An adaptive sand control screen for weakly cemented reservoir oil and gas wells and its preparation method and application

Abstract

The present invention discloses an adaptive sand-control screen for oil and gas wells in weakly cemented reservoirs, as well as its preparation method and application, belonging to the technical field of oil and gas resource extraction. The adaptive sand-control screen comprises, from the inside out, an electrically heated base pipe, an adaptive high-molecular polymer layer, and a protective coating layer. The present invention also discloses a preparation method for the adaptive sand-control screen and its application in weakly cemented reservoirs. The present invention solves the problems of wellbore blockage and near-wellbore formation collapse that exist in existing sand-control methods applied to wells in weakly cemented oil and gas reservoirs such as muddy silt sand. Furthermore, the present invention addresses the inability of existing organic high-molecular polymer materials to meet the long-term sand control requirements of unconventional oil and gas reservoirs.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil and gas resource exploitation, and in particular relates to an adaptive sand control screen pipe for weakly cemented reservoir oil and gas wells, and a preparation method and application thereof. Background Art

[0002] During the development of weakly cemented reservoirs, significant pressure drops can cause changes in the mechanical properties of the formation. This can lead to wellbore instability and other phenomena, reducing production efficiency while potentially causing other associated geological hazards. Sand production occurs when soft, fine-grained silt and muddy silt migrate with the gas near the wellbore and clog the gas pipelines. Currently, most methods for extracting oil and gas from weakly cemented reservoirs face the problems of sand production and near-wellbore blockage. Consequently, the implementation of effective sand control technology is crucial for this type of oil and gas development.

[0003] In terms of sand control, current sand control methods for conventional oil and gas resource extraction include wire-wound screen sand control, gravel pack sand control, and chemical sand control. However, in practice, gravel pack sand control has been proven to be unsuitable for oil and gas reservoirs with weakly cemented reservoirs. It has led to problems such as severe sand production and near-wellbore collapse, which block seepage channels, affect gas and water production, and lead to reduced production capacity. Furthermore, when chemical sand consolidation is applied to oil and gas reservoirs with high clay content, problems such as low curing strength can occur, which affects the effectiveness of sand control. Therefore, traditional sand control methods cannot meet the sand control and cementing needs of other unconventional energy sources such as weakly cemented reservoirs during long-term extraction.

[0004] Therefore, how to provide a cementing and sand control completion method based on weakly cemented oil and gas reservoirs and provide an adaptive sand control screen pipe suitable for weakly cemented reservoir oil and gas wells is a technical problem that those skilled in the art urgently need to solve. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention proposes an adaptive sand control screen for weakly cemented reservoir oil and gas wells, a preparation method and application thereof.

[0006] To achieve the above objectives, the present invention provides the following technical solutions:

[0007] An adaptive sand control screen pipe for weakly cemented reservoir oil and gas wells comprises, from the inside to the outside, an electrically heated base pipe, an adaptive high molecular polymer layer and a protective coating layer.

[0008] Preferably, the electrically heated base pipe includes a main body pipe and a connector, and the connector is arranged at both ends of the main body pipe; the electrically heated base pipe is connected to a drill pipe, a drill collar, a reamer, etc. through the connector; the connection mode of the connection includes but is not limited to a plug-in type or a threaded type.

[0009] The main tube includes a high-strength inner layer, a high-electrical and thermally conductive middle layer, and an outer layer of high-thermal conductivity material from the inside to the outside; wherein, the outer layer of high-thermal conductivity material is a metal composite material, which is a good conductor of heat, has high temperature resistance and high corrosion resistance, and has an inert surface and does not react with the adaptive high molecular polymer in the present invention.

[0010] The inner wall of the middle interlayer includes a heating wire, which can receive an electrical signal and convert it into a thermal signal, thereby playing a heating role.

[0011] More preferably, the high thermal conductivity material includes but is not limited to low carbon steel, copper alloy, aluminum alloy and metal composite conductive material made of low carbon steel and other high conductive materials, which has good electrical and thermal conductivity and a compressive strength of more than 10 MPa.

