Oil sulfonate surfactant for pressure drive, oil displacement agent for fracture energy supplement and preparation method

Abstract

This application discloses a petroleum sulfonate surfactant for hydraulic fracturing, a fracturing energy recovery agent, and a preparation method thereof. The petroleum sulfonate surfactant is obtained by sulfonating a feedstock oil, which comprises the following components: ketone-benzene dewaxing oil; and two of the following: furfural extract oil, upper distillate oil, heavy alkylbenzene, and lower distillate oil. The feedstock oil has a molecular weight of 280-400 and a carbon number distribution in the C... 12 -C 28 It solves the problem that existing petroleum sulfonate surfactants are not suitable for peripheral oil fields, resulting in poor compatibility between fracturing and energy-boosting oil displacement agents and formation rocks and fluids.

Description

Technical Field

[0001] This disclosure relates to fracturing and energy recovery agents for peripheral oilfield development, specifically petroleum sulfonate surfactants as their active ingredients. Background Technology

[0002] The statements in this section provide only background information in connection with this disclosure and do not constitute prior art.

[0003] As domestic oilfields enter the later stages of development, the amount of exploitable conventional oil and gas reservoirs is decreasing. Therefore, complex oilfields such as tight oil layers and shale oil are receiving increasing attention. For example, the oilfields surrounding Daqing Oilfield's No. 7, No. 8, and No. 10 plants are low-permeability and tight, high-temperature oilfields. Due to high formation temperature, high salinity, and low permeability, conventional water injection development results in low initial production, rapid decline, low stage recovery, and a high shut-in ratio. Therefore, under the existing water injection development model, it is difficult to further improve the development level of the blocks.

[0004] To address the practical contradictions of existing fracturing and extraction methods in some peripheral oilfields in China, the previous planar waterflooding development approach has been transformed. Domestic oilfields are now adopting a development method of "pre-fracturing energy enhancement + volumetric fracturing + post-fracturing energy replenishment." One of its core technologies is the use of fracturing energy replenishment agents, which not only increase reservoir energy but also alter the oil-water interfacial tension in the target oilfield, bringing it to 10... -3 Ultra-low interfacial tension improves the oil extraction rate through seepage and seepage.

[0005] However, if the fracturing and oil displacement agent used is poorly compatible with the composition of the formation rocks and minerals and the properties of the formation fluids, it will inevitably undergo various complex physicochemical reactions with the formation rocks and fluids. When phenomena such as clay expansion, particle blockage, and changes in phase permeability occur, adverse pollution and damage problems such as reduced permeability will appear in the formation and on the walls of the sand-filled fractures, thereby reducing the fracturing effect.

[0006] The active ingredient in fracturing and revitalizing agents is a surfactant. The inventors of this application are aware that most reservoir rock surfaces exhibit negative charge, leading to the adsorption of large amounts of cations and rendering cationic surfactants inactive. Meanwhile, traditional anionic surfactants require large quantities and exhibit poor stability at temperatures exceeding 80°C. For example, petroleum sulfonate surfactants are suitable for oilfields with low formation temperatures (45°C), low salinity (4500 mg / L), and medium to high permeability (greater than 100 mD), but are not suitable for the Daqing peripheral oilfield with high temperatures (80-105°C), low permeability (10-100 mD), and high salinity (5000-10000 mg / L). Nonionic and fluorocarbon surfactants are relatively expensive, making them unaffordable for oilfield companies in terms of extraction costs.

[0007] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art. Summary of the Invention

[0008] In view of at least one of the above technical problems, this disclosure provides a petroleum sulfonate surfactant for hydraulic fracturing, which solves the problem that existing petroleum sulfonate surfactants are not suitable for high-temperature, low-permeability, and high-salinity oil reservoirs, resulting in poor compatibility between hydraulic fracturing and oil displacement agents and formation rocks and fluids.

[0009] In addition, this disclosure also provides a method for preparing fracturing booster oil displacement agent and petroleum sulfonate surfactant for fracturing.

[0010] Firstly, the petroleum sulfonate surfactant for pressure drive is derived from sulfonated feedstock oil, wherein the feedstock oil comprises:

[0011] Ketone-benzene dewaxing oil;

[0012] Two of the following: furfural extract oil, upper distillate oil, heavy alkylbenzene, and lower distillate oil;

[0013] The molecular weight of the feedstock oil is 280-400, and the carbon number distribution is C... 12 -C 28 between.

