Visualizing experimental apparatus and method for evaluating sand control techniques for screen gravel pack

Abstract

The application discloses a kind of visualization experimental device and method for evaluating screen gravel packing sand control technology, belong to oil and gas exploitation technical field, including visualization model box;Visualization model box inside upper portion is slid along vertical direction and is matched with top screen, and visualization model box top is provided with loading part;Visualization model box inside lower portion is provided with bottom screen;The internal space of visualization model box between top screen, bottom screen forms filter simulation space for placing gravel;Visualization model box is connected with injection system;The lower portion of bottom screen in visualization model box is provided with sand collecting pipe.The application can simulate the sand production condition when well bottom formation sand grain gravity direction and fluid flow direction are same and the invasion process of formation sand to gravel layer, and can be used for the evaluation determination of optimal particle size range of sand control gravel;Sand production effect evaluation research experiment of gravel particle size range filling under selected use of production flow rate, sand concentration and multiple variables can also be carried out.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas extraction technology, specifically relating to a visual experimental device and method for evaluating gravel-filled sand control technology in screen tubes. Background Technology

[0002] Most oil wells are prone to sand production, which can lead to significant economic losses. The production and geological parameters of each sand-producing well vary, so appropriate sand control measures need to be selected based on the specific sand production situation.

[0003] Among them, the gravel-filled screen method for sand control is widely used in oilfield sand control due to its good sand control effect, strong adaptability, simple operation, and low cost. Currently, considering the improvement of single-well utilization or the development of well networks, drilling types are increasingly moving towards horizontal wells. When carrying out sand control during horizontal well production, such as... Figure 1 As shown, formation sand 03 is blocked from entering the wellbore by filling a gravel layer between the wellbore screen 01 and the well wall 02. The specific operation process is as follows: the wellbore screen 01 is run into the producing section, forming an annular space between it and the well wall 02; gravel with optimized particle size is pumped into the annular space using a high-pressure pump; the gravel forms a multi-layer filter structure between the formation sand 03 and the wellbore screen 01, allowing oil and gas to pass through while blocking the formation sand 03. Among them, the migration capacity of formation sand is related to the gravity direction 04 of sand particles and the fluid flow direction 05. When the two directions coincide, the migration capacity of sand particles is the strongest, and the reservoir sand production is the easiest and most severe.

[0004] Before applying the screen-tube gravel-filled sand control method to horizontal well sand control, it is necessary to conduct sand control effect experiments to evaluate the working conditions in which sand production is most likely to occur in the reservoir, in order to select a suitable gravel particle size range.

[0005] However, existing experimental devices generally do not simulate the sand discharge situation when the gravity direction of the sand particles is the same as the fluid flow direction, and their visualization level is low, which greatly hinders operators from determining the particle size range of the sand control gravel.

[0006] Based on this, this application proposes a visual experimental device and method for evaluating gravel-filled sand control technology in screen pipes. It can simulate the sand production situation when the gravity direction of sand particles and the fluid flow direction are the same in the well bottom. It can be used to evaluate and determine the optimal particle size range of sand control gravel based on the target formation sand particle size, fluid viscosity, production flow rate, and sand carrying concentration. It can also be used to conduct research experiments to evaluate the sand control effect of the selected gravel particle size range under multiple variables such as production flow rate and sand carrying concentration. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a visual experimental device for evaluating gravel-filled sand control technology in sieve tubes.

[0008] To achieve the above object, the present application adopts the following technical scheme:

[0009] The visual experiment device for evaluating sand control technology of screen gravel packing comprises a visual model box.

[0010] A top screen for dispersing sand-carrying fluid is slidably fitted on the inner upper portion of the visual model box in the vertical direction, and a loading portion for simulating reservoir overburden pressure is arranged on the top of the visual model box and connected with the top screen.

[0011] A bottom screen for simulating a wellbore screen is arranged on the inner lower portion of the visual model box.

[0012] The internal space of the visual model box between the top screen and the bottom screen forms a filtration simulation space for placing gravel.

[0013] The visual model box is connected with an injection system for injecting sand-carrying fluid into the filtration simulation space.

[0014] The lower portion of the bottom screen in the visual model box is provided with a sand collecting pipe for collecting sand particles.

[0015] A plurality of pressure transmitters for measuring the pressure at different positions in the filtration simulation space are uniformly arranged on the visual model box in the vertical direction.

[0016] Preferably, the visual model box comprises a main cylinder in a cylindrical structure, a top cover arranged at the top end of the main cylinder, and a bottom plate arranged at the bottom end of the main cylinder.

[0017] A plurality of annular grooves are arranged on the inner wall of the main cylinder in the axial direction, and the central axis of the annular grooves is consistent with the central axis of the main cylinder.

[0018] Preferably, the main cylinder comprises an upper sand cylinder and a lower sand cylinder coaxially connected, and the lower sand cylinder comprises a plurality of cylindrical structures coaxially connected.

[0019] The top cover is arranged at the top end of the upper sand cylinder, the radially outer end of the bottom screen is coaxially fixedly arranged with an upwardly extending lower mounting ring, the lower end of the lower sand cylinder is clamped into the lower mounting ring, and the bottom plate is arranged at the bottom end of the bottom screen.

[0020] A clamping mechanism is arranged between the top cover and the bottom plate for clamping and fixing the top cover, the upper sand cylinder, the lower sand cylinder, the bottom screen, and the bottom plate.

[0021] Preferably, the main cylinder is nested and fitted through a clamping mechanism between adjacent two cylindrical structures.

