Tracer adsorption migration law evaluation system and method based on flowing coal reservoir water

Abstract

The invention provides a tracer adsorption migration law evaluation system based on flowing coal reservoir water, a coal reservoir migration law model of the system comprises a first plate body, an annular sealing layer and a second plate body which are sequentially stacked and connected, and a coal sample is flatly laid in the first plate body, the annular sealing layer and the second plate body; a plurality of first through holes are vertically formed in the first plate body in a manner of penetrating through the plate body, a valve is arranged on each first through hole, a groove is formed in the top surface of the second plate body in a manner of being vertical to the plate surface, and a second through hole communicated with the groove is formed in the side wall of the second plate body; a liquid outlet of the first piston filling equipment is communicated with any first through hole through a pipeline; a liquid outlet of the second piston filling equipment is connected with the second through hole through a pipeline; when sampling is carried out, any first through hole which is not connected with the first piston filling equipment is selected as a sampling hole, and adsorption water sample sampling is carried out at a certain time interval. The invention further provides a tracer adsorption and migration rule evaluation method. According to the method, the coal reservoir tracer fluid flow rule is revealed through the sampling concentration.

Description

Technical Field

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

[0002] Coalbed methane is a hydrocarbon gas that exists mainly in an adsorbed state on the surface of coal matrix particles, and is partially free in coal pores or dissolved in coal reservoir water. Coalbed methane coexists and accompanies coalbed water during its generation, migration, storage and production. The development and utilization of coalbed methane is an important chapter in the exploration and development of unconventional oil and gas, and is an important part of opening up new energy fields and realizing diversified energy supply. The rational development and utilization of coalbed methane is of great significance to my country's optimization of its 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 laws of coalbed methane, and it is of great significance to the exploration and development of coalbed methane. For example: The patent number applied for by the Exploration and Research Institute of the China Coal Geology Bureau is CN202311271575.2, and the invention patent named "A coal reservoir hydrodynamic field modeling method, device, equipment and storage medium" provides the selection of coal reservoir hydrodynamic field control equations in the preset hydrodynamic field simulation software to construct a three-dimensional geometric model of the coal reservoir hydrodynamic field; according to the hydrogeological parameters set for 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 equations are solved for 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 to establish 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, tracing method, fracturing fluid and use for multi-stage fracturing". It provides a quinoline chemical tracer with a low detection limit, which is suitable for inter-well 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, so 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. It is therefore necessary to provide a system and method for evaluating the adsorption and migration laws of tracers based on flowing coal reservoir water. Summary of the invention

[0004] In view of the deficiencies of the above-mentioned 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 the flat plate model, the adsorption of tracers by the coal reservoir can be truly reflected, thereby providing accurate theoretical data support for the actual recovery rate of the coal reservoir.

[0005] In order to solve the above technical problems, the first technical solution provided by the present invention is: a tracer adsorption migration law evaluation system based on flowing coal reservoir water, including a detection device for detecting adsorbed water samples containing tracers, and the adsorbed water samples containing tracers are obtained by a coal reservoir adsorbed water sample sampling device, and the coal reservoir adsorbed water sample sampling device includes:

[0006] A coal reservoir migration law model includes a first plate body, an annular sealing layer and a second plate body 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, the annular sealing layer and the second plate body, a plurality of first through holes are vertically opened on the first plate body and penetrate the plate body, each of the first through holes is provided with a valve, a groove is vertically opened on the top surface of the second plate body, and a second through hole connected to the groove is opened on the side wall of the second plate body;

[0007] a first piston filling device, the liquid outlet of which is connected to any first through hole through a pipeline, and is used to send 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 through 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, both the first plate body and the second plate body are visible plates, and a plurality of the first through hole matrices are arranged on the first plate body.

[0011] Preferably, the first piston filling device comprises a water injector, a first pressure pump and a first water storage device, the liquid outlet of the water injector is connected to any first through hole through a pipeline, and the injection end of the water injector 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 a pipeline and the second pressure pump.

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

[0014] The selected and reserved dry coal sample particles of different particle sizes are spread flat in the space formed by the first plate body, the annular sealing layer and the second plate body, and then the first plate body, the annular sealing layer and the second plate body are assembled and connected, and then a first through hole on the first plate body is connected to a water injector through a pipeline, and a second through hole on the second plate body is connected to a tracer injector through a pipeline;

[0015] The first pressure pump is started, the second pressure pump is closed, the 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, start the second pressure pump, select a first through hole as the sampling hole, open the valve on the first through hole until liquid is discharged, and take samples multiple times at intervals of a certain length;

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

[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 purified before the experiment, and dried for later 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 adsorption and migration law of tracers based on studying coal reservoirs. A coal reservoir model is constructed by spreading a coal sample in a coal reservoir migration law model composed of a first plate body, an annular sealing layer and a second plate body, and water is injected into the coal sample of the coal reservoir through a water injector to saturate the coal sample. Then, the tracer is sent into the coal sample of the coal reservoir after water saturation through the tracer injector. At a certain interval, any other first through hole except the first through hole 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 of different time periods. According to the study on the adsorption of the coal reservoir to the tracer, the recovery rate of the coal reservoir can be truly reflected, and accurate theoretical data support is provided 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, so as to study the effect of the angle between the groundwater flow direction and the tracer flow direction on the flow law of the injected fluid in the coal reservoir.

