WO2025256345A1 - 封堵剂、油基钻井液及其应用 - Google Patents

封堵剂、油基钻井液及其应用

Info

Publication number
WO2025256345A1
WO2025256345A1 PCT/CN2025/095385 CN2025095385W WO2025256345A1 WO 2025256345 A1 WO2025256345 A1 WO 2025256345A1 CN 2025095385 W CN2025095385 W CN 2025095385W WO 2025256345 A1 WO2025256345 A1 WO 2025256345A1
Authority
WO
WIPO (PCT)
Prior art keywords
sulfonate
plugging
oil
graphite
drilling fluid
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/CN2025/095385
Other languages
English (en)
French (fr)
Inventor
李大奇
王显光
张玉彬
金军斌
韩秀贞
杨枝
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
China Petroleum and Chemical Corp
Sinopec Petroleum Engineering Technology Research Institute Co Ltd
Original Assignee
China Petroleum and Chemical Corp
Sinopec Petroleum Engineering Technology Research Institute Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from CN202410760399.7A external-priority patent/CN121136690A/zh
Priority claimed from CN202410785481.5A external-priority patent/CN121162212A/zh
Application filed by China Petroleum and Chemical Corp, Sinopec Petroleum Engineering Technology Research Institute Co Ltd filed Critical China Petroleum and Chemical Corp
Publication of WO2025256345A1 publication Critical patent/WO2025256345A1/zh
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
    • C09K8/02—Well-drilling compositions
    • C09K8/04—Aqueous well-drilling compositions
    • C09K8/06—Clay-free compositions
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
    • C09K8/50—Compositions for plastering borehole walls, i.e. compositions for temporary consolidation of borehole walls
    • C09K8/502—Oil-based compositions

Definitions

  • This invention relates to the field of oil drilling technology, specifically to plugging agents, oil-based drilling fluids, and their applications.
  • the purpose of this invention is to overcome the problems in existing technologies, such as the lack of effective sealing of microfractures by oil-based drilling fluids in oil exploration of complex deep formations, which easily leads to wellbore instability.
  • This invention provides sealing agents, oil-based drilling fluids, and their applications.
  • a first aspect of the present invention provides a plugging agent comprising an oil phase and a plugging material dispersed in the oil phase I, wherein the plugging material comprises expandable graphite, expanded graphite, and silica.
  • the particle size distribution of the sealing material is 1 nm-50 ⁇ m, and after the sealing agent is heated at 240°C for 16 h, the D50 value of the sealing material increases by at least 10% compared with that before heating.
  • a second aspect of the present invention provides a drilling fluid comprising the plugging agent described in the first aspect.
  • the third aspect of the present invention provides the application of the plugging agent described in the first aspect, or the drilling fluid described in the second aspect, in improving the microfracture plugging effect during drilling, and/or reducing filtration loss during drilling, and/or improving wellbore stability during drilling.
  • the present invention can achieve at least the following beneficial effects:
  • the plugging agent provided by this invention uses a plugging agent material with a specific composition and specific particle size distribution characteristics. This plugging agent can achieve broad-spectrum strong plugging of formation microfractures. Oil-based drilling fluids formulated with this plugging agent have good microfracture plugging effect and can effectively solve the problem of wellbore instability.
  • the sealing agent preparation method provided by the present invention is simple, low-cost, safe and environmentally friendly.
  • the sealing agent can exist in the form of an oil suspension with good stability. During production and transportation, the solid components in the sealing agent will not undergo significant floating or settling.
  • the plugging agent provided by the present invention has good compatibility with common components of oil-based drilling fluids. When oil-based drilling fluids are prepared using this plugging agent, the fluidity changes are small.
  • the plugging agent provided by the present invention when combined with a specific emulsifier, can obtain an oil-based drilling fluid that has both good temperature resistance and plugging properties. Tests show that the oil-based drilling fluid can effectively reduce PPA filtration loss, indicating that it has a good plugging effect on formation microfractures.
  • Figure 1 is a morphology diagram of the various particles of the sealing material according to the present invention, wherein a is silicon dioxide, b is flake graphite, c is dry expandable graphite, d is the state of expandable graphite after absorbing oil in the oil phase, e is dry expanded graphite, and f is the state of expanded graphite after absorbing oil in the oil phase.
  • the inventors of this invention discovered in their research that by adding various types and scales of specific plugging materials to oil-based drilling fluids used in deep oil and gas exploration, the plugging performance of formation microfractures can be effectively improved, thereby solving the problem of wellbore instability.
  • the inventors developed an emulsifier composition with good high-temperature resistance, prepared key components of a plugging agent capable of achieving broad-spectrum plugging of microfractures at multiple scales, and based on this, formed an oil-based drilling fluid that can be used to prepare oil-based drilling fluids with good temperature resistance and broad-spectrum plugging effect on microfractures.
  • a first aspect of the present invention provides a plugging agent comprising an oil phase and a plugging material dispersed in the oil phase I, wherein the plugging material comprises expandable graphite, expanded graphite, and silica.
  • the particle size distribution of the sealing material is 1 nm-50 ⁇ m, and after the sealing agent is heated at 240°C for 16 h, the D50 value of the sealing material increases by at least 10% compared with that before heating.
  • the numbering of the oil phase (such as “I” and “II” in oil phase I and oil phase II) is only used for convenient description to distinguish the oil phase in different formulations, but has no effect on the specific components or dosages used.
  • D50 and “median particle size” in particle size distribution have the same meaning and can be used interchangeably herein.
  • Median particle size refers to the particle size value corresponding to a cumulative percentage of 50 wt% on the particle size distribution curve (also known as the particle gradation curve) of the sample. That is, at this particle size, 50 wt% of the particles in the sample have a diameter less than or equal to this value, and the other 50 wt% have a diameter greater than or equal to this value.
  • terms such as D10 and D90 are also particle size distribution characteristic values obtained from the particle size distribution curve, referring to the particle size values corresponding to cumulative percentages of 10 wt% and 90 wt%, respectively, on the particle size distribution curve.
  • Particle size distribution can be detected by instruments such as laser particle size analyzers and obtained directly through the computer software accompanying the instruments; alternatively, it can be obtained by observing the sample with an electron microscope, statistically analyzing the particle size within the field of view, and calculating the distribution (some electron microscope software also has the function of statistically analyzing the particle size distribution within the field of view).
  • the particle size distribution of the sample can be obtained by statistically analyzing the particle size of multiple fields of view (for example, statistically analyzing the particle size of at least 3 fields of view and calculating the particle size distribution).
  • the plugging agent provided by this invention is used in the formulation of oil-based drilling fluids and innovatively introduces various carbon-based materials (different types of graphite materials).
  • expandable graphite is natural graphite (usually flake graphite) that has been treated under appropriate conditions by the action of oxidants, intercalating agents, and other chemical substances. This allows the oxidants and intercalating agents to insert into the graphite layers and combine with carbon atoms to form a new chemical phase—graphite intercalation on compounds (GIC). Under high temperatures (usually above 800°C), the oxidants and intercalating agents inserted into the graphite layers "explode,” causing the graphite to expand along the axial direction into a worm-like substance, which is expanded graphite.
  • GIC graphite intercalation on compounds
  • Natural flake graphite, expandable graphite, and expanded graphite exhibit significant differences in macroscopic and/or microscopic morphology.
  • macroscopically, natural flake graphite and expandable graphite are quite similar, but expanded graphite displays a distinct worm-like structure.
  • Expanded graphite on the other hand, has a loose and porous structure. After being impregnated in an oil phase, expanded graphite absorbs oil and exhibits a fluffy, blocky morphology.
  • the plugging agent provided by this invention when added to oil-based drilling fluids, can achieve more thorough sealing of microfractures during deep and ultra-deep oil and gas exploration and development.
  • the inventors of this invention have conducted long-term research on the morphology of formation microfractures and the operational environment for sealing complex formation microfractures. Based on these characteristics, they selected inorganic particulate materials with different morphologies and properties, and through their synergistic effects, cleverly obtained the unique plugging agent formulation of this invention. For example, nano-micro silica, being rigid spherical particles containing silica particles of different sizes, can directly enter and fill microfractures during sealing. Expanded graphite, after absorbing oil, becomes fluffy and has good deformability.
  • Expandable graphite itself has a sheet-like structure, allowing it to insert into microfractures and the tiny gaps in other sealing materials. Moreover, it expands to a certain extent at temperatures of 200-300°C, thus making the sealing of microfractures even tighter.
  • the plugging agent provided by this invention is provided directly in the form of an oil phase suspension, which makes it easier to mix with other components when preparing oil-based drilling fluids on site. It also helps to obtain a uniform oil-based drilling fluid, avoiding the problem that micro-nano-sized particulate plugging components are difficult to disperse evenly when added to the drilling fluid on site in the form of solid powder, resulting in poor plugging effect.
  • the plugging agent provided by this invention uses expandable graphite as one of the plugging materials. Under a certain temperature (such as oil well temperature), the volume of expandable graphite will expand, while the expanded graphite and silicon dioxide will not undergo significant volume changes during the heat treatment process. Therefore, after the plugging agent provided by this invention is treated at a certain temperature for a period of time, the size of the expandable graphite will increase, resulting in an increase in the D50 of the plugging material in the plugging agent compared with that before the heat treatment.
  • a certain temperature such as oil well temperature
  • the D50 value of the sealing material increases by 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 50% compared to before heating, or it can be a range consisting of any two of the above values, or any intermediate value in that range.
  • the presence of silica (containing Si-O bonds) and graphite materials can be further confirmed by using environmental scanning electron microscopy (ESEM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDS) (also known as EDX spectroscopy).
  • ESEM environmental scanning electron microscopy
  • SEM scanning electron microscopy
  • TEM transmission electron microscopy
  • EDS energy dispersive X-ray spectroscopy
  • EDS energy dispersive X-ray spectroscopy
  • EDS can usually be mounted on the aforementioned electron microscope. Therefore, the particle morphology and elemental distribution of the sealing material under the same scanning field of view can be obtained simultaneously. With the help of the matching computer software, it is more convenient to compare the morphology and elemental composition of each sealing material particle observed under the same field of view, and then determine the composition of the sealing material.
  • the composition of the sealing material can be determined as follows: First, observe the particle morphology of the sealing material under an electron microscope to initially identify silica particles (with spherical or near-spherical morphology), expandable graphite (with a lamellar structure), and expanded graphite (with a loose porous structure, appearing under the microscope as an "irregular sponge block") in a certain field of view, as shown in Figure 1. Then, through the EDS energy dispersive spectroscopy scan results of this field of view, the silica and graphite materials can be further confirmed, and the expandable graphite and expanded graphite can be distinguished and confirmed by the C content in the graphite material shown in the scan results.
  • the basis for distinguishing between expandable graphite and expanded graphite based on C content is as follows: Because the chemical substances inserted between the graphite layers "explode and fly out" during the high-temperature treatment of expanded graphite, the content of these inserted chemical substances in expanded graphite is significantly reduced compared with untreated expandable graphite. Generally, particles with a C content of 50-80 wt% are identified as expandable graphite, while particles with a C content of more than 90 wt% are identified as expanded graphite.
  • the blocking agent sample needs to be treated before using ESEM, SEM, TEM, or EDS energy dispersive spectroscopy.
  • it may be diluted to ensure the effective solid content does not exceed 5% (mass-volume ratio, i.e., less than 5 g/100 mL), or the blocking agent sample may be dried, from which the blocking material is extracted for analysis.
  • the purpose of drying the blocking agent sample is to remove the oil phase.