[0022] The clamping mechanism comprises an upper annular clamping groove on the inner side of the bottom end of the upper cylinder structure and a lower annular clamping groove on the outer side of the bottom end of the lower cylinder structure, the upper annular clamping groove forms an upper annular clamping block corresponding to the bottom end of the upper cylinder structure, and the lower annular clamping groove forms a lower annular clamping block corresponding to the top end of the lower cylinder structure;

[0023] In the clamping mechanism, the upper annular clamping block is fitted in the lower annular clamping groove, the lower annular clamping block is fitted in the upper annular clamping groove, and a first annular sealing piece is arranged between the bottom end of the upper annular clamping block and the bottom end of the lower annular clamping groove; when the upper annular clamping block is pressed against the corresponding first annular sealing piece, an annular groove is formed between the top end of the upper annular clamping groove and the top end of the lower annular clamping block.

[0024] Preferably, the bottom end of the top cover is provided with a top cover clamping ring capable of being clamped into the upper sand cylinder, and a second annular sealing piece is arranged between the top end of the upper sand cylinder and the top cover;

[0025] Third annular sealing pieces are arranged between the bottom screen and the lower sand cylinder and between the bottom screen and the bottom plate.

[0026] Preferably, the clamping mechanism comprises three clamping screws distributed in the circumferential direction, the bottom plate is provided with first countersunk head holes through which the clamping screws pass upward, and the top cover is provided with first connecting holes through which the clamping screws pass upward;

[0027] After the clamping screws pass through the corresponding first countersunk head holes and first connecting holes upward, clamping nuts are screwed onto the clamping screws at the upper part of the first connecting holes, and the clamping nuts on all the clamping screws are tightened to realize clamping and sealing of the top cover, the upper sand cylinder, the lower sand cylinder, the bottom screen and the bottom plate.

[0028] Preferably, the bottom plate is provided with a tapered hole in communication with the sand collecting pipe, the large end of the tapered hole faces the bottom screen, and the small end of the tapered hole faces the sand collecting pipe.

[0029] Preferably, the loading part comprises a gas cylinder fixedly arranged on the top outside of the visualization model box, and the piston rod of the gas cylinder is connected with the upper pressing plate after penetrating into the inside of the visualization model box downward;

[0030] The outer side wall of the upper pressing plate is provided with an annular mounting groove at the upper part, the annular mounting groove is provided with a first sealing ring, and the bottom end of the upper pressing plate is coaxially provided with an upper pressing ring;

[0031] The top end of the top screen is coaxially fixedly provided with an upper mounting ring, and the inner side wall of the upper mounting ring is threadedly connected with the outer side wall of the upper pressing ring;

[0032] A second sealing ring is arranged between the top end of the upper mounting ring and the upper pressing plate.

[0033] The application also provides a visualization experiment method for evaluating screen gravel packing sand control technology.

[0034] The visualization experiment method for evaluating screen gravel packing sand control technology is implemented based on a visualization experiment device for evaluating screen gravel packing sand control technology, and comprises the following steps.

[0035] Step 1, preparation of gravel and experimental formation sand;

[0036] The experimental formation sand is prepared by using formation sand of a corresponding reservoir or by mixing; when mixed, the experimental formation sand is prepared by using fine sand screening and mixing in a certain proportion according to the grain size distribution curve of the target formation sand;

[0037] N1 groups of experimental gravel with different particle size ranges are prepared;

[0038] Step 2, selection of the optimal experimental gravel particle size range based on the fluid viscosity, sand-carrying concentration and production flow rate of the target formation, specifically as follows:

[0039] Step 21, preparation of sand-carrying fluid;

[0040] The experimental fluid is determined, and the viscosity of the experimental fluid is consistent with the fluid viscosity of the target formation; the experimental fluid is mixed with the experimental formation sand to form sand-carrying fluid according to the sand-carrying concentration of the target formation;

[0041] Step 22, let i=1, i represents the particle size range sequence number of the experimental gravel, and the smaller i is, the smaller the median in the corresponding particle size range is;

[0042] Step 23, clean the visualization model box and detect the sealing performance;

[0043] Step 24, preparation of the packing layer;

[0044] The experimental gravel in the i-th particle size range is placed in the visualization model box, and the experimental gravel layer is compacted by driving the top screen through the loading part;

[0045] Step 25, injection of sand-carrying fluid;

[0046] A collection barrel is arranged at the bottom of the sand collection pipe, the injection system is started, the sand-carrying fluid is injected from the upper part of the visualization model box into the experimental gravel layer in the filtration simulation space until the required experimental time is reached, and the injection flow rate of the sand-carrying fluid is consistent with the production flow rate of the target formation;

[0047] During the process, the migration and deposition of sand particles in the experimental gravel layer in the visualization model box are photographed by a camera; and pressure data are collected by a pressure transmitter;

[0048] Step 26, sand production amount statistics;

[0049] The experimental formation sand collected in the collecting barrel is filtered, dried and weighed to obtain the sand production mass of the experimental gravel corresponding to the ith particle size range;

[0050] Step 27, when i < N1, let i = i + 1, and enter step 23;

[0051] Otherwise, enter step 28;

[0052] Step 28, based on the comprehensive judgment method of sand blocking and fluid flow capacity, determine the optimal experimental gravel particle size range based on the fluid viscosity, sand-carrying concentration and production flow rate of the target formation;

[0053] Step 3, considering the differences in production flow rate and sand-carrying concentration before and after production, prepare sand-carrying fluid with different sand-carrying concentrations according to the actual production situation, select different injection flow rates within the production range, and further evaluate the gravel in the optimal particle size range determined in step 2 under different sand-carrying concentrations and injection flow rates; The specific steps are as follows:

[0054] Step 31, the sand-carrying concentration and injection flow rate form a variable combination, and the specific values of each variable in the variable combination in each experiment are determined as experimental input data, and each set of experimental input data is numbered, wherein the total number of experimental input data is N2;

