Anti-salt-sensitivity reservoir protection system as well as preparation method and application thereof

Abstract

The invention discloses a salt-sensitive-resistant reservoir protection system as well as a preparation method and application thereof. The protection system comprises the following raw materials in percentage by mass: 1-3% of an anti-swelling agent, 1-2% of a scale inhibitor, 0.3-0.6% of a solubilizer and the balance of water, wherein the anti-swelling agent is oligomeric quaternary ammonium salt DETA-FP; the scale inhibitor is EDTA (ethylene diamine tetraacetic acid); and the solubilizer is alkyl glucoside APG. When the salt-sensitive reservoir protection system is evaluated indoors, the anti-swelling rate is 93%, the scale inhibition rate is 81.3%, and the oil washing rate is 95.6%; during on-site injection testing application, after 2% of the protection system is added in a water injection front section, the apparent water absorption index of clear water injected into the stratum is obviously increased, and the stratum water injection starting pressure is reduced by 2.7 MPa. The salt-sensitive reservoir protection system provided by the invention is suitable for a salt-sensitive reservoir water injection well of which the temperature is less than or equal to 150 DEG C and the degree of mineralization is less than or equal to 220000 mg / L.

Description

Technical Field

[0001] The invention relates to an anti-salt-sensitive reservoir protection system and a preparation method and application thereof. Background Art

[0002] The Xinghua block of Bayan Oilfield is a realistic replacement area for increasing reserves and production in the North China Oilfield. The block is a high-temperature and high-salinity oil reservoir with a reservoir temperature of 150°C and a formation water mineralization of 8×10 4 mg / L~22×10 4 mg / L, instability has a strong tendency to self-scaling, crude oil wax content of 19.4%, gelatin content of 27.2%, freezing point of 50℃. The main production layer of this block is the Linhe Formation reservoir, which usually has problems such as strong water sensitivity and extremely strong salt sensitivity. Because the oil field is in the early stage of development, the oil well output fluid cannot meet the water injection demand. In order to supplement the formation energy, other water sources need to be injected into the formation. After the external injected water enters the formation, it is easy to cause reservoir damage.

[0003] At present, the commonly used reservoir protective agents for water injection wells include high-molecular polymer anti-swelling agents, inorganic salt KCl, surfactants, etc. However, these protective agents are difficult to be used at 150℃ and 22×10 4 Used under conditions of mg / L mineralization.

[0004] Patent CN106281288A discloses a pressure-reducing and injection-increasing agent for low-permeability reservoir water injection wells, which uses a fluorocarbon surfactant / alkyl ammonium chloride / fatty alcohol polyoxyethylene ether compound to form an anti-swelling main agent, ethylenediaminetetramethylene sodium phosphate as a slow-release scale inhibitor, and dimethyl ketoxime as a bactericide. However, the pressure-reducing and injection-increasing agent is not suitable for high-temperature oil reservoirs; Patent CN109913193A discloses a pressure-reducing and injection-increasing agent for low-permeability oil reservoir water injection wells, which uses a dehydrogenated rosin anionic surfactant and a cationic surfactant to form an anti-swelling main agent. Betaine amphoteric surfactants and cetyl alcohol are used as rock wetting agents, which mainly use the surfactant to wet the rock surface and reduce the water injection resistance, but have no inhibitory effect on the scaling of formation fluids. Patent CN111117586A discloses a pressure-reducing and injection-increasing active system with reservoir protection performance and high temperature and salt resistance. It uses cationic surfactant alkyl quaternary ammonium salt to reduce interfacial tension, organic anti-swelling agent polyamine ether to reduce clay hydration expansion, and scale inhibitor to reduce injection water scaling. This pressure-reducing and injection-increasing active system is only suitable for 120°C, 20×10 4 The temperature and salt resistance of injection wells with a concentration of mg / L still need to be improved. Summary of the invention

[0005] In order to at least partially solve the above technical problems existing in the prior art, the embodiment of the present invention provides a salt-sensitive reservoir protection system and a preparation method and application thereof, which is suitable for 150°C, 22×10 4 mg / L mineralization conditions.

[0006] As one aspect of the present invention, a salt-sensitive reservoir protection system is provided, wherein the protection system comprises the following raw materials by mass percentage: 1-3% of an anti-swelling agent, 1-2% of a scale inhibitor, 0.3-0.6% of a solubilizing agent, and the balance is water;

[0007] The anti-swelling agent is oligomeric quaternary ammonium salt DETA-FP; the scale inhibitor is EDTA; and the solubilizing agent is alkyl glucoside APG.