[0014] In some embodiments of this disclosure, the ketone-benzene dewaxing oil has a distillation range of 376-491°C, a pour point of -9°C to -15°C, and an aromatic hydrocarbon content of 30-35%.

[0015] The furfural extract oil has a distillation range of 383-521℃ and an aromatic content of 55-65%.

[0016] The distillation range of the upper column distillate is 160-336℃;

[0017] The distillation range of the heavy alkylbenzene is 315-410℃, and the molecular weight is 280-360;

[0018] The distillation range of the lower column distillate is 170-338℃.

[0019] In some embodiments of this disclosure, the component content of the raw material oil, calculated by mass ratio, is such that the ratio of the ketone-benzene dewaxed oil to the other two components is 1:1-5:1-5.

[0020] In some embodiments of this disclosure, the components of the feedstock oil are:

[0021] Ketone-benzene dewaxing oil;

[0022] Furfural extract oil;

[0023] One of the following: upper distillate oil, heavy alkylbenzene, and lower distillate oil.

[0024] Secondly, the fracturing energy-enhancing oil displacement agent includes:

[0025] The petroleum sulfonate surfactant for pressure drive described in the first aspect.

[0026] Thirdly, the method for preparing the petroleum sulfonate surfactant for pressure drive includes a sulfonation reaction using a feedstock oil, wherein the feedstock oil comprises the following components:

[0027] Ketone-benzene dewaxing oil;

[0028] Two of the following: furfural extract oil, upper distillate oil, heavy alkylbenzene, and lower distillate oil;

[0029] The molecular weight of the feedstock oil is 280-400, and the carbon number distribution is C... 12 -C 28 between.

[0030] In some embodiments of this disclosure, the ketone-benzene dewaxing oil has a distillation range of 376-491°C, a pour point of -9°C to -15°C, and an aromatic hydrocarbon content of 30-35%.

[0031] The furfural extract oil has a distillation range of 383-521℃ and an aromatic content of 55-65%.

[0032] The distillation range of the upper column distillate is 160-336℃;

[0033] The distillation range of the heavy alkylbenzene is 315-410℃, and the molecular weight is 280-360;

[0034] The distillation range of the lower column distillate is 170-338℃.

[0035] In some embodiments of this disclosure, the component content of the raw material oil, calculated by mass ratio, is such that the ratio of the ketone-benzene dewaxed oil to the other two components is 1:1-5:1-5.

[0036] In some embodiments of this disclosure, the components of the feedstock oil are:

[0037] Ketone-benzene dewaxing oil;

[0038] Furfural extract oil;

[0039] One of the following: upper distillate oil, heavy alkylbenzene, and lower distillate oil.

[0040] In some embodiments of this disclosure, the sulfonation reaction is carried out at a temperature of 50-65°C.

[0041] In some embodiments of this disclosure, the acid value of the product of the sulfonation reaction is 80-120 mg NaOH / g.

[0042] In some embodiments of this disclosure, the sulfonating agent used in the sulfonation reaction is sulfur trioxide gas with a volume concentration of 2.5-5%;

[0043] The gas-liquid molar ratio of sulfur trioxide to the feedstock oil is 1.01-1.1:1.

[0044] This disclosure has the following beneficial effects:

[0045] The petroleum sulfonate surfactant for pressure drive disclosed herein, firstly, utilizes the characteristic that the components of the feedstock oil required for sulfonation reactions are rich in aromatics. For example, ketone-benzene dewaxing is obtained by removing straight-chain alkanes (paraffin components) from petroleum distillate oil in lubricating oil production through a ketone-benzene dewaxing unit, thereby increasing the content of aromatic components; furfural extract oil is a fraction of oil rich in aromatics extracted and separated by a furfural refining unit in lubricating oil production. Secondly, the feedstock oil used has a specific molecular weight distribution range and carbon number distribution range. The petroleum sulfonate surfactant obtained by sulfonating the feedstock oil under the influence of the above two key factors has the following excellent properties: its interfacial tension reaches 10. -3 Below mN / m, even reaching 10 -4 mN / m, natural core permeation and oil extraction rate reaches 61.5% (180 hours), emulsification capacity and water absorption rate are 100% (after 24 hours), stability reaches 30 days, and interfacial tension is less than 10. -3 With a strength of less than mN / m and a temperature resistance of over 85°C, the petroleum sulfonate surfactant disclosed herein, as the active ingredient in the fracturing and energy-boosting oil displacement agent, can naturally be well-matched with rocks and fluids in high-temperature, low-permeability, and high-salinity oil reservoirs, thereby effectively improving the development level of peripheral oil fields. Attached Figure Description