[0055] Step 32, let j = 1, j represents the serial number of experimental input data;

[0056] Step 33, clean the visualization model box and perform a leak detection;

[0057] Step 34, prepare the packing layer;

[0058] Place the experimental gravel in the optimal particle size range in the visualization model box, and drive the top screen to compact the experimental gravel layer through the loading part;

[0059] Step 35, injection of sand-carrying fluid;

[0060] A collecting barrel is arranged at the bottom of the sand collection pipe, the injection system is started, the sand-carrying fluid with the sand-carrying concentration value corresponding to the serial number j is injected into the experimental gravel layer in the filtration simulation space from the upper part of the visualization model box, until the required experimental time is reached, wherein the injection flow rate is the injection flow rate value corresponding to the serial number j;

[0061] During the process, the migration and deposition of sand particles in the experimental gravel layer in the visualization model box are photographed by the camera; pressure data is collected by the pressure transmitter;

[0062] Step 36, sand production mass statistics;

[0063] The experimental formation sand collected in the collecting barrel is filtered, dried and weighed to obtain the sand production mass corresponding to the jth experimental input data;

[0064] Step 37, when j < N2, j = j + 1, and step 33 is entered;

[0065] Otherwise, step 38 is entered;

[0066] Step 38, the sand control performance of the optimal particle size range of gravel under different sand-carrying concentrations and injection flow rates is evaluated based on the comprehensive judgment method of sand blocking and fluid flow capacity.

[0067] Preferably, the comprehensive judgment method based on sand blocking and fluid flow capacity is specifically:

[0068] Constructing sand control parameters The calculation formula is:

[0069] Formula (1)

[0070] Formula (2)

[0071] Formula (3)

[0072] Formula (4)

[0073] Among them, is the sand production rate; is the sand production mass; is the total mass of injected sand; is the injection flow rate; is the cross-sectional area of the filtration simulation space; is the experimental time; is the sand-carrying concentration of the sand-carrying fluid; is the permeability; is the absolute value of the pressure difference detected by the uppermost and lowermost pressure transmitters at the end of the experiment; is the viscosity of the experimental fluid; is the vertical distance between the uppermost and lowermost pressure transmitters;

[0074] In the step 28, the values of the sand control parameters of each experiment are calculated, and the experimental gravel particle size range corresponding to the sand control parameter with the smallest value is taken as the optimal particle size range based on the fluid viscosity, sand-carrying concentration and production flow rate of the target formation;

[0075] In the step 38, the values of the sand control parameters of each experiment are calculated, and the sand control parameter The numerical evaluation of different sand-carrying concentrations, injection flow rates and optimal particle size range of gravel is carried out, and the sand control parameters are obtained The smaller the numerical value is, the better the sand control performance is.

[0076] The beneficial effects of the present application are:

[0077] (1) The present application can simulate the sand-out condition when the gravity direction of the formation sand particles is the same as the fluid flow direction and the invasion process of the formation sand to the gravel layer, and can be used for the evaluation and determination of the optimal particle size range of the sand control gravel based on the target formation sand particle size, fluid viscosity, production flow rate and sand-carrying concentration; and the filling sand control effect evaluation experiment of the selected gravel particle size range under the conditions of multiple variables of production flow rate and sand-carrying concentration can also be carried out.

[0078] (2) In the present application, the annular groove is arranged to overcome the phenomenon of "inner wall bypassing" of the sand particles, and can effectively avoid the influence of the fluid flowing along the cylinder wall on the sand particle migration, and significantly improve the accuracy and reliability of the experimental data.

[0079] (3) In the present application, the visual model box is assembled by nesting multiple cylinders through the clamping structure, which is convenient for installation and disassembly.

[0080] (4) In the present application, the annular groove is formed at the connection of each cylinder structure of the main cylinder, which avoids the boring cutter process on the inner wall of the main cylinder, reduces the workload, and ensures the strength of the main cylinder. BRIEF DESCRIPTION OF DRAWINGS

[0081] The drawings accompanying the specification of the present application are used to provide further understanding of the present application, the illustrative embodiments of the present application and the description thereof are used to explain the present application, and do not constitute improper limitation on the present application.

[0082] Figure 1 is a sand control schematic diagram in the production process of a horizontal well;

[0083] Figure 2 is a connection schematic diagram of the visual experimental device for evaluating the screen gravel filling sand control technology of the present application;

[0084] Figure 3 is a structural schematic diagram of the visual model box in the present application;

[0085] Figure 4 is a structural schematic sectional view of the visual model box in the present application;

[0086] Figure 5 is a structural schematic diagram of the clamping mechanism in the present application;

[0087] Figure 6 is a cooperation schematic diagram of the upper pressing plate and the top screen in the present application;

[0088] wherein:

[0089] 01, well screen; 02, wellbore; 03, formation sand; 04, direction of sand gravity; 05, fluid flow direction;

[0090] 1, visualization model box; 11, upper sand cylinder; 12, cylindrical body; 13, top cover; 131, top cover snap ring; 132, second annular sealing piece; 14, bottom plate; 141, conical hole; 15, upper annular clamping groove; 151, upper annular clamping block; 16, lower annular clamping groove; 161, lower annular clamping block; 17, first annular sealing piece; 18, clamping screw; 181, clamping nut; 19, base; 191, supporting screw; 192, supporting nut; 2, top screen; 21, upper mounting ring; 22, second sealing ring; 3, loading part; 31, air cylinder; 32, two-position five-way valve; 33, pressure gauge; 34, pressure regulator; 35, air compressor; 36, upper pressing plate; 361, first sealing ring; 362, upper pressing ring; 4, bottom screen; 41, lower mounting ring; 42, third annular sealing piece; 5, filtration simulation space; 51, annular groove; 6, injection system; 61, medium box; 62, mud pump; 63, injection pipeline; 64, injection valve; 7, sand collecting pipe; 8, pressure transmitter; 81, display screen. DETAILED DESCRIPTION

[0091] It should be noted that the following detailed description is merely exemplary and is intended to provide further description of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0092] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0093] In the present application, the terms such as "upper", "lower", "bottom", "top", and the like indicate the orientation or positional relationship shown in the drawings, which are only the relationship words determined for the convenience of describing the structural relationship of the components or elements of the present application, and are not intended to specify any component or element in the present application, and cannot be understood as a limitation of the present application.