[0026] 3. The present invention obtains the concentration data of the tracer adsorbed water sample through the detection device. Since each data corresponds to a sampling point of the tracer adsorbed water sample, the flow of the tracer in the coal reservoir can be deduced, and the influence of the coal reservoir and groundwater on the flow law of the tracer fluid in the coal reservoir can be further clarified. In addition, the experimental simulation of the influence of groundwater flow on the flow law of the tracer fluid in the coal reservoir can be realized. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0028] Figure 2 It 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 The present invention provides a structure after the coal reservoir migration law model is assembled in the tracer adsorption migration law evaluation system based on flowing coal reservoir water.

[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 5The present invention is a block diagram of an evaluation method of a tracer adsorption and migration law evaluation system based on flowing coal reservoir water.

[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. a first plate body, 2. a second plate body, 3. an annular sealing layer, 4. a threaded hole, 5. a water injection hole, 6. a sampling hole, 7. a groove, 8. a water injector, 9. a tracer injector, 10. a first booster pump, 11. a first water storage device, 12. a second booster pump, 13. a second water storage device. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention is described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work 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 Figure 1 to Figure 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 sample sampling device, and the coal reservoir adsorption water sample 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 which are stacked and detachably connected in sequence from top to bottom, 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 vertical 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 first through hole through a pipeline, and is used to send 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 through 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 visible plates, and a plurality of the first through hole matrices are arranged 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 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 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 the water injector 8 through a pipeline, and a second through hole on the second plate body 2 is connected to the tracer injector 9 through a pipeline;

[0046] The first booster pump 10 is started, the second booster 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 booster 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 liquid is discharged, and multiple samplings are performed 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 images and data obtained, 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 injection concentration of the tracer is 50 mg / L, and the injection speed is 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 purified before the experiment, and then dried for use.

[0054] The inventors found that coal seams are in contact with water during storage. The coal seam gas extraction method is to drain water and reduce pressure to extract gas. Clarifying the flow law of coal reservoir water can be conducive to the efficient extraction of coal seam gas. However, the existing technology only considers the adsorption of tracers by the formation, but does not involve coal reservoirs. Coal reservoirs have strong adsorption, so when the invention is applied to coal reservoirs, it may not work well 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 migration law evaluation system based on flowing coal reservoir water includes the following steps:

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

[0059] Step 2: vertically stack the first plate body 1 as a visible acrylic glass plate 1, the second plate body 2 as a visible acrylic glass plate 2, and the annular sealing layer 3 as an annular silicone gasket 3, and a storage space can be formed in the annular space of the annular silicone gasket 3 for filling coal sample particles to simulate the coal reservoir; threaded holes 4 are evenly drilled on the edges of the visible acrylic glass plate 1, the visible acrylic glass plate 2, and the annular silicone gasket 3, and bolts can be passed 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, and 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 dug 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, and the second through hole is a threaded hole used to connect the groove as an injection end.

[0060] Step 3: Paste a layer of double-sided tape on the inner side of acrylic glass plate 1 and acrylic glass plate 2, and evenly spread the coal sample particles prepared in step 1 on the double-sided tape to ensure that the particles are laid in a single layer. Stack the visible acrylic glass plate 1, visible acrylic glass plate 2, and annular silicone gasket 3 vertically and fix them with bolts.

[0061] Step 4: Connect the second through hole to the tracer injector 9 through a pipeline, and the tracer injector 9 is connected to the second water storage tank 13 through a pipeline and the 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 six: Start the experiment, open all valves on the first through holes except the water injection hole 5, start the first booster pump 10, close the second booster pump 12, when all valves are discharging water, the coal reservoir coal seam is saturated with water, and then close the first booster pump 10 and the valves connected to the other first through holes.

[0064] The second booster pump 12 was turned on, and the valves on the water injection holes 6 except the sampling hole 5 were closed. Samarium chloride hexahydrate was injected at an injection concentration of 50 mg / L and an injection rate of 3 mL / min. From the first discharge of the sampling hole 5, water samples were extracted from the sampling hole 5 at intervals of 20 min, 30 min, 40 min, and 60 min, respectively, and the tracer concentration was monitored.

[0065] Step 7: Test the obtained samples using an inductively coupled plasma mass spectrometer, summarize the obtained data, draw a tracer concentration profile of the well group, and analyze the tracer adsorption and migration rules under the influence of coal reservoir water flow based on the obtained images and data.

[0066] Example 2

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

[0068] Step 1: Crush the coal and rock samples in the target area, screen out coal sample particles of 16 to 30 mesh, clean and remove impurities from the screened coal sample particles, dry them and set them aside.

