer syringe (9), a second pressure pump (12) and a second water storage device (13); the liquid outlet of the tracer syringe (9) is connected to the second through hole via a pipeline; the injection end of the tracer syringe (9) is connected to the second water storage device (13) via a pipeline and the second pressure pump (12).

4. The evaluation method of the tracer adsorption and migration law evaluation system based on flowing coal reservoir water according to any one of claim 3, characterized in that: The steps include: Selected and reserved dry coal sample particles of different particle sizes are spread flat in the space formed by the first plate body (1), the annular sealing layer (3) and the second plate body (2), and then the first plate body (1), the annular sealing layer (3) and the second plate body (2) are assembled and connected, and then a first through hole on the first plate body (1) is connected to a water injector (8) through a pipeline, and a second through hole on the second plate body (2) is connected to a tracer injector (9) through a pipeline; The first pressure pump (10) is started, the second pressure pump (12) is closed, the water in the water injector (8) is injected from a first through hole, the valves connected to the other first through holes are opened until water flows out of the other first through holes, so that the dry coal sample particles are in a water-saturated state, and then the first pressure pump (10) and the valves connected to the other first through holes are closed; When sampling, the second pressure pump (12) is started, a first through hole is selected as a sampling hole, the valve on the first through hole is opened until liquid is discharged, and multiple samplings are performed at intervals of a certain length; The samples were tested using an adsorption water sample detection device, the obtained data were summarized, and a tracer concentration profile image was drawn. Based on the obtained images and data, the tracer adsorption and migration laws under the influence of coal reservoir water flow were analyzed.

5. The evaluation method of the tracer adsorption and migration law evaluation system based on flowing coal reservoir water according to claim 4, characterized in that: A first through hole connected to a water injector (8) is selected as an injection hole, and any other first through hole is selected as a sampling hole. The injection hole is used as a starting point and the sampling hole is used as an end point as a water flow direction. By changing the sampling position of the sampling hole, the angle between the water flow direction and the tracer injection direction is adjusted to study the flow law of the tracer fluid in the coal reservoir.

6. The evaluation method of the tracer adsorption and migration law evaluation system based on flowing coal reservoir water according to claim 4, characterized in that: The sampling intervals of the samples are 20 minutes, 30 minutes, 40 minutes and 60 minutes.

7. The evaluation method of the tracer adsorption and migration law evaluation system based on flowing coal reservoir water according to claim 4, characterized in that: The tracer was injected at a concentration of 50 mg / L and an injection rate of 3 mL / min.

8. The evaluation method of the tracer adsorption and migration law evaluation system based on flowing coal reservoir water according to claim 4, characterized in that: The tracer is samarium chloride hexahydrate or lanthanum chloride hexahydrate.

9. The evaluation method of the tracer adsorption and migration law evaluation system based on flowing coal reservoir water according to claim 4, characterized in that: The coal sample particles are 16-60 meshes and need to be cleaned and decontaminated before the experiment and then dried for later use.

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