[0094] In this invention, terms such as "connected" and "linked" should be interpreted broadly, indicating a fixed connection, an integral connection, or a detachable connection; a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can determine the specific meaning of these terms in this invention based on the specific circumstances, and they should not be construed as limitations on the invention.

[0095] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0096] Example 1:

[0097] like Figures 2-6 As shown, the visualization experimental device for evaluating the gravel-filled sand control technology of sieve tubes includes a visualization model box 1, which is made of high-strength transparent acrylic glass to achieve full visualization.

[0098] The upper inner side of the visualization model box 1 is fitted with a top screen 2 for dispersing sand-carrying fluid, which slides vertically. The top of the visualization model box 1 is provided with a loading part 3 connected to the top screen 2 to simulate reservoir overburden pressure.

[0099] The lower inner side of the visualization model box 1 is provided with a bottom screen 4 for simulating the well shaft screen 01;

[0100] The internal space of the visualization model box 1 between the top screen 2 and the bottom screen 4 forms a filtration simulation space 5 for placing gravel;

[0101] The visualization model box 1 is connected to the injection system 6 used to inject sand-carrying fluid into the filtration simulation space 5;

[0102] The bottom of the bottom screen 4 in the visualization model box 1 is equipped with a sand collection pipe 7 for collecting sand particles.

[0103] The visualization model box 1 is uniformly equipped with several pressure transmitters 8 along the vertical direction for measuring the pressure at different locations within the filter simulation space 5. The real-time monitoring data of the pressure transmitters 8 can be displayed on the computer screen 81.

[0104] Preferably, the visualization model box 1 includes a main cylinder with a cylindrical structure, a top cover 13 is provided at the top of the main cylinder, and a bottom plate 14 is provided at the bottom of the main cylinder;

[0105] The inner wall of the main cylinder corresponding to the filter simulation space 5 is provided with several annular grooves 51 arranged axially, and the central axis of the annular grooves 51 is consistent with the central axis of the main cylinder.

[0106] The setting of the annular groove 51 in the application overcomes the phenomenon of "inner wall bypassing" of sand particles, effectively avoids the influence of fluid flow along the cylinder wall on sand particle migration, and significantly improves the accuracy and reliability of experimental data. Inner wall bypassing refers to the phenomenon that fluid will flow downstream along the smooth inner wall of the visualization model box 1 based on the law of least resistance. When the device of the application is used for experiments, the interior of the visualization model box 1 is filled with gravel layers, which hinders the movement of fluid, and there are large pores between the gravel and the inner wall of the visualization model box 1. Therefore, fluid tends to flow along the inner wall, which will weaken the displacement effect of the experimental formation sand and affect the experimental results. In order to avoid this phenomenon, the annular groove 51 is arranged in the interior of the visualization model box 1 in the application, so that the gravel will be embedded in the annular groove 51, which can effectively avoid the influence of fluid flow along the cylinder wall on sand particle migration, and significantly improve the accuracy and reliability of experimental data.

[0107] Preferably, the main cylinder body includes an upper sand cylinder 11 and a lower sand cylinder coaxially connected, and the lower sand cylinder includes a plurality of cylindrical bodies 12 coaxially connected;

[0108] The top cover 13 is arranged at the top end of the upper sand cylinder 11, the radially outer end of the bottom screen 4 is fixedly arranged with an upwardly extending lower mounting ring 41, the lower end of the lower sand cylinder is clamped into the lower mounting ring 41, and the bottom plate 14 is arranged at the bottom end of the bottom screen 4; Specifically, the bottom plate 14 is provided with a circular sunken hole matched with the lower mounting ring 41 and the bottom screen 4.

[0109] The clamping mechanism is arranged between the top cover 13 and the bottom plate 14 to clamp and fix the top cover 13, the upper sand cylinder 11, the lower sand cylinder, the bottom screen 4 and the bottom plate 14.

[0110] Preferably, the main cylinder body is nested and matched by the clamping mechanism between adjacent two cylinder body structures, that is, the upper sand cylinder 11 and the cylindrical body 12 and the adjacent cylindrical bodies 12 are matched by the clamping mechanism.

[0111] The clamping mechanism includes an upper annular clamping groove 15 located at the inner side of the bottom end of the upper cylinder body structure and a lower annular clamping groove 16 located at the outer side of the bottom end of the lower cylinder body structure, the upper annular clamping groove 15 forms an upper annular clamping block 151 corresponding to the bottom end of the upper cylinder body structure, and the lower annular clamping groove 16 forms a lower annular clamping block 161 corresponding to the top end of the lower cylinder body structure.

[0112] The clamping mechanism, the upper annular clamping block 151 is matched in the lower annular clamping groove 16, the lower annular clamping block 161 is matched in the upper annular clamping groove 15, and the bottom end of the upper annular clamping block 151 is provided with the first annular sealing sheet 17 between the bottom end of the lower annular clamping groove 16; when the upper annular clamping block 151 is pressed on the corresponding first annular sealing sheet 17, the annular groove 51 is formed between the top end of the upper annular clamping groove 15 and the top end of the lower annular clamping block 161.

