Preparation method of heavy oil hydrogen donor

Abstract

The present invention relates to the field of crude oil catalysis technology, and in particular to a method for preparing a heavy oil hydrogen donor, comprising the following steps: A. crushing biomass with a pulverizer and then screening the resulting biomass particles to prepare slurry biomass; B. conveying the slurry biomass to a steam pipeline via a delivery pump, wherein steam generated by a steam boiler is introduced into the steam pipeline, and the slurry biomass is liquefied under the action of the steam to obtain a heavy oil hydrogen donor. This method utilizes the heat of the steam to liquefy the biomass, and the resulting hydrogen donor can enter the formation along with the steam. The hydrogen donor undergoes aquathermal cracking with the heavy oil, thereby in-situ reforming the heavy oil and reducing its viscosity, thereby achieving the purpose of improving the recovery rate.

Description

Technical Field

[0001] The present invention relates to the technical field of crude oil catalysis, and in particular to a method for preparing a heavy oil hydrogen donor. Background Art

[0002] With the increasing development of oil fields, shallow, light crude oil reserves are gradually decreasing. Therefore, the effective extraction of heavy oil resources has become crucial. Currently, a variety of heavy oil extraction technologies are available, including thermal recovery (such as steam flooding, steam stimulation, and oil layer combustion), chemical recovery, and mechanical recovery. In my country, miscible gas injection has been widely used. To improve the efficiency of steam injection for heavy oil recovery, common methods include injecting nitrogen, air, mixed gases, and chemicals. Steam injection is the most common method. However, this method also faces high costs, requiring extensive steam generation equipment and energy, and is highly dependent on water resources, limiting its application in areas with water scarcity or high water prices. Furthermore, technical complexity and operational difficulties also hinder its effectiveness. Particularly in heterogeneous reservoirs, uneven steam coverage can lead to reduced recovery.

[0003] Chinese invention patent CN 107664031 A (application number 201610620741.9) discloses a method for improving oil recovery by determining the pattern of horizontal well steam flooding. This method involves selecting the physical properties of the horizontal well steam flooding reservoir, optimizing the horizontal well deployment, switching to steam stimulation before flooding, determining the steam flooding pattern and timing, and setting other steam flooding parameters. Suitable for shallow and medium-deep ultra-heavy oil reservoirs, switching from steam stimulation to steam flooding improves oil recovery and significantly increases oil recovery. However, this method still utilizes high-temperature steam for flooding, and its effectiveness decreases with increasing reservoir depth.

[0004] Chinese invention patent CN103670351A (application number 201210345782.3) discloses a steam flooding method for heavy oil reservoirs. The method comprises: while performing steam flooding, injecting an aqueous solution of an oil-displacing agent into the reservoir formation; the oil-displacing agent comprises, by weight, 0.001 to 20 parts of a sodium and / or calcium salt of a sulfonated phenolic resin and 0.001 to 20 parts of a nonionic surfactant and / or a nonionic-anionic surfactant for oil displacement; the sulfonated phenolic resin has a number-average molecular weight of 2,000 to 200,000, and the mass fraction of sulfur in the sulfonated phenolic resin is 5% to 20%. While this method improves steam flooding recovery, the incorporation of chemical reagents into the formation inevitably causes environmental pollution and increases the difficulty of secondary processing of the heavy oil.

[0005] In summary, steam flooding, supplemented with other fluids, is a widely used method for oil recovery. However, balancing the reduced heat transfer efficiency of steam as the depth of the formation increases with the environmental pollution caused by the addition of chemical reagents is an urgent issue that needs to be addressed in the field of heavy oil recovery. Summary of the Invention

[0006] In order to solve the above technical problems, an embodiment of the present invention provides a method for preparing a heavy oil hydrogen donor.

[0007] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions:

[0008] The present invention provides a method for preparing a heavy oil hydrogen donor, comprising the following steps:

[0009] A. crushing the biomass by a grinder and then screening the obtained biomass particles to prepare slurry biomass;

[0010] B. The slurry biomass is transported to a steam pipeline through a delivery pump. Steam generated in a steam boiler is introduced into the steam pipeline. Under the action of the steam, the slurry biomass is liquefied to obtain a heavy oil hydrogen donor.