[0012] The electrically heated base pipe can be a closed pipe body or a slotted screen pipe, including one or a combination of circular holes, axial slots and circumferential slots, which form a double sand barrier with the adaptive polymer layer.

[0013] Preferably, the adaptive high molecular polymer is formed by curing an adaptive high molecular polymer slurry at a high temperature above 80°C;

[0014] The self-adaptive high molecular polymer slurry comprises the following raw materials in parts by weight: 17.6-37.8 parts of polyisocyanate, 20.0-30.0 parts of polyester polyol, 2.9-9.5 parts of crosslinking chain extender, 103.5-198.6 parts of pore-forming agent, 0-2.8 parts of surfactant and 30-60 parts of slurry solvent.

[0015] Beneficial Effects: The adaptive polymer in this invention possesses excellent thermodynamic properties and a porous structure. It can be significantly compressed and fixed at high temperatures, but responds to thermal stimulation at a certain temperature underground by expanding and adapting to the wellbore diameter. The pore size can also be adapted to the sand particle size control requirements of completion sand control.

[0016] Preferably, the polyisocyanate is one or a mixture of any of toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymethylene polyphenyl isocyanate (PAPI), and dimers, trimers and mixed polymers modified with polymethylene polyphenyl isocyanate as the matrix.

[0017] Preferably, the polyester polyol includes polycaprolactone diol (PCL) and / or polycarbonate diol (PCDL) with a molecular weight of 1000-3000.

[0018] Preferably, the cross-linking chain extender comprises one or a mixture of any of hydroxyl compounds, amine compounds and carboxylic acid compounds;

[0019] The hydroxy compound includes one or a mixture of 1,4-butanediol, glycerol, and ethylene glycol;

[0020] The amine compound includes one or a mixture of any of MOCA, TDA, and trimethylethylenediamine;

[0021] The carboxylic acid compound includes one of oxalic acid, succinic acid, and terephthalic acid, or a mixture of any of them.

[0022] Preferably, the pore-forming agent includes pore-forming agent A and / or pore-forming agent B;

[0023] The mass ratio of the pore-forming agent A to the pore-forming agent B is (0.2-0.5): (103.3-198.1).

[0024] The pore-forming agent A includes one or more of water, liquid carbon dioxide, dichloromethane, and cyclopentane;

[0025] The pore-forming agent B includes one of calcium oxide particles, urea particles, and solid paraffin particles, or a mixture of any of the above.

[0026] More preferably, the pore-forming agent is pore-forming agent A.

[0027] Preferably, the surfactant includes a foam stabilizer and / or a foam cell opener;

[0028] The foam stabilizer includes one or a mixture of any of AK9905, BF2270, B8629, and DC198;

[0029] The foam cell opener includes one of AK8805, Ortegol 500, Voranol CP1421, H-4002, and Niax L-6164, or a mixture of any of them.

[0030] Preferably, the slurry solvent includes one or a combination of ethyl acetate, toluene, and dimethylformamide.

[0031] Preferably, the protective coating layer is an organic polymer solid coating.

[0032] Beneficial effects: The organic polymer coating can be evenly dispersed on the surface of the adaptive polymer, protecting it from hydrolysis and at the same time protecting the adaptive polymer from being damaged by the well wall when it is lowered into the well bottom along with the adaptive sand control screen.

[0033] A method for preparing an adaptive sand control screen for a weakly cemented reservoir oil and gas well comprises the following steps:

[0034] The electrically heated base pipe is sleeved in a thin-walled plastic pipe, and an adaptive high molecular polymer slurry is injected into the gap between the electrically heated base pipe and the thin-walled plastic pipe. After the adaptive high molecular polymer slurry is solidified, a protective coating is evenly attached to the outer surface of the solidified adaptive high molecular polymer to obtain the adaptive sand control screen pipe.

[0035] More preferably, the method for injecting the adaptive polymer slurry specifically includes the following steps: first, polyester polyol, cross-linking chain extender, pore-forming agent, surfactant and slurry solvent are mixed evenly to obtain an adaptive polymer slurry pre-liquid, and continuously stirred at a high temperature above 80°C for standby use, and then polyisocyanate is quickly injected into the adaptive polymer slurry pre-liquid, and after high-speed stirring, an adaptive polymer slurry is obtained, and it is quickly transferred and injected into the annular area between the electric heating base tube and the tetrafluoroplastic tube, and cured at 80-100°C for 8-10h.

