Microbial activator for high-wax-content oil reservoir and application thereof
By using a high-wax reservoir microbial activator to activate wellbore microorganisms, the wax content and pour point of crude oil are reduced, solving the wax blockage problem in low-temperature, high-wax reservoirs and achieving efficient production increase and environmentally friendly wax removal and prevention effects.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- PETROCHINA CO LTD
- Filing Date
- 2023-09-28
- Publication Date
- 2026-06-23
AI Technical Summary
Low-temperature, high-wax reservoirs developed by conventional water injection suffer from problems such as wax blockage of the reservoir, reduced permeability, and wax precipitation in oil wells. Existing wax removal and prevention methods are costly, complex, or environmentally polluting, while microbial activator processes are complex and have not completely eliminated the use of chemical wax removal and prevention agents.
A microbial activator for high-wax reservoirs is provided, comprising glucose, sodium nitrate, sodium chloride, magnesium sulfate, yeast extract, dipotassium hydrogen phosphate, potassium dihydrogen phosphate, and trace elements. This activates wellbore microorganisms, reduces crude oil wax content and pour point, and enhances fluidity.
Activated microorganisms can effectively reduce the wax content and pour point of crude oil, increase oil well production, reduce lifting difficulties, and are low in cost and free from secondary pollution. They are suitable for increasing production in single wells in high-wax reservoirs.
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Figure CN119712044B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of petroleum extraction technology, and in particular to a microbial activator for high-wax reservoirs and its application. Background Technology
[0002] For shallow, low-temperature, high-wax oil reservoirs, conventional water injection development can easily cause cold damage to the formation. Injecting cold water lowers the reservoir temperature, and when the temperature drops to near or below the crude oil's freezing point, wax precipitates, increasing viscosity and clogging rock pores, leading to reduced reservoir permeability and increased flow resistance. Simultaneously, high-wax oil wells also experience wax precipitation during lift operations due to temperature drops. In conventional tubing production, excessive wax precipitation results in excessive load, slow well descent, tubing wear, and even tubing breakage.
[0003] Currently, for low-temperature, high-wax oil reservoirs developed using conventional water injection, there are no effective methods to improve oil recovery. More research focuses on wax removal and prevention in oil wells. One method is hot washing to remove wax from the wellbore through periodic hot water washing, but frequent well shutdowns affect well productivity, increase production costs, and reduce economic efficiency. Another method is electric heating of the oil rod to raise the wellbore temperature and prevent wax precipitation, but this method consumes a lot of energy and has high production costs. A third method is chemical wax prevention, which slows down wax buildup in the wellbore through periodic chemical injection, but this method has a short effective period, high cost, and can pollute the environment. These methods only address the problem of wax buildup in the wellbore. Some studies have applied microorganisms to improve the production of high-wax oil wells, but this requires the injection of air and water-based wax-removing agents, making the process complex and risky, and not completely eliminating the use of chemical wax-removing agents. Summary of the Invention
[0004] This application provides a microbial activator for high-wax reservoirs and its application, to eliminate the use of chemical wax removers.
[0005] In a first aspect, this application provides a microbial activator for high-wax oil reservoirs, the components of which include: glucose, sodium nitrate, sodium chloride, magnesium sulfate, yeast extract, dipotassium hydrogen phosphate, potassium dihydrogen phosphate, and trace elements.
[0006] As an optional implementation, the activator comprises, by mass fraction: 0.1%–0.2% glucose, 0.2%–0.45% sodium nitrate, 0.03%–0.1% sodium chloride, 0.01%–0.025% magnesium sulfate, 0.05%–0.2% yeast extract, 0.2%–0.5% dipotassium hydrogen phosphate, 0.2%–0.35% potassium dihydrogen phosphate, and 0.1%–0.17% trace elements.
[0007] As an optional implementation, the activator comprises, by mass fraction: 0.12%–0.18% glucose, 0.25%–0.4% sodium nitrate, 0.04%–0.09% sodium chloride, 0.015%–0.020% magnesium sulfate, 0.1%–0.15% yeast extract, 0.3%–0.4% dipotassium hydrogen phosphate, 0.25%–0.3% potassium dihydrogen phosphate, and 0.12%–0.15% trace elements.