  • the blocking agent sample can be processed by vacuum filtration, and the resulting solid component (i.e., the blocking material) is washed (e.g., with ethanol) and dried.
  • drying is usually carried out using methods such as air drying at room temperature without heating.
  • a 100g sample of plugging agent can be filtered.
  • the collected filtrate is returned for filtration five times.
  • the collected solid i.e., the separated plugging material
  • washed with ethanol To improve the washing effect, this washing process can be repeated five times, with each wash using approximately 10 times the volume of the solid.
  • the sample is filtered, and the collected filtrate is returned for filtration five times.
  • the filtered solid is air-dried at room temperature, weighed, and then subjected to ESEM, SEM, TEM, and EDS energy dispersive spectroscopy using the methods described above. This allows for observation of the morphological characteristics and elemental composition of the plugging material within the plugging agent, thereby determining its constituent components.
  • the plugging agent sample can be diluted to reduce the solid content to 5%, and then ESEM, SEM, TEM, and EDS energy dispersive spectroscopy can be performed to observe the morphological characteristics and elemental composition of the solid particles (i.e., the plugging material) contained in the plugging agent, thereby determining the components contained therein.
  • the content of the sealing material can also be calculated based on the amount of raw materials fed.
  • the sealing agent provided by this invention has excellent stability; during long-term storage, the sealing material in the sealing agent will not settle or float.
  • stability can be tested by observing the distribution of solid components in the sealing agent after a period of stillness.
  • this stillness observation method is time-consuming.
  • the stability of this sealing agent can also be tested using the following method: Take a certain amount of the sealing agent sample and place it in a centrifuge tube. Centrifuge at 10-100g (i.e., 10-100 times the acceleration due to gravity) for at least 5 minutes.
  • Equation I G is the centrifugal force, which is a multiple of the gravitational acceleration g; R is the centrifugal radius (cm); and a is the centrifugal rotation speed (rpm). For example, if the calculated centrifugal force G is ten times the gravitational acceleration g, it can be written as 10g.
  • the density ratio of the upper liquid to the lower liquid can be calculated using the following formula II:
  • the sealing agent is centrifuged for 10 minutes under a centrifugal force of 100g (g is the acceleration due to gravity, that is, the centrifugal force is 100 times the acceleration due to gravity), and the density of the upper liquid is 70-100% of the density of the lower liquid.
  • the sealing agent is centrifuged at 100g for 10 minutes, and the density of the upper liquid is 80-100% of the density of the lower liquid.
  • the density of the upper liquid is 80-100% of the density of the lower liquid.
  • it can be 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, or 100%, or it can be a range consisting of any two of the above values, or any intermediate value within that range.
  • the sealing agent when the sealing agent is centrifuged for 10 minutes under a centrifugal force of 100g (g is the acceleration due to gravity, i.e., the centrifugal force is 100 times the acceleration due to gravity), the density difference between the upper and lower liquids in the centrifuged product does not exceed 0.05g/ cm3 , preferably not exceeding 0.03g/ cm3 .
  • the density difference between the upper and lower liquids in the centrifuged product can be 0, 0.001g/cm3, 0.002g/cm3, 0.003g/cm3, 0.004g/cm3 , 0.005g / cm3 , 0.01g/ cm3 , 0.015g/ cm3 , 0.02g/ cm3 , 0.025g/cm3, 0.03g/ cm3 , or a range consisting of any two of the above values, or any intermediate value within that range.
  • the particle size distribution of the sealing material in the sealing agent is D10 of 50-1500 nm, D50 of 1-10 ⁇ m, and D90 of 1-15 ⁇ m.
  • the particle size distribution of the sealing material is D10 of 300-1500 nm, D50 of 1-5 ⁇ m, and D90 of 5-15 ⁇ m.
  • the silica used in the sealing agent is nano-micro silica.
  • nano-micro silica refers to a silica mixture containing both nano- and micro-sized silica, characterized by a rigid spherical structure, wide particle size distribution, and diverse sizes.
  • Nano-sized silica refers to silica with a particle size not exceeding 1 ⁇ m
  • micro-sized silica refers to silica with a particle size greater than or equal to 1 ⁇ m and less than 1 mm. Since the particle size distribution of the sealing material in the sealing agent of this invention is 1 nm-50 ⁇ m, the nano-micro silica used in this invention preferably has a particle size distribution of 1 nm-50 ⁇ m.
  • the sealing material used in the sealing agent.
  • the sealing material can be obtained by compounding commercially available expandable graphite, expanded graphite, and silica according to the requirements of this invention, or it can be prepared in-house to meet the requirements of this invention.
  • the sealing agent provided by this invention can use novel materials developed by the inventors in previous research.
  • the nano-micro silica can be provided by the high-temperature resistant, oleophilic nano-micro silica sealing dispersion system prepared in CN202310894527.2; the expandable graphite can be the expandable graphite prepared in CN202410001951.4; and the expanded graphite can be the (ultrafine) expanded graphite prepared in CN202410785481.5. All of the above applications are incorporated herein by reference.
  • the inventors of this invention have ingeniously discovered in their research that a plugging agent prepared by compounding these materials possessing the characteristics described in this invention can achieve broad-spectrum and strong plugging of formation microfractures.
  • the plugging agent provided by this invention can be provided in the form of a stable oil-phase suspension. "Stable” means that the plugging agent provided by this invention maintains the characteristics of a suspension during long-term storage and transportation; its fluidity does not change significantly, and the solid substances therein do not or substantially do not precipitate (i.e., do not settle or float on the surface).
  • the particle size distribution of the sealing material i.e., the solid component in the sealing agent
  • the particle size distribution of the sealing material is 5 nm-30 ⁇ m.
  • the lower end of the particle size of the sealing material can be 5nm, 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, 55nm, 60nm, 65nm, 70nm, 75nm, 80nm, 85nm, 90nm, 95nm, 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, etc.
  • the particle size distribution of the sealing material can be 1 ⁇ m, 2 ⁇ m, 3 ⁇ m, 4 ⁇ m, 5 ⁇ m, 6 ⁇ m, 7 ⁇ m, 8 ⁇ m, 9 ⁇ m, 10 ⁇ m, 12 ⁇ m, 14 ⁇ m, 16 ⁇ m, 18 ⁇ m, 20 ⁇ m, 22 ⁇ m, 24 ⁇ m, 26 ⁇ m, 28 ⁇ m, or 30 ⁇ m.
  • the particle size distribution of the nano-micro silica can be any range consisting of the aforementioned low and high points.
  • particle size distribution refers to the range of particle sizes in the sealing material, that is, the range between the smallest and largest particle sizes of the sealing material.
  • particle size distribution refers to the characteristic values of the sealing material's size, such as D10, D50, and D90.
  • the particle size distribution reveals the range of the largest and smallest particle sizes of the sealing material in the sealing agent, while the particle size distribution reveals the particle size characteristics of the sealing material in the sealing agent. Both particle size distribution and particle size distribution can be detected using a laser particle size analyzer or similar device.
  • the particle size distribution of the nano-micro silica is D10 of 20-40 nm, D50 of 230-280 nm, and D90 of 1200-1500 nm.
  • the particle size distribution of the nano-micro silica is D10 of 25-40 nm, D50 of 240-275 nm, and D90 of 1200-1450 nm.
  • the D10 of the nano-micro silicon dioxide can be 25nm, 26nm, 27nm, 28nm, 29nm, 30nm, 31nm, 32nm, 33nm, 34nm, 35nm, 36nm, 37nm, 38nm, 39nm, or 40nm, or it can be any range consisting of any two of the above values, or any intermediate value in that range.
  • the D50 of the nano-micro silicon dioxide can be 240nm, 242nm, 246nm, 248nm, 250nm, 252nm, 254nm, 256nm, 258nm, 260nm, 262nm, 264nm, 26nm, 268nm, 270nm, 272nm, 274nm, 275nm, or it can be a range consisting of any two of the above values, or any intermediate value in that range.
  • the D90 of the nano-micro silicon dioxide can be 1200nm, 1220nm, 1240nm, 1280nm, 1300nm, 1320nm, 1340nm, 1360nm, 1380nm, 1400nm, 1420nm, 1440nm, 1450nm, or it can be a range consisting of any two of the above values, or any intermediate value in that range.
  • the surface of the nano-micro silica is hydrophobic.
  • the nano-micro silica obtains good hydrophobicity through hydrophobic surface modification (i.e., the surface of the nano-micro silica has a hydrophobic modifier).
  • the hydrophobic surface modifier can be a silane coupling agent.
  • the silane coupling agent is selected from at least one of 3-aminopropyltrimethoxysilane (KH540), 3-aminopropyltriethoxysilane (KH550), and ⁇ -methacryloyloxypropyltrimethoxysilane (KH570).
  • the nano-micro silica when formulating the blocking agent, can be provided in the form of a silica solid (powder) having the above-described characteristics, or in the form of an oil-phase suspension.
  • a silica solid having the above-described characteristics
  • oil-phase suspension for example, it can be provided in the liquid (oil-phase suspension) form of the nano-micro silica blocking dispersion system as described in CN202310894527.2.
  • the nano-micro silica is provided in the form of an oil phase suspension (also referred to as a "nano-micro silica dispersion system" in this invention).
  • the nano-micro silica dispersion system comprises an oil phase and nano-silica and micro-silica dispersed in the oil phase.
  • the characteristics of the nano-silica and micro-silica are as described above and will not be repeated here.
  • the nano-micro silica dispersion system further includes a dispersant.
  • the dispersant is selected from at least one of alkyl sulfonates, alkyl polyoxyethylene ethers, and alkylamidopropyl betaine.
  • the expansion ratio of the expandable graphite after heating at 240°C for 16 hours is 1-10 times, preferably 1.5-3 times.
  • expandable graphite products obtained through commercial purchases can also have their expansion ratio and other product parameter information after heating at a specific temperature obtained from the supplier.
  • the expansion ratio of the expandable graphite after being heated at 240°C for 16 hours can be 1.5 times, 1.6 times, 1.7 times, 1.8 times, 1.9 times, 2 times, 2.1 times, 2.2 times, 2.3 times, 2.4 times, 2.5 times, 2.6 times, 2.7 times, 2.8 times, 2.9 times, or 3 times, or it can be a range consisting of any two of the above values, or any intermediate value within that range.
  • the D50 (D50 before heating at 240°C for 16 hours, or the initial D50 value, or the D50 value at room temperature) of the expandable graphite is 1-100 ⁇ m, preferably 1-20 ⁇ m, and more preferably 1-5 ⁇ m.
  • the D10 of the expandable graphite is 1-3 ⁇ m
  • the D50 is 1-5 ⁇ m
  • the D90 is 4-7 ⁇ m.
  • the particle size distribution characteristic parameters such as "D10, D50, D90" of expandable graphite refer to the corresponding parameter values before it expands, before heat treatment.
  • the expansion coefficient of the expanded graphite is >285 mL/g, preferably 290-400 mL/g, and more preferably 290-350 mL/g.
  • “Expansion coefficient” refers to the volume (mL) of expanded graphite obtained after expansion treatment of a unit weight (g) of expandable graphite before expansion.
  • the expansion coefficient of expanded graphite can usually be determined using the graduated cylinder volume method.
  • the graduated cylinder volume method involves weighing a unit weight (e.g., 1 g) of expandable graphite before expansion treatment, performing expansion treatment (the expansion treatment temperature is the temperature at which it can rapidly expand to its maximum volume, typically 800-1000°C, preferably 960 ⁇ 10°C), placing the resulting expanded graphite in a graduated cylinder to measure its volume, and calculating the expansion coefficient of the expanded graphite.
