Loose sandstone heavy oil reservoir blocking remover and use method thereof

Abstract

The invention relates to the technical field of oil and gas exploitation, in particular to a loose sandstone heavy oil reservoir blocking remover and a using method thereof. The blocking remover for the loose sandstone heavy oil reservoir is composed of the organic blocking remover and the inorganic blocking remover, the blocking remover is good in blocking removal performance, and the construction cost can be remarkably reduced while the productivity of an oil well is improved.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas exploitation, and in particular to a loose sandstone heavy oil reservoir plugging remover and a use method thereof. Background Art

[0002] In the process of developing loose sandstone heavy oil reservoirs, it is generally necessary to adopt viscosity reduction and sand control technology to improve the development efficiency of oil wells. The viscosity reduction method is mainly thermal viscosity reduction, and the extrusion filling sand control is used to improve the sand control strength and increase the effective period of sand control. After multiple rounds of huff-and-puff operations in heavy oil wells, heavy components such as asphaltene and colloid in the oil are mixed with mud and fine sand and accumulated in the near-well area and the periphery of the sand filter, which reduces the permeability of these areas and leads to a decrease in oil well production. The effects of cold production viscosity reduction or acid plugging are not ideal. In production, due to low liquid production, it can only be moved to the operation. During dissection, it is often found that there is no formation sand plugging in the sand filter. The traditional treatment method is to pull out the sand control column and refill it for sand control, and then implement viscosity reduction measures to restore normal production of the oil well. The existing problems are high cost of measures, long construction period, and affect the oil production time rate. It is necessary to invent a plugging remover to increase oil well production and reduce operating costs.

[0003] At present, the known method for unblocking oil layers is to take conventional acidification measures, but conventional acidification cannot solve the above problems at one time, and the unblocking efficiency and effect are low. Gao Manglai has also applied for a patent for "Use of single-molecule quaternary ammonium salt compounds as clay stabilizing, anti-swelling and unblocking injection agents", patent publication number: CN1556169A. Mainly aimed at unblocking formations, it can stabilize formation clay and minerals, prevent clay swelling, and improve the permeability of formations (especially low permeability reservoirs), thereby greatly improving the water well injection effect and the sand control and imbibition effect of oil wells. The composition, mechanism of action (anti-swelling), and structure of the agent of this invention are significantly different from the mechanism of action (viscosity reduction + dissolution) of the present invention. The existing invention has a narrow scope of application. The existing invention can only solve the inorganic blockage caused by clay expansion. The present invention can solve the inorganic blockage caused by clay (or particles) expansion, shedding, migration, accumulation, scaling and sand screen blockage, and can also solve the organic blockage caused by oil viscosity and reverse emulsification, such as asphalt colloid blockage.

[0004] Patent publication number: CN105419760B, discloses a multi-component synergistic type plugging remover, the mass ratio of which is: 80-120 parts of water, 5-10 parts of cleaning dissolving agent, 15-20 parts of dissolving agent, 0.5-1 part of ammonium bifluoride, 0.4-0.6 parts of ninar, 2.5-3 parts of dodecyl trimethyl ammonium chloride, 0.1-0.3 parts of ammonium persulfate, 2.5-3 parts of SA-3 corrosion inhibitor, 3-5 parts of iron ion stabilizer for acidification. This patent is significantly different from the applied patent in terms of ingredients. The existing invention has a wide range of applications but has two defects. (1) The existing invention has a weak effect on reducing the viscosity of blockages caused by deep oil viscosity. (2) The existing invention has a strong corrosive effect on metals and is not suitable for unblocking sand screen blockages. The formula of the present invention has been optimized through several experiments, and has high viscosity reduction efficiency in reducing blockage caused by deep oil viscosity, and has been specially processed in removing blockage of sand control screen pipes, with high blockage removal efficiency and low damage.