[0008] As an optional implementation, the activator comprises, by mass fraction: 0.14%–0.16% glucose, 0.3%–0.35% sodium nitrate, 0.05%–0.08% sodium chloride, 0.016%–0.018% magnesium sulfate, 0.12%–0.13% yeast extract, 0.33%–0.37% dipotassium hydrogen phosphate, 0.27%–0.28% potassium dihydrogen phosphate, and 0.13%–0.14% trace elements.
[0009] As an optional implementation, the trace element components include: boric acid, sodium citrate, manganese sulfate, sodium molybdate, trichloride, zinc sulfate, copper sulfate, and cobalt chloride.
[0010] As an optional implementation, the trace element components, by mass concentration, include: boric acid 0.4–0.6 g / L, sodium citrate 1.5–2.5 g / L, manganese sulfate 2.5–3.5 g / L, sodium molybdate 0.05–0.15 g / L, ferric chloride 0.2–0.4 g / L, zinc sulfate 1–1.4 g / L, copper sulfate 1–1.4 g / L, and cobalt chloride 1–1.4 g / L.
[0011] As an optional implementation, the trace element components, by mass concentration, include: boric acid 0.5 g / L, sodium citrate 2 g / L, manganese sulfate 3 g / L, sodium molybdate 0.1 g / L, ferric chloride 0.28 g / L, zinc sulfate 1.2 g / L, copper sulfate 1.2 g / L, and cobalt chloride 1.2 g / L.
[0012] Secondly, this application provides an application of a high-wax reservoir microbial activator, wherein the activator is the high-wax reservoir microbial activator described in the first aspect, and the application includes applying the activator to oil extraction.
[0013] As an optional implementation, applying the activator to oil extraction includes:
[0014] The activator is prepared into an activation solution;
[0015] The activation solution is injected into the oil well or production well to activate the interaction between microorganisms in the formation and crude oil.
[0016] As an optional implementation, the microorganisms include hydrocarbon-oxidizing bacteria.
[0017] The technical solutions provided in this application have the following advantages compared with the prior art:
[0018] The activator provided in this application embodiment can be injected into oil wells to activate the microorganisms in the wells. The activated microorganisms can interact with crude oil, thereby reducing the wax content and pour point of high-wax crude oil, enhancing its fluidity, increasing well production, and reducing lift difficulties, making it easier for crude oil to flow out of the wellbore. This activator is characterized by low corrosivity, no secondary pollution, and low cost, and can be used to increase single-well production in high-wax reservoirs, meeting the needs of oilfield production. Attached Figure Description
[0019] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.
[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0021] Figure 1 This is a schematic diagram illustrating the application process of the activator provided in the embodiments of this application;
[0022] Figure 2 This is a schematic diagram of the injection process provided in Embodiment 1 of this application;
[0023] Figure 3 The diagram illustrates the injection process provided in Embodiments 2 and 3 of this application. Detailed Implementation
[0024] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0025] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.
[0026] This application provides a microbial activator for high-wax oil reservoirs. The activator comprises glucose, sodium nitrate, sodium chloride, magnesium sulfate, yeast extract, dipotassium hydrogen phosphate, potassium dihydrogen phosphate, and trace elements.
[0027] In some embodiments, the activator comprises, by mass fraction: 0.1%–0.2% glucose, 0.2%–0.45% sodium nitrate, 0.03%–0.1% sodium chloride, 0.01%–0.025% magnesium sulfate, 0.05%–0.2% yeast extract, 0.2%–0.5% dipotassium hydrogen phosphate, 0.2%–0.35% potassium dihydrogen phosphate, and 0.1%–0.17% trace elements. Furthermore, the activator comprises, by mass fraction: 0.12%–0.18% glucose, 0.25%–0.4% sodium nitrate, 0.04%–0.09% sodium chloride, 0.015%–0.020% magnesium sulfate, 0.1%–0.15% yeast extract, 0.3%–0.4% dipotassium hydrogen phosphate, 0.25%–0.3% potassium dihydrogen phosphate, and 0.12%–0.15% trace elements. Furthermore, the activator comprises, by mass fraction: 0.14%–0.16% glucose, 0.3%–0.35% sodium nitrate, 0.05%–0.08% sodium chloride, 0.016%–0.018% magnesium sulfate, 0.12%–0.13% yeast extract, 0.33%–0.37% dipotassium hydrogen phosphate, 0.27%–0.28% potassium dihydrogen phosphate, and 0.13%–0.14% trace elements.