[0046] The above and other objects, features, and advantages of this disclosure will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0047] Figure 1 This is a process flow diagram of the petroleum sulfonate surfactant for pressure drive according to an embodiment of this disclosure;

[0048] In the diagram: 1-Membrane sulfonation reactor, 2-Gas-liquid separator, 3-Sulfonic acid discharge pump, 4-Alkali addition pump, 5-Neutralization pump, 6-Neutralization circulation pump, 7-Product discharge pump, 8-Product preparation tank. Detailed Implementation

[0049] The present disclosure is described below based on embodiments; however, it is worth noting that the present disclosure is not limited to these embodiments. In the detailed description of the present disclosure below, certain specific details are described in detail. However, those skilled in the art will fully understand the present disclosure for the parts not described in detail.

[0050] Furthermore, unless the context explicitly requires it, the words "comprising," "including," and similar terms throughout the specification and claims should be interpreted as including rather than exclusive or exhaustive; that is, meaning "including but not limited to."

[0051] Figure 1 This is a process flow diagram of the petroleum sulfonate surfactant for pressure drive according to embodiments of this disclosure. The petroleum sulfonate surfactants for pressure drive in embodiments of this disclosure are all manufactured according to... Figure 1 The process shown is sulfonation, and the specific process steps are as follows:

[0052] 1. Gas-phase sulfur trioxide and the feedstock oil participating in the sulfonation reaction react in the same direction in a membrane sulfonation reactor 1 to produce liquid sulfonic acid and some unsulfonated oil, which enter the gas-liquid separator 2. The unreacted sulfur trioxide tail gas flows to the tail gas treatment unit. The sulfonic acid and unsulfonated oil liquid are pumped into a neutralization pump 5 by a sulfonic acid discharge pump, and neutralized with the alkali solution pumped in by an alkali addition pump 4 under high-speed stirring and shearing in the neutralization pump 5. In this embodiment, the alkali solution is a 30-40% sodium hydroxide solution.

[0053] Specifically, solid sulfur is heated into a stable liquid and transported to a sulfur combustion furnace, where it reacts to generate SO2. This SO2 is then converted to SO3 via a vanadium pentoxide catalyst. The SO3 gas is diluted with dry air to the concentration required for the sulfonation reaction. In this embodiment, the SO3 gas is diluted with dry air with a dew point below -60°C to a concentration of 2.5-5%. After being filtered through an SO3 filter, it enters the head of the membrane sulfonation reactor 1 and is precisely and equally distributed to each reaction tube. The components of the feed oil are mixed and transported to the head of the membrane sulfonation reactor 1 via a feed pump, feed filter, and feed heater (not shown). The feed flow rate is automatically controlled by a feed regulating valve. The distribution mechanism at the head of the membrane sulfonation reactor 1 automatically and evenly distributes the feed oil to each reaction tube, where it falls evenly in a film along the inner wall of the reaction tube, flowing down in parallel with the sulfur trioxide gas introduced from the top. The sulfonation reaction is completed in a short time. The heat of reaction is removed by the jacket cooling water, and the sulfonation temperature is automatically adjusted by the sulfonation cooling water circulation pump through a temperature control valve.

[0054] The molar ratio of crude oil to sulfur trioxide regulates the content of active ingredients, which has a certain control effect on the content of active ingredients in petroleum sulfonate products. In this embodiment, the gas-liquid molar ratio is controlled within the range of 1.01-1.1:1.

[0055] 2. The petroleum sulfonate generated by the neutralization reaction is partially refluxed into the gas-liquid separator 2 by the neutralization circulation pump 6 to pre-neutralize with the sulfonic acid produced by the membrane sulfonation reactor, and partially refluxed into the neutralization pump head to adjust the neutralization reaction intensity. The reflux ratio is controlled within the range of 10-5:1.