[0005] Patent Publication No.: CN103224775B, discloses a low-carbon mixed organic acid for oil well unblocking and its preparation method and application. The low-carbon mixed organic acid is mainly prepared from the following raw materials in mass percentage: fatty alcohol 4-6%, ethylene oxide 2.4-2.5%, alkylbenzene sulfonic acid 4-6%, aminosulfonic acid 34-36%, oxalic acid 24-26%, biuret 4-6%, furazolidone 8-12%, 3-benzofuranone 8-12%, sodium nitrite 2.4-2.6%. This patent is significantly different from the applied patent in terms of ingredients. The existing invention has a narrow scope of application. The existing invention can only remove the oil layer blockage (generally organic blockage such as asphalt colloid blockage) caused by the heavy oil steam stimulation process, and improve the steam stimulation production effect. The present invention can not only solve the inorganic formation blockage and sand screen blockage caused by clay (or particles) expansion, shedding, migration, accumulation, scaling, but also solve the organic blockage caused by oil thickness and reverse emulsification, including asphalt colloid blockage.

[0006] Patent Publication No.: CN107325800A, discloses a method for unblocking and inhibiting blockage in heavy oil production and the application of nitrogen-containing organic compounds as unblocking and inhibiting agents in heavy oil production. The method comprises: contacting an unblocking and inhibiting agent with a blockage, wherein the unblocking and inhibiting agent contains a nitrogen-containing organic compound; the method for inhibiting blockage in heavy oil production comprises: first mixing an unblocking and inhibiting agent with a thin oil, and then injecting the thin oil containing the unblocking and inhibiting agent into an oil well to contact the thick oil, wherein the unblocking and inhibiting agent contains a nitrogen-containing organic compound. This patent is significantly different from the applied patent in terms of composition. The existing invention has a narrow scope of application. The existing invention can only remove the blockage of asphaltene, colloid and paraffin in the oil layer caused by the production process of heavy oil wells. The present invention can not only remove inorganic formation blockage and sand screen blockage caused by clay (or particles) expansion, shedding, migration, accumulation and scaling, but also remove organic blockage caused by oil viscosity and reverse emulsification, including asphalt colloid blockage.

[0007] Patent Publication No.: CN111019621B, discloses a plugging remover and its preparation method, including the following raw materials: Bacillus Potsdam biosurfactant fermentation broth and hydrophobic nano-silica; it may also include emulsifiers, anti-scaling agents, anti-swelling agents and cosolvents. The preparation method of the plugging remover includes the following steps: first, adding the biosurfactant fermentation broth, emulsifier and cosolvent into a reaction container, heating up, and stirring evenly; second, adding anti-scaling agents and anti-swelling agents into the above solution, stirring and dissolving; finally, continuing to heat up the prepared solution, adding hydrophobic inorganic nanoparticles into the reaction container, and stirring evenly. The plugging remover has a low oil-water interfacial tension, can effectively strip and emulsify the residual oil and colloidal asphaltene deposits in the low and medium permeability layers, form a low-viscosity emulsion, remove organic blockages, resist high mineralization, and can be completely degraded by microorganisms, green and environmentally friendly, this patent is significantly different from the applied patent in terms of composition. The existing invention has a narrow scope of application. The existing invention can only remove the blockage of residual oil and deposited colloid asphaltene and clay hydration expansion in the bottom and near-wellbore area of ​​the injection well. The present invention can not only remove the inorganic formation blockage and sand screen blockage caused by clay (or particles) expansion, shedding, migration, accumulation, scaling, but also remove the organic blockage caused by oil viscosity and reverse emulsification.

[0008] Patent Publication No.: CN102250602A, discloses a composite acid plugging remover for oil wells, which is composed of the following materials in parts by weight: 50-90 hydrochloric acid, 20-50 hydrofluoric acid, 15-35 acetic acid, 15-35 nitric acid, 4-10 corrosion inhibitors, 2-8 penetrants, 5-10 inorganic salts, 12-25 oxidants, and 10-30 clay stabilizers. This patent is significantly different from the applied patent in terms of ingredients. The existing invention has a narrow scope of application. From the formula, the existing invention can only remove inorganic blockages and clay hydration expansion in the near-well area. The present invention can not only remove inorganic formation blockages and sand screen blockages caused by clay (or particles) expansion, shedding, migration, accumulation, and scaling, but also remove organic blockages caused by oil viscosity and reverse emulsification, especially unique high-efficiency heavy oil polymer viscosity reduction effect, which is not available in the existing invention.