[0113] In the application, the annular groove 51 is formed at the connection of each cylinder structure constituting the main cylinder, so that the boring cutter process is avoided on the inner wall of the main cylinder, the workload is reduced, and the strength of the main cylinder is ensured.

[0114] Preferably, the bottom end of the top cover 13 is provided with a top cover clamping ring 131 capable of being clamped into the upper sand cylinder 11, and the top end of the upper sand cylinder 11 is provided with a second annular sealing sheet 132 between the top cover 13.

[0115] The third annular sealing sheet 42 is arranged between the bottom screen 4 and the lower sand cylinder and between the bottom screen 4 and the bottom plate 14.

[0116] Preferably, the clamping mechanism comprises three clamping screws 18 distributed in the circumferential direction, the first countersunk hole is arranged on the bottom plate 14 for the clamping screw 18 to pass upward, and the first connecting hole is arranged on the top cover 13 for the clamping screw 18 to pass upward.

[0117] After the clamping screw 18 passes upward through the corresponding first countersunk hole and first connecting hole, the clamping nut 181 is screwed on the clamping screw 18 at the upper part of the first connecting hole, and the clamping nuts 181 on all clamping screws 18 are tightened, so as to realize the clamping and sealing of the top cover 13, the upper sand cylinder 11, the lower sand cylinder, the bottom screen 4 and the bottom plate 14.

[0118] Preferably, the bottom plate 14 is provided with a tapered hole 141 in communication with the sand collecting pipe 7, the large end of the tapered hole 141 faces the bottom screen 4, and the small end of the tapered hole 141 faces the sand collecting pipe 7.

[0119] The included angle between the generatrix of the wall surface of the tapered hole 141 and the central axis is 65°-70°.

[0120] Specifically, the bottom of the visualization model box 1 is provided with a base 19, and the base 19 and the bottom plate 14 are connected through three support screws 191 distributed in the circumferential direction.

[0121] The second countersunk hole is arranged on the base 19 for the support screw 191 to pass upward, and the second connecting hole is arranged on the bottom plate 14 for the support screw 191 to pass upward.

[0122] After the support screw 191 passes through the corresponding second countersunk hole upward, the first support nut 192 is screwed, and after the support screw 191 passes through the corresponding second connecting hole upward, the second support nut 192 is screwed, and all the support nuts 192 on the support screw 191 are tightened to keep the bottom plate 14 horizontal and support the visualization model box 1.

[0123] Preferably, the loading part 3 comprises a cylinder 31 fixedly arranged outside the top of the visualization model box 1, and the piston rod of the cylinder 31 is connected to the upper pressing plate 36 after penetrating into the inside of the visualization model box 1 downward; specifically, the piston rod of the cylinder 31 is connected to the upper pressing plate 36 in the visualization model box 1 after penetrating through the top cover 13 downward.

[0124] The outer side wall of the upper pressing plate 36 is provided with an annular mounting groove in the upper part, and a first sealing ring 361 is arranged in the annular mounting groove, which is used to realize the axial sealing sliding fit of the upper pressing plate 36 and the inner wall of the visualization model box 1, and the bottom end of the upper pressing plate 36 is coaxially provided with an upper pressing ring 362.

[0125] The top end of the upper installation ring 21 is coaxially fixedly arranged with the top end of the top screen 2, and the inner side wall of the upper installation ring 21 is threadedly connected with the outer side wall of the upper pressing ring 362.

[0126] A second sealing ring 22 is arranged between the top end of the upper installation ring 21 and the upper pressing plate 36, which is used to realize the axial sealing sliding fit of the top screen 2 and the inner wall of the visualization model box 1.

[0127] Specifically, the rod cavity and the rodless cavity in the cylinder 31 are connected with two interfaces of a two-position five-way valve 32, and the other interface of the two-position five-way valve 32 is sequentially connected with a pressure gauge 33, a pressure regulator 34 and an air compressor 35.

[0128] Preferably, the injection system 6 comprises a medium tank 61 for containing the sand-carrying fluid, and a stirrer is arranged in the medium tank 61 to ensure the uniformity of the mixture.

[0129] The outlet of the medium tank 61 is connected with the inlet of a mud pump 62, the outlet of the mud pump 62 is connected with an injection pipeline 63, and the injection pipeline 63 penetrates through the top cover 13 from top to bottom.

[0130] An injection valve 64 is arranged on the injection pipeline 63.

[0131] Embodiment 2:

[0132] The visualization experiment method for evaluating the screen gravel packing sand prevention technology is implemented based on the visualization experiment device for evaluating the screen gravel packing sand prevention technology, and comprises the following steps:

[0133] Step 1, preparation of gravel and experimental formation sand;

[0134] The experimental formation sand is prepared by using the formation sand 03 of the corresponding reservoir or by preparation; in the preparation, the experimental formation sand is prepared by using the method of screening fine sand and then mixing in proportion according to the particle size mass distribution curve of the target formation sand 03;

[0135] The experimental gravel of N1 different particle size ranges is prepared; wherein the particle size range of the experimental gravel is determined as follows:

[0136] When the uniformity coefficient , the minimum particle size of the experimental gravel is , and the maximum particle size of the experimental gravel is ;

[0137] When the uniformity coefficient , the minimum particle size of the experimental gravel is , and the maximum particle size of the experimental gravel is ;