[0036] More preferably, the protective coating layer forming method includes casting molding, spray molding, reaction injection molding and plate continuous molding.

[0037] It should be noted that the diameter of the thin-walled plastic tube is larger than the electrically heated base tube and serves only to facilitate the solidification and molding of the adaptive polymer slurry. The inner diameter of the PTFE tube can be selected based on the actual wellbore diameter used in weakly cemented reservoir oil and gas production projects by flexibly controlling the high-temperature expansion of the adaptive polymer. After the adaptive polymer slurry solidifies, the thin-walled plastic tube is removed, and a protective coating is evenly sprayed on the exterior of the solidified adaptive polymer.

[0038] An application of an adaptive sand control screen for a weakly cemented reservoir oil and gas well in a weakly cemented reservoir comprises the following steps:

[0039] After being compressed at high temperature, the adaptive sand control screen is connected to the drill bit and transported to the bottom of the well. Then, an electrical signal is used to cause the electrically heated base pipe to expand and conform to the well wall. This completes the engineering application of the adaptive sand control screen in the sand control process of weakly cemented reservoir oil and gas wells.

[0040] More preferably, after the adaptive polymer completely fills the wellbore annulus, the electrical signal on the well should be removed, and the thermal stimulation of the electrically heated base pipe on the adaptive polymer will disappear, which can effectively prevent the mechanical properties of the electrically heated base pipe from being reduced due to continuous high temperature.

[0041] Preferably, the weakly cemented reservoir includes one of shallow gas, coalbed methane, and natural gas hydrate, such as mud-cemented fine sand, unconsolidated muddy silt sand, etc.

[0042] Compared with the prior art, the present invention has the following advantages and technical effects:

[0043] The present invention solves the problems of wellbore blockage and near-wellbore formation collapse that exist in existing sand control methods when applied to wells producing weakly cemented oil and gas reservoirs such as muddy silt sand. It also addresses the inability of existing organic polymer materials to meet the long-term downhole sand control needs of unconventional oil and gas reservoirs. The adaptive sand control screen for weakly cemented reservoir oil and gas wells in operation in the present invention can, on the one hand, meet the need for controlling formation sand particle size in oil and gas resource exploitation and sand control, and on the other hand, can adapt to various wellbore diameters, fully conforming to the wellbore wall while providing a certain degree of support. This can meet the need for "wall protection and sand control" in oil and gas production from weakly cemented reservoirs. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of this application. The exemplary embodiments and descriptions of this application are intended to explain this application and do not constitute an improper limitation on this application. In the accompanying drawings:

[0045] Figure 1 This is a schematic structural diagram of the adaptive sand control screen obtained in Example 15 of the present invention;

[0046] Figure 2 This is a schematic structural diagram of the adaptive sand control screen obtained in Example 15 of the present invention;

[0047] Figure 3 This is a schematic diagram of the structure of the adaptive sand control screen obtained in Example 15 of the present invention when it is lowered into the well bottom;

[0048] Figure 4 This is a schematic structural diagram of the adaptive sand control screen obtained in Example 15 of the present invention during normal operation;

[0049] The numbers are: connector 1, protective coating layer 2, adaptive polymer layer 3, electric heating base pipe 4, inner layer 5, middle interlayer 6, outer layer of high thermal conductivity material 7, production casing 8, extraction pipe 9, compressed adaptive polymer layer 10, electric heating base pipe with slits 11, adaptive polymer in working state 12, adaptive sand control screen 13. DETAILED DESCRIPTION

[0050] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only 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 making creative efforts are within the scope of protection of the present invention.

[0051] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0052] The sources of raw materials used in the embodiments of the present invention include:

[0053] Foam cell opener AK8805 is produced by Jiangsu Meside Chemical Co., Ltd.

[0054] Foam stabilizer AK9905 was produced by Jiangsu Meside Chemical Co., Ltd.