[0056] 3. A portion of the material from the outlet of the neutralization circulation pump 6 is pumped into the product preparation tank 8 via the product discharge pump 7 for the preparation of fracturing energy-boosting oil displacement agent.

[0057] 4. The membrane sulfonation reactor controls the sulfonation depth, i.e., the acid value, by adjusting the reaction temperature. The acid value has a certain controlling effect on the molecular weight of petroleum sulfonate products and the proportions of monosulfonic acid, disulfonic acid, and polysulfonic acid. In this embodiment, the acid value is controlled at 80-120 mg NaOH / g. The reaction temperature control range in this embodiment is 50-65℃, the feedstock oil temperature control range is 55-65℃, and the sulfur trioxide temperature control range is 55-65℃.

[0058] The feedstock oil disclosed herein has the characteristic of high content of sulfonable aromatic hydrocarbons, no coking occurs during the reaction process, and the target product can be obtained without extraction and separation after neutralization of sulfonates, with the product having an active ingredient content as high as 38-55%.

[0059] The feedstock components in this embodiment all come from Daqing Petrochemical Company. Specifically, the ketone-benzene dewaxing oil comes from the lubricating oil ketone-benzene unit, the furfural extract oil comes from the furfural unit, the heavy alkylbenzene comes from the refining alkylation unit, and the upper and lower distillate oils come from the refining ARGG (catalytic cracking) unit. The ketone-benzene dewaxing oil has a boiling range of 376-491℃, a pour point of -15℃, and an aromatic content of 31%; the furfural extract oil has a boiling range of 383-521℃ and an aromatic content of 60%; the upper distillate oil has a boiling range of 160-336℃; the heavy alkylbenzene has a boiling range of 315-410℃ and a molecular weight of 300; and the lower distillate oil has a boiling range of 170-338℃.

[0060] Example 1

[0061] 1. Preparation of petroleum sulfonate surfactants and fracturing energy-boosting oil displacement agents for hydraulic displacement

[0062] Ketone-benzene dewaxing oil, furfural extract oil, and heavy alkylbenzene were mixed evenly in a mass ratio of 1:1:1. The average molecular weight of the mixed feedstock oil was approximately 300, and the carbon number distribution was C10. 12 —C 24In the process, the feed oil is heated to 60°C and then pumped into a membrane sulfonation reactor. Sulfur trioxide gas at 60°C and a volume concentration of 3.5% is introduced to carry out the sulfonation reaction. The sulfonation reaction temperature is controlled at 55°C, and a sodium hydroxide solution with a mass concentration of 35% is used for neutralization. The neutralization pH value is controlled at 8-11, and the reflux ratio is 8:1 to obtain the final product, petroleum sulfonate surfactant for pressure drive.

[0063] Different concentrations of fracturing and energy-boosting oil displacement agents were prepared by mixing the surfactant with oil and water from the No. 7 factory's Pu 333 block.

[0064] 2. Performance Testing

[0065] Different concentrations of fracturing booster oil displacement agent from Example 1 were sent to the recovery laboratory of the Exploration and Development Research Institute of Daqing Oilfield Company Limited for testing. The specific test results are shown in Table 1:

[0066] Table 1. Surfactant test results

[0067]

[0068]

[0069] As can be seen from the data in Table 1, under a temperature condition of 90°C, the minimum interfacial tension reaches an ultra-low value of 10. -3 mN / m, while the enterprise standard only requires 10 -2 mN / m; stability fully meets product quality requirements, maintaining ultra-low interfacial tension even after 30 days; emulsification performance: 100% water separation rate after 24 hours, with minimal viscosity increase; natural core permeation oil separation rate: 61.55% after 180 hours, far exceeding the enterprise standard (greater than 20%). Because these indicators far surpass the enterprise standards used in oilfields, especially the permeation oil separation rate reaching 71.3% (after 48 hours) and 61.5% (after 180 hours), the potential for utilizing crude oil in the matrix system through permeation in tight reservoirs is greater than in medium-to-high permeability reservoirs. Spontaneous permeation is a crucial mechanism for the effective development of fractured tight reservoirs.