[0009] Patent Publication No.: CN115124989A discloses a heavy oil viscosity reduction cold production method and its application. The active polymer viscosity reducer used contains a series of active groups, and the surfactant is prepared by reacting at least one selected from polyvinyl alcohol, sulfonate and aromatic acid with a second alkaline solution. The monomers for preparing the active polymer viscosity reducer include acrylamide, acrylic acid, N-vinyl pyrrolidone, and sodium styrene sulfonate; and the molar ratio of acrylamide, acrylic acid, N-vinyl pyrrolidone and sodium styrene sulfonate is 1:1:1:3. Obviously, this patent is significantly different from the present invention in terms of composition, preparation and formulation. The existing invention has a narrow scope of application. The existing invention can only achieve heavy oil viscosity reduction, while the present invention can solve the inorganic formation blockage and sand screen blockage caused by clay (or particles) expansion, shedding, migration, accumulation and scaling, and can also solve the organic blockage caused by oil viscosity and reverse emulsification, including the function of high-efficiency heavy oil viscosity reduction. Summary of the invention

[0010] In order to solve the problems that conventional acidification in the prior art cannot solve the problem of high sand control cost due to the dual blockage of organic and inorganic materials at one time, the present invention provides a loose sandstone heavy oil reservoir unblocking agent and a method of using the same. The loose sandstone heavy oil reservoir unblocking agent of the present invention is composed of an organic unblocking agent and an inorganic unblocking agent. The unblocking agent of the present invention has good unblocking performance, and can significantly reduce construction costs while increasing oil well productivity.

[0011] To achieve the above object, the present invention adopts the following technical solutions:

[0012] The first aspect of the present invention provides an organic plugging remover, which is composed of the following raw materials: a polymer surfactant, an organic solvent, water and dodecylphenol polyoxyethylene ether;

[0013] The structural formula of the polymer surfactant is shown in Formula I below:

[0014]

[0015] Furthermore, the raw material ratio of the organic blocking remover is: 5-10 parts by weight of high molecular surfactant, 3-8 parts by weight of dodecylphenol polyoxyethylene ether, and 30-50 parts by weight of water per 100 parts by weight of organic solvent.

[0016] Furthermore, the organic solvent is one or more of toluene, xylene, methylnaphthalene, and 200# solvent oil.

[0017] The second aspect of the present invention provides a method for preparing the organic blocking remover described in the first aspect, the method comprising the following steps:

[0018] Preparation of the polymer surfactant:

[0019] Mix 60-100 parts of xylene, 30-60 parts of octadecyl acrylate and 50-100 parts of polymerizable surfactant NE-10, stir and heat. When the reactants are completely dissolved, heat to 75-85°C under nitrogen protection, add azobisisobutyronitrile to carry out reflux polymerization, and remove the solvent after the reaction is completed to obtain;

[0020] Add high molecular surfactant and dodecylphenol polyoxyethylene ether in proportion to the organic solvent, add water while stirring, and then stir at a high speed to obtain the product.

[0021] According to a third aspect of the present invention, a plugging remover for loose sandstone heavy oil reservoirs is provided, which is composed of an inorganic plugging remover and the organic plugging remover described in the first aspect.

[0022] Furthermore, the organic blocking agent and the inorganic blocking agent are composed in a volume ratio of 1-5:1-2.

[0023] Furthermore, the inorganic blocking agent is composed of the following ingredients and their weight parts: 20-25 parts of hydrochloric acid, 5-15 parts of hydrofluoric acid, 1-10 parts of fluoroboric acid, 1-5 parts of hydroxyethylidene diphosphonic acid, 1-5 parts of diethylenetriamine penta (methylene phosphonic acid), 1-5 parts of polyaspartic acid, 3-5 parts of acidifying corrosion inhibitor, 1-3 parts of anti-emulsifier, and 30-70 parts of water.

[0024] Furthermore, the acidifying corrosion inhibitor is a quinoline quaternary ammonium salt type acidifying corrosion inhibitor.