[0008] In one or some possible embodiments, the oligomeric quaternary ammonium salt DETA-FP is a mixture of a dimeric quaternary ammonium salt DETA-FP2 and a tetrameric quaternary ammonium salt DETA-FP4 in any mass ratio.

[0009] In one or some possible embodiments, the anti-salt-sensitive reservoir protection system according to claim 2 is characterized in that the mass ratio of the dimerized quaternary ammonium salt DETA-FP2 to the tetramerized quaternary ammonium salt DETA-FP4 is 1:(1-2).

[0010] In one or some possible embodiments, the dimeric quaternary ammonium salt DETA-FP2 is as shown in formula (I):

[0011]

[0012] The tetrameric quaternary ammonium salt DETA-FP4 is shown in formula (II):

[0013]

[0014] In one or some possible embodiments, the alkyl glucoside APG is selected from C10-C12 alkyl glucoside.

[0015] In one or some possible embodiments, the anti-salt-sensitive reservoir protection system is suitable for salt-sensitive reservoir water injection wells with a temperature of ≤150°C and a mineralization of ≤220,000 mg / L.

[0016] As another aspect of the present invention, it relates to a method for preparing the above-mentioned anti-salt-sensitive reservoir protection system, the method comprising:

[0017] According to the formula, under stirring conditions, oligomeric quaternary ammonium salt is added to water, and after dissolution, EDTA is added to the solution, and after stirring until dissolved, alkyl glucoside is added to prepare an anti-salt-sensitive reservoir protection system.

[0018] In one or some possible embodiments, the preparation of the oligomeric quaternary ammonium salt comprises:

[0019] Add 2,3-epoxypropyltrimethylammonium chloride to water, stir until dissolved, heat to a certain temperature, drop hydrochloric acid, mix and react; then drop the reacted liquid into diethylenetriamine, stir at a constant temperature for a certain period of time, cool, extract, and distill the water phase under reduced pressure to obtain an oligomeric quaternary ammonium salt.

[0020] As another aspect of the present invention, it relates to the application of the above-mentioned anti-salt-sensitive reservoir protection system in oil field exploitation.

[0021] As another aspect of the present invention, it relates to a method for oilfield exploitation, characterized in that the method uses the above-mentioned anti-salt-sensitive reservoir protection system, comprising:

[0022] Inject 2-3wt% of anti-salt-sensitive reservoir protection system slug;

[0023] Stop the injection for 3 to 5 days;

[0024] Water injection slug.

[0025] The beneficial effects of the above technical solution provided by the embodiment of the present application include at least:

[0026] The reservoir protection system of the present invention uses a synthetic oligomeric quaternary ammonium salt as an anti-swelling agent, EDTA as a scale inhibitor, and alkyl glucoside as a solubilizing agent, so that when the protection system of the present invention is applied to a water injection well, it can have a good inhibitory effect on clay hydration expansion in a high-temperature and high-salt environment, and can also react with Ca 2+ Mg 2+ The metal ions form a chelated five-membered ring, making the upper temperature limit reach 150°C. In addition, the reservoir protection system of the present invention has an excellent solubility limit effect, which can not only reduce the adverse effects of inorganic scale produced by external fluids on the reservoir, but also reduce the blockage effect of particles such as crude oil, colloid, and asphalt in the reservoir pores.

[0027] When the salt-sensitive reservoir protection system of the present invention was evaluated indoors, the anti-swelling rate was 93%, the scale inhibition rate was 81.3%, and the oil washing rate was 95.6%. When it was used in field trials, after 2% of the protection system was added in the pre-water injection stage, the apparent water absorption index of clean water injected into the formation was significantly increased, and the formation water injection start-up pressure was reduced by 2.7MPa.

[0028] The anti-salt-sensitive reservoir protection system of the present invention is suitable for salt-sensitive reservoir water injection wells with a temperature of ≤150°C and a mineralization of ≤220,000 mg / L.

[0029] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0031] Figure 1 is a curve diagram of the core permeability of Example 2 of the present invention as a function of different displacement media;

[0032] Figure 2 This is a water absorption indication curve diagram of the trial injection test of Example 2 of the present invention. DETAILED DESCRIPTION

[0033] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0034] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0035] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which the invention belongs. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0036] In the description of the present invention, it should be noted that the terms "include", "including", "have", "contain" and the like are open terms, meaning including but not limited to.