  • the expansion coefficient can be calculated using the following formula:
  • expanded graphite obtained through commercial purchases can have its expansion coefficient and other product parameters obtained from the supplier.
  • Expanded graphite prepared in-house can have its expansion coefficient calculated using the methods described above.
  • the expansion coefficient of the expanded graphite can be 290mL/g, 295mL/g, 300mL/g, 305mL/g, 310mL/g, 315mL/g, 320mL/g, 325mL/g, 330mL/g, 335mL/g, 340mL/g, 345mL/g, or 350mL/g, or it can be a range consisting of any two of the above values, or any intermediate value within that range.
  • the expanded graphite has a D50 of 1-5 ⁇ m, more preferably 1-3 ⁇ m.
  • the D50 of the expanded graphite can be 1 ⁇ m, 1.2 ⁇ m, 1.4 ⁇ m, 1.6 ⁇ m, 1.8 ⁇ m, 2 ⁇ m, 2.2 ⁇ m, 2.4 ⁇ m, 2.6 ⁇ m, 2.8 ⁇ m, 3 ⁇ m, or it can be a range consisting of any two of the above values, or any intermediate value in that range.
  • the oil phase I in the plugging agent of this invention can typically be provided by the base oil used in the preparation of drilling fluids.
  • Base oil refers to conventional oily substances used in the formulation of oil-based drilling fluids. Any oil in the art that can be used in the formulation of oil-based drilling fluids is suitable for the plugging agent of this invention.
  • the oil phase I is provided by at least one of diesel oil, white oil and straight-chain or branched ⁇ -olefins having more than 5 C atoms.
  • the oil phase I is selected from at least one of diesel oil with a pour point of -30°C to 0°C, white oil with a pour point of -30°C to 0°C, and straight-chain or branched ⁇ -olefins with 6-30 C atoms.
  • the pour point of the diesel fuel can be -30°C, -28°C, -25°C, -22°C, -20°C, -18°C, -15°C, -12°C, -10°C, -8°C, -5°C, -2°C, or 0°C, or it can be a range consisting of any two of the above values, or any intermediate value in that range.
  • the freezing point of the white oil can be -30°C, -28°C, -25°C, -22°C, -20°C, -18°C, -15°C, -12°C, -10°C, -8°C, -5°C, -2°C, or 0°C, or it can be a range consisting of any two of the above values, or any intermediate value in that range.
  • the number of carbon atoms in the straight-chain or branched ⁇ -olefin can be 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30, or it can be a range consisting of any two of the above values, or any intermediate value within that range.
  • the weight ratio of expandable graphite, expanded graphite and nano-micro silica in the sealing agent is 1:0.1-5:0.1-5, preferably 1:0.2-2:0.2-2.
  • the weight ratio of expandable graphite to expanded graphite can be 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, or 1:2, or it can be any range of any two of the above ratios, or any intermediate ratio within that range.
  • the weight ratio of expandable graphite to nano-micro silica can be 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, or 1:2, or it can be any range of any two of the above ratios, or any intermediate ratio within that range.
  • the content of the sealing material in the sealing agent is 20-200g relative to 100mL of oil phase I.
  • “Content of sealing material” refers to the total weight of various sealing materials (including silica, expandable graphite, and expanded graphite) added to 100mL of oil phase I.
  • the content of the sealing material relative to 100 mL of oil phase can be 20 g, 25 g, 30 g, 35 g, 40 g, 45 g, 50 g, 55 g, 60 g, 65 g, 70 g, 75 g, 80 g, 85 g, 90 g, 95 g, 100 g, 105 g, 110 g, 115 g, 120 g, 125 g, 130 g, 135 g, 140 g, 145 g, 150 g, 155 g, 160 g, 165 g, 170 g, 175 g, 180 g, 185 g, 190 g, 195 g, or 200 g, or it can be a range consisting of any two of the above values, or any intermediate value within that range.
  • the content of the sealing material is 30-100g relative to 100mL of oil phase I.
  • the sealing agent may further include flake graphite, preferably with a thickness not exceeding 2 nm and a width not exceeding 2 ⁇ m.
  • the width of the flake graphite refers to the length of its widest diagonal.
  • flake graphite As mentioned above, the presence and content of flake graphite can be determined by observing its morphology under a microscope and by EDS energy dispersive spectroscopy scanning. Flake graphite that exhibits a sheet-like morphology under a microscope and whose elemental composition is completely or substantially entirely C, as shown by EDS energy dispersive spectroscopy scanning results, is flake graphite.
  • the thickness of the flake graphite can be 0.1nm, 0.2nm, 0.3nm, 0.4nm, 0.5nm, 0.6nm, 0.7nm, 0.8nm, 0.9nm, 1nm, 1.1nm, 1.2nm, 1.3nm, 1.4nm, 1.5nm, 1.6nm, 1.7nm, 1.8nm, 1.9nm, or 2nm, or it can be a range consisting of any two of the above values, or any intermediate value within that range.
  • the width of the flake graphite can be 0.1 ⁇ m, 0.2 ⁇ m, 0.3 ⁇ m, 0.4 ⁇ m, 0.5 ⁇ m, 0.6 ⁇ m, 0.7 ⁇ m, 0.8 ⁇ m, 0.9 ⁇ m, 1 ⁇ m, 1.1 ⁇ m, 1.2 ⁇ m, 1.3 ⁇ m, 1.4 ⁇ m, 1.5 ⁇ m, 1.6 ⁇ m, 1.7 ⁇ m, 1.8 ⁇ m, 1.9 ⁇ m, or 2 ⁇ m, or it can be a range consisting of any two of the above values, or any intermediate value within that range.
  • the weight ratio of expandable graphite to flake graphite in the sealing agent is 1:0.1-5, and more preferably 1:0.2-2.
  • the weight ratio of expandable graphite to flake graphite can be 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, or 1:2, or it can be a range consisting of any two of the above ratios, or any intermediate ratio within that range.
  • the content of flake graphite in the sealing agent is 0.5-150g relative to 100mL of oil phase I.
  • the content of flake graphite relative to 100 mL of oil phase I can be 0.5 g, 1 g, 2 g, 3 g, 4 g, 5 g, 6 g, 7 g, 8 g, 9 g, 10 g, 11 g, 12 g, 13 g, 14 g, 15 g, 16 g, 17 g, 18 g, 19 g, 20 g, 25 g, 30 g, 35 g, 40 g, 45 g, 50 g, 60 g, 70 g, 80 g, 90 g, 100 g, 110 g, 120 g, 130 g, 140 g, or 150 g, or it can be a range consisting of any two of the above ratios, or any intermediate ratio within that range.
  • the content of flake graphite in the sealing agent is 1-50g relative to 100mL of oil phase I.
  • the weight ratio of expandable graphite, expanded graphite, nano-micro silica, and flake graphite in the sealing agent is 1:0.1-5:0.1-5:0.1-5, preferably 1:0.2-2:0.2-2:0.1-2.
  • a second aspect of the present invention provides a drilling fluid comprising the plugging agent described in the first aspect.
  • the drilling fluid provided by this invention may contain any components commonly used in oil-based drilling fluids in the art, in addition to the plugging agent. This invention does not impose any particular restrictions on the specific selection and source of other components in the drilling fluid; they can be conventional products obtained through commercial purchase.
  • the inventors of this invention have ingeniously discovered in their research that emulsifiers containing both oligomeric fatty acid salts and alkyl sulfonates have better temperature resistance, making them more suitable for use in deep and ultra-deep oil and gas exploration and development.
  • the drilling fluid further contains an emulsifier.
  • the present invention does not impose any particular limitation on the specific selection of the emulsifier; any emulsifier suitable for use in oil-based drilling fluids, especially for formulating oil-based drilling fluids used in deep and ultra-deep oil and gas exploration and development, is applicable to the present invention.
  • the present invention also does not impose any particular limitation on the specific source of the emulsifier; it can be a commercially available finished emulsifier or a related product prepared in-house.
  • the emulsifier comprises an oligomeric fatty acid salt and an alkyl-containing sulfonate, wherein the total carbon number of the oligomeric fatty acid salt does not exceed 108.
  • oligomeric fatty acid salt refers to a polyfatty acid salt with a low degree of polymerization (typically not exceeding 10, for example, 10, 9, 8, 7, 6, 5, 4, 3, 2).
  • the preferred emulsifier used in the drilling fluid provided by this invention has a better high-temperature resistance than commonly used fatty amide and fatty acid ester emulsifiers, as its emulsion system consists entirely of carbon-carbon and carbon-sulfur bonds, and lacks carbon-nitrogen bonds of amides and carbon-oxygen bonds of esters. It can withstand temperatures up to 240°C and exhibits excellent emulsification, making it more suitable for deep exploration.
  • This emulsifier can be a high-temperature resistant emulsifier prepared according to the method described in 202410760399.7, which is incorporated herein by reference in its entirety.
  • the emulsifier further contains oil phase II.
  • oil phase II in the emulsifier can also be provided by base oil commonly used in the art for formulating oil-based drilling fluids.
  • the specific selection can be referred to the aforementioned oil phase I, and will not be repeated here.
  • the drilling fluid provided by this invention can use only one type of base oil or multiple types. That is, oil phase II contained in the emulsifier and oil phase I contained in the plugging agent can be the same or different.
  • base oil can be further added.
  • the base oil added during the preparation of the drilling fluid can be provided by base oil commonly used in the art for formulating oil-based drilling fluids.
  • the specific selection can also be referred to the aforementioned oil phase I.
  • the base oil added during the preparation of the drilling fluid can be the same as or different from oil phase I and oil phase II in the emulsifier and plugging agent.
  • the emulsifier contains, based on the total weight of the emulsifier, 10-50% by weight of oligomeric fatty acid salts, 5-25% by weight of alkyl sulfonates, and the remainder is base oil.
  • the degree of polymerization of the oligomeric fatty acid salt is 2-5.
  • the oligomeric fatty acid salt is selected from at least one of oligooleate, oligolinoleate, oligolinoleate, and oligotalc fatty acid salt.
  • the oligomeric fatty acid salt is selected from at least one of calcium oligooleate, sodium oligooleate, potassium oligooleate, calcium oligolinoleate, sodium oligolinoleate, potassium oligolinoleate, calcium oligolinolenate, sodium oligolinolenate, potassium oligolinolenate, calcium oligolinolenate, sodium oligolinolenate, potassium oligolinolenate, calcium oligolinolenate, sodium oligolinolenate, potassium oligolinolenate, calcium oligotrol fatty acid, sodium oligotrol fatty acid, and potassium oligotrol fatty acid.
  • the fatty acid portion of the oligomeric fatty acid salt is provided by at least one of dimer oleic acid, dimer linoleic acid, dimer tall oleic acid, trioleic acid, trilinolenic acid, trilinolenic acid, trilinolenic acid, tritall oleic acid, tetrameric linoleic acid, tetrameric oleic acid, pentameric linoleic acid, and pentatall oleic acid.
  • the alkyl-containing sulfonate is selected from at least one of alkylbenzene sulfonates, alkyl sulfonates, and alkylnaphthalene sulfonates; preferably at least one of potassium alkylbenzene sulfonate, sodium alkylbenzene sulfonate, calcium alkylbenzene sulfonate, potassium alkyl sulfonate, calcium alkyl sulfonate, sodium alkyl sulfonate, potassium alkylnaphthalene sulfonate, sodium alkylnaphthalene sulfonate, and calcium alkylnaphthalene sulfonate.