[0055] Methylene diphenyl diisocyanate (MDI), Jining Zhongjian Chemical Co., Ltd., model 100ll;

[0056] Polycarbonate diol (PCDL), Jining Zhongjian Chemical Co., Ltd., molecular weight 1000;

[0057] 1,4-Butanediol, Xilong Scientific Co., Ltd., model: BDO;

[0058] The solvent of the adaptive polymer slurry pre-solution was ethyl acetate, which was purchased from Xilong Science Co., Ltd.

[0059] Pore-forming agent B-1 is commercially available calcium oxide particles with a particle size of 300 μm;

[0060] The pore-forming agent B-2 is commercially available calcium oxide particles with a particle size of 100 μm;

[0061] The pore-forming agent B-3 is commercially available polyethylene wax solid particles with a particle size of 100 μm.

[0062] The main body tube of the electric heating base tube in the embodiment of the present invention is a commercially available electric heating tube.

[0063] Example 1

[0064] An adaptive high molecular polymer, the preparation method of which comprises the following steps:

[0065] 25g of polycarbonate diol (PCDL), softened at 80°C, was mixed with 8.63g of 1,4-butanediol (BDO), 0.5g of pore-forming agent A (distilled water), 0.6g of foam cell opener AK8805, and 0.3g of foam stabilizer AK9905 using a variable frequency high-speed stirrer at high mechanical speed without adding solvent to obtain an adaptive polymer pre-slurry. 34.8g of diphenylmethane diisocyanate (MDI) was then weighed and added to the adaptive polymer pre-slurry. After high-speed stirring, the adaptive polymer slurry was obtained, which was then cured at 80°C for 8 hours to obtain the adaptive polymer.

[0066] The adaptive polymer obtained in this example has a glass transition temperature of 59.8°C. It has a well-defined pore structure with a pore size distribution ranging from 0.07 to 372 μm, with pores at 1.61 μm accounting for the largest proportion, exceeding 10.2%. This allows for sand control accuracy in most oil and gas wells.

[0067] The adaptive polymer obtained in this example exhibits excellent adaptive properties. Above its glass transition temperature, radial deformation of the adaptive polymer was restricted, and an external axial force was applied to compress the polymer to 40% of its height. The axial force was maintained until the sample cooled. The compressed adaptive polymer was then subjected to a temperature stimulus above its glass transition temperature. The adaptive expansion rate of the adaptive polymer in this example was found to be 100%, and the adaptive expansion time at 120°C was less than 30 minutes.

[0068] By applying axial restraint, samples of the adaptive polymer obtained using the example formulation were obtained at two different states of adaptive expansion: 80% L and 100% L, and their permeability characteristics were measured. The permeability test method was based on the GB / T 34533-2017 standard. The permeability of the adaptive polymer at 80% L was found to be lower than the 8.37D without adaptive compression, but still reached 5.88D, indicating that the adaptive polymer in this state still has good permeability characteristics. At 100% L, the permeability reached a high of 10.44D, exceeding the expansion rate before adaptive compression.

[0069] Example 2

[0070] An adaptive polymer, different from Example 1, comprises the following raw materials: 25 g polycaprolactone diol, 9.51 g 1,4-butanediol, 0.2 g to 0.5 g pore former A (distilled water), 0.75 g foam cell opener AK8805, 2 g foam stabilizer AK9905, and 36.92 g diphenylmethane diisocyanate (MDI), with no solvent added. Other process steps and parameters are the same as in Example 1.

[0071] The performance testing method is the same as that of Example 1. In the hydrate mining process of this embodiment, the permeability of the adaptive high molecular polymer can reach 4.44D, the compressive strength is 0.95 MPa, and the adaptive expansion rate can reach 97.4%.

[0072] Example 3

[0073] An adaptive polymer, which differs from Example 1 in that the mass ratio of polyisocyanate (methylene diphenyl diisocyanate (MDI)), polyester polyol (polycarbonate diol (PCDL)), crosslinking chain extender (1,4-butanediol), and solvent (ethyl acetate) is 18:25:3:20, and no surfactant is added;

[0074] The mass ratio of polyester polyol to pore-forming agent B-1 is 1:4.3;

[0075] During the curing process of the adaptive polymer slurry, a vacuum drying oven was used with a constant temperature of 80°C and a curing time of 10 h;

[0076] Other process steps and parameters are the same as those in Example 1.