[0025] Furthermore, the anti-emulsifier is polyoxyethylene polyoxypropylene stearyl alcohol ether.

[0026] In a fourth aspect, the present invention provides a method for using the above-mentioned loose sandstone heavy oil reservoir plugging remover: after determining the formation blockage situation, first inject the organic plugging remover, then inject the inorganic plugging remover after the well is shut down, inject displacement fluid, and shut down the well for reaction.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] The organic plugging remover of the present invention has good dispersing and dissolving effects on colloid, asphaltene and wax, can quickly remove organic blockages in the near-well zone, restore the permeability of the near-well zone, and improve the oil well production capacity; the organic plugging remover of the present invention can effectively prevent wax, colloid and asphaltene from re-aggregating, and has a certain anti-wax and anti-blocking effect; compared with the oil-based plugging remover, the organic plugging remover of the present invention can be prepared into a 5% to 10% aqueous solution, and the dissolving and dispersing effects on colloid, asphaltene and wax are almost the same as those of the oil-based plugging remover. Under the condition that the total amount of the plugging remover is the same, the plugging removal range of the plugging remover of the present invention is wider, the plugging removal radius is larger, and the deep organic matter can be unblocked.

[0029] The inorganic plugging removal system of the present invention contains multi-stage ionized weak acids such as fluoroboric acid, hydroxyethylidene diphosphonic acid, and diethylenetriamine penta (methylene phosphonic acid). The acid-rock reaction speed is slow, and deep acid plugging removal in the reservoir can be achieved. The plugging removal radius is large, and the plugging removal effect is better than that of the existing acid solution system. Hydroxyethylidene diphosphonic acid, diethylenetriamine penta (methylene phosphonic acid), and polyaspartic acid react with the Ca in the formation after the acid-rock reaction. 2+ Mg 2+ , Fe 2+ , Fe 3+ It has strong chelating ability for metal ions such as ferrite, which can effectively prevent these metal ions from forming secondary precipitation in the reservoir and avoid secondary damage to the reservoir.

[0030] The inorganic plugging remover and the organic plugging remover are mixed in different proportions to form a uniform emulsion without precipitation or flocculent formation, and the two have good compatibility. The simultaneous use of the two will not cause secondary damage to the reservoir, nor will it affect the performance of the two.

[0031] The unblocking agent for loose sandstone heavy oil reservoirs of the present invention can increase the production capacity of oil wells by more than 30% and reduce the construction cost by 70% after unblocking. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The viscosity reduction curves of organic matter with different concentrations of organic plugging remover;

[0033] Figure 2 The blockage removal curves of inorganic substances with different concentrations of inorganic blockage removers are shown in Figure 2.

[0034] Figure 3 This is a diagram showing the morphology of the emulsion after the organic plugging remover and the inorganic plugging remover of the present invention are mixed. DETAILED DESCRIPTION

[0035] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0036] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations and / or combinations thereof.

[0037] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in conjunction with specific embodiments.

[0038] Example 1 An organic plugging remover

[0039] (I) Preparation method of polymer surfactant

[0040] In a three-necked flask equipped with a condenser, a thermometer and a stirrer, 60 parts of solvent xylene, 30 parts of octadecyl acrylate and 50 parts of NE-10 were added, stirring was started, the stirring speed was controlled to 100 rpm, and the temperature was raised to 60°C. When the reactants were completely dissolved, the temperature was raised to 80°C under nitrogen protection, about 0.1 parts of azobisisobutyronitrile was weighed and added to the three-necked flask, refluxed and polymerized at 80°C for 8 hours, and the solvent was evaporated using a rotary evaporator to obtain a polymer surfactant.

[0041] The structural formula of polymer surfactant is as follows:

[0042]

[0043] (II) Preparation method of organic plugging remover

[0044] Add 5 parts of the above-synthesized high molecular surfactant and 8 parts of OP-10 to 100 parts of toluene, start stirring and control the speed to 500 rpm, add 30 parts of water while stirring, and stir at high speed for 1 hour to obtain an organic plugging remover.