[0011] In some embodiments, in step A, the biomass comprises at least one of sawdust, microcrystalline cellulose, lignin, chlorella, sweetgum leaves, wheat straw, corn stalks, paper scraps, cherry blossoms, rape blossoms, bamboo shoots, crabapple blossoms, morning glory, mugwort, clover, sugarcane bagasse, qingming vegetable, melon seed shells, orange peels, banana peels, grapefruit peels, poultry feathers, pig manure, and cow manure.

[0012] In some embodiments, in step A, the biomass particles have a mesh size of 200-500 mesh.

[0013] In some embodiments, in step B, the temperature of the steam is 260°C to 380°C.

[0014] In some embodiments, in step B, the volume ratio of the slurry biomass to steam is 1:(5-15).

[0015] Compared with the prior art, the present invention has at least the following beneficial effects:

[0016] This method uses the heat of steam to liquefy biomass, and the generated hydrogen donor can enter the formation with the steam. The hydrogen donor will undergo hydrothermal cracking with the heavy oil, and the heavy oil will be modified in situ to reduce the viscosity of the heavy oil, thereby achieving the purpose of improving the recovery rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the production and injection of the heavy oil hydrogen donor of the present invention. DETAILED DESCRIPTION

[0018] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in some embodiments of the present disclosure. Obviously, the embodiments described are only some embodiments of the present disclosure, not all embodiments. Based on the embodiments provided by the present disclosure, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of the present disclosure.

[0019] The present application provides an embodiment of the present invention. A method for preparing a hydrogen donor for heavy oil is provided. Biomass is mixed into the steam during steam injection during steam flooding, with the volume ratio of biomass to steam being 1 / 5 to 1 / 20. Under the action of steam, the biomass is liquefied and converted into a mixture of bio-crude oil and steam. The bio-crude oil contains methoxy compounds, small molecule alcohols, etc., and can enter the formation with the steam to perform in-situ modification of the heavy oil.

[0020] Specifically, the method includes the following steps:

[0021] First, the biomass is pretreated. The biomass is crushed using a grinder and then sieved. The biomass particles with a mesh size of 200 to 500 are mixed with a liquid at a mass ratio of 1:10 to prepare a slurry of biomass. The liquid can be waste water solution, flowback liquid, domestic sewage or mineral water from an oil field. The petroleum content of the oil field waste water solution is greater than 0.05 ppm, the residual peroxide concentration of the flowback liquid is 60-120 mg / L, the chemical demand COD concentration of the domestic sewage is 300-500 mg / L, the biochemical oxygen demand BOD concentration is 180-250 mg / L, and the mineral water concentration is greater than 1000 mg / L.

[0022] The slurry biomass is transported by a transport pump 1 .

[0023] like Figure 1 As shown, the slurry biomass is transported into the steam pipeline 2 by using the delivery pump 1. The injection position of the slurry biomass can be located at the outlet of the steam boiler 3, the wellhead, the wellbore and the formation. During the soaking process, the steam pipe 2 continuously injects steam, and the steam temperature is between 260 and 380°C. During the injection process, it will mix with the continuously injected slurry biomass. The temperature of biomass liquefaction is between 280 and 350°C. During the mixing process, the steam will liquefy the biomass to produce bio-crude oil, and form bio-crude oil vapor droplets at high temperature, which follow the steam into the formation.

[0024] The mixture of steam and bio-crude oil reaches the formation through injection well 4 and contacts the heavy oil. After 3-7 days of soaking, the hydrogen donor in the bio-crude oil undergoes hydrothermal cracking with the heavy oil, thereby in-situ modifying the heavy oil. Then, the production well 5 is opened to produce oil.

[0025] The biomass mentioned above includes at least one of sawdust, microcrystalline cellulose, lignin, chlorella, liquidambar leaves, wheat straw, corn stalks, paper scraps, cherry blossoms, rape blossoms, bamboo, crabapple blossoms, morning glory, mugwort, clover, bagasse, qingming vegetable, melon seed shells, orange peels, banana peels, grapefruit peels, poultry feathers, pig manure and cow manure.