[0037] The present invention is further described below in conjunction with specific examples, and the protection scope of the present invention is not limited by the following examples. The sources of materials mainly involved in the examples or preparation examples are all industrial-grade commercial products.

[0038] The oligomeric quaternary ammonium salts used in the following examples are all prepared by the following steps.

[0039] Preparation Example 1

[0040] This preparation example provides a method for preparing a dimerized quaternary ammonium salt DETA-FP2, comprising the following steps:

[0041] (1) Add 50 g of 2,3-epoxypropyltrimethylammonium chloride to a three-necked flask, add 50 ml of water, stir until dissolved, heat to 50°C, then add 165.5 ml of 2 mol / L hydrochloric acid, stir and react for 60 min to obtain the product;

[0042] (2) Add 16.98 g of diethylenetriamine to a three-necked flask, heat to 70° C., slowly add dropwise the product of step (1) while stirring magnetically, and stir at a constant temperature for 8 h to obtain a brown liquid; after cooling to room temperature, add toluene, propylene glycol, and water for extraction, retain the aqueous phase, and distill under reduced pressure at 150° C. to obtain a white solid, which is the dimer quaternary ammonium salt DETA-FP2.

[0043] The relative molecular mass of the dimeric quaternary ammonium salt DETA-FP2 synthesized in this preparation example is 335.

[0044] Preparation Example 2

[0045] This preparation example provides a method for preparing tetrameric quaternary ammonium salt DETA-FP4, comprising:

[0046] (1) Add 50 g of 2,3-epoxypropyltrimethylammonium chloride to a three-necked flask, add 50 ml of water, stir until dissolved, heat to 50°C, then add 165.5 ml of 2 mol / L hydrochloric acid, stir and react for 60 min to obtain the product;

[0047] (2) Add 8.49 g of diethylenetriamine to a three-necked flask, raise the temperature to 70° C., slowly add the product of step (1) dropwise while stirring with a magnetic stirrer, and stir at a constant temperature for 8 h to obtain a brown liquid; after cooling to room temperature, add toluene, propylene glycol, and water for extraction, retain the aqueous phase, and distill under reduced pressure at 150° C. to obtain a white solid, which is the tetrameric quaternary ammonium salt DETA-FP4.

[0048] The relative molecular mass of the tetrameric quaternary ammonium salt DETA-FP4 synthesized in this preparation example is 567.

[0049] The following are examples of the present invention. The oligomeric quaternary ammonium salts used in the examples are all selected from the above-mentioned preparation examples. Examples 1 to 2 respectively provide a salt-sensitive reservoir protection system.

[0050] Example 1

[0051] The anti-salt-sensitive reservoir protection system GCYFP-C of this embodiment is prepared by the following steps:

[0052] At room temperature, 1.5 g of each of the dimerized quaternary ammonium salt DETA-FP2 and the tetramerized quaternary ammonium salt DETA-FP4 was added to 100 g of water, and after stirring to dissolve, 2 g of EDTA was added, and stirring was continued. After dissolution, 0.6 g of dodecyl glucoside was slowly added to obtain a light yellow liquid, which was the anti-salt-sensitive reservoir protection system GCYFP-C.

[0053] The high temperature anti-swelling test of the anti-salt-sensitive reservoir protection system GCYFP-C prepared in Example 1 was carried out, specifically including:

[0054] The experimental temperature was set at 90°C, the bentonite soaking time was 12 hours, and the anti-swelling rate test and evaluation were performed using the centrifugal test method in accordance with SY / T5971-2016 "Performance Evaluation Method of Clay Stabilizer for Fracturing Acidification and Water Injection in Oil and Gas Fields". In addition, three commonly used water injection well protection agents on the market were compared with the anti-salt sensitive reservoir protection system GCYFP-C prepared in Example 1 of the present invention, and the test results were recorded in Table 1 below.

[0055] Table 1 Test data of anti-swelling effect of different types of protection systems

[0056]

[0057] From the test results in Table 1, we can see that the anti-salt-sensitive reservoir protection system prepared in Example 1 of the present invention has a better anti-swelling effect than conventional protective agent systems on the market at 90°C and a concentration range of 1-3%. This shows that the anti-salt-sensitive reservoir protection system prepared in the present invention has excellent anti-swelling properties.