[0045] Example 2: An organic plugging remover

[0046] (I) Preparation method of polymer surfactant

[0047] In a three-necked flask equipped with a condenser, a thermometer and a stirrer, 100 parts of solvent xylene, 60 parts of octadecyl acrylate and 100 parts of NE-10 were added, stirring was started, the stirring speed was controlled to 100 rpm, and the temperature was raised to 60°C. When the reactants were completely dissolved, the temperature was raised to 80°C under nitrogen protection, about 0.1 parts of azobisisobutyronitrile was weighed and added to the three-necked flask, refluxed and polymerized at 80°C for 8 hours, and the solvent was evaporated using a rotary evaporator to obtain a polymer surfactant.

[0048] (II) Preparation method of organic plugging remover

[0049] Add 10 parts of the above-synthesized high molecular surfactant and 3 parts of OP-10 to 100 parts of organic solvent (a mixture of toluene, xylene, methylnaphthalene, and 200# solvent oil), start stirring and control the speed to 500rpm, add 50 parts of tap water while stirring, and stir at high speed for 1 hour to obtain an organic plugging remover.

[0050] Example 3: An organic plugging remover

[0051] (I) Preparation method of polymer surfactant

[0052] In a three-necked flask equipped with a condenser, a thermometer and a stirrer, add 80 parts of solvent xylene, then add 50 parts of octadecyl acrylate and 80 parts of NE-10, start stirring, control the stirring speed to 100 rpm, and heat to 60°C. When the reactants are completely dissolved, heat to 80°C under nitrogen protection, weigh about 0.1 parts of azobisisobutyronitrile and add it to the three-necked flask, reflux polymerization at 80°C for 8 hours, evaporate the solvent using a rotary evaporator, and you can get a polymer surfactant.

[0053] (II) Preparation method of organic plugging remover

[0054] Add 7 parts of the above-synthesized high molecular surfactant and 5 parts of OP-10 to 100 parts of the organic solvent xylene, start stirring and control the speed to 500 rpm, add 40 parts of water while stirring, and stir at high speed for 1 hour to obtain an organic plugging remover.

[0055] Example 4 A plugging remover for loose sandstone heavy oil reservoirs

[0056] The blocking remover is composed of an inorganic blocking remover and the organic blocking remover described in Example 1 in a volume ratio of 1:1.

[0057] The inorganic plugging remover is composed of the following ingredients and their weight parts: 20 parts of hydrochloric acid, 5 parts of hydrofluoric acid, 1 part of fluoroboric acid, 1 part of hydroxyethylidene diphosphoric acid, 1 part of diethylenetriamine penta (methylene phosphonic acid), 1 part of polyaspartic acid, 3 parts of acidifying corrosion inhibitor, 1 part of anti-emulsifier, and 67 parts of water.

[0058] The acidifying corrosion inhibitor is a quinoline quaternary ammonium salt type acidifying corrosion inhibitor.

[0059] The anti-emulsifier is polyoxyethylene polyoxypropylene octadecyl alcohol ether.

[0060] Example 5 A plugging remover for loose sandstone heavy oil reservoirs

[0061] The blocking agent is composed of an inorganic blocking agent and the organic blocking agent described in Example 2 in a volume ratio of 1:2.

[0062] The inorganic plugging remover is composed of the following ingredients and their weight parts: 22.5 parts of hydrochloric acid, 9.6 parts of hydrofluoric acid, 5.2 parts of fluoroboric acid, 2.9 parts of hydroxyethylidene diphosphoric acid, 2.5 parts of diethylenetriamine penta (methylene phosphonic acid), 2.3 parts of polyaspartic acid, 4.1 parts of acidifying corrosion inhibitor, 1.9 parts of demulsifier, and 49 parts of water.

[0063] The acidifying corrosion inhibitor is a quinoline quaternary ammonium salt type acidifying corrosion inhibitor.

[0064] The anti-emulsifier is polyoxyethylene polyoxypropylene octadecyl alcohol ether.

