A pharmaceutical composition for improving the suspension effect of proppant and its application.

Abstract

This invention pertains to the field of fluid mineral extraction, including petroleum, natural gas, and shale gas, specifically relating to a reagent composition for improving the suspension effect of proppant and its preparation method. The reagent composition comprises a surface modifier and fibers. The surface modifier includes agent A, agent B, and a dispersion medium. Agent A is one or more of cocotrimethylammonium chloride, dioctadecyl dimethylammonium bromide, and laurylamine. Agent B is one or more of lactic acid, citric acid, acetic acid, and hydrofluoric acid. The method of application involves spraying the surface modifier onto the surface of the proppant and adding it along with the fibers to the fracturing fluid. This invention utilizes readily available raw materials and a simple, environmentally friendly preparation method. Using the reagent composition and method of this invention, a 100% suspension rate of the proppant in clean water and slickwater can be achieved at room temperature, demonstrating promising application prospects.

Description

Technical Field

[0001] This invention belongs to the field of fluid mineral extraction such as oil, natural gas and shale gas, and specifically relates to a pharmaceutical composition for improving the suspension effect of proppant and its application. Background Technology

[0002] In the development of unconventional oil and gas reservoirs, hydraulic fracturing technology is an important means to increase the production of oil and gas in the target reservoir. Currently, conventional fracturing processes use fracturing fluid with a certain viscosity to carry proppant to the fractures, increasing the conductivity of the hydraulic fractures and thus achieving increased production. The proppants currently used are mainly quartz sand and ceramsite. Research has found that this fracturing process has the following main problems: the viscosity of the proppant-carrying fluid decreases after entering the fracture, and the proppant settles rapidly under gravity, failing to migrate to the far end of the fracture. This results in a small effective support volume in both the lateral and longitudinal directions, making it difficult to achieve large-scale and efficient reservoir activation, thus limiting the stimulation effect.

[0003] Chinese patent application CN106832145A discloses an air-suspension proppant suitable for slickwater fracturing, its preparation method, and its application method. This air-suspension proppant comprises orthopedic particles, and its surface is modified by a hydrophobic-aerophilic emulsion. The modified emulsion is prepared by polymerization of fluorinated polymeric monomers, polymeric binders, silane coupling agents, surfactants, and deionized water. During slickwater fracturing, this air-suspension proppant is accompanied by the injection of 10-20% nitrogen. The hydrophobic-aerophilic coating adsorbs the microbubbles formed by nitrogen in the slickwater, keeping the proppant suspended even at low viscosity. This achieves the purpose of cross-linking fluid carrying proppant, thus eliminating the need for large amounts of organic materials to increase the viscosity of the fracturing fluid, causing no damage to the formation, and facilitating flowback.

[0004] Chinese patent application CN108084989A discloses an effervescent air-suspension proppant suitable for slickwater fracturing and its preparation method. This air-suspension proppant requires coating the surface of a conventional proppant, including an inner coating and an outer coating. The outer coating is prepared by spraying an effervescent agent, which generates bubbles upon contact with water. These bubbles adhere to the surface of the inner coating, allowing the proppant to float in water. The inner coating is a hydrophobic-aerophilic coating, prepared by curing a hydrophobic-aerophilic emulsion. The proppant of this invention is freely suspended in slickwater, achieving the same proppant-carrying effect as ordinary cross-linked liquids.

[0005] Chinese patent application CN114032085A discloses a high-efficiency air-suspended proppant for fracturing and its preparation method. The preparation method includes: providing proppant particles, a surface modification treatment liquid, a modifier solution, and an organic molecular linker; using the surface modification treatment liquid to stir the proppant particles at 25-120℃ to roughen their surface, separating and drying to obtain surface-roughened proppant particles; mixing the surface-roughened proppant particles with the modifier solution and the organic molecular linker to carry out a modification reaction, separating and drying to obtain the modified proppant. This proppant can significantly reduce the requirements for fracturing fluids and achieve good suspension effects in various water-based fracturing fluids.