[0138] Wherein, , is the sand particle diameter corresponding to the cumulative mass fraction of 50% on the particle size mass distribution curve of the target formation sand 03, is the sand particle diameter corresponding to the cumulative mass fraction of 40% on the particle size mass distribution curve of the target formation sand 03, is the sand particle diameter corresponding to the cumulative mass fraction of 90% on the particle size mass distribution curve of the target formation sand 03;

[0139] After the minimum particle size and the maximum particle size of the experimental gravel are determined, the difference between the maximum particle size and the minimum particle size is calculated, then the particle size range of the first group of experimental gravel is ~ , the particle size range of the second group of experimental gravel is ~ , and so on, the particle size range of the N1th group of experimental gravel is ~ , that is ~ ~ ;

[0140] Step 2, selection of the optimal experimental gravel particle size range based on the fluid viscosity, sand-carrying concentration and production flow rate of the target formation, specifically as follows:

[0141] Step 21, preparation of sand-carrying fluid;

[0142] ​​​​​Determine the experimental fluid, the viscosity of the experimental fluid is consistent with the fluid viscosity of the target formation; according to the sand carrying concentration of the target formation, the experimental fluid is mixed with the experimental formation sand to form a sand carrying fluid;

[0143] Step 22, let i=1, i represents the particle size range number of the experimental gravel, the smaller the i is, the smaller the median in the corresponding particle size range is;

[0144] Step 23, clean the visualization model box 1 and detect the sealing performance;

[0145] Step 24, prepare the filling layer;

[0146] Place the experimental gravel of the i-th particle size range in the visualization model box 1, and compact the experimental gravel layer by driving the top screen 2 through the loading part 3;

[0147] Step 25, injection of the sand carrying fluid;

[0148] Set a collection barrel at the bottom of the sand collection pipe 7, start the injection system 6, and inject the sand carrying fluid from the upper part of the visualization model box 1 into the experimental gravel layer in the filtration simulation space 5 until the required experimental time is reached, wherein the injection flow rate of the sand carrying fluid is consistent with the production flow rate of the target formation;

[0149] During the process, the migration and deposition of the sand particles in the experimental gravel layer in the visualization model box 1 are photographed by the camera; and the pressure data are collected by the pressure transmitter 8;

[0150] Step 26, sand production amount statistics;

[0151] After filtering and drying, the experimental formation sand collected in the collection barrel is weighed to obtain the sand production mass corresponding to the i-th particle size range experimental gravel;

[0152] Step 27, when i

[0153] Otherwise, go to step 28;

[0154] Step 28, based on the comprehensive judgment method of sand blocking and fluid flow capacity, determine the optimal experimental gravel particle size range based on the fluid viscosity, sand carrying concentration and production flow rate of the target formation;

[0155] Step 3, considering the differences in production flow rate and sand carrying concentration before and after production, prepare sand carrying fluids with different sand carrying concentrations according to the actual production situation, select different injection flow rates within the production range, and further evaluate the gravel in the optimal particle size range determined in step 2 under different sand carrying concentrations and injection flow rates; the specific steps are as follows:

[0156] Step 31, the combination of sand-carrying concentration and injection flow rate forms a variable combination, the specific value of each variable in the variable combination in each experiment is determined as the experimental input data, and each set of experimental input data is numbered, wherein the total number of experimental input data is N2;

[0157] Step 32, let j = 1, j represents the serial number of experimental input data;

[0158] Step 33, clean the visualization model box 1 and perform a sealing test;

[0159] Step 34, prepare the packing layer;

[0160] Place the experimental gravel with the optimal particle size range in the visualization model box 1, and drive the top screen 2 to compact the experimental gravel layer through the loading part 3;

[0161] Step 35, injection of sand-carrying fluid;

[0162] Set a collection barrel at the bottom of the sand collection pipe 7, start the injection system 6, and inject the sand-carrying fluid with the sand-carrying concentration value corresponding to the serial number j into the experimental gravel layer in the filtration simulation space 5 from the upper part of the visualization model box 1 until the required experimental time is reached, wherein the injection flow rate is the injection flow rate value corresponding to the serial number j;

[0163] During the process, the migration and deposition of sand particles in the experimental gravel layer in the visualization model box 1 are captured by the camera; and the pressure data are collected by the pressure transmitter 8;

[0164] Step 36, sand production amount statistics;

[0165] After filtering and drying, the experimental formation sand collected in the collection barrel is weighed to obtain the sand production mass corresponding to the jth experimental input data;

[0166] Step 37, when j < N2, let j = j + 1, and enter step 33;

[0167] Otherwise, enter step 38;

[0168] Step 38, based on the comprehensive judgment method of sand retention and fluid flow capacity, the sand control performance of the gravel with the optimal particle size range under different sand-carrying concentrations and injection flow rates is evaluated.

[0169] Preferably, the comprehensive judgment method based on sand retention and fluid flow capacity is specifically:

[0170] Constructing sand control parameters The calculation formula is:

[0171] Formula (1)

[0172] Formula (2)

[0173] Formula (3)

[0174] Formula (4)

[0175] wherein, is the sand production rate, the sand control performance of the reaction; is the sand production mass; is the total mass of the injected sand; is the injection flow rate; is the cross-sectional area of the filtration simulation space 5; is the experimental time; is the sand-carrying concentration of the sand-carrying fluid; is the permeability, the fluid flow capacity of the reaction; is the absolute value of the pressure difference detected by the uppermost and lowermost pressure transmitters 8 at the end time of the experiment; is the viscosity of the experimental fluid; is the vertical distance between the uppermost and lowermost pressure transmitters 8;

[0176] In the step 28, the values of the sand control parameters of each experiment are calculated, and the experimental gravel size range corresponding to the experimental gravel size range with the smallest value of the sand control parameter is taken as the optimal gravel size range based on the fluid viscosity, the sand-carrying concentration and the production flow rate of the target formation.