[0065] Example 6 A plugging remover for loose sandstone heavy oil reservoirs

[0066] The blocking remover is composed of an inorganic blocking remover and the organic blocking remover described in Example 3 in a volume ratio of 2:1.

[0067] The inorganic plugging remover is composed of the following ingredients and their weight parts: 25 parts of hydrochloric acid, 15 parts of hydrofluoric acid, 10 parts of fluoroboric acid, 5 parts of hydroxyethylidene diphosphoric acid, 5 parts of diethylenetriamine penta (methylene phosphonic acid), 5 parts of polyaspartic acid, 5 parts of acidifying corrosion inhibitor, 3 parts of anti-emulsifier, and 30 parts of water.

[0068] The acidifying corrosion inhibitor is a quinoline quaternary ammonium salt type acidifying corrosion inhibitor.

[0069] The anti-emulsifier is polyoxyethylene polyoxypropylene octadecyl alcohol ether.

[0070] Test example

[0071] The organic plugging remover in Example 3 was prepared into aqueous solutions of different concentrations, and its viscosity reduction rate on heavy oil was evaluated according to the method specified in Q / SH CG 0065-20216.6.3. The results are shown in the attached figure. Figure 1 It can be seen that with the increase of organic plugging remover concentration, the viscosity reduction rate gradually increases, and the viscosity reduction rate of 10% organic plugging remover can reach more than 95%, with high viscosity reduction efficiency.

[0072] The plugging remover for sandstone heavy oil reservoirs in Example 6 was prepared into aqueous solutions of different concentrations to test its plugging removal rate on sandstone cores. The results are shown in the attached figure. Figure 2 As shown. Figure 2 It can be seen that the plugging removal rate of 40% organic plugging remover for sandstone core can reach more than 80%, and the plugging removal effect is good.

[0073] Compatibility evaluation of inorganic and organic plugging removers

[0074] The inorganic plugging remover and the organic plugging remover are mixed in different proportions to form a uniform emulsion without precipitation or flocculent formation. The two have good compatibility. Figure 3 shown.

[0075] Subsequently, the wax dissolution rate, colloidal asphaltene dissolution rate, sandstone dissolution rate, corrosion rate and other indicators after mixing the organic plugging remover and the inorganic plugging remover in different proportions in Example 5 were investigated, and the results are shown in Table 1 below.

[0076] Table 1 Effects of mixing organic and inorganic plugging removers in different proportions

[0077]

[0078] From the above experimental data, it can be seen that the mixing of organic plugging removers and inorganic plugging removers in different proportions has no significant effect on the wax dissolution rate and colloid asphaltene dissolution rate of the organic plugging remover. It also has no effect on the sandstone core dissolution rate and corrosion rate of the inorganic plugging remover. This shows that the simultaneous use of the two will not cause secondary damage to the reservoir, nor will it affect the performance of the two.

[0079] On-site construction methods

[0080] Construction wellhead requirements: The pressure resistance value must comply with relevant technical standards.

[0081] Construction vehicle requirements: 1 700-type pump truck, 12m 3 There is one fiberglass pool, two residual liquid recovery tank trucks, and two water tank trucks.

[0082] The construction procedure is as follows, and the following are necessary steps.

[0083] (1) The construction personnel will stop the pumping unit at the top dead center, brake the pumping unit, and tighten the wellhead top screw and the first and second level packings.

[0084] (2) Connect the backwash well pipeline. After the surface pipeline passes the pressure test, use the produced water from the oil field in this block to backwash the well for more than two weeks.

[0085] (3) According to the operating procedures, the pumping unit is pressurized. When the pressure rises to 3.0 MPa, the well is stopped and the pressure is stabilized for 5 minutes. If the pressure drop is not greater than 0.2 MPa, it is qualified. If it is unqualified, the pumping and unblocking construction is stopped and a new plan is determined.

[0086] (4) Turn the light rod upside down, close the main gate of the wellhead, tighten the wellhead top screw, and fix the wellhead to the ground anchor with four tension ropes.

[0087] (5) Close the high-pressure gate at the process outlet, and try to squeeze out the produced water from the oil field through the casing. After the pressure stabilizes, continue squeezing for 20m 3 , measure the water absorption capacity and pressure drop, and determine the blockage of the formation.