[0006] The above three types of modified air suspension proppant formulations involve a wide variety of agents and have high costs; under high temperature and high pressure reservoir conditions, the volume of the bubbles is reduced after compression, which affects the suspension effect of the proppant and reduces the volume of the fracture support; during large-volume slickwater construction, the need to inject gas reduces the liquid column pressure, leading to high construction pressure, increased risk of sand blockage, and limited application scope. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a pharmaceutical composition for improving the suspension effect of proppant. By using a pharmaceutical agent to modify the surface of the proppant, making it hydrophilic to hydrophobic, it can interact with fibers in water to form a spatial network structure, thereby improving the suspension effect of the proppant in cracks.

[0008] To achieve the objectives of this invention, the following technical solution is adopted:

[0009] A pharmaceutical composition for improving the proppant placement effect, the raw materials of the pharmaceutical composition include a surface modifier and fibers, the surface modifier including agent A, agent B and a dispersion medium; agent A is one or more of cocotrimethylammonium chloride, dioctadecyl dimethylammonium bromide, laurylamine; agent B is one or more of lactic acid, citric acid, acetic acid, hydrofluoric acid.

[0010] Preferably, the volume ratio of agent A, agent B, and dispersion medium is 2-5:0.5-2:83-97.

[0011] Preferably, the ratio of agent A, agent B, dispersion medium and fiber is 2-5ml: 0.5-2ml: 83-97ml: 0.1-1.0g.

[0012] Preferably, agent A is laurylamine.

[0013] Preferably, agent B is citric acid or lactic acid.

[0014] Preferably, the fiber is a polyester fiber.

[0015] Preferably, the dispersion medium is one or more of water, ethanol, ethylene glycol and methanol.

[0016] Preferably, the preparation method of the surface-modifying agent includes the following steps:

[0017] (1) Add agent A to the dispersion medium and mix;

[0018] (2) Add agent B to the system of step (1) and mix; heat and stir to obtain the final product.

[0019] Preferably, the mixing in step (1) is a stirring mixing, the stirring temperature is 40-50℃, and the stirring time is 1-5 min; preferably 1.5-2 min.

[0020] Preferably, the heating temperature in step (2) is 40-50℃, and the stirring time is 1-5 min; more preferably 1.5-2 min.

[0021] Another object of the present invention is to provide a method of using a pharmaceutical composition, wherein a surface-modifying agent is sprayed onto the surface of a proppant and then added together with fibers to water or slickwater fracturing fluid for use.

[0022] Preferably, the volume-to-mass ratio of the surface-modifying agent to the proppant is 0.2-0.5 mL / 100 g.

[0023] Another object of the present invention is to provide the application of the above-mentioned pharmaceutical composition in improving the proppant placement effect.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] (1) This invention breaks the traditional rules governing the viscosity and velocity of fracturing fluids in carrying sand. The modified proppant can exhibit a clustered distribution in clear water and slickwater, forming dispersed and open high-speed flow channels in the fractures, increasing the sand-carrying volume in the horizontal and vertical directions, and improving the fracturing effect of unconventional oil and gas reservoirs. During field construction, it is only necessary to spray the modified agent onto the surface of the proppant online and add a small amount of fiber. The modified proppant can be directly introduced into the well along with the fiber without pre-construction modification, making the construction process simple.

[0026] (2) Traditional fracturing fluid viscosity and velocity proppant-carrying processes cannot carry proppant to the far end of the fracture, resulting in short fractures and limited proppant volume. This invention, by spraying modified agents onto the proppant surface and adding fibers, enables the proppant to suspend in clusters in clear water and slickwater, preventing sedimentation. Compared to traditional proppant + fiber technology, this invention effectively increases fracture proppant volume and conductivity, enhancing reservoir fracturing effects. This technology breaks away from the traditional concept of proppant relying on fracturing fluid viscosity and velocity for proppant transport, representing a creative new concept and technology.

[0027] (3) The present invention can achieve a 100% suspension rate of proppant in fracturing fluids such as water and slickwater at room temperature.

[0028] (4) The present invention achieves a 100% suspension rate of proppant in fracturing fluids of clean water and slippery water at room temperature that can be maintained for 60 days. Attached Figure Description

[0029] Figure 1 This image shows a comparison of the suspension effects of fiber + modified quartz sand proppant in Example 1 and fiber + conventional quartz sand proppant in the control group in clear water; the left side shows the suspension effect of the control group; the right side shows the suspension effect of Example 1. Detailed Implementation

[0030] The present invention will be further described below with reference to specific embodiments. All raw materials used in the following embodiments are commercially available conventional raw materials, wherein the polyamide fiber supplier is Shenzhen Yataida Technology Co., Ltd., and the model is CPF-15-12.