  • the alkyl group in the alkyl-containing sulfonate is selected from C6 - C40 alkyl groups.
  • the number of carbon atoms in the alkyl group of the alkyl-containing sulfonate can be 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, or 40, or it can be a range consisting of any two of the above values, or any intermediate value within that range.
  • the alkyl-containing sulfonate is selected from at least one of sodium dodecyl sulfonate, calcium dodecyl sulfonate, calcium octadecylbenzene sulfonate, calcium octylnaphthalene sulfonate, calcium decylnaphthalene sulfonate, potassium hexadecylbenzene sulfonate, sodium eicosyl sulfonate, and calcium octadecyl sulfonate.
  • the weight ratio of oligomeric fatty acid salt to alkyl-containing sulfonate is 0.5-20:1, more preferably 0.5-15:1.
  • the weight ratio of the oligomeric fatty acid salt to the alkyl-containing sulfonate can be 0.5:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1, 7:1, 7.5:1, 8:1, 8.5:1, 9:1, 9.5:1, 10:1, 10.5:1, 11:1, 11.5:1, 12:1, 12.5:1, 13:1, 13.5:1, 14:1, 14.5:1, or 15:1, or it can be a range consisting of any two of the above ratios, or any intermediate ratio within that range.
  • the weight ratio of emulsifier to plugging agent in the drilling fluid is 1:0.5-5, preferably 1:0.6-3.
  • the weight ratio of emulsifier to plugging agent can be 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.2, 1:1.4, 1:1.6, 1:1.8, 1:2, 1:2.2, 1:2.4, 1:2.6, 1:2.8, 1:3, or it can be a range consisting of any two of the above ratios, or any intermediate ratio within that range.
  • the amount of emulsifier used in every 100 mL of the drilling fluid is 3-8 g, more preferably 4-6 g.
  • the amount of emulsifier in every 100 mL of the drilling fluid can be 4g, 4.2g, 4.4g, 4.6g, 4.8g, 5g, 5.2g, 5.4g, 5.6g, 5.8g, or 6g, or it can be a range consisting of any two of the above values, or any intermediate value within that range.
  • the amount of plugging agent in every 100 mL of the drilling fluid is 2-10 g, more preferably 3-7 g.
  • the amount of plugging agent in every 100 mL of the drilling fluid can be 3g, 3.1g, 3.2g, 3.3g, 3.4g, 3.5g, 3.6g, 3.7g, 3.8g, 3.9g, 4g, 4.2g, 4.5g, 4.8g, 5g, 5.2g, 5.5g, 5.8g, 6g, 6.2g, 6.5g, 6.8g, or 7g, or it can be a range consisting of any two of the above values, or any intermediate value within that range.
  • the plugging agent provided by this invention and the above-mentioned preferred emulsifier are used in drilling fluid, they have good high-temperature resistance and can achieve multi-scale broad-spectrum strong plugging of bottom microfractures, which is more conducive to maintaining wellbore stability.
  • the drilling fluid system contains expandable graphite, expanded graphite, hydrophobically modified nano-sized silica, hydrophobically modified micron-sized silica, oligomeric fatty acid salts, and alkyl-containing sulfonates, and the weight ratio of expandable graphite, expanded graphite, hydrophobically modified nano-sized silica, hydrophobically modified micron-sized silica, oligomeric fatty acid salts, and alkyl-containing sulfonates is 1:0.1-5:0.1-5:0.1-5:0.5-4:0.1-2.
  • the drilling fluid further contains at least one of the following: base oil, dispersant, filtration reducer, wetting agent, organoclase, weighting agent, and shearing agent.
  • base oil dispersant
  • filtration reducer wetting agent
  • organoclase organoclase
  • weighting agent and shearing agent.
  • shearing agent shearing agent
  • the dispersant is selected from at least one of alkyl sulfonates, alkyl polyoxyethylene ethers, and alkylamidopropyl betaine.
  • the drilling fluid contains 0.5-8% expandable graphite by weight, based on the total weight of the drilling fluid.
  • the drilling fluid may also contain other plugging components commonly used in the art, such as hydrophobic supercalcium, oil-soluble resin, and asphalt.
  • the hydrophobic supercalcium has a particle size of not less than 1 ⁇ m, and more preferably 5-50 ⁇ m.
  • the particle size of the hydrophobic supercalcium can be 5 ⁇ m, 5.5 ⁇ m, 6 ⁇ m, 6.5 ⁇ m, 7 ⁇ m, 7.5 ⁇ m, 8 ⁇ m, 8.5 ⁇ m, 9 ⁇ m, 9.5 ⁇ m, 10 ⁇ m, 15 ⁇ m, 20 ⁇ m, 25 ⁇ m, 30 ⁇ m, 35 ⁇ m, 40 ⁇ m, 45 ⁇ m, or 50 ⁇ m, or it can be a range consisting of any two of the above values, or any intermediate value within that range.
  • the softening point of the asphalt is not lower than 180°C.
  • the content of hydrophobic supercalcium in each 100 mL of drilling fluid can be 0-3 g.
  • the drilling fluid may further contain a flow pattern regulator, an alkali (preferably CaO), and calcium chloride.
  • a flow pattern regulator preferably CaO
  • an alkali preferably CaO
  • calcium chloride preferably CaO
  • the content of wetting agent is 1-2g
  • the content of flow pattern regulator is 0.3-0.8g
  • the content of organic soil is 3-5g
  • the content of alkali is 3-5g
  • the content of filtration loss reducer is 4-6g per 100mL of drilling fluid.
  • each component of the drilling fluid can be packaged and stored independently, and then mixed before use.
  • the plugging agent, emulsifier (as well as base oil, dispersant, filtration reducer, wetting agent, organoclase, weighting agent, and shearing agent, etc.) can be packaged separately according to the aforementioned dosages.
  • each component is added to the base oil and mixed to obtain the drilling fluid provided by the present invention.
  • the present invention further provides a method for preparing the above-mentioned drilling fluid, which may include mixing a plugging agent and an emulsifier in the presence of a base oil.
  • a method for preparing the above-mentioned drilling fluid may include mixing a plugging agent and an emulsifier in the presence of a base oil.
  • the characteristics of the base oil, plugging agent, and emulsifier are as described above and will not be repeated here.
  • the method further includes the step of preparing expandable graphite, expanded graphite and micro/nano silica (dispersion system) used in the sealing agent.
  • the preparation of expandable graphite may include: contacting flake graphite with a pre-oxidizing agent to obtain pre-oxidized graphite, and then contacting the pre-oxidized graphite with an intercalating agent and an oxidizing agent to obtain expandable graphite.
  • a pre-oxidizing agent to obtain pre-oxidized graphite
  • an intercalating agent and an oxidizing agent to obtain expandable graphite.
  • the method for preparing the expandable graphite includes:
  • the oxidant is selected from at least one of hydrogen peroxide, concentrated sulfuric acid, fuming nitric acid, sodium nitrate (acidic), and potassium permanganate.
  • the intercalating agent is selected from at least one of concentrated sulfuric acid, perchloric acid and concentrated nitric acid.
  • the mass ratio of oxidant to flake graphite is 0.1-2.
  • the mass ratio of the intercalating agent to the flake graphite is 2-15.
  • the pre-oxidant is hydrogen peroxide.
  • the mass ratio of the pre-oxidant to flake graphite is 5-20.
  • the auxiliary intercalating agent is selected from at least one of glacial acetic acid, ammonium nitrate and acetic acid.
  • the mass ratio of the auxiliary intercalating agent to the flake graphite is 1-15.
  • the preparation of expanded graphite includes: contacting flake graphite with an oxidant and an intercalating agent to obtain expandable graphite, and then subjecting the expandable graphite to an expansion treatment.
  • a specific method for preparing this expanded graphite please refer to CN202410785481.5.
  • the method for preparing the expanded graphite includes:
  • Expandable graphite is obtained by mixing flake graphite with an oxidizing agent and an intercalating agent and then performing oxidation intercalation.
  • the oxidant is selected from at least one of hydrogen peroxide, sulfuric acid, nitric acid, sodium nitrate, and potassium permanganate, and more preferably potassium permanganate.
  • the intercalating agent is selected from at least one of sulfuric acid, perchloric acid, and nitric acid, and more preferably perchloric acid.
  • the mass ratio of the oxidant to the flake graphite is 0.2-0.5:1.
  • the mass ratio of the intercalating agent to the flake graphite is 6-12:1.
  • the temperature of the oxidative intercalation is 30-50°C.
  • the expansion temperature is 900-1000°C and the time is 30-180s.
  • the method further includes a step of pulverizing the expanded graphite obtained in step (2).
  • the pulverization results in the graphite having the aforementioned particle size characteristics.
  • the preparation of the nano-micro silica dispersion system includes: sequentially mixing nano-sized silica and micro-sized silica with a dispersion medium in the presence of a dispersant.
  • the preparation method of this nano-micro silica dispersion system can be found in CN202310894527.2.
  • the method for preparing the nano-micro silica dispersion system includes:
  • the dispersant and the dispersion medium are first mixed to obtain a dispersed liquid phase
  • nano-sized silica is mixed with the dispersion liquid phase for a second time to obtain a nano-silica dispersion
  • micron-sized silica and the nano-sized silica dispersion are mixed for the third time to obtain the nano-micron silica dispersion system.
  • the dispersion medium is oil phase I.
  • oil phase I is oil phase I.
  • specific characteristics of oil phase I are as described above and will not be repeated here.
  • the dispersant is selected from at least one of alkyl sulfonates, alkyl polyoxyethylene ethers, and alkylamidopropyl betaine.
  • step (2) further includes classifying the hydrophobically modified nano-sized silica according to D50 before the second mixing.
  • the nano-sized silica is divided into 2-5 sub-levels according to D50 size. More preferably, the D50 difference between two adjacent sub-levels of nano-sized silica is 30-500 nm, and the D50 difference between different sub-levels of nano-sized silica and their adjacent sub-levels can be the same or different.
  • step (2) includes mixing the nanoscale silica of each sub-level with the dispersion in order of increasing D50.
  • step (2) may include:
  • step (2-2) The second sub-scale nano-silica is mixed with the product of step (2-1) for a second time.
  • the third sub-level nano-silica is mixed with the product of step (2-2) for a second time to obtain a nano-silica dispersion.
  • the D50 of the first sub-level, second sub-level, and third sub-level nano-silica can be 20-40nm, 80-150nm, and 500-600nm, respectively.
  • step (3) further includes classifying the hydrophobically modified micron-sized silica according to D50 before the third mixing.
  • the micron-sized silica is divided into 2-4 sub-levels according to D50 size. More preferably, the D50 difference between two adjacent sub-levels of micron-sized silica is 2-20 ⁇ m. The D50 difference between different sub-levels of micron-sized silica and their adjacent sub-levels can be the same or different.
  • step (3) includes mixing the micron-sized silica and nano-silica dispersion of each sub-level in order of increasing D50.
  • step (3) may include:
  • step (3-2) The second sub-micron silica is mixed with the product of step (3-1) for a third time to obtain a nano-micron silica dispersion.
  • the D50 of the first sub-level and the second sub-level micron silica can be 2-5 ⁇ m and 6-10 ⁇ m, respectively.
  • the method for preparing drilling fluid provided by the present invention includes: providing the aforementioned plugging agent and emulsifier, as well as other optional components (such as dispersants, filtration reducers, wetting agents, organoclay, weighting agents, and shearing agents, etc.); and mixing the plugging agent, emulsifier, and other optional components in the presence of base oil.