[0177] In the step 38, the values of the sand control parameters of each experiment are calculated, and the sand control performance of the optimal gravel size range gravel under different sand-carrying concentrations and injection flow rates is evaluated using the values of the sand control parameters , and the smaller the value of the sand control parameter , the better the sand control performance.

[0178] In addition, when each experiment is performed using the device, the top screen 2 and the bottom screen 4 are replaced according to the particle size range of the experimental gravel, wherein the pore size of the top screen 2 is equal to the minimum particle size of the experimental gravel to avoid the return flow of the gravel, and the pore size of the bottom screen 4 is 2 / 3 of the minimum particle size of the experimental gravel.

[0179] The above describes the specific embodiments of the present application in conjunction with the drawings, but is not a limitation of the present application, and those skilled in the art should understand that various modifications or changes made by those skilled in the art on the basis of the technical solutions of the present application without creative labor are still within the protection scope of the present application.

Claims

1. A visualization experiment method for evaluating screen gravel pack sand control technology, which is implemented based on a visualization experiment device for evaluating screen gravel pack sand control technology, characterized in that, The visualized experimental device for evaluating sand control technology of screen gravel packing comprises a visualized model box; A top screen for dispersing the sand-carrying fluid is slidably fitted on the inner upper portion of the visualized model box in the vertical direction, and a loading portion for simulating reservoir overburden pressure is arranged on the top of the visualized model box and connected with the top screen; A bottom screen for simulating the wellbore screen is arranged on the inner lower portion of the visualized model box; The internal space of the visualized model box between the top screen and the bottom screen forms a filtration simulation space for placing gravel; The visualized model box is connected with an injection system for injecting the sand-carrying fluid into the filtration simulation space; The lower portion of the bottom screen in the visualized model box is provided with a sand collection pipe for collecting sand particles; A plurality of pressure transmitters for measuring the pressure at different positions in the filtration simulation space are uniformly arranged on the visualized model box in the vertical direction; The experimental method comprises the following steps: Step 1, preparation of gravel and experimental formation sand; The experimental formation sand is prepared by using the formation sand of the corresponding reservoir or by mixing fine sand through screening and mixing in proportion according to the grain size distribution curve of the target formation sand; N1 groups of experimental gravel with different particle size ranges are prepared; Step 2, selection of the optimal experimental gravel particle size range based on the fluid viscosity, sand-carrying concentration and production flow rate of the target formation, specifically as follows: Step 21, preparation of the sand-carrying fluid; The experimental fluid is determined, and the viscosity of the experimental fluid is consistent with the fluid viscosity of the target formation; the experimental fluid is mixed with the experimental formation sand to form the sand-carrying fluid according to the sand-carrying concentration of the target formation; Step 22, let i=1, i represents the particle size range sequence number of the experimental gravel, and the smaller i is, the smaller the median in the corresponding particle size range is; Step 23, cleaning and sealing detection of the visualized model box; Step 24, preparation of the packing layer; The experimental gravel in the i-th particle size range is placed in the visualized model box, and the experimental gravel layer is compacted by driving the top screen through the loading portion; Step 25, injection of the sand-carrying fluid; A collection barrel is arranged at the bottom of the sand collection pipe, the injection system is started, and the sand-carrying fluid is injected from the upper portion of the visualized model box into the experimental gravel layer in the filtration simulation space until the required experimental time is reached, wherein the injection flow rate of the sand-carrying fluid is consistent with the production flow rate of the target formation; In this process, the migration and deposition of the sand particles in the experimental gravel layer in the visualized model box are photographed by the camera; and the pressure data are collected by the pressure transmitters; Step 26, sand production amount statistics; After the experimental formation sand collected in the collection barrel is filtered and dried, the weight is measured to obtain the sand production mass corresponding to the experimental gravel in the i-th particle size range; Step 27, when i Otherwise, step 28 is entered; Step 28, determination of the optimal experimental gravel particle size range based on the fluid viscosity, sand-carrying concentration and production flow rate of the target formation based on the comprehensive judgment method of sand blocking and fluid flow capacity. Step 3, considering the difference in production flow rate and sand-carrying concentration before and after production, different sand-carrying fluids with different sand-carrying concentrations are prepared according to the actual production situation, and different injection flow rates within the production range are selected, and the gravel in the optimal particle size range determined in step 2 is further evaluated for sand control under different sand-carrying concentrations and injection flow rates; specifically as follows: Step 31, the sand-carrying concentration and injection flow rate form a variable combination, the specific values of each variable in the variable combination in each experiment are determined as experimental input data, and each set of experimental input data is numbered, wherein the total number of experimental input data is N2; Step 32, let j=1, j represents the serial number of experimental input data; Step 33, clean the visualization model box and perform a sealing test; Step 34, prepare the packing layer; Place the experimental gravel in the optimal particle size range in the visualization model box, and drive the top screen to compact the experimental gravel layer by the loading part; Step 35, injection of sand-carrying fluid; A collection barrel is arranged at the bottom of the sand collection pipe, the injection system is started, the sand-carrying fluid with the sand-carrying concentration value corresponding to the serial number j is injected from the upper part of the visualization model box into the experimental gravel layer in the filtration simulation space, until the required experimental time is reached, wherein the injection flow rate is the injection flow rate value corresponding to the serial number j; During this process, the migration and deposition of sand particles in the experimental gravel layer in the visualization model box are captured by the camera; the pressure data are collected by the pressure transmitter; Step 36, sand production amount statistics; After filtering and drying, the experimental formation sand collected in the collection barrel is weighed to obtain the sand production mass corresponding to the jth experimental input data; Step 37, when j Otherwise, go to step 38; Step 38, based on the comprehensive judgment method of sand blocking and fluid flow capacity, the sand control performance of the gravel in the optimal particle size range under different sand-carrying concentrations and injection flow rates is evaluated; Based on the comprehensive judgment method of sand blocking and fluid flow capacity, specifically as follows: Constructing sand control parameters The calculation formula is: Equation (1) Equation (2) Equation (3) Equation (4) wherein, is the sand production rate; is the sand production mass; is the total mass of injected sand; is the injection flow rate; is the cross-sectional area of the filtration simulation space; is the experimental time; is the sand-carrying concentration of the sand-carrying fluid; is the permeability; is the absolute value of the pressure difference detected by the uppermost and lowermost pressure transmitters at the end of the experiment; is the viscosity of the experimental fluid; is the vertical distance between the uppermost and lowermost pressure transmitters; In step 28, the sand control parameters corresponding to each experiment are calculated The numerical value of the sand control parameters The experimental gravel size range corresponding to the experiment with the smallest numerical value of the sand control parameters is taken as the optimal size range based on the target formation fluid viscosity, sand concentration, and production flow rate. In step 38, the sand control parameters corresponding to each experiment are calculated. The values ​​are obtained using sand control parameters. Numerical evaluation of the sand control performance of gravel with optimal particle size range under different sand-carrying concentrations and injection flow rates, and sand control parameters. The smaller the value, the better the sand-proof performance.