[0031] Example 1

[0032] This embodiment is composed of the following raw materials: Agent A, Agent B, dispersion medium and fiber; the volume ratio of Agent A, Agent B and dispersion medium is 3:2:85; the dispersion medium is water, Agent A is cocoa-based trimethylammonium chloride, Agent B is lactic acid, and the fiber is polyamide fiber.

[0033] Its preparation method includes the following steps:

[0034] (1) Add the dispersion medium to a beaker, add agent A to the dispersion medium, and stir continuously with a glass rod for 1.5 min at 40°C to obtain a mixture;

[0035] (2) Add agent B to the mixture obtained in step (1), place it in a 40°C water bath and heat for 2 minutes while stirring continuously with a glass rod for 1.5 minutes to obtain the proppant surface modification agent;

[0036] (3) Spray 0.2 ml of surface modification agent onto the surface of 100 g of quartz sand proppant (40 / 70 mesh), and add the modified quartz sand proppant and 0.1 g of polyamide fiber together into 300 ml of water; to obtain a mixture of fiber + modified quartz sand proppant and water.

[0037] The obtained mixture was placed in a 500ml graduated blue-capped bottle and shaken up and down for 10 seconds. The suspension rate of the quartz sand was then calculated.

[0038] In the control group, unmodified quartz sand proppant and 0.1g of polyamide fiber were added to 300ml of water, and the mixture was then placed in a 500ml graduated blue-capped bottle and shaken for 10 seconds. The suspension rate of the unmodified quartz sand was calculated. Results are shown below. Figure 1 .

[0039] The formula for calculating the suspension rate is as follows:

[0040]

[0041] W—Suspension rate, %;

[0042] B1 -- Volume of suspended silica sand, ml;

[0043] B2 -- Volume of settled quartz sand, ml.

[0044] Example 2

[0045] This embodiment is composed of the following raw materials: Agent A, Agent B, dispersion medium and fiber; the volume ratio of Agent A, Agent B and dispersion medium is 4:1.5:84.5; the dispersion medium is a 50% aqueous ethanol solution, Agent A is bis(octadecyldimethylammonium bromide), Agent B is citric acid, and the fiber is polyamide fiber.

[0046] Its preparation method includes the following steps:

[0047] (1) Add the dispersion medium to a beaker, add agent A to the dispersion medium, and stir continuously with a glass rod for 1.5 min at 40°C to obtain a mixture;

[0048] (2) Add agent B to the mixture obtained in step one and heat it in a 40°C water bath for 2 minutes while stirring continuously for 1.5 minutes to obtain the proppant surface modification agent.

[0049] (3) Spray 0.2 ml of the modified agent onto the surface of 100 g of quartz sand proppant (40 / 70 mesh), and add the modified quartz sand proppant and 0.15 g of polyamide fiber together into 300 ml of water; to obtain a mixture of fiber + modified quartz sand proppant and water.

[0050] The obtained mixture was placed in a 500ml graduated blue-capped bottle and shaken up and down for 10 seconds. The quartz sand suspension rate was calculated according to the method in Example 1.

[0051] Example 3

[0052] This embodiment is composed of the following raw materials in the following volume parts: Agent A, Agent B, dispersion medium and fiber; the volume ratio of Agent A, Agent B and dispersion medium is 5:0.5:84.5; the dispersion medium is water, Agent A is lauryl amine, Agent B is citric acid, and the fiber is polyamide fiber.

[0053] Its preparation method includes the following steps:

[0054] (1) Add the dispersion medium to a beaker, add agent A to the dispersion medium, and stir continuously with a glass rod for 1.5 min at 40°C to obtain a mixture;

[0055] (2) Add agent B to the mixture obtained in step (1) and heat it in a 40°C water bath for 2 minutes while stirring continuously for 1.5 minutes to obtain the proppant surface modification agent.