[0028] In some embodiments, the trace element component comprises: boric acid, sodium citrate, manganese sulfate, sodium molybdate, ferric chloride, zinc sulfate, copper sulfate, and cobalt chloride. Specifically, the trace element component, by mass concentration, comprises: boric acid 0.4–0.6 g / L, sodium citrate 1.5–2.5 g / L, manganese sulfate 2.5–3.5 g / L, sodium molybdate 0.05–0.15 g / L, ferric chloride 0.2–0.4 g / L, zinc sulfate 1–1.4 g / L, copper sulfate 1–1.4 g / L, and cobalt chloride 1–1.4 g / L. Further, the trace element component, by mass concentration, comprises: boric acid 0.5 g / L, sodium citrate 2 g / L, manganese sulfate 3 g / L, sodium molybdate 0.1 g / L, ferric chloride 0.28 g / L, zinc sulfate 1.2 g / L, copper sulfate 1.2 g / L, and cobalt chloride 1.2 g / L.
[0029] This activator can be injected into oil wells to activate the microorganisms within them and prolong the activity time of hydrocarbon-oxidizing bacteria. The activated microorganisms then interact with the crude oil, resulting in a 11°C decrease in pour point, a 13.8% reduction in wax content, and a 57% decrease in viscosity. This reduces the wax content and pour point of high-wax crude oil, enhances its fluidity, increases well production, and reduces lift difficulties, making it easier for the crude oil to flow out of the wellbore. The activator is characterized by low corrosivity, no secondary pollution, and low cost, and can be used to increase single-well production in high-wax reservoirs, meeting the needs of oilfield production.
[0030] Based on a general inventive concept, embodiments of this application also provide an application of a high-wax reservoir microbial activator, wherein the activator is the high-wax reservoir microbial activator provided above, and the application includes applying the activator to oil extraction.
[0031] Figure 1 This is a schematic diagram illustrating the application process of the activator provided in the embodiments of this application, such as... Figure 1 As shown, in some embodiments, applying the activator to oil extraction includes:
[0032] S1. Prepare the activator into an activation solution;
[0033] S2. Inject the activation solution into the oil well or water injection well to activate the interaction between the microorganisms in the formation and the crude oil.
[0034] The present application is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards. If there is no corresponding national standard, then general international standards, conventional conditions, or conditions recommended by the manufacturer are followed.
[0035] Example 1
[0036] A microbial activator for high-wax oil reservoirs, the activator formula is as follows: glucose 0.1%, sodium nitrate 0.2%, sodium chloride 0.05%, magnesium sulfate 0.015%, yeast extract 0.1%, dipotassium hydrogen phosphate 0.25%, potassium dihydrogen phosphate 0.25%, and trace elements 0.12%.
[0037] Trace element formula: boric acid 0.5g / L, sodium citrate 2g / L, manganese sulfate 3g / L, sodium molybdate 0.1g / L, ferric chloride 0.28g / L, zinc sulfate 1.2g / L, copper sulfate 1.2g / L, cobalt chloride 1.2g / L.
[0038] The activator was applied to the Quan 42-36X well in the HB oilfield for in-situ oil displacement test. Figure 2The diagram illustrates the injection process. The on-site preparation and injection process is as follows:
[0039] 1. Turn on the water filling switch and add clean water or sewage to the tank until it is 1 / 3 full. Then add the required amount of glucose (crush and add).
[0040] 2. When the clean water or wastewater has been added to half of the tank, turn on the agitator switch to start stirring;
[0041] 3. While stirring, continue to add clean water or wastewater and then add other agents in sequence;
[0042] 4. After all the chemicals have been added, stop adding water when the volume of clean or wastewater is 20 cm from the top of the tank, and continue stirring;
[0043] 5. Reverse the process, injecting the prepared nutrient solution into the injection well together with the online water injection process.