[0026] Table 1 below shows the physical properties of existing heavy oil:

[0027] Table 1 Physical properties of two heavy oils

[0028]

[0029] In order to illustrate the viscosity reduction effect of heavy oil, the viscosity reduction rate is used in the following. The calculation formula is as follows:

[0030] Viscosity reduction rate = (viscosity of heavy oil before modification - viscosity of heavy oil after modification) / viscosity of heavy oil before modification * 100%

[0031] The following will be analyzed and explained through specific examples.

[0032] Example 1

[0033] First, the sawdust is pretreated by crushing it in a grinder and then screening it. 200-mesh sawdust pellets are mixed with flowback liquid at a mass ratio of 1:10 to prepare a biomass slurry. This slurry is then transported by pump 1. Steam is continuously injected into steam pipe 2 at a temperature of 360°C. During the injection process, steam mixes with the continuously injected sawdust slurry. The volume ratio of sawdust slurry to steam is 1:8, and the sawdust slurry liquefies at a temperature of 320°C. During this mixing process, the steam liquefies the sawdust (hydrothermal reactions of biomass below 400°C are called liquefaction), producing biocrude oil. At high temperatures, these droplets form biocrude vapor, which follow the steam into the formation through injection well 4. The steam-biocrude mixture is then injected into well 1, where it comes into contact with the heavy oil. After a five-day well soak, the hydrogen donor in the biocrude undergoes hydrothermal cracking with the heavy oil, upgrading the heavy oil in situ. Production well 5 is then opened for oil production. The viscosity of the dehydrated heavy oil in well 1# was 4630 mPa·s, and the viscosity reduction rate was 63.0%.

[0034] Example 2

[0035] First, the Chlorella vulgaris is pretreated by crushing it in a grinder and then screening it. 300-mesh Chlorella granules are mixed with domestic sewage at a mass ratio of 1:10 to prepare a Chlorella slurry. This slurry is then transported using pump 1. Steam is continuously injected into steam pipe 2 at a temperature of 350°C. During the injection process, steam mixes with the continuously injected Chlorella slurry. The volume ratio of the slurry to steam is 1:10. The Chlorella liquefaction temperature is 300°C. During this mixing process, the steam liquefies the Chlorella, producing bio-crude oil. At high temperatures, these droplets form bio-crude vapor, which follow the steam into the formation through injection well 4. The steam-bio-crude mixture is then injected into well 1, where it comes into contact with the heavy oil. After six days of well simmering, the hydrogen donor in the bio-crude undergoes aquathermolysis with the heavy oil, upgrading it in situ. Production well 5 is then opened for oil production. The viscosity of the dehydrated heavy oil in well 1# was 2350 mPa·s, and the viscosity reduction rate was 81.2%.

[0036] Example 3

[0037] First, the liquidambar leaves are pretreated by crushing them in a grinder and then sieving them. 500-mesh liquidambar leaf particles are mixed with flowback liquid in a mass ratio of 1:10 to prepare a liquidambar leaf slurry. This slurry is then transported via pump 1. Steam is continuously injected into steam pipe 2 at a temperature of 360°C. During the injection process, steam mixes with the continuously injected liquidambar leaf slurry. The volume ratio of liquidambar leaf slurry to steam is 1:15, and the liquidambar leaf liquefaction temperature is 290°C. During this mixing process, the steam liquefies the liquidambar leaf, producing biocrude oil. At high temperatures, biocrude vapor droplets form, which follow the steam into the formation through injection well 4. The steam-biocrude mixture is injected into well 1, where it comes into contact with the heavy oil. After a seven-day well soak, the hydrogen donor in the biocrude undergoes a hydrothermal cracking reaction with the heavy oil, upgrading the heavy oil in situ. Production well 5 is then opened for oil production. The viscosity of the dehydrated heavy oil in well 1# was 4310 mPa·s, and the viscosity reduction rate was 65.5%.

[0038] Example 4

[0039] First, wheat straw is pretreated by pulverizing it in a grinder and then screening it. 400-mesh wheat straw particles are mixed with domestic sewage at a mass ratio of 1:10 to prepare a wheat straw slurry. This slurry is then transported via pump 1. Steam is continuously injected into steam pipe 2 at a temperature of 360°C. During the injection process, steam mixes with the continuously injected wheat straw slurry. The volume ratio of wheat straw to steam is 1:10. The wheat straw liquefaction temperature is 330°C. During this mixing process, the steam liquefies the wheat straw, producing biocrude oil. At high temperatures, biocrude vapor droplets form, which follow the steam into the formation through injection well 4. The steam-biocrude mixture is then injected into well 1, where it contacts the heavy oil. After a five-day well soak, the hydrogen donor in the biocrude undergoes aquathermolysis with the heavy oil, upgrading it in situ. Production well 5 is then opened for oil production. The viscosity of the dehydrated heavy oil obtained in well 1 is 3320 mPa·s, with a viscosity reduction of 73.4%.