[0058] Example 2

[0059] The anti-salt-sensitive reservoir protection system GCYFP-C of this embodiment is prepared by the following steps:

[0060] Add 5g of anti-swelling agent DETA-FP2 and 10g of anti-swelling agent DETA-FP4 to 500g of water, stir and dissolve, then add 10g of EDTA, continue stirring and add 1.5g of dodecyl glucoside APG to obtain a light yellow liquid anti-salt-sensitive reservoir protection system.

[0061] The salt-sensitive reservoir protection system prepared in this embodiment has a pH value of 6 and a density of 1.12 g / cm 3 , miscible with water without precipitation, viscosity 1.2mPa·s.

[0062] The anti-salt-sensitive reservoir protection system prepared in Example 2 was subjected to the following performance tests.

[0063] Test-Anti-scouring performance evaluation test

[0064] The test refers to the static evaluation method of Q / SH 0053-2010 "Technical Requirements for Clay Stabilizers" and designs a dynamic anti-scour evaluation method for the reservoir protection system: pour formation water (mineralization 190,000 mg / L), 2% GCYFP-C solution prepared with clean water, and clean water (mineralization 700 mg / L) into the parallel intermediate containers ①, ②, and ③ respectively. The constant flow pump is set at a flow rate of 0.2 ml / min and the core holder temperature is 90°C. The reservoir protection system and clean water are injected alternately to observe the changes in core permeability. The results are as follows: Figure 1 shown.

[0065] Test results: Reference Figure 1 The core permeability curve of the core with different displacement media shows that after the injection of 2% GCYFP-C plug, the core permeability decreased by 30% when the volume of the first clean water flushing was about 20 times the volume of the reservoir protection system; the core permeability decreased by 30% when the volume of the second clean water flushing was about 8 times the volume of the reservoir protection system. Therefore, the inventor believes that the salt-sensitive reservoir protection system GCYFP-C prepared by the present invention exhibits good anti-scouring performance.

[0066] Test 2: Scale inhibition performance evaluation test

[0067] Referring to the performance evaluation method of slow-release scale inhibitors for oil fields in Q / SY17126-2019, the scale inhibition rate of the anti-salt-sensitive reservoir protection system prepared in Example 2 was tested. 2+ Concentration 21870mg / L, HCO3 - The concentration is 172.4 mg / L and the free CO2 concentration is 12.4 mg / L. It is a CaCl2 water type and has a strong CaCO3 scaling tendency. The scale inhibition effect of the oilfield slow-release scale inhibitor HZ-3 is compared, and the results are shown in Table 2.

[0068] Table 2 Test data of scale inhibition effect of different types of protective agent systems

[0069]

[0070] Test results: It can be seen from Table 2 that as the temperature increases, the scale inhibition performance of the agent decreases, but the developed reservoir protection system GCYFP-C has a scale inhibition performance of 84.5% at a high temperature of 120°C, which is better than the commonly used slow-release scale inhibitor HZ-3.

[0071] Test 3 Washing oil performance evaluation test

[0072] Referring to the evaluation method of surfactant oil washing performance in Q / SY17583-2018, the oil washing rate of the anti-salt sensitive reservoir protection system prepared in Example 2 was tested. Crude oil from a certain block was taken, with a wax content of 19.4%, a gelatin content of 27.2%, and a freezing point of 50°C. The experimental temperature was 40°C, and the oil washing rates of GCYFP-C at different concentrations were tested. The results are shown in Table 3.

[0073] Table 3 Antiscaling effect test data of different types of protective agent systems

[0074]

[0075] Test results: It can be seen from Table 3 that the developed reservoir protection system GCYFP-C has excellent oil washing performance in the concentration range of 0.3% to 0.6%, and can effectively reduce the cold damage caused by the entry of foreign low-temperature liquid into the reservoir during water injection.

[0076] Test 4: Water injection effect test

[0077] The anti-salt-sensitive reservoir protection system GCYFP-C prepared in Example 2 was applied to a salt-sensitive reservoir mine, with a reservoir temperature of 150°C, a mineralization of 220,000 mg / L, and a critical salinity of 50,000 mg / L. The water injection effect of the reservoir protection system GCYFP-C was tested. Specifically, a clean water test was carried out in a water injection well, and 1,100 cubic meters of 2% reservoir protection system solution was injected in the pre-stage displacement stage, followed by 6,000 cubic meters of clean water. The test results are as follows: Figure 2 shown.