  • the method for preparing the plugging agent includes:
  • Step 1) The nano-micro silica dispersion system can be prepared using the aforementioned method, and the specific process will not be described in detail here.
  • step 2) any method capable of mixing expandable graphite and expanded graphite in a nano-micro silica dispersion system is applicable to this invention.
  • expanding graphite and expanded graphite can be mixed in a nano-micro silica dispersion system by stirring.
  • step 2) further includes adding flake graphite.
  • expandable graphite expanded graphite, and flake graphite used in the above methods are as described above and will not be repeated here.
  • step 2) can involve simultaneously adding expandable graphite, expanded graphite, and flake graphite to the nano-micro silica dispersion system, or adding them stepwise.
  • This invention does not have specific requirements regarding the method or order of addition; as long as the system is thoroughly mixed after addition, it is acceptable.
  • emulsifier can be prepared using the method described in 202410760399.7, the contents of which are incorporated herein by reference in their entirety.
  • the method for preparing the emulsifier includes:
  • oligomeric fatty acids and alkaline substances are contacted and reacted, wherein the total carbon number of the oligomeric fatty acids does not exceed 108.
  • the alkaline substance is selected from alkali metal hydroxides and/or alkaline earth metal hydroxides, and more preferably at least one of calcium oxide, sodium oxide, potassium oxide, calcium hydroxide, sodium hydroxide, potassium hydroxide, and lithium hydroxide.
  • the oligomeric fatty acids and alkaline substances react to form oligomeric fatty acid salts in the emulsifier.
  • Those skilled in the art can select the types and amounts of oligomeric fatty acids and alkaline substances used in this method based on actual conditions and the characteristics of the oligomeric fatty acid salts in the emulsifier; specific details will not be elaborated further.
  • the characteristics of the emulsifier prepared by this method are as described above and will not be repeated here.
  • the third aspect of the present invention provides the application of the plugging agent described in the first aspect, or the drilling fluid described in the second aspect, in improving the microfracture plugging effect during drilling, and/or reducing filtration loss during drilling, and/or improving wellbore stability during drilling.
  • the drilling process is carried out in a high temperature and high pressure environment.
  • the temperature of the high-temperature and high-pressure environment is not lower than 180°C, more preferably 200-260°C, and the pressure is not lower than 100MPa.
  • reducing filtration loss includes reducing high-temperature, high-pressure filtration loss and reducing PPA filtration loss.
  • PPA filtration loss refers to the volume of filtrate that permeates into a porous formation under differential pressure within a certain time period when tested using a drilling fluid plugging performance evaluation instrument (PPA). Specific testing procedures and operations can be found in the instruction manual provided by the PPA supplier.
  • the fourth aspect of the present invention provides the application of the plugging agent described in the first aspect, or the drilling fluid system described in the second aspect, in improving wellbore stability during the drilling process.
  • the thickness of the flake graphite (i.e., natural flake graphite) used in the following examples is 1.5 ⁇ 0.5nm and the width is 1 ⁇ 0.5 ⁇ m; the pour point of 0# diesel oil is 0°C; the pour point of 3# white oil is -30°C, the pour point of 5# white oil is -25°C, and the pour point of 10# white oil is -10°C.
  • Expandable graphite was prepared according to the method described in CN202410001951.4. The specific method is as follows:
  • Expanded graphite was prepared according to the method described in CN202410785481.5. The specific method is as follows:
  • Expandable graphite is placed at 960 ⁇ 10°C for 60s to expand, and then the expanded product is gas-pulverized (pulverization time 45min) to obtain expanded graphite.
  • the expansion coefficient of the expanded graphite was measured; the particle size characteristics of the expanded graphite were detected using a nanolaser particle size analyzer. The results are detailed in Table 2.
  • the nano-micron silica dispersion system was prepared according to the method in CN202310894527.2. The specific method is as follows:
  • step (1) Add the micron-sized D50 modified silica particles obtained in step (1) to the nano-dispersion obtained in step (3) in sequence (see Table 3 for the specific selection and dosage ratio of micron-sized silica) and perform a third mixing (stir for 35 min at a stirring speed of 350 rpm and a temperature of 30°C for each addition of silica) to obtain a nano-micron silica dispersion system.
  • the particle size distribution and particle size distribution of nano- and micro-sized silica in a dispersion system were determined using laser particle size analysis.
  • Dispersion (wt%) (Total weight of silica in the system / Total weight of the nano-micro silica dispersion system) ⁇ 100%
  • the hydrophobic modifiers used in the nano-micro silica dispersion systems #1 to #4 are KH540, KH550, KH570 and KH570, respectively; the density of white oil #3 is 0.86 g/ cm3 ; and the density of white oil #5 is 0.82 g/ cm3 .
  • the emulsifier was prepared according to the method described in 202410760399.7. The specific method is as follows:
  • the oligomeric fatty acids and base oil (oil phase II) are mixed and heated to 60 ⁇ 5°C, stirred until fully dissolved, and then an alkaline compound (i.e., the hydroxide corresponding to the alkali metal contained in the oligomeric fatty acid salt) is added.