[0040] Example 5

[0041] First, the cornstalks are pretreated by crushing them in a grinder and then sieving them. 500-mesh cornstalk pellets are mixed with demineralized water in a mass ratio of 1:10 to prepare cornstalk slurry, which is then transported by pump 1. Steam is continuously injected into steam pipe 2 at a temperature of 320°C. During the injection process, steam mixes with the continuously injected cornstalk slurry. The volume ratio of cornstalk slurry to steam is 1:15. The biomass liquefaction temperature is 310°C. During this mixing process, the steam liquefies the cornstalks, producing biocrude oil. At high temperatures, biocrude vapor droplets form, which follow the steam into the formation through injection well 4. The steam-biocrude mixture is then injected into well 1, where it comes into contact with the heavy oil. After a six-day well soak, the hydrogen donor in the biocrude undergoes aquathermolysis with the heavy oil, upgrading it in situ. Production well 5 is then opened for oil production. The viscosity of the dehydrated heavy oil obtained in well 1 is 3890 mPa·s, with a viscosity reduction of 68.9%.

[0042] Example 6

[0043] First, the paper scraps are pre-treated by pulverizing them in a pulverizer and then screening them. 300-mesh paper scrap particles are mixed with flowback fluid at a mass ratio of 1:10 to create a paper scrap slurry. This slurry is then transported by pump 1. Steam is continuously injected into steam pipe 2 at a temperature of 350°C. During the injection process, steam mixes with the continuously injected paper scrap slurry. The volume ratio of paper scrap slurry to steam is 1:10, and the paper scrap liquefaction temperature is 330°C. During this mixing process, the steam liquefies the waste paper, producing biocrude oil. At high temperatures, biocrude vapor droplets form, which follow the steam into the formation through injection well 4. The steam-biocrude mixture is then injected into well 2, where it comes into contact with the heavy oil. After a seven-day well soak, the hydrogen donor in the biocrude undergoes aquathermolysis with the heavy oil, upgrading it in situ. Production well 5 is then opened for oil production. The viscosity of the dehydrated heavy oil in well 2 is 8360 mPa·s, with a viscosity reduction of 82.5%.

[0044] Example 7

[0045] First, the bagasse is pretreated by crushing it in a pulverizer and then screening it. 500-mesh bagasse particles are mixed with domestic sewage at a mass ratio of 1:10 to create a slurry. This slurry is then transported by pump 1. Steam is continuously injected into steam pipe 2 at a temperature of 360°C. During the injection process, steam mixes with the continuously injected slurry, with a volume ratio of 1:5. The biomass liquefaction temperature is 320°C. During this mixing process, the steam liquefies the bagasse, producing bio-crude oil. At high temperatures, these droplets form bio-crude vapor, which follow the steam into the formation through injection well 4. This high-temperature steam-bio-crude mixture is injected into well 2, where it contacts the heavy oil. After five days of well soaking, the hydrogen donor in the bio-crude undergoes aquathermolysis with the heavy oil, upgrading it in situ. Production well 5 is then opened for oil production. The viscosity of the dehydrated heavy oil in Well 2# was 6040 mPa·s, and the viscosity reduction rate was 87.4%.