[0077] Example 4

[0078] An adaptive polymer, which differs from Example 1 in that the mass ratio of polyisocyanate (methylene diphenyl diisocyanate (MDI)), polyester polyol (polycarbonate diol (PCDL)), crosslinking chain extender (1,4-butanediol), and solvent (ethyl acetate) is 18:25:3:25, and no surfactant is added;

[0079] The mass ratio of polyester polyol to pore-forming agent B-1 is 1:6.4;

[0080] During the curing process of the adaptive polymer slurry, a vacuum drying oven was used with a constant temperature of 80°C and a curing time of 10 h;

[0081] Other process steps and parameters are the same as those in Example 1.

[0082] Example 5

[0083] An adaptive polymer, which differs from Example 1 in that the mass ratio of polyisocyanate (methylene diphenyl diisocyanate (MDI)), polyester polyol (polycarbonate diol (PCDL)), crosslinking chain extender (1,4-butanediol), and solvent (ethyl acetate) is 18:25:3:43, and no surfactant is added;

[0084] The mass ratio of polyester polyol to pore-forming agent B-1 and pore-forming agent B-2 is 1:3.4:1.7;

[0085] During the curing process of the adaptive polymer slurry, a vacuum drying oven was used with a constant temperature of 80°C and a curing time of 10 h;

[0086] Other process steps and parameters are the same as those in Example 1.

[0087] Example 6

[0088] An adaptive polymer, which differs from Example 1 in that the mass ratio of polyisocyanate (methylene diphenyl diisocyanate (MDI)), polyester polyol (polycarbonate diol (PCDL)), crosslinking chain extender (1,4-butanediol), and solvent (liquid paraffin) is 18:25:3:60, and no surfactant is added;

[0089] The mass ratio of polyester polyol to pore-forming agent B-1 and pore-forming agent B-2 is 1:4:0.8;

[0090] During the curing process of the adaptive polymer slurry, a vacuum drying oven was used with a constant temperature of 80°C and a curing time of 10 h;

[0091] Other process steps and parameters are the same as those in Example 1.

[0092] Example 7

[0093] An adaptive polymer, which differs from Example 1 in that the mass ratio of polyisocyanate (methylene diphenyl diisocyanate (MDI)), polyester polyol (polycarbonate diol (PCDL)), crosslinking chain extender (1,4-butanediol), and solvent (ethyl acetate) is 18:25:3:80, and no surfactant is added;

[0094] The mass ratio of polyester polyol to pore-forming agent B-1 and pore-forming agent B-3 is 1:4.8:2.4;

[0095] During the curing process of the adaptive polymer slurry, a vacuum drying oven was used with a constant temperature of 80°C and a curing time of 10 h;

[0096] Other process steps and parameters are the same as those in Example 1.

[0097] Example 8

[0098] An adaptive polymer, which differs from Example 1 in that the mass ratio of polyisocyanate (methylene diphenyl diisocyanate (MDI)), polyester polyol (polycarbonate diol (PCDL)), crosslinking chain extender (1,4-butanediol), and solvent (ethyl acetate) is 5:5:1:20, and no surfactant is added;

[0099] The mass ratio of polyester polyol to pore-forming agent B-1 and pore-forming agent B-3 is 1:5.8:3;

[0100] During the curing process of the adaptive polymer slurry, a vacuum drying oven was used with a constant temperature of 80°C and a curing time of 10 h;

[0101] Other process steps and parameters are the same as those in Example 1.

[0102] Example 9

[0103] An adaptive polymer, which differs from Example 1 in that the mass ratio of polyisocyanate (methylene diphenyl diisocyanate (MDI)), polyester polyol (polycarbonate diol (PCDL)), cross-linking chain extender (1,4-butanediol), and solvent (ethyl acetate) is 38:25:9:120, and no surfactant is added;

[0104] The mass ratio of polyester polyol to pore-forming agent B-1 and pore-forming agent B-3 is 1:7.4:3.8;

[0105] During the curing process of the adaptive polymer slurry, a vacuum drying oven was used with a constant temperature of 80°C and a curing time of 10 h;

[0106] Other process steps and parameters are the same as those in Example 1.