[0078] Test results: Reference Figure 2 The test injection water absorption indication curve shown in the figure shows that: by injecting the reservoir protection system in the stage of increasing displacement, the apparent water absorption index measured in the stage of decreasing displacement significantly increases, the formation water injection start-up pressure decreases by 2.7MPa, and the injection pressure is stable in the later stage of the test injection, and the test is successful. It can be shown that the anti-salt-sensitive reservoir protection system prepared by the present invention has achieved a good effect of reducing pressure and increasing injection in mine construction.

[0079] In summary, the anti-salt-sensitive reservoir protection system of the present invention has excellent comprehensive performance, with an anti-swelling rate of up to 93%, a scale inhibition rate of not less than 81.3%, and an oil washing rate of 95.6%. During on-site trial injection application, after adding 2% of the agent in the pre-water injection stage, the apparent water absorption index of clean water injected into the formation was significantly increased, and the formation water injection start-up pressure was reduced by 2.7MPa.

[0080] Although the description of the present invention has been quite detailed and has been described in particular with respect to several described embodiments, it is not intended to be limited to any of these details or embodiments or any particular embodiment, so as to effectively cover the intended scope of the present invention. In addition, the present invention is described above with the embodiments foreseeable by the inventors, and its purpose is to provide a useful description, and those non-substantial changes to the present invention that are not currently foreseen may still represent equivalent changes of the present invention.

[0081] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0082] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. Anti-salt-sensitive reservoir protection system, characterized in that: The protection system comprises the following raw materials by mass percentage: 1-3% anti-swelling agent, 1-2% anti-scaling agent, 0.3-0.6% solubilizing agent, and the balance is water; The anti-swelling agent is oligomeric quaternary ammonium salt DETA-FP; the scale inhibitor is EDTA; and the solubilizing agent is alkyl glucoside APG.

2. The anti-salinity sensitive reservoir protection system according to claim 1, characterized in that: The oligomeric quaternary ammonium salt DETA-FP is a mixture of a dimerized quaternary ammonium salt DETA-FP2 and a tetramerized quaternary ammonium salt DETA-FP4 in any mass ratio.

3. The anti-salinity sensitive reservoir protection system according to claim 2 is characterized in that: The mass ratio of the dimeric quaternary ammonium salt DETA-FP2 to the tetrameric quaternary ammonium salt DETA-FP4 is 1:(1-2).

4. The anti-salinity sensitive reservoir protection system according to claim 2 or 3, characterized in that: The dimeric quaternary ammonium salt DETA-FP2 is shown in formula (I): The tetrameric quaternary ammonium salt DETA-FP4 is shown in formula (II):

5. The anti-salinity sensitive reservoir protection system according to claim 1, characterized in that: The alkyl glucoside APG is selected from C10-C12 alkyl glucoside.

6. The anti-salinity sensitive reservoir protection system according to claim 1, characterized in that: The anti-salt-sensitive reservoir protection system is suitable for salt-sensitive reservoir water injection wells with a temperature of ≤150°C and a mineralization of ≤220,000 mg / L.

7. A method for preparing the anti-salinity sensitive reservoir protection system according to any one of claims 1 to 6, characterized in that: The method comprises: According to the formula, under stirring conditions, oligomeric quaternary ammonium salt is added to water, and after dissolution, EDTA is added to the solution, and after stirring until dissolved, alkyl glucoside is added to prepare an anti-salt-sensitive reservoir protection system.

8. The method for preparing the anti-salinity sensitive reservoir protection system according to claim 7, characterized in that: The preparation of the oligomeric quaternary ammonium salt comprises: Add 2,3-epoxypropyltrimethylammonium chloride to water, stir until dissolved, heat to a certain temperature, drop hydrochloric acid, mix and react; then drop the reacted liquid into diethylenetriamine, stir at a constant temperature for a certain period of time, cool, extract, and distill the water phase under reduced pressure to obtain an oligomeric quaternary ammonium salt.

9. Use of the anti-salinity sensitive reservoir protection system according to any one of claims 1 to 6 in oil field exploitation.

10. A method for oil field exploitation, characterized in that: The method uses the anti-salt-sensitive reservoir protection system according to any one of claims 1 to 6, comprising: Inject 2-3wt% of anti-salt-sensitive reservoir protection system slug; Stop the injection for 3 to 5 days; Water injection slug.

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