[0046] Example 8

[0047] First, the melon seed shells are pretreated by crushing them in a grinder and then sieving them. 400-mesh melon seed shell particles are mixed with demineralized water at a mass ratio of 1:10 to prepare a melon seed shell slurry. This slurry is then transported via pump 1. Steam is continuously injected into steam pipe 2 at a temperature of 330°C. During the injection process, steam mixes with the continuously injected melon seed shell slurry. The volume ratio of melon seed shell slurry to steam is 1:15, and the melon seed shell liquefaction temperature is 300°C. During this mixing process, the steam liquefies the melon seed shells, producing bio-crude oil. At high temperatures, these droplets form bio-crude vapor, which follow the steam into the formation through injection well 4. The steam-bio-crude mixture is then injected into well 2, where it comes into contact with the heavy oil. After four days of well soaking, the hydrogen donor in the bio-crude undergoes aquathermolysis with the heavy oil, upgrading the heavy oil in situ. Production well 5 is then opened for oil production. The viscosity of the dehydrated heavy oil in Well 2# was 7820 mPa·s, and the viscosity reduction rate was 83.6%.

[0048] Example 9

[0049] First, the banana peels are pretreated by pulverizing them in a grinder and then screening them. 200-mesh banana peel particles are mixed with domestic sewage at a mass ratio of 1:10 to prepare a banana peel slurry. This slurry is then transported via pump 1. Steam is continuously injected into steam pipe 2 at a temperature of 360°C. During the injection process, steam mixes with the continuously injected banana peel slurry. The volume ratio of banana peel to steam is 1:8, and the banana peel liquefaction temperature is 340°C. During this mixing process, the steam liquefies the banana peels, producing biocrude oil. At high temperatures, biocrude vapor droplets form, which follow the steam into the formation through injection well 4. The steam-biocrude mixture is then injected into well 2, where it contacts the heavy oil. After a seven-day well soak, the hydrogen donor in the biocrude undergoes aquathermolysis with the heavy oil, upgrading it in situ. Production well 5 is then opened for oil production. The viscosity of the dehydrated heavy oil obtained in well 2 is 6170 mPa·s, with a viscosity reduction of 87.1%.

[0050] Example 10

[0051] First, the poultry feathers are pretreated by crushing them in a grinder and then sieving them. 400-mesh poultry feather pellets are mixed with mineralized water in a mass ratio of 1:10 to form a slurry. This slurry is then transported by pump 1. Steam is continuously injected into steam pipe 2 at a temperature of 320°C. During the injection process, steam mixes with the continuously injected slurry of poultry feathers. The volume ratio of slurry biomass to steam is 1:10, and the poultry feathers liquefy at a temperature of 280°C. During this mixing process, the steam liquefies the feathers, producing biocrude oil. At high temperatures, these droplets form biocrude vapor, which follow the steam into the formation through injection well 4. The steam-biocrude mixture is then injected into well 2, where it comes into contact with the heavy oil. After six days of well soaking, the hydrogen donor in the biocrude undergoes aquathermolysis with the heavy oil, upgrading it in situ. Production well 5 is then opened for oil production. The viscosity of the dehydrated heavy oil in Well 2# was 6220 mPa·s, and the viscosity reduction rate was 87.0%.

[0052] The viscosity changes of 1# and 2# heavy oils after hydrothermal in-situ modification of different biomasses were obtained from Examples 1-10, and the results are shown in Table 2 below.

[0053] Table 2 Viscosity of heavy oil after hydrothermal modification of different biomasses

[0054]

[0055]

[0056] In the description of this specification, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0057] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for preparing a heavy oil hydrogen donor, characterized in that: The following steps are involved: A. crushing the biomass by a grinder and then screening the obtained biomass particles to prepare slurry biomass; B. The slurry biomass is transported to a steam pipeline through a delivery pump. Steam generated in a steam boiler is introduced into the steam pipeline. Under the action of the steam, the slurry biomass is liquefied to obtain a heavy oil hydrogen donor.

2. The preparation method according to claim 1, characterized in that In step A, the biomass includes at least one of sawdust, microcrystalline cellulose, lignin, chlorella, liquidambar leaves, wheat straw, corn stalks, paper scraps, cherry blossoms, rape blossoms, bamboo shoots, crabapple blossoms, morning glory, mugwort, clover, bagasse, qingmingcai, melon seed shells, orange peels, banana peels, grapefruit peels, poultry feathers, pig manure and cow manure.

3. The preparation method according to claim 1, characterized in that In step A, the mesh size of the biomass particles is 200-500 meshes.

4. The preparation method according to claim 1, characterized in that In step B, the temperature of the steam is 260°C to 380°C.

5. The preparation method according to claim 1, characterized in that In step B, the volume ratio of the slurry biomass to steam is 1:(5-15).

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