[0107] Example 10

[0108] An adaptive polymer, which differs from Example 1 in that the mass ratio of polyisocyanate (methylene diphenyl diisocyanate (MDI)), polyester polyol (polycarbonate diol (PCDL)), crosslinking chain extender (1,4-butanediol), and solvent (ethyl acetate) is 38:25:9:60, and no surfactant is added;

[0109] The mass ratio of polyester polyol to pore-forming agent B-1 and pore-forming agent B-3 is 1:5:1.2;

[0110] During the curing process of the adaptive polymer slurry, a vacuum drying oven was used with a constant temperature of 80°C and a curing time of 10 h;

[0111] Other process steps and parameters are the same as those in Example 1.

[0112] Example 11

[0113] An adaptive polymer, which differs from Example 1 in that the mass ratio of polyisocyanate (methylene diphenyl diisocyanate (MDI)), polyester polyol (polycarbonate diol (PCDL)), crosslinking chain extender (1,4-butanediol), and solvent (ethyl acetate) is 38:25:9:60, and no surfactant is added;

[0114] The mass ratio of polyester polyol to pore-forming agent B-1 and pore-forming agent B-3 is 1:5.4:1.1;

[0115] During the curing process of the adaptive polymer slurry, a vacuum drying oven was used with a constant temperature of 80°C and a curing time of 10 h;

[0116] Other process steps and parameters are the same as those in Example 1.

[0117] Example 12

[0118] An adaptive polymer, which differs from Example 1 in that the mass ratio of polyisocyanate (methylene diphenyl diisocyanate (MDI)), polyester polyol (polycarbonate diol (PCDL)), crosslinking chain extender (1,4-butanediol), and solvent (ethyl acetate) is 38:25:9:60, and no surfactant is added;

[0119] The mass ratio of polyester polyol to pore-forming agent B-1 and pore-forming agent B-3 is 1:5.8:1;

[0120] During the curing process of the adaptive polymer slurry, a vacuum drying oven was used with a constant temperature of 80°C and a curing time of 10 h;

[0121] Other process steps and parameters are the same as those in Example 1.

[0122] Example 13

[0123] An adaptive polymer, which differs from Example 1 in that the mass ratio of polyisocyanate (methylene diphenyl diisocyanate (MDI)), polyester polyol (polycarbonate diol (PCDL)), crosslinking chain extender (1,4-butanediol), and solvent (ethyl acetate) is 38:25:9:60, and no surfactant is added;

[0124] The mass ratio of polyester polyol to pore-forming agent B-1 and pore-forming agent B-3 is 1:6:0.9;

[0125] During the curing process of the adaptive polymer slurry, a vacuum drying oven was used with a constant temperature of 80°C and a curing time of 10 h;

[0126] Other process steps and parameters are the same as those in Example 1.

[0127] Example 14

[0128] An adaptive polymer, which differs from Example 1 in that the mass ratio of polyisocyanate (methylene diphenyl diisocyanate (MDI)), polyester polyol (polycarbonate diol (PCDL)), crosslinking chain extender (1,4-butanediol), and solvent (ethyl acetate) is 38:25:9:60, and no surfactant is added;

[0129] The mass ratio of polyester polyol to pore-forming agent B-1 and pore-forming agent B-3 is 1:6.2:0.8;

[0130] During the curing process of the adaptive polymer slurry, a vacuum drying oven was used with a constant temperature of 80°C and a curing time of 10 h;

[0131] Other process steps and parameters are the same as those in Example 1.

[0132] Technical effects:

[0133] The permeability, compressive strength, and adaptive expansion rate of the adaptive high molecular polymers obtained in Examples 3-14 were measured, and the test results are shown in Table 1. The permeability test method was based on the GB / T 34533-2017 standard, the compressive strength test method was based on the GB50107-2010 standard, and the adaptive expansion rate test method was based on the test method in Example 1.