[0088] (6) Back-extrusion of the organic plugging remover described in Example 4, and the well was kept for 3 days.

[0089] (7) Back-extrusion of the inorganic plugging remover described in Example 4.

[0090] (8) Backsqueeze displacement fluid (oilfield produced water).

[0091] (9) After shutting in the well for one hour, release the pressure on the oil and casing, install the bare rod and blowout preventer, and then drain the fluid externally. Use pH test paper to test. If the pH value reaches 6-7, it is qualified and is handed over to the oil production management unit for dry production.

[0092] The implementation results of each well are shown in Table 2 below.

[0093] Table 2 Statistics of the effects of on-site implementation of plugging relief measures

[0094]

[0095] The comparison of construction cost accounting is shown in Table 3 below.

[0096] Table 3 Construction cost accounting table*

[0097]

[0098] * Note: Based on the oil layer thickness of 12.0m, porosity of 39.0%, and permeability of 920×10 -3 um 2 , the designed treatment radius is 5.8m.

[0099] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. An organic plugging remover, characterized in that: It is composed of the following raw materials: High molecular surfactant, organic solvent, water and dodecylphenol polyoxyethylene ether; The structural formula of the polymer surfactant is shown in Formula I below:

2. The organic plugging remover according to claim 1, characterized in that: The proportion of each raw material is as follows: 5-10 parts by weight of high molecular surfactant, 3-8 parts by weight of dodecylphenol polyoxyethylene ether and 30-50 parts by weight of water per 100 parts by weight of organic solvent.

3. The organic plugging remover according to claim 1 or 2, characterized in that: The organic solvent is one or more of toluene, xylene, methylnaphthalene and 200# solvent oil.

4. The method for preparing the organic blocking remover according to any one of claims 1 to 3, characterized in that: The following steps are involved: Preparation of the polymer surfactant: Mix 60-100 parts of xylene, 30-60 parts of octadecyl acrylate and 50-100 parts of polymerizable surfactant NE-10, stir and heat. When the reactants are completely dissolved, heat to 75-85°C under nitrogen protection, add azobisisobutyronitrile to carry out reflux polymerization, and remove the solvent after the reaction is completed to obtain; Add high molecular surfactant and dodecylphenol polyoxyethylene ether in proportion to the organic solvent, add water while stirring, and then stir at a high speed to obtain the product.

5. A loose sandstone heavy oil reservoir plugging remover, characterized in that: The invention is composed of an inorganic blocking remover and the organic blocking remover according to any one of claims 1 to 3.

6. The loose sandstone heavy oil reservoir plugging remover according to claim 5, characterized in that: The organic blocking agent and the inorganic blocking agent are composed of a volume ratio of 1-5:1-2.

7. The loose sandstone heavy oil reservoir plugging remover according to claim 5 or 6, characterized in that: The inorganic plugging remover is composed of the following components and their weight parts: 20-25 parts of hydrochloric acid, 5-15 parts of hydrofluoric acid, 1-10 parts of fluoroboric acid, 1-5 parts of hydroxyethylidene diphosphoric acid, 1-5 parts of diethylenetriamine penta (methylene phosphonic acid), 1-5 parts of polyaspartic acid, 3-5 parts of acidifying corrosion inhibitor, 1-3 parts of anti-emulsifier, and 30-70 parts of water.

8. The plugging remover for loose sandstone heavy oil reservoirs according to claim 7, characterized in that: The acidifying corrosion inhibitor is a quinoline quaternary ammonium salt type acidifying corrosion inhibitor.

9. The plugging remover for loose sandstone heavy oil reservoirs according to claim 7, characterized in that: The anti-emulsifier is polyoxyethylene polyoxypropylene octadecyl alcohol ether.

10. The method for using the loose sandstone heavy oil reservoir plugging remover according to any one of claims 5 to 9, characterized in that: After the formation blockage is determined, the organic blockage remover is first injected, and after the well is shut down, the inorganic blockage remover is injected, and the displacement fluid is injected to shut down the well for reaction.

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