  • the mixture is reacted at 90 ⁇ 5°C for about 2 hours, and then an alkyl-containing sulfonate is added.
  • the mixture is reacted at 90 ⁇ 5°C for about 3 hours. After cooling, the emulsifier is obtained.
  • the emulsifier composition is detailed in Table 5. Content refers to the weight percentage of the component in the emulsifier (calculated based on the amount of raw materials).
  • This embodiment illustrates the preparation of the sealing agent provided by the present invention.
  • *a9 is a sealing agent made by directly adding expandable graphite, expanded graphite and flake graphite to base oil (3# white oil, 100mL) according to the above method, which does not contain silica.
  • Preparation method According to the formula in Table 9, first measure the base oil and place it in the material cup of a high-speed mixer, add the emulsifier and wetting agent, and stir at 12000 r/min for 15 min; measure the calcium chloride solution and add it to the material cup, and continue stirring at 12000 r/min for 20 min; weigh the organic soil and slowly add it to the material cup, and stir at 12000 r/min for 20 min; continue to weigh the shearing agent and add it to the material cup, and stir at 12000 r/min for 20 min; add the filtration loss reducer to the material cup, and stir at 12000 r/min for 10 min; add the alkali to the material cup, and stir at 12000 r/min for 10 min; then add the sealing agent to the material cup, and stir for 10 min; finally, add 270 g of weighting agent (barite), and stir at 12000 r/min for 20 min.
  • weighting agent barite
  • This test example is used to illustrate the uniformity, stability, and compatibility characteristics of the plugging agent provided by the present invention.
  • This embodiment is used to test the rheological properties and filtration properties of the drilling fluid prepared in the preparation example.
  • AV is the apparent viscosity (mPa ⁇ s); PV is the plastic viscosity (mPa ⁇ s); YP is the dynamic shear force (Pa); API is the medium-pressure filtration loss (mL); HTHP is the high-temperature, high-pressure filtration loss (240°C, 500psi) (mL); and ES is the demulsification voltage (V).
  • This embodiment is used to test the plugging performance of the drilling fluid prepared in the preparation example.
  • the drilling fluids prepared in the preparation examples were heated at 240°C for 16 hours. Then, the filtration loss (PPA loss) of the heated drilling fluid at 180°C was tested using a drilling fluid plugging performance evaluation experimental apparatus (Permeability Plug-in (PAA), purchased from Fann, model: Model 389A). The test used a 20 ⁇ m sand disc, with a pressure differential of 500psi and a test time of 30 minutes. The test results are shown in Table 13.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Sealing Material Composition (AREA)

Abstract

本发明涉及石油钻井技术领域，公开了封堵剂、油基钻井液及其应用。本发明提供的封堵剂对地层微裂隙具有多尺度广谱强封堵效果，在油基钻井液中添加该封堵剂可以有效解决井壁失稳问题，提高深层油气勘探的安全性。

Description

封堵剂、油基钻井液及其应用
相关申请的交叉引用
本申请要求2024年06月13日提交的中国专利申请202410760399.7和2024年06月18日提交的中国专利申请202410785481.5的权益，上述申请的内容通过引用被合并于本文。
技术领域
本发明涉及石油钻井技术领域，具体涉及封堵剂、油基钻井液及其应用。
背景技术
随着非常规油气开采力度的不断增大，钻井难度也随之不断加大。油基钻井液由于较水基钻井液更好的抑制性和润滑性，在深层超深层、非常规油气勘探开发中扮演着越来越重要的角色。在实际钻井施工中，基于平衡地层压力和井控的需求，采用油基钻井液钻遇微裂隙发育地层时，油基钻井液或其滤液会沿着地层微裂隙向内侵入、将压力传递至井筒地层深部，导致微裂隙发育地层井壁失稳，影响钻井安全。因此，如何有效提升油基钻井液对微裂隙封堵能力是解决油基钻井液复杂地层井壁失稳问题的关键途径。
由于油基钻井液是一种以油为连续相，同时含有多种添加剂和水、固相(封堵材料与加重材料)等组分的热力学不稳定的分散体系，目前油基钻井液在提升其封堵方面主要存在两方面行业难题：一方面，现有纳微米封堵材料多具亲水特征，适用于水基钻井液使用，这种具有超高比表面积的纳米、微米尺度封堵颗粒于油相中难以分散的问题未能解决，直接影响了多尺度微裂隙的封堵效果；另一方面，现有封堵材料和钻井液其他组分在深层、超深层等高温高压工况下的稳定性也存在一定问题，从而影响了高温工况下的应用。从而，目前尚未形成可规模化使用且有效解决井壁失稳问题的强封堵油基钻井液。
因此，亟需开发能够实现多尺度、宽广谱、超低滤失、刚柔协同的高温油基钻井液多尺度广谱封堵技术及相关产品。
发明内容
本发明的目的是为了克服现有技术存在的复杂深部地层的石油勘探工作中油基钻井液缺乏对微裂隙进行有效封堵从而易产生井壁失稳等问题，提供封堵剂、基钻井液及其应用。
为了实现上述目的，本发明第一方面提供一种封堵剂，所述封堵剂包括油相以及分散于油相I中的封堵材料，所述封堵材料包括可膨胀石墨、膨胀石墨和二氧化硅，
其中，所述封堵材料的粒径分布为1nm-50μm，所述封堵剂在240℃下加热16h后，封堵材料的D50值相比于加热前增加至少10％。
本发明第二方面提供一种钻井液，所述钻井液包含第一方面所述的封堵剂。
本发明第三方面提供第一方面所述的封堵剂，或者，第二方面所述的钻井液在提高钻井过程中的微裂隙封堵效果，和/或降低钻井过程中的滤失量，和/或提高钻井过程中的井壁稳定性中的应用。
通过上述技术方案，本发明至少能够取得如下有益效果：
(1)本发明提供的封堵剂中采用特定组成且具有特定的粒径分布特点的封堵剂材料。该封堵剂能够实现对地层微裂隙的广谱强封堵，采用该封堵剂配制的油基钻井液的微裂隙封堵效果好，能够有效解决井壁失稳问题。
(2)本发明提供的封堵剂制备方法简单、成本较低、安全环保。该封堵剂可以以具有较好的稳定性的油悬浮液形式存在，在生产和运输过程中，封堵剂中的固体成分不会发生明显的漂浮或沉降。
(3)本发明提供的封堵剂与油基钻井液的常用成分具有很好的配伍性，采用该封堵剂配制油基钻井液时，其流动性变化幅度较小。
(4)优选情况下，本发明提供的封堵剂配合特定的乳化剂，能够获得兼具良好抗温性和封堵性的油基钻井液，通过测试可知，该油基钻井液能够有效降低PPA滤失量，说明其对于地层微裂隙具有良好的封堵效果。
附图说明
图1是根据本发明的封堵材料的各个颗粒的形态图，其中，a为二氧化硅，b为鳞片石墨，c为干燥状态的可膨胀石墨，d为可膨胀石墨置于油相中吸油后的状态，e为干燥状态的膨胀石墨，f为膨胀石墨置于油相中吸油后的状态。
具体实施方式
本发明的发明人在研究中发现，通过在深层油气勘探使用的油基钻井液中添加多类型、多尺度的特定封堵材料，能够有效提高地层微裂隙的封堵性，从而解决井壁失稳的问题。通过大量研究，发明人开发了具有良好抗高温效果的乳化剂组合物，制备了能够实现微裂隙多尺度广谱封堵的封堵剂的关键成分，并在此基础上形成了能够用于制备具有良好抗温和微裂隙广谱封堵效果的油基钻井液。
至少基于上述发现，本发明第一方面提供一种封堵剂，所述封堵剂包括油相以及分散于油相I中的封堵材料，所述封堵材料包括可膨胀石墨、膨胀石墨和二氧化硅，
其中，所述封堵材料的粒径分布为1nm-50μm，所述封堵剂在240℃下加热16h后，封堵材料的D50值相比于加热前增加至少10％。
本发明中，对于油相的编号(如油相I和油相II中的“I”、“II”等)仅用于描述上方便区分不同制剂中的油相，但对于其所选用的具体成分、用量等无限制作用。
本发明中，“D50”和粒度分布中的“中值粒径”是相同含义，其在本文中可以互换使用。中值粒径是指样本的粒度分布曲线(又可称为颗粒级配曲线)上累积百分比为50wt％时对应的粒径值，即在该粒径下，样本中50wt％的颗粒直径小于或等于此值，另外50wt％的颗粒直径大于或等于此值。同理，本发明中D10、D90等术语也是根据粒度分布曲线可以得到的粒度分布特征值，分别是指粒度分布曲线上累计百分比为10wt％和90wt％时对应的粒径值。粒度分布可以通过激光粒度仪等仪器检测，并通过仪器配套的计算机软件直接获得；也可以通过电子显微镜等对样品进行观察，对视野内的颗粒尺寸进行统计，并自行计算获得(某些电子显微镜配套的计算机软件也具有统计视野内颗粒的粒度分布情况的功能)，为了获得更加准确的结果，通过可以对多个视野的颗粒尺寸进行统计并得到样品的粒度分布情况(例如至少统计3个视野的颗粒尺寸并计算粒度分布)。
本发明提供的封堵剂用于油基钻井液的配制，其创新地引入了多种碳基材料(不同种类的石墨材料)。其中，可膨胀石墨是天然石墨(通常为鳞片石墨)通过氧化剂、插层剂等化学物质的作用，在适当的条件下经过处理，从而使得氧化剂、插层剂等在石墨层间插入，并与碳原子结合形成新的化学相——石墨层间化合物(Graphite Intercalation on Compounds，简称GIC)。而可膨胀石墨在高温的作用下(通常在800℃以上)，插入石墨层间的氧化剂、插层剂发生“爆炸”，使得石墨沿轴方向膨胀成蠕虫状的物质，即为膨胀石墨。天然鳞片石墨、可膨胀石墨和膨胀石墨在宏观和/或微观的形态上具有明显差异，例如，宏观上来看，天然鳞片石墨和可膨胀石墨较为类似，但膨胀石墨表现出明显的蠕虫状结构；从微观上看，由于化学物质(氧化剂和插层剂)的插入，可膨胀石墨具有“片层状”结构，也即，相比于天然鳞片石墨的“一片单层”结构形态而言，可膨胀石墨在显微镜下可观察到“一片多层”的结构，而膨胀石墨则是具有疏松多孔的结构，在浸润于油相中后，膨胀石墨吸收油而呈现出蓬松的块状形态。