[0134] Table 1

[0135]

[0136]

[0137] As can be seen from Table 1, the adaptive polymers obtained in Examples 3-4, 5-6 and 7-14 have high mechanical strength and permeability under different types of pore-forming agent ratios. In Examples 3-14, due to the different types and mass percentages of the pore-forming agents, the mass percentages of the solvents added to the adaptive polymer pre-liquid are also different. In Examples 10-12, the pore-forming agent combination of the adaptive polymer is a mixture of pore-forming agent B-1 and pore-forming agent B-3, and the resulting adaptive polymer has a high permeability, up to 13.4D. In Examples 13-14, the pore-forming agent combination of the adaptive polymer is a compound of pore-forming agent B-1 and pore-forming agent B-3, and the resulting adaptive polymer has a high compressive strength, fluctuating around 4.5MPa.

[0138] Example 15

[0139] A method for preparing an adaptive sand control screen for weakly cemented reservoir oil and gas wells, comprising preparing an adaptive high molecular polymer according to the raw material ratios in Examples 1-14, comprising the following steps:

[0140] (1) Weighing polyester polyol, cross-linking chain extender and other pore-forming agents and surfactants added in a certain proportion to obtain an adaptive polymer slurry pre-liquid, continuously stirring at a high temperature above 80°C or standing still for use, waiting for the injection of polyisocyanate.

[0141] (2) Prepare polytetrafluoroethylene thin-walled plastic tubes of different inner diameters at the same height as the electric heating base tube. The inner diameter of the polytetrafluoroethylene thin-walled plastic tube should be significantly larger than the outer diameter of the base tube. Rapidly inject polyisocyanate into the adaptive polymer slurry precursor obtained in step (1), and after high-speed stirring, quickly transfer the polymer slurry to the annular space between the electric heating base tube and the polytetrafluoroethylene plastic tube, and maintain the temperature at 80-100°C for more than 8 hours of curing. After the adaptive polymer slurry is cured, remove the polytetrafluoroethylene thin-walled plastic tube, and evenly spray an outer layer of protective coating on the outer surface of the adaptive polymer to obtain an adaptive sand control screen for weakly cemented reservoir oil and gas wells.

[0142] like Figure 1-2 As shown, the structure of an adaptive sand control screen for weakly cemented reservoir oil and gas wells is as follows: from the inside to the outside, it includes: an electrically heated base pipe 4, an adaptive high molecular polymer layer 3 and a protective coating layer 2.

[0143] The electrically heated base pipe comprises a main body pipe and a connector 1, wherein the connector is provided at both ends of the main body pipe; the electrically heated base pipe is connected to a drill pipe, a drill collar, a reamer, etc. through the connector; the connection mode of the connection includes but is not limited to a plug-in type or a threaded type.

[0144] The main tube includes an inner layer and a middle interlayer 5, and an outer layer 7 of a high thermal conductivity material from the inside to the outside; wherein the outer layer of the high thermal conductivity material is a metal composite material, which is a good conductor of heat, has high temperature resistance and high corrosion resistance, and has an inert surface and does not react with the adaptive high molecular polymer in the present invention.

[0145] The inner wall of the middle interlayer includes a heating wire, which can receive an electrical signal and convert it into a thermal signal, thereby playing a heating role.

[0146] Example 16

[0147] like Figure 3-4 As shown, an application of an adaptive sand control screen for weakly cemented reservoir oil and gas wells is shown. The adaptive sand control screen obtained in Example 15 is used in weakly cemented reservoir oil and gas wells. The application range includes weakly cemented reservoirs such as muddy cemented fine sand, unconsolidated muddy fine sand, shallow gas, coalbed methane, natural gas hydrate, etc. The specific application method includes the following steps:

[0148] (1) In a radial compressor, the outer adaptive polymer layer and the outer protective coating of the electrically heated base pipe of the adaptive sand control screen are radially compressed by applying a high temperature confining pressure without causing axial deformation;

[0149] The ambient temperature of the environment in which the confining pressure is applied is at least 20° C. higher than the glass transition temperature of the adaptive polymer. The confining pressure is applied via liquid or gas, and the compression amount of the adaptive polymer in the radial compressor is varied by adjusting the magnitude of the confining pressure.