[0044] Field tests showed that after injecting the activator into well Quan 42-36X, the concentration of hydrocarbon-oxidizing bacteria in the produced fluids of the corresponding oil wells Quan 42-32X and Quan 42-33X1 was effectively increased, from 5×10⁻⁶ to 10⁻⁶. 4 The number of cells / ml increased to 4.1 × 10⁻⁶. 6 The decrease in wax content, lower pour point, and improved emulsification of crude oil, along with the reduction in maximum upward current, indicates that the oil well load has been reduced, resulting in a cumulative increase in oil production of 550 tons.
[0045] Example 2
[0046] A microbial activator for high-wax oil reservoirs, the activator formula is as follows: glucose 0.2%, sodium nitrate 0.45%, sodium chloride 0.1%, magnesium sulfate 0.025%, yeast extract 0.2%, dipotassium hydrogen phosphate 0.5%, potassium dihydrogen phosphate 0.35%, and trace elements 0.17%.
[0047] Trace element formula: boric acid 0.5g / L, sodium citrate 2g / L, manganese sulfate 3g / L, sodium molybdate 0.1g / L, ferric chloride 0.28g / L, zinc sulfate 1.2g / L, copper sulfate 1.2g / L, cobalt chloride 1.2g / L.
[0048] The activator was applied to the Quan 42-61X well in the HB oilfield for an in-situ oil displacement test. Figure 3 The diagram illustrates the injection process. The on-site preparation and injection process is as follows:
[0049] 1. Turn on the water filling switch and add clean water or sewage to the tank until it is 1 / 3 full. Then add the required amount of glucose (crush and add).
[0050] 2. When the clean water or wastewater has been added to half of the tank, turn on the agitator switch to start stirring;
[0051] 3. While stirring, continue to add clean water or wastewater and then add other agents in sequence;
[0052] 4. After all the chemicals have been added, stop adding water when the volume of clean or wastewater is 20 cm from the top of the tank, and continue stirring;
[0053] 5. Use a pump truck to inject the prepared activator into the annulus of the oil well, maintaining an injection rate and displacement of 20-30 m³ / h. 3 / h, the injection pressure is controlled in a timely manner according to the water absorption situation.
[0054] Before the intervention, the crude oil in this well had a wax content of 40.3%, a pour point of 41℃, a daily oil production of 0.7 tons, and a water content of 90%. After injecting an activator, the hydrocarbon-oxidizing bacteria were effectively activated, and the bacterial concentration increased from 4.3 × 10⁻⁶. 4 The number of cells / ml increased to 6.2 × 10⁻⁶. 6 The crude oil properties were significantly improved, with wax content decreasing by 21%, freezing point dropping to 35℃, daily oil production increasing to 2.9 tons, water content decreasing to 63%, and a cumulative increase of 475 tons of oil. The oil's shelf life can reach more than one year.
[0055] Example 3
[0056] A microbial activator for high-wax oil reservoirs, the activator formula is as follows: glucose 0.15%, sodium nitrate 0.35%, sodium chloride 0.08%, magnesium sulfate 0.02%, yeast extract 0.15%, dipotassium hydrogen phosphate 0.35%, potassium dihydrogen phosphate 0.3%, and trace elements 0.15%.
[0057] Trace element formula: boric acid 0.5g / L, sodium citrate 2g / L, manganese sulfate 3g / L, sodium molybdate 0.1g / L, ferric chloride 0.28g / L, zinc sulfate 1.2g / L, copper sulfate 1.2g / L, cobalt chloride 1.2g / L.
[0058] The activator was applied to the Quan 42-31X well in the HB oilfield for an in-situ oil displacement test. Figure 3 The diagram illustrates the injection process. The on-site preparation and injection process is as follows:
[0059] 1. Turn on the water filling switch and add clean water or sewage to the tank until it is 1 / 3 full. Then add the required amount of glucose (crush and add).
[0060] 2. When the clean water or wastewater has been added to half of the tank, turn on the agitator switch to start stirring;
[0061] 3. While stirring, continue to add clean water or wastewater and then add other agents in sequence;
[0062] 4. After all the chemicals have been added, stop adding water when the volume of clean or wastewater is 20 cm from the top of the tank, and continue stirring;
[0063] 5. Use a pump truck to inject the prepared activator into the annulus of the oil well, maintaining an injection rate and displacement of 20-30 m³ / h. 3 / h, the injection pressure is controlled in a timely manner according to the water absorption situation.