本发明提供的封堵剂添加于油基钻井液中，在进行深层、超深层等油气勘探开发过程中可以对微裂隙进行更为严密的封堵。本发明的发明人对于地层微裂隙的形态和复杂地层微裂隙封堵的作业环境进行了长期研究，根据其特点甄选了不同形态和特点的无机颗粒材料，通过其相互配合，巧妙地获得了本发明的独特封堵剂配方。例如，纳微米二氧化硅属于刚性球状颗粒，其包含了不同尺寸的二氧化硅粒子，在封堵微裂隙时可以直接进入裂隙中，对其进行填充，而膨胀石墨吸油后变得蓬松，具有良好的可变形性，在地层压力的作用下，可以进一步构建网络，夯实裂隙，而可膨胀石墨本身是类似片状的结构，能够插入到微裂隙以及其他封堵材料的细微缝隙中，而且在200-300℃的温度下会发生一定幅度的膨胀，从而使得微裂隙的封堵更加紧实。
本发明提供的封堵剂直接以油相悬浮液的形式提供，可以在现场配制油基钻井液时与其他成分更加方便地混合，也利于得到均匀的油基钻井液，避免了微纳米级的颗粒状封堵成分直接以固体粉末形式在现场加入钻井液中难以分散均匀，造成封堵效果差的问题。
本发明提供的封堵剂中由于采用了可膨胀石墨作为封堵材料之一，在一定温度(如油井温度)的作用下，可膨胀石墨的体积会膨大，而膨胀石墨和二氧化硅在加热处理过程则不会发生明显的体积变化，从而，本发明提供的封堵剂在一定温度下处理一段时间后，由于可膨胀石墨的尺寸会变大，导致封堵剂中封堵材料的D50与加热处理前相比有所增加。
在本发明的一些优选实施方式中，所述封堵剂在240℃下加热16h后，封堵材料的D50值相比于加热前增加10-50％(加热后封堵材料的D50增加量＝(加热后封堵材料的D50值-加热前封堵材料的D50值)/加热前封堵材料的D50值)。
例如，所述封堵剂在240℃下加热16h后，封堵材料的D50值相比于加热前增加10％、15％、20％、25％、30％、35％、40％、45％、50％，或者也可以为上述任意两个数值构成的范围，或是该范围中的任意中间值。
同时，在上述检测的基础上，配合环境扫描电子显微镜(ESEM)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、微束分析与能谱仪(EDS)能谱扫描(又称为EDX能谱，能量色散X射线谱)等方式能够进一步确定其中含有二氧化硅(含Si-O键)和石墨材料(主要组成元素为C)。例如，通过ESEM、SEM、TEM等显微镜观察封堵剂样品中的固体颗粒的形态，可以初步确认封堵材料中含有二氧化硅颗粒(通常为球状或类球状)，在此基础上，配合EDS能谱扫描确定固体颗粒的元素组成，从而确认二氧化硅和石墨材料(如可膨胀石墨和膨胀石墨)的存在。
EDS通常可以装载于前述电子显微镜上，因此，在同一个扫描视野中可以同时得到该视野下的封堵材料的颗粒形态和元素分布情况，配合配套计算机软件，可以更为方便地比对该视野下观察到的各封堵材料颗粒的形态和元素组成情况，进而判断封堵材料的组成。
例如，可以采用如下方式判断封堵材料的组成：首先，在电子显微镜下观察封堵材料的颗粒形态，初步确认出某个视野中二氧化硅颗粒(具有球状或类球状形态)、可膨胀石墨(具有片层结构)和膨胀石墨(具有疏松孔状结构，显微镜下呈现出类似于“不规则海绵块”的形态)，各个颗粒的形态如图1所示；然后，通过该视野的EDS能谱扫描结果，可以进一步确认二氧化硅和石墨材料，并通过扫描结果所显示的石墨材料中的C含量多少来区分和确认可膨胀石墨和膨胀石墨。根据C含量区分可膨胀石墨和膨胀石墨的依据如下：由于膨胀石墨在高温处理过程中插入石墨层间的化学物质“爆炸飞出”，因此与未高温处理的可膨胀石墨相比，膨胀石墨中这些插入的化学物质含量大幅降低。通常，C含量为50-80wt％的颗粒判定为可膨胀石墨，而C含量在90wt％以上的颗粒判定为膨胀石墨。
一般情况下，在采用ESEM、SEM、TEM、EDS能谱扫描之前需要对封堵剂样品进行处理，例如对其进行稀释，以使得其中的有效固体含量不超过5％(质量体积比，即低于5g/100mL)水平，或者，对封堵剂样品进行干燥，从中取出封堵材料进行检测。对封堵剂样品进行干燥的目的是去除其中的油相，方便起见，可以采用抽滤的方式处理封堵剂样品，并对得到的固体成分(即封堵材料)进行洗涤(例如采用乙醇洗涤)和干燥，为了避免可膨胀石墨在干燥过程中发生膨胀，通常干燥采用室温晾干等无需加热的方式进行。
例如，可以将100g封堵剂样品进行抽滤，为了减少封堵材料的损失，收集的滤液返回抽滤5次。然后用乙醇洗涤收集到的固体(即分离出的封堵材料)，为了提高清洗效果，可以反复洗涤5次，每次洗涤的乙醇加量为固体体积的约10倍，每次洗涤后进行抽滤，收集的滤液返回抽滤5次。最后一次洗涤后，将抽滤得到的固体在室温下晾干，称重，然后采用前述方法进行ESEM、SEM、TEM、EDS能谱扫描，观察从封堵剂中的即封堵材料的形态特征和元素组成，从而确定其中所含的成分。
又例如，还可以将封堵剂样品进行稀释，使其中固体物质的含量降低至5％，然后进行ESEM、SEM、TEM、EDS能谱扫描，观察封堵剂中所含的固体颗粒(即其中的封堵材料)的形态特征和元素组成，从而确定其中所含的成分。
此外，在已知原料的情况下，所述封堵材料的含量也可以根据原料投料量计算得到。
经过研究，发明人发现本发明提供的封堵剂具有极好的稳定性，在长期存储过程中，封堵剂中的封堵材料不会发生沉降或漂浮。通常，可以采用静置一段时间后观察封堵剂中固体成分的分布情况的方式来检测其稳定性。然而，静置观察的检测方式耗时较长，为了方便检测，该封堵剂的稳定性还可以通常以下方法进行检测：取一定量的封堵剂样品置于离心管中，以10-100g(即10-100倍重力加速度)离心5min以上，以离心后的离心管内液面的中间位置为分界线，取一定量分界线以上的液体(记作“上部液体”)和等量的分界线以下的液体(记作“下部液体”)后分别称重，比较二者的重量差，或者根据称重结果计算其密度(g/cm3)，比较上部液体和下部液体的密度差。若重量差/密度差较大则说明稳定性差，若重量差/密度差较小或基本没有密度差，则说明具有良好的稳定性。
上述方法中，g可以通过以下式I与离心转速进行换算：
G＝1.11×10-5×R×a2   式I
式I中，G为离心力，即重力加速度g的倍数；R为离心半径(cm)；a为离心转速(rpm)。例如，计算出的离心力G为重力加速度g的十倍，即可记作10g。
上述方法中，可以通过以下式II计算上部液体和下部液体的密度比：
密度比(％)＝上部液体密度/下部液体密度×100％式II
根据本发明的优选实施方式，其中，所述封堵剂在100g(g为重力加速度，也即，离心力为重力加速度的100倍)的离心力作用下离心10min，上部液体的密度为下部液体密度的70-100％。
优选地，所述封堵剂在100g的离心力作用下离心10min，上部液体的密度为下部液体密度的80-100％。例如可以为80％、81％、82％、83％、84％、85％、86％、87％、88％、89％、90％、91％、92％、93％、94％、95％、96％、97％、98％、99％、99.1％、99.2％、99.3％、99.4％、99.5％、99.6％、99.7％、99.8％、99.9％、100％，或者也可以为上述任意两个数值构成的范围，或是该范围中的任意中间值。
根据本发明的优选实施方式，其中，所述封堵剂在100g(g为重力加速度，也即，离心力为重力加速度的100倍)的离心力作用下离心10min时，离心产物中，上部液体和下部液体的密度差不超过0.05g/cm3，优选不超过0.03g/cm3。例如，离心产物中，上部液体和下部液体的密度差可以为0、0.001g/cm3、0.002g/cm3、0.003g/cm3、0.004g/cm3、0.005g/cm3、0.01g/cm3、0.015g/cm3、0.02g/cm3、0.025g/cm3、0.03g/cm3，或者也可以为上述任意两个数值构成的范围，或是该范围中的任意中间值。
根据本发明的优选实施方式，其中，所述封堵剂中，封堵材料的粒度分布为D10为50-1500nm、D50为1-10μm、D90为1-15μm。
优选地，所述封堵剂中，封堵材料的粒度分布为D10为300-1500nm、D50为1-5μm、D90为5-15μm。
本发明中，为了提高封堵效果，封堵剂中采用的二氧化硅为纳微米二氧化硅。未做特殊说明的情况下，“纳微米二氧化硅”是指同时包含纳米(级)和微米(级)二氧化硅的二氧化硅混合物，其具有刚性球状结构、粒径分布宽、尺寸多样等特点。纳米(级)二氧化硅是指粒径不超过1μm的二氧化硅，微米级二氧化硅是指粒径大于等于1μm且小于1mm的二氧化硅。由于本发明的封堵剂中，封堵材料的粒径分布为1nm-50μm，因此，本发明采用的纳微米二氧化硅优选粒径分布为1nm-50μm。
本发明中，对于封堵剂中采用的封堵材料的来源没有特别限制，可以采用商购获得的可膨胀石墨、膨胀石墨和二氧化硅按照本发明的要求进行复配得到所述封堵材料，也可以自行制备符合本发明要求的可膨胀石墨、膨胀石墨和二氧化硅作为封堵材料。在一些优选实施方式中，本发明提供的封堵剂中可以采用发明人在前期研究中开发的新型材料，其中，纳微米二氧化硅可以由CN202310894527.2中制备的抗高温亲油性的纳微米二氧化硅封堵分散体系提供；可膨胀石墨可以为CN202410001951.4中制备的可膨胀石墨；膨胀石墨可以为CN202410785481.5中制备的(超细)膨胀石墨。上述申请全部通过引用并入本文。
本发明的发明人在研究中巧妙地发现，通过将具有本发明所述的特征的这些材料进行复配制成的封堵剂能够实现对地层微裂隙的广谱强封堵。此外，当采用本发明的优选配方时，本发明提供的封堵剂可以以稳定的油相悬浮液的形式提供。“稳定”是指本发明提供的封堵剂在长期存放、运输过程中仍能保持悬浮液的特征，其流动性不会发生明显变化，其中的固体物质不会或基本不会析出(即不会沉淀或漂浮于表面)。
根据本发明的优选实施方式，其中，所述封堵材料(即封堵剂中的固体成分)的粒径分布为5nm-30μm。
例如，所述封堵材料的粒径的低端点可以为5nm、10nm、15nm、20nm、25nm、30nm、35nm、40nm、45nm、50nm、55nm、60nm、65nm、70nm、75nm、80nm、85nm、90nm、95nm、100nm、200nm、300nm、400nm、500nm、600nm、700nm、800nm、900nm、950nm、960nm、970nm、980nm、990nm、995nm、999nm；所述封堵材料的粒径的高端点可以为1μm、2μm、3μm、4μm、5μm、6μm、7μm、8μm、9μm、10μm、12μm、14μm、16μm、18μm、20μm、22μm、24μm、26μm、28μm、30μm。所述纳微米二氧化硅的粒径分布可以为上述任意低端点和任意高端点构成的范围。
本发明中，“粒径分布”是指封堵材料的颗粒尺寸范围，也即，封堵材料的最小尺寸至最大尺寸之间的范围，而“粒度分布”则是指封堵材料尺寸的特征值，例如D10、D50、D90等，通过粒径分布情况能够得知该封堵剂中封堵材料的最大和最小粒径的范围，而粒度分布情况能够得知该封堵剂中封堵材料的粒径特征。粒径分布和粒度分布均可通过激光粒度仪等进行检测。
根据本发明的优选实施方式，所述纳微米二氧化硅的粒度分布为D10为20-40nm、D50为230-280nm、D90为1200-1500nm。
优选地，所述纳微米二氧化硅的粒度分布为D10为25-40nm、D50为240-275nm、D90为1200-1450nm。
例如，所述纳微米二氧化硅的D10可以为25nm、26nm、27nm、28nm、29nm、30nm、31nm、32nm、33nm、34nm、35nm、36nm、37nm、38nm、39nm、40nm，或者也可以为上述任意两个值构成的范围，或该范围中的任意中间值。
例如，所述纳微米二氧化硅的D50可以为240nm、242nm、246nm、248nm、250nm、252nm、254nm、256nm、258nm、260nm、262nm、264nm、26nm、268nm、270nm、272nm、274nm、275nm，或者也可以为上述任意两个值构成的范围，或该范围中的任意中间值。
例如，所述纳微米二氧化硅的D90可以为1200nm、1220nm、1240nm、1280nm、1300nm、1320nm、1340nm、1360nm、1380nm、1400nm、1420nm、1440nm、1450nm，或者也可以为上述任意两个值构成的范围，或该范围中的任意中间值。
根据本发明的优选实施方式，其中，所述纳微米二氧化硅表面具有疏水性。优选纳微米二氧化硅通过疏水表面改性而获得良好的疏水性(也即，所述纳微米二氧化硅的表面具有疏水改性剂)。
优选地，所述疏水表面改性剂可以为硅烷偶联剂。
更优选地，所述硅烷偶联剂选自3-氨丙基三甲氧基硅烷(KH540)、3-氨基丙基三乙氧基硅烷(KH550)和γ-甲基丙烯酰氧基丙基三甲氧基硅烷(KH570)中的至少一种。
本发明中，在配制本发明的封堵剂时，所述纳微米二氧化硅可以以具有上述特征的二氧化硅固体(粉末)形式提供，也可以以油相悬浮液形式提供。例如可以以CN202310894527.2中的纳微米二氧化硅封堵分散体系的液体(油相悬浮液)形式提供。
根据本发明的优选实施方式，其中，所述纳微米二氧化硅以油相悬浮液(本发明中，又可称为“纳微米二氧化硅分散体系”)的形式提供。
优选地，所述纳微米二氧化硅分散体系中包括油相和分散于所述油相中的纳米二氧化硅和微米二氧化硅。所述纳米二氧化硅和微米二氧化硅的特征如前所述，在此不再赘述。
更优选地，所述纳微米二氧化硅分散体系中还包括分散剂。优选所述分散剂选自烷基磺酸盐、烷基聚氧乙烯醚和烷基酰胺丙基甜菜碱中的至少一种。