[0056] (3) Spray 0.2 ml of surface modification agent onto the surface of 100 g of quartz sand proppant (40 / 70 mesh), and add the modified quartz sand proppant and 0.15 g of polyamide fiber together into 300 ml of water; to obtain a mixture of fiber + modified quartz sand proppant and water.

[0057] The obtained mixture was placed in a 500ml graduated blue-capped bottle and shaken up and down for 10 seconds. The quartz sand suspension rate was calculated according to the method in Example 1.

[0058] Comparative Example 1

[0059] This comparative example is composed of the following raw materials in parts by volume: Agent A, Agent B, dispersion medium and fiber; the volume ratio of Agent A, Agent B and dispersion medium is 5:0.5:84.5; the dispersion medium is water, Agent A is oleic acid, Agent B is citric acid, and the fiber is polyamide fiber.

[0060] Its preparation method includes the following steps:

[0061] (1) Add the dispersion medium to a beaker, add agent A to the dispersion medium, and stir continuously with a glass rod for 1.5 min at 40°C to obtain a mixture;

[0062] (2) Add agent B to the mixture obtained in step (1) and heat it in a 40°C water bath for 2 minutes while stirring continuously for 1.5 minutes to obtain the proppant surface modification agent.

[0063] (3) Spray 0.2 ml of the modified agent onto the surface of 100 g of quartz sand proppant (40 / 70 mesh), and add the modified quartz sand proppant and 0.15 g of polyamide fiber together into 300 ml of water; to obtain a mixture of fiber + modified quartz sand proppant and water.

[0064] The obtained mixture was placed in a 500ml graduated blue-capped bottle and shaken up and down for 10 seconds. The quartz sand suspension rate was calculated according to the method in Example 1.

[0065] Comparative Example 2

[0066] This comparative example is composed of the following raw materials in parts by volume: Agent A, Agent B, dispersion medium and fiber; the volume ratio of Agent A, Agent B and dispersion medium is 5:0.5:84.5; the dispersion medium is water, Agent A is stearic acid, Agent B is citric acid, and the fiber is polyamide fiber.

[0067] Its preparation method includes the following steps:

[0068] (1) Add the dispersion medium to a beaker, add agent A to the dispersion medium, and stir continuously with a glass rod for 1.5 min at 40°C to obtain a mixture;

[0069] (2) Add agent B to the mixture obtained in step (1) and heat it in a 40°C water bath for 2 minutes while stirring continuously for 1.5 minutes to obtain the proppant surface modification agent.

[0070] (3) Spray 0.2 ml of the modified agent onto the surface of 100 g of quartz sand proppant (40 / 70 mesh), and add the modified quartz sand proppant and 0.15 g of polyamide fiber together into 300 ml of water; to obtain a mixture of fiber + modified quartz sand proppant and water.

[0071] The obtained mixture was placed in a 500ml graduated blue-capped bottle and shaken up and down for 10 seconds. The quartz sand suspension rate was calculated according to the method in Example 1.

[0072] Comparative Example 3

[0073] This embodiment is composed of the following raw materials in the following volume parts: Agent A, Agent B, dispersion medium and fiber; the volume ratio of Agent A, Agent B and dispersion medium is 5:0.5:84.5; the dispersion medium is water, Agent A is octadecyltrimethylammonium chloride, Agent B is citric acid, and the fiber is polyamide fiber.

[0074] Its preparation method includes the following steps:

[0075] (1) Add the dispersion medium to a beaker, add agent A to the dispersion medium, and stir continuously with a glass rod for 1.5 min at 40°C to obtain a mixture;

[0076] (2) Add agent B to the mixture obtained in step (1) and heat it in a 40°C water bath for 2 minutes while stirring continuously for 1.5 minutes to obtain the proppant surface modification agent.

[0077] (3) Spray 0.2 ml of the modified agent onto the surface of 100 g of quartz sand proppant (40 / 70 mesh), and add the modified quartz sand proppant and 0.15 g of polyamide fiber together into 300 ml of water; to obtain a mixture of fiber + modified quartz sand proppant and water.

[0078] The obtained mixture was placed in a 500ml graduated blue-capped bottle and shaken up and down for 10 seconds. The quartz sand suspension rate was calculated according to the method in Example 1.