[0150] (2) The compressed adaptive sand control screen pipe of the weakly cemented reservoir oil and gas well is connected to the drill bit through the upper and lower connectors of the electric heating base pipe and then lowered into the bottom of the well. Electric stimulation is applied on the well and transmitted to the electric heating base pipe through the drill pipe. The electric heating base pipe senses the electrical signal and converts it into a thermal signal. The compressed adaptive high molecular polymer expands after sensing the thermal stimulation and can completely fit the well wall, forming a porous seepage channel and playing a certain supporting role on the well wall. That is, the engineering application of the adaptive sand control screen pipe in the sand control process of the weakly cemented reservoir oil and gas well is completed.

[0151] Among them, after the adaptive polymer completely fills the wellbore annulus, the electrical signal on the well should be removed, and the thermal stimulation of the electric heating base pipe on the adaptive polymer will disappear, which can effectively prevent the mechanical properties of the electric heating base pipe from being reduced due to continuous high temperature.

[0152] The above are merely preferred embodiments of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. An adaptive sand control screen for weakly cemented reservoir oil and gas wells, characterized by: From the inside to the outside, it includes: an electric heating base tube, an adaptive polymer layer and a protective coating layer; The self-adaptive high molecular polymer is formed by curing the self-adaptive high molecular polymer slurry at a high temperature of 80 to 120°C; The adaptive high molecular polymer slurry comprises the following raw materials in parts by weight: 17.6-37.8 parts of polyisocyanate, 20.0-30.0 parts of polyester polyol, 2.9-9.5 parts of crosslinking chain extender, 0.2-198.6 parts of pore-forming agent, 0-2.8 parts of surfactant and 30-60 parts of slurry solvent; The polyisocyanate is one or a mixture of any of toluene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl isocyanate, and a dimer, trimer, and mixed polymer modified with polymethylene polyphenyl isocyanate as a matrix; The polyester polyol includes polycaprolactone diol and / or polycarbonate diol, and has a molecular weight of 1000-3000; The cross-linking chain extender includes one or a mixture of any of hydroxyl compounds, amine compounds and carboxylic acid compounds; The hydroxy compound includes one or a mixture of 1,4-butanediol, glycerol, and ethylene glycol; The amine compound includes one or a mixture of any of MOCA, TDA, and trimethylethylenediamine; The carboxylic acid compound includes one or a mixture of oxalic acid, succinic acid, and terephthalic acid; The pore-forming agent is calcium oxide and / or polyethylene wax; The protective coating layer is an organic polymer solid coating.

2. The adaptive sand control screen for weakly cemented reservoir oil and gas wells according to claim 1, characterized in that: The electric heating base tube includes a main body tube and a connector, and the connector is provided at both ends of the main body tube; The main body tube comprises an inner layer, a middle interlayer and an outer layer of a high thermal conductivity material from the inside to the outside; The inner wall of the middle interlayer includes a heating wire.

3. A method for preparing an adaptive sand control screen for a weakly cemented reservoir oil and gas well according to claim 1 or 2, characterized in that: The following steps are involved: The electrically heated base pipe is sleeved in a thin-walled plastic pipe, and an adaptive high molecular polymer slurry is injected into the gap between the electrically heated base pipe and the thin-walled plastic pipe. After the adaptive high molecular polymer slurry is solidified, a protective coating is evenly attached to the outer surface of the solidified adaptive high molecular polymer to obtain the adaptive sand control screen pipe.

4. An application of the adaptive sand control screen for weakly cemented reservoir oil and gas wells according to claim 1 or 2 in weakly cemented reservoirs, characterized in that: The following steps are involved: After being compressed at high temperature, the adaptive sand control screen is connected to the drill bit and transported to the bottom of the well. Then, an electrical signal is used to cause the electrically heated base pipe to expand and conform to the well wall. This completes the engineering application of the adaptive sand control screen in the sand control process of weakly cemented reservoir oil and gas wells.

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