[0064] Before the intervention, the crude oil in this well had a wax content of 41.5%, a pour point of 40℃, a daily oil production of 0.2 tons, and a water content of 83.3%. After injecting an activator, the hydrocarbon-oxidizing bacteria were effectively activated, and the bacterial concentration increased from 3.7 × 10⁻⁶. 4 The number of cells / ml increased to 5×10 6 The crude oil properties were significantly improved, with wax content decreasing by 19%, freezing point dropping to 34℃, daily oil production increasing to 1.2 tons, water content decreasing to 33%, and a cumulative increase of 315 tons of oil. The oil's shelf life can reach more than one year.
[0065] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.
[0066] In this application, unless otherwise stated, directional terms such as "upper" and "lower" specifically refer to the drawing directions in the accompanying drawings. Furthermore, in the description of this application, terms such as "comprising" and "including" mean "including but not limited to." In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this document, "and / or" describes the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. In this document, "at least one" means one or more, and "more than one" means two or more. "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c" or "at least one of a, b, and c" can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be a single or multiple.
[0067] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.
Claims
1. A microbial activator for high-wax oil reservoirs, characterized in that, The activator comprises, by mass fraction: 0.1%–0.2% glucose, 0.2%–0.45% sodium nitrate, 0.03%–0.1% sodium chloride, 0.01%–0.025% magnesium sulfate, 0.05%–0.2% yeast extract, 0.2%–0.5% dipotassium hydrogen phosphate, 0.2%–0.35% potassium dihydrogen phosphate, and 0.1%–0.17% trace elements. The trace element components, by mass concentration, include: boric acid 0.4–0.6 g / L, sodium citrate 1.5–2.5 g / L, manganese sulfate 2.5–3.5 g / L, sodium molybdate 0.05–0.15 g / L, ferric chloride 0.2–0.4 g / L, zinc sulfate 1–1.4 g / L, copper sulfate 1–1.4 g / L, and cobalt chloride 1–1.4 g / L.
2. The microbial activator for high-wax oil reservoirs according to claim 1, characterized in that, The activator comprises, by mass fraction: 0.12%–0.18% glucose, 0.25%–0.4% sodium nitrate, 0.04%–0.09% sodium chloride, 0.015%–0.020% magnesium sulfate, 0.1%–0.15% yeast extract, 0.3%–0.4% dipotassium hydrogen phosphate, 0.25%–0.3% potassium dihydrogen phosphate, and 0.12%–0.15% trace elements.
3. The microbial activator for high-wax oil reservoirs according to claim 1, characterized in that, The activator comprises, by mass fraction: 0.14%–0.16% glucose, 0.3%–0.35% sodium nitrate, 0.05%–0.08% sodium chloride, 0.016%–0.018% magnesium sulfate, 0.12%–0.13% yeast extract, 0.33%–0.37% dipotassium hydrogen phosphate, 0.27%–0.28% potassium dihydrogen phosphate, and 0.13%–0.14% trace elements.
4. The microbial activator for high-wax oil reservoirs according to any one of claims 1-3, characterized in that, The trace element components, by mass concentration, include: boric acid 0.5 g / L, sodium citrate 2 g / L, manganese sulfate 3 g / L, sodium molybdate 0.1 g / L, ferric chloride 0.28 g / L, zinc sulfate 1.2 g / L, copper sulfate 1.2 g / L, and cobalt chloride 1.2 g / L.
5. The application of a microbial activator for high-wax oil reservoirs, characterized in that, The activator is the high-wax reservoir microbial activator according to any one of claims 1 to 4, and the application includes applying the activator to oil extraction.
6. The application of the high-wax reservoir microbial activator according to claim 5, characterized in that, The application of the activator in oil extraction includes: The activator is prepared into an activation solution; The activation solution is injected into the oil well or water injection well to activate the interaction between the microorganisms in the formation and the crude oil.
7. The application of the microbial activator for high-wax oil reservoirs according to claim 5, characterized in that, The microorganisms include hydrocarbon-oxidizing bacteria.