[0070] 3. Application Examples

[0071] The No. 7 and No. 10 oil production plants in Daqing are located in tight oil reservoirs with high temperature (80-105℃) and high salinity (5000-10000mg / L). The fracturing and energy-boosting oil displacement agent in Example 1 of this disclosure is compatible with the oil-water mixture from the No. 7 oil production plant in Daqing. No chromatographic separation was observed in the compound system after 30 days, indicating good performance in field applications. According to a report on the China Petroleum website on February 18, 2022: The pilot test well Pufu 162-332 in the Pu 333 block of the No. 7 oil production plant, which successfully switched to water injection development on January 19, has increased from no fluid and no oil production before the test to a current daily fluid production of 20.2 tons and a daily oil production of 10.2 tons. In the Chao 65 block of the No. 10 oil production plant in Daqing, two wells with volumetric fracturing and water injection systems successfully switched to water injection and have been operating stably for more than two months, with an average daily fluid production of over 20 tons and a daily oil production of approximately 4 tons per well. The results of the two application examples above indicate that the first water injection development experiment conducted by Daqing Oilfield has achieved initial success and provides a reference for the optimization of subsequent test well schemes, which has a good demonstration effect.

[0072] Example 2

[0073] 1. Preparation of petroleum sulfonate surfactants and fracturing energy-boosting oil displacement agents for pressure displacement: Ketone-benzene dewaxing oil, furfural extract oil, and upper distillate oil were mixed uniformly in a mass ratio (1:1.5:1). The average molecular weight of the mixed feedstock oil was approximately 320, and the carbon number distribution was C... 14 —C 26 In the process, the feedstock oil is heated to 55°C and then pumped into a membrane sulfonation reactor via a centrifugal pump. Sulfonation reaction is initiated by introducing sulfur trioxide gas at 55°C and a volume concentration of 3.2%, with the reaction temperature controlled at 55°C. Neutralization is achieved using a 35% sodium hydroxide solution, with the neutralization pH controlled at 8-11 and a reflux ratio of 10:1, yielding the final product: a petroleum sulfonate surfactant for pressure displacement.

[0074] Different concentrations of fracturing and energy-boosting oil displacement agents were prepared by mixing the surfactant with oil and water from the No. 7 factory's Pu 333 block.

[0075] 2. Performance Testing

[0076] Different concentrations of fracturing booster oil displacement agent from Example 2 were sent to the recovery laboratory of the Exploration and Development Research Institute of Daqing Oilfield Company Limited for testing. The specific test results are shown in Table 2.

[0077] Table 2. Surfactant test results

[0078]

[0079] Example 3

[0080] 1. Preparation of petroleum sulfonate surfactants and fracturing energy-boosting oil displacement agents for hydraulic displacement

[0081] The ketone-benzene dewaxing oil, furfural extract oil, and lower column distillate oil were mixed evenly in a mass ratio of 1:2:2. The average molecular weight of the mixed feedstock oil was approximately 350, and the carbon number distribution was C10. 12 —C 26 In the process, the feedstock oil is heated to 60°C and then pumped into a membrane sulfonation reactor via a centrifugal pump. Sulfonation reaction is initiated by introducing sulfur trioxide gas at 60°C and a volume concentration of 3.2%. The reaction temperature is controlled at 60°C, and the sulfonation reaction is carried out using a 3.2% sulfur trioxide gas concentration. Neutralization is performed using a 35% sodium hydroxide solution, controlling the neutralization pH at 8-11 and the reflux ratio at 9:1, to obtain the final product: a petroleum sulfonate surfactant for pressure displacement.

[0082] Different concentrations of fracturing and energy-boosting oil displacement agents were prepared by mixing the surfactant with oil and water from the Zhou 201 block of Daqing Oilfield No. 8 Plant.

[0083] 2. Performance Testing

[0084] Different concentrations of fracturing booster oil displacement agent from Example 3 were sent to the recovery laboratory of the Exploration and Development Research Institute of Daqing Oilfield Company Limited for testing. The specific test results are shown in Table 3.