2. The visualized experimental method for evaluating sand control technology of screen gravel pack filling according to claim 1, characterized in that, The visualization model box comprises a main cylinder in a cylindrical structure, a top cover is arranged at the top end of the main cylinder, and a bottom plate is arranged at the bottom end of the main cylinder; A plurality of annular grooves are arranged on the inner wall of the main cylinder corresponding to the filtration simulation space in the axial direction, and the central axis of the annular grooves is consistent with the central axis of the main cylinder.

3. The visualized experiment method for evaluating sand control technology of screen gravel pack as claimed in claim 2, wherein, The main cylinder comprises an upper sand cylinder and a lower sand cylinder connected coaxially, and the lower sand cylinder comprises a plurality of cylindrical bodies connected coaxially; The top cover is arranged at the top end of the upper sand cylinder, the radially outer end of the bottom screen is fixedly arranged with an upwardly extending lower mounting ring, the lower sand cylinder is clamped in the lower mounting ring, and the bottom plate is arranged at the bottom end of the bottom screen; A clamping mechanism is arranged between the top cover and the bottom plate for clamping and fixing the top cover, the upper sand cylinder, the lower sand cylinder, the bottom screen and the bottom plate.

4. The visualized experiment method for evaluating sand control technology of screen gravel packing of claim 3, wherein, The main cylinder is nested and matched through the clamping mechanism between two adjacent cylinder structures; The clamping mechanism comprises an upper annular clamping groove on the inner side of the bottom end of the upper cylinder structure and a lower annular clamping groove on the outer side of the bottom end of the lower cylinder structure, the upper annular clamping groove forms an upper annular clamping block at the bottom end of the upper cylinder structure, and the lower annular clamping groove forms a lower annular clamping block at the top end of the lower cylinder structure; The upper annular clamping block is matched in the lower annular clamping groove, the lower annular clamping block is matched in the upper annular clamping groove, and the first annular sealing piece is arranged between the bottom end of the upper annular clamping block and the bottom end of the lower annular clamping groove.

5. The visualized experiment method for evaluating sand control technology of screen gravel packing of claim 3 wherein, The bottom end of the top cover is provided with a top cover clasp ring capable of being clamped into the upper sand cylinder, and the top end of the upper sand cylinder and the top cover are provided with a second annular sealing piece; The third annular sealing piece is arranged between the bottom screen and the lower sand cylinder and between the bottom screen and the bottom plate.

6. The visualized experiment method for evaluating sand control technology of screen gravel pack filling according to claim 3, characterized in that, The clamping mechanism comprises three clamping screws distributed in the circumferential direction, the bottom plate is provided with first countersunk holes for the clamping screws to pass upward, and the top cover is provided with first connecting holes for the clamping screws to pass upward; After the clamping screw passes upward through the corresponding first countersunk hole and the first connecting hole, the clamping nut is screwed on the clamping screw at the upper part of the first connecting hole, and the clamping nuts on all clamping screws are tightened to realize clamping and sealing of the top cover, the upper sand cylinder, the lower sand cylinder, the bottom screen and the bottom plate.

7. The visualized experiment method for evaluating sand control technology of screen gravel pack filling according to claim 2, characterized in that, The bottom plate is provided with a tapered hole connected with the sand collecting pipe, the large end of the tapered hole faces the bottom screen, and the small end of the tapered hole faces the sand collecting pipe.

8. The method of visualizing an experiment for evaluating sand control screen gravel pack technology of claim 1, wherein, The loading part comprises a gas cylinder fixedly arranged outside the top of the visualization model box, and the piston rod of the gas cylinder penetrates downward into the inside of the visualization model box and is connected with the upper pressing plate; The outer side wall of the upper pressing plate is provided with an annular mounting groove at the upper part, the annular mounting groove is provided with a first sealing ring, and the bottom end of the upper pressing plate is coaxially provided with an upper pressing ring; The top end of the upper mounting ring is coaxially fixedly arranged with an upper mounting ring, and the inner side wall of the upper mounting ring is threadedly connected with the outer side wall of the upper pressing ring; The second sealing ring is arranged between the top end of the upper mounting ring and the upper pressing plate. The second sealing ring is arranged between the top end of the upper mounting ring and the upper pressing plate.

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