[0079] Comparative Example 4

[0080] This embodiment is composed of the following raw materials in the following volume parts: Agent A, Agent B, dispersion medium and fiber; the volume ratio of Agent A, Agent B and dispersion medium is 5:0.5:84.5; the dispersion medium is water, Agent A is lauryl amine, Agent B is acetic acid, and the fiber is polyamide fiber.

[0081] Its preparation method includes the following steps:

[0082] (1) Add the dispersion medium to a beaker, add agent A to the dispersion medium, and stir continuously with a glass rod for 1.5 min at 40°C to obtain a mixture;

[0083] (2) Add agent B to the mixture obtained in step (1) and heat it in a 40°C water bath for 2 minutes while stirring continuously for 1.5 minutes to obtain the proppant surface modification agent.

[0084] (3) Spray 0.2 ml of the modified agent onto the surface of 100 g of quartz sand proppant (40 / 70 mesh), and add the modified quartz sand proppant and 0.15 g of polyamide fiber together into 300 ml of water; to obtain a mixture of fiber + modified quartz sand proppant and water.

[0085] The obtained mixture was placed in a 500ml graduated blue-capped bottle and shaken up and down for 10 seconds. The quartz sand suspension rate was calculated according to the method in Example 1.

[0086] The suspension rates of the proppants manufactured in Examples 1-3 and Comparative Examples 1-4 are shown in Table 1 below.

[0087] The proppant prepared in Examples 1-3 and Comparative Examples 1-2 were placed in clean water or slickwater fracturing fluid at room temperature for 60 days, and the suspension rate was measured again according to the method of Example 1. The results are shown in Table 1 below.

[0088] Table 1. Suspension rate results of modified quartz sand proppant

[0089] Example Suspension rate (%) Suspension rate (%) after 60 days at room temperature Example 1 95 94 Example 2 97 97 Example 3 100 100 Comparative Example 1 10 5 Comparative Example 2 14 10 Comparative Example 3 83 78 Comparative Example 4 87 85

[0090] The above detailed description is a specific description of one of the feasible embodiments of the present invention. This embodiment is not intended to limit the patent scope of the present invention. All equivalent implementations or modifications that do not depart from the present invention should be included within the scope of the technical solution of the present invention.

Claims

1. A composition of agents to enhance the suspension effect of proppants, characterized in that, The raw material of the pharmaceutical composition comprises a surface modifier and a fiber, the surface modifier comprises an A agent, a B agent and a dispersion medium; the A agent is one or several of cocotrimethylammonium chloride, dioctadecyldimethylammonium bromide and laurylamine; the B agent is one or several of lactic acid, citric acid and acetic acid; The fiber is a polyester fiber; The ratio of the A agent, the B agent, the dispersion medium and the fiber is 2-5ml:0.5-2ml:83-97ml:0.1-1.0g; The dispersion medium is one or several of water, ethanol, ethylene glycol and methanol; The use method of the composition is to spray the surface modifier to the surface of the proppant, and to add the fiber into clean water or slick water fracturing fluid together; The volume-mass ratio of the surface modifier to the proppant is 0.2-0.5mL / 100g; The proppant is quartz sand proppant.

2. The pharmaceutical composition according to claim 1, characterized by The A agent is laurylamine.

3. The pharmaceutical composition according to claim 1, characterized by The B agent is citric acid or lactic acid.

4. The pharmaceutical composition according to claim 1, characterized by The preparation method of the surface modifier comprises the following steps: (1) adding the A agent into the dispersion medium and mixing; (2) adding the B agent into the system of step (1) and mixing; heating and stirring, and then obtaining.

5. The pharmaceutical composition according to claim 4, characterized by The mixing in step (1) is stirring mixing, the stirring temperature is 40-50℃, and the stirring time is 1-5min.

6. The pharmaceutical composition according to claim 4, characterized by The heating temperature in step (2) is 40-50℃, and the stirring time is 1-5min.

7. A method of using the pharmaceutical composition of any one of claims 1-6, wherein, Spraying the surface modifier to the surface of the proppant, and adding the fiber into clean water or slick water fracturing fluid together.

8. The use of the pharmaceutical composition of any one of claims 1-6 in improving the suspension effect of the proppant.

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