[0085] Table 3. Surfactant test results

[0086]

[0087] Example 4

[0088] 1. Preparation of petroleum sulfonate surfactants and fracturing energy-boosting oil displacement agents for hydraulic displacement

[0089] The ketone-benzene dewaxing oil, furfural extract oil, and upper distillate oil were mixed evenly in a mass ratio of 1:5:5. The average molecular weight of the feed oil after uniform mixing was approximately 380, and the carbon number distribution was C. 15 —C 28 In the process, the feed oil is heated to 65°C and then pumped into a membrane sulfonation reactor via a centrifugal pump. Sulfur trioxide gas at 65°C and a volume concentration of 3.2% is introduced to carry out the sulfonation reaction. The reaction temperature is controlled at 60°C, and a 35% sodium hydroxide solution is used for neutralization. The neutralization pH is controlled at 8-11, and the reflux ratio is 10:1 to obtain the final product, a petroleum sulfonate surfactant for pressure drive.

[0090] Different concentrations of fracturing and energy-boosting oil displacement agents were prepared by mixing the surfactant with oil and water from the Zhou 201 block of Daqing Oilfield No. 8 Plant.

[0091] 2. Performance Testing

[0092] Different concentrations of fracturing and energy-boosting agents from Example 4 were sent to the recovery laboratory of the Exploration and Development Research Institute of Daqing Oilfield Company Limited for testing. The specific test results are shown in Table 4.

[0093] Table 4. Surfactant test results

[0094]

[0095]

[0096] The specific details in the embodiments disclosed herein are not limited to the described scenarios, and other alternative methods may also be used. For example, in addition to using a membrane sulfonation reactor, a batch sulfonator or a jet sulfonator may also be used for the sulfonation reaction.

[0097] The embodiments described above are merely illustrative of implementation methods of this disclosure, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent disclosure. It should be noted that those skilled in the art can make various modifications, equivalent substitutions, and improvements without departing from the concept of this disclosure, and these all fall within the protection scope of this disclosure. Therefore, the protection scope of this patent disclosure should be determined by the appended claims.

Claims

1. A method for preparing a petroleum sulfonate surfactant for pressure displacement, comprising a sulfonation reaction using feedstock oil, characterized in that, The raw material oil comprises the following components: Ketone-benzene dewaxing oil; Furfural extract oil; One of the following: upper distillate oil, heavy alkylbenzene, and lower distillate oil; The molecular weight of the feedstock oil is 280-400, and the carbon number distribution is C... 12 -C 28 between; The ketone-benzene dewaxing oil has a distillation range of 376-491℃, a pour point of -9℃ to -15℃, and an aromatic content of 30-35%. The furfural extract oil has a distillation range of 383-521℃ and an aromatic hydrocarbon content of 55-65%. The distillation range of the upper column distillate is 160-336℃; The distillation range of the heavy alkylbenzene is 315-410℃, and the molecular weight is 280-360; The distillation range of the lower column distillate is 170-338℃; The component content of the raw material oil, calculated by mass ratio, is 1:1-5:1-5 for the ketone-benzene dewaxed oil, furfural extract oil, and another component. The upper and lower distillate fractions come from the ARGG refining unit. The steps of the sulfonation reaction are as follows: gaseous sulfur trioxide and the raw material oil participating in the sulfonation reaction react in the same direction through a membrane sulfonation reactor to generate liquid sulfonic acid and some unsulfonated oil, which enter the gas-liquid separator. The unreacted sulfur trioxide tail gas flows to the tail gas treatment unit. The sulfonic acid and unsulfonated oil liquid are pumped into the neutralization pump through the sulfonic acid discharge pump, and the neutralization reaction is completed with the alkali solution pumped in by the alkali addition pump under the high-speed stirring and shearing of the neutralization pump. The sulfonation reaction is carried out at a temperature of 50-65°C. The sulfonating agent used in the sulfonation reaction is sulfur trioxide gas with a volume concentration of 2.5-5%; The gas-liquid molar ratio of sulfur trioxide to the feedstock oil is 1.01-1.1:

1.

2. A petroleum sulfonate surfactant for pressure displacement, characterized in that: The petroleum sulfonate surfactant for pressure drive is prepared by the method described in claim 1.

3. A fracturing energy-enhancing oil displacement agent, characterized in that, include: The petroleum sulfonate surfactant for pressure drive as described in claim 2.

Images