[0069] Step 2: vertically stack the first plate body 1 as a visible acrylic glass plate 1, the second plate body 2 as a visible acrylic glass plate 2, and the annular sealing layer 3 as an annular silicone gasket 3, and a storage space can be formed in the annular space of the annular silicone gasket 3 for filling coal sample particles to simulate the coal reservoir; threaded holes 4 are evenly drilled on the edges of the visible acrylic glass plate 1, the visible acrylic glass plate 2, and the annular silicone gasket 3, and bolts can be passed 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, and 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 dug 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, and the second through hole is a threaded hole used to connect the groove as an injection end.

[0070] Step 3: Paste a layer of double-sided tape on the inner side of acrylic glass plate 1 and acrylic glass plate 2, and evenly spread the coal sample particles prepared in step 1 on the double-sided tape to ensure that the particles are laid in a single layer. Stack the visible acrylic glass plate 1, visible acrylic glass plate 2, and annular silicone gasket 3 vertically and fix them with bolts.

[0071] Step 4: Connect the second through hole to the tracer injector 9 through a pipeline, and the tracer injector 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 six: Start the experiment, open all valves on the first through holes except the water injection hole 5, start the first booster pump 10, close the second booster pump 12, when all valves are discharging water, the coal reservoir coal seam is saturated with water, and then close the first booster pump 10 and the valves connected to the other first through holes.

[0074] The second booster pump 12 was turned on, and the valves on the water injection holes 6 except the sampling hole 5 were closed. Samarium chloride hexahydrate was injected at an injection concentration of 50 mg / L and an injection rate of 3 mL / min. From the first discharge of the sampling hole 5, each sampling well was sampled at intervals of 20 min, 30 min, 40 min, and 60 min to monitor the tracer concentration.

[0075] Step 7: Test the obtained samples using an inductively coupled plasma mass spectrometer, summarize the obtained data, draw a tracer concentration profile of the well group, and analyze the tracer adsorption and migration rules under the influence of coal reservoir water flow based on the obtained images and data.

[0076] Example 3

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

[0078] Step 1: Crush the coal and rock samples in the target area, screen out coal sample particles of 16 to 30 mesh, clean and remove impurities from the screened coal sample particles, dry them and set them aside.

[0079] Step 2: vertically stack the first plate body 1 as a visible acrylic glass plate 1, the second plate body 2 as a visible acrylic glass plate 2, and the annular sealing layer 3 as an annular silicone gasket 3, and a storage space can be formed in the annular space of the annular silicone gasket 3 for filling coal sample particles to simulate the coal reservoir; threaded holes 4 are evenly drilled on the edges of the visible acrylic glass plate 1, the visible acrylic glass plate 2, and the annular silicone gasket 3, and bolts can be passed 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, and 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 dug 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, and the second through hole is a threaded hole used to connect the groove as an injection end.

[0080] Step 3: Paste a layer of double-sided tape on the inner side of acrylic glass plate 1 and acrylic glass plate 2, and evenly spread the coal sample particles prepared in step 1 on the double-sided tape to ensure that the particles are laid in a single layer. Stack the visible acrylic glass plate 1, visible acrylic glass plate 2, and annular silicone gasket 3 vertically and fix them with bolts.

[0081] Step 4: Connect the second through hole to the tracer injector 9 through a pipeline, and the tracer injector 9 is connected to the second water storage tank 13 through a pipeline and a second pressure pump 12, and 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 six: Start the experiment, open all valves on the first through holes except the water injection hole 5, start the first booster pump 10, close the second booster pump 12, when all valves are discharging water, the coal reservoir coal seam is saturated with water, and then close the first booster 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, inject samarium chloride hexahydrate at an injection concentration of 50 mg / L and an injection rate of 3 mL / min, and take samples from each production well at intervals of 20 min, 30 min, 40 min, and 60 min to monitor the tracer concentration.

[0085] Step 8: Test the obtained samples using an inductively coupled plasma mass spectrometer, summarize the obtained data, draw a tracer concentration profile of the well group, and analyze the tracer adsorption and migration rules under the influence of coal reservoir water flow based on the obtained images and data.

[0086] Experimental Section

[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 well group tracer concentration profile, as shown in 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 of 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 of 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 significant difference from the results 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 results obtained are significantly different from those 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, this method can achieve the problems that need 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 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 adsorbed water sample containing the tracer is obtained by a coal reservoir adsorbed water sampling device, and the coal reservoir adsorbed 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) 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 vertical to the plate surface, and 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 first through hole through a pipeline, and is used to send 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 through 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 visible 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 injector (9), a second booster pump (12) and a second water storage device (13); the liquid outlet of the tracer injector (9) is connected to the second through hole via a pipeline, and the injection end of the tracer injector (9) is connected to the second water storage device (13) via a pipeline and the second booster 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, 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 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 the sampling hole, the valve on the first through hole is opened until liquid is discharged, and sampling is performed multiple times 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 a sampling hole, and any other first through hole is selected as a sampling hole. The sampling 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 20min, 30min, 40min and 60min.

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 the coal sample particles need to be cleaned and purified before the experiment, and then dried for use.

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