根据本发明的优选实施方式，其中，所述可膨胀石墨经240℃加热16h后的膨胀倍数为1-10倍，优选为1.5-3倍。“膨胀倍数”是指可膨胀石墨经过加热处理后与处理前的尺寸的比值，通常用D50进行比较，也即膨胀倍数＝240℃加热16h后的D50值/240℃加热16h前的D50值。通常可以用激光粒度分析仪进行D50的检测。通常，除自行测试外，通过商购途径获得的可膨胀石墨产品也可通过供应商获得其在特定温度下加热后的膨胀倍数等产品参数信息。
例如，所述可膨胀石墨经240℃加热16h后的膨胀倍数可以为1.5倍、1.6倍、1.7倍、1.8倍、1.9倍、2倍、2.1倍、2.2倍、2.3倍、2.4倍、2.5倍、2.6倍、2.7倍、2.8倍、2.9倍、3倍，或者也可以为上述任意两个值构成的范围，或该范围中的任意中间值。
根据本发明的优选实施方式，所述可膨胀石墨的D50(240℃加热16h前的D50，或称初始D50值，或常温下的D50值)为1-100μm，优选为1-20μm，更优选为1-5μm。优选地，所述可膨胀石墨的D10为1-3μm，D50为1-5μm，D90为4-7μm。
本发明中，未做特殊说明的情况下，“可膨胀石墨的D10、D50、D90”等粒度分布特征参数是指其在加热处理之前，还未膨胀时的相应参数数值。
根据本发明的优选实施方式，其中，所述膨胀石墨的膨胀系数＞285mL/g，优选为290-400mL/g，更优选为290-350mL/g。“膨胀系数”是指在未膨胀前单位重量(g)的可膨胀石墨经膨胀处理后所得膨胀石墨的体积(mL)。通常可以采用量筒体积法检测膨胀石墨的膨胀系数。量筒体积法即在膨胀处理前称取单位重量(例如1g)的可膨胀石墨，经过膨胀处理(膨胀处理的温度是使其能够迅速膨胀为最大体积的温度，通常可以为800-1000℃，优选960±10℃)后，将得到的膨胀石墨置于量筒中测量其体积，并计算膨胀石墨的膨胀系数的方法，该方法中，可采用如下公式计算膨胀系数：
膨胀系数(mL/g)＝膨胀后膨胀石墨的体积(mL)/膨胀前可膨胀石墨的重量(g)
通常，通过商购途径获得的膨胀石墨可以从供应商处获取其膨胀系数等产品参数信息，自行制备的膨胀石墨可以按照上述方法计算得到其膨胀系数。
例如，所述膨胀石墨的膨胀系数可以为290mL/g、295mL/g、300mL/g、305mL/g、310mL/g、315mL/g、320mL/g、325mL/g、330mL/g、335mL/g、340mL/g、345mL/g、350mL/g，或者也可以为上述任意两个值构成的范围，或该范围中的任意中间值。
优选地，所述膨胀石墨的D50为1-5μm，更优选为1-3μm。
例如，所述膨胀石墨的D50可以为1μm、1.2μm、1.4μm、1.6μm、1.8μm、2μm、2.2μm、2.4μm、2.6μm、2.8μm、3μm，或者也可以为上述任意两个值构成的范围，或该范围中的任意中间值。
本发明的封堵剂中的油相I通常可以由制备钻井液所采用的基础油提供。“基础油”是指用于配制油基钻井液采用的常规油类物质。任意本领域中能够用于油基钻井液配置的油均可适用于本发明的封堵剂。
根据本发明的一些优选实施方式，其中，所述油相I由柴油、白油和C原子数在5以上的直链或支链α-烯烃中的至少一种提供。
优选地，所述油相I选自凝固点在-30℃至0℃的柴油、凝固点在-30℃至0℃的白油和C原子数为6-30的直链或支链α-烯烃中的至少一种。
例如，所述柴油的凝固点可以为-30℃、-28℃、-25℃、-22℃、-20℃、-18℃、-15℃、-12℃、-10℃、-8℃、-5℃、-2℃、0℃，或者也可以为上述任意两个值构成的范围，或该范围中的任意中间值。
例如，所述白油的凝固点可以为-30℃、-28℃、-25℃、-22℃、-20℃、-18℃、-15℃、-12℃、-10℃、-8℃、-5℃、-2℃、0℃，或者也可以为上述任意两个值构成的范围，或该范围中的任意中间值。
例如，所述直链或支链α-烯烃的碳原子数可以为5、6、7、8、9、10、11、12、13、14、15、16、17、18、19、20、21、22、23、24、25、26、27、28、29、30，或者也可以为上述任意两个值构成的范围，或该范围中的任意中间值。
根据本发明的一些优选实施方式，其中，所述封堵剂中，可膨胀石墨、膨胀石墨、纳微米二氧化硅的重量比为1:0.1-5:0.1-5，优选为1:0.2-2:0.2-2。
例如，所述封堵剂中，可膨胀石墨和膨胀石墨的重量比可以为1:0.2、1:0.3、1:0.4、1:0.5、1:0.6、1:0.7、1:0.8、1:0.9、1:1、1:1.1、1:1.2、1:1.3、1:1.4、1:1.5、1:1.6、1:1.7、1:1.8、1:1.9、1:2，或者也可以为上述任意两个比值构成的范围，或该范围中的任意中间比值。
例如，所述封堵剂中，可膨胀石墨和纳微米二氧化硅的重量比可以为1:0.2、1:0.3、1:0.4、1:0.5、1:0.6、1:0.7、1:0.8、1:0.9、1:1、1:1.1、1:1.2、1:1.3、1:1.4、1:1.5、1:1.6、1:1.7、1:1.8、1:1.9、1:2，或者也可以为上述任意两个比值构成的范围，或该范围中的任意中间比值。
优选地，所述封堵剂中，相对于100mL的油相I，封堵材料的含量为20-200g。“封堵材料的含量”是指在100mL油相I中加入的各类封堵材料(包括二氧化硅、可膨胀石墨、膨胀石墨)的总重量。
例如，所述封堵剂中，相对于100mL的油相，封堵材料的含量可以为20g、25g、30g、35g、40g、45g、50g、55g、60g、65g、70g、75g、80g、85g、90g、95g、100g、105g、110g、115g、120g、125g、130g、135g、140g、145g、150g、155g、160g、165g、170g、175g、180g、185g、190g、195g、200g，或者也可以为上述任意两个值构成的范围，或该范围中的任意中间值。
优选地，所述封堵剂中，相对于100mL的油相I，封堵材料的含量为30-100g。
根据本发明的优选实施方式，其中，所述封堵剂还可以包括鳞片石墨，优选所述鳞片石墨的厚度不超过2nm，宽度不超过2μm。鳞片石墨的宽度是指其最宽对角线的长度。虽然本发明的封堵剂中的封堵材料仅选用具备前述特征的二氧化硅、可膨胀石墨和膨胀石墨时已经能够取得较为理想的微裂隙封堵效果，但是在此基础上进一步加入鳞片石墨还使得封堵效果进一步提高。鳞片石墨与前述封堵材料相互配合，可以起到片状变形、架桥支撑的作用，从而提高封堵效果。如前所述，可以通过显微镜观察形态和EDS能谱扫描来确定鳞片石墨的存在及其含量。鳞片石墨在显微镜下呈现片状形态，且EDS能谱扫描结果显示其元素组成完全或是基本上全部为C的即为鳞片石墨。
例如，所述鳞片石墨的厚度可以为0.1nm、0.2nm、0.3nm、0.4nm、0.5nm、0.6nm、0.7nm、0.8nm、0.9nm、1nm、1.1nm、1.2nm、1.3nm、1.4nm、1.5nm、1.6nm、1.7nm、1.8nm、1.9nm、2nm，或者也可以为上述任意两个值构成的范围，或该范围中的任意中间值。
例如，所述鳞片石墨的宽度可以为0.1μm、0.2μm、0.3μm、0.4μm、0.5μm、0.6μm、0.7μm、0.8μm、0.9μm、1μm、1.1μm、1.2μm、1.3μm、1.4μm、1.5μm、1.6μm、1.7μm、1.8μm、1.9μm、2μm，或者也可以为上述任意两个值构成的范围，或该范围中的任意中间值。
优选地，所述封堵剂中，可膨胀石墨与鳞片石墨的重量比为1:0.1-5，优选为1:0.2-2。
例如，所述封堵剂中，可膨胀石墨和鳞片石墨的重量比可以为1:0.2、1:0.3、1:0.4、1:0.5、1:0.6、1:0.7、1:0.8、1:0.9、1:1、1:1.1、1:1.2、1:1.3、1:1.4、1:1.5、1:1.6、1:1.7、1:1.8、1:1.9、1:2，或者也可以为上述任意两个比值构成的范围，或该范围中的任意中间比值。
根据本发明的一些优选实施方式，其中，所述封堵剂中，相对于100mL的油相I，鳞片石墨的含量为0.5-150g。
例如，所述封堵剂中，相对于100mL的油相I，鳞片石墨的含量可以为0.5g、1g、2g、3g、4g、5g、6g、7g、8g、9g、10g、11g、12g、13g、14g、15g、16g、17g、18g、19g、20g、25g、30g、35g、40g、45g、50g、60g、70g、80g、90g、100g、110g、120g、130g、140g、150g，或者也可以为上述任意两个比值构成的范围，或该范围中的任意中间比值。
优选地，所述封堵剂中，相对于100mL的油相I，鳞片石墨的含量为1-50g。
根据本发明的一些优选实施方式，其中，所述封堵剂中，可膨胀石墨、膨胀石墨、纳微米二氧化硅、鳞片石墨的重量比为1:0.1-5:0.1-5:0.1-5，优选为1:0.2-2:0.2-2:0.1-2。
本发明第二方面提供一种钻井液，所述钻井液包含第一方面所述的封堵剂。
本发明提供的钻井液中，除封堵剂外，还可以含有任意本领域常用于油基钻井液的成分。本发明对于该钻井液中的其他成分的具体选择和来源没有特别限制，其可以为通过商购获得的常规产品。
本发明的发明人在研究中巧妙地发现，同时含有低聚脂肪酸盐和含烷基的磺酸盐的乳化剂具有较好的抗温性，从而更加适合深层、超深层油气勘探开发时使用。
根据本发明的优选实施方式，其中，所述钻井液中还含有乳化剂。本发明对于乳化剂的具体选择没有特别限制，任意能够用于油基钻井液，尤其是用于深层、超深层油气勘探开发工作中的油基钻井液配制的乳化剂均可适用于本发明。本发明对于乳化剂的具体来源也没有特别限制，其可以为商购获得的成品乳化剂，也可以为自行制备的相关产品。
根据本发明的一些优选实施方式，其中，所述乳化剂包括低聚脂肪酸盐和含烷基的磺酸盐，所述低聚脂肪酸盐的总碳数不超过108。本发明中，“低聚脂肪酸盐”是指聚合度较低(通常不超过10，例如可以为10、9、8、7、6、5、4、3、2)的聚脂肪酸盐。
本发明提供的钻井液中采用的上述优选乳化剂由于乳化体系中的分子内均为碳-碳键和碳-硫键，不含酰胺的碳-氮键和酸酯的碳-氧键，使得该乳化剂较目前本领域常用的脂肪酰胺类、脂肪酸酯类乳化剂具有更好的抗高温效果，抗温可达240℃，乳化效果好，从而更适合深层勘探使用。该乳化剂可以为根据202410760399.7的方法制备得到的抗高温乳化剂，该申请通过引用全部引入本文。
优选地，所述乳化剂中还含有油相II。与前述封堵剂中的油相I类似，乳化剂中的油相II也可以由本领域常用于油基钻井液配制的基础油提供，其具体选择可参考前述油相I，在此不再赘述。需要说明的是，本发明提供的钻井液中，基础油可以仅选用一种，也可以选用多种。也即，乳化剂中所含的油相II与封堵剂中所含的油相I可以相同也可以不同。另外，在配制该钻井液的过程中，还可以进一步添加基础油，配制钻井液时添加的基础油可以由本领域常用于油基钻井液配制的基础油提供，其具体选择也可参考前述油相I，同理，配制钻井液时添加的基础油也可以与乳化剂、封堵剂中的油相I、油相II相同或者不同。
根据本发明的优选实施方式，其中，所述乳化剂中，以乳化剂的总重量为基准，低聚脂肪酸盐的含量为10-50重量％，含烷基的磺酸盐的含量为5-25重量％，余量为基础油。
根据本发明的优选实施方式，其中，所述低聚脂肪酸盐的聚合度为2-5。
优选地，所述低聚脂肪酸盐选自低聚油酸盐、低聚亚油酸盐、低聚亚麻酸盐、低聚妥尔油脂肪酸盐中的至少一种。
更优选地，所述低聚脂肪酸盐选自低聚油酸钙、低聚油酸钠、低聚油酸钾、低聚亚油酸钙、低聚亚油酸钠、低聚亚油酸钾、低聚亚麻酸钙、低聚亚麻酸钠、低聚亚麻酸钾、低聚妥尔油脂肪酸钙、低聚妥尔油脂肪酸钠、低聚妥尔油脂肪酸钾中的至少一种。
进一步优选地，所述低聚脂肪酸盐的脂肪酸部分由二聚油酸、二聚亚油酸、二聚妥尔油酸、三聚油酸、三聚亚麻酸、三聚亚油酸、三聚妥尔油酸、四聚亚油酸、四聚油酸、五聚亚油酸、五聚妥尔油酸中的至少一种提供。
根据本发明的优选实施方式，其中，所述含烷基的磺酸盐选自烷基苯磺酸盐、烷基磺酸盐、烷基萘磺酸盐中的至少一种；优选为烷基苯磺酸钾、烷基苯磺酸钠、烷基苯磺酸钙、烷基磺酸钾、烷基磺酸钙、烷基磺酸钠、烷基萘磺酸钾、烷基萘磺酸钠和烷基萘磺酸钙中的至少一种。
优选地，所述含烷基的磺酸盐中的烷基选自C6-C40的烷基。例如，所述含烷基的磺酸盐中的烷基的碳原子数可以为6、8、10、12、14、16、18、20、22、24、26、28、30、32、34、36、38、40，或者也可以为上述任意两个值构成的范围，或该范围中的任意中间值。
更优选地，所述含烷基的磺酸盐选自十二烷基磺酸钠、十二烷基磺酸钙、十八烷基苯磺酸钙、辛基萘磺酸钙、癸基萘磺酸钙、十六烷基苯磺酸钾、二十烷基磺酸钠、十八烷基磺酸钙中的至少一种。
优选地，所述乳化剂组合物中，低聚脂肪酸盐与含烷基的磺酸盐的重量比为0.5-20:1，优选为0.5-15:1。
例如，所述乳化剂组合物中，低聚脂肪酸盐与含烷基的磺酸盐的重量比可以为0.5:1、1:1、1.5:1、2:1、2.5:1、3:1、3.5:1、4:1、4.5:1、5:1、5.5:1、6:1、6.5:1、7:1、7.5:1、8:1、8.5:1、9:1、9.5:1、10:1、10.5:1、11:1、11.5:1、12:1、12.5:1、13:1、13.5:1、14:1、14.5:1、15:1，或者也可以为上述任意两个比值构成的范围，或该范围中的任意中间比值。
根据本发明的优选实施方式，其中，所述钻井液中，乳化剂和封堵剂的重量比为1:0.5-5，优选为1:0.6-3。
例如，所述钻井液中，乳化剂和封堵剂的重量比可以为1:0.6、1:0.7、1:0.8、1:0.9、1:1、1:1.2、1:1.4、1:1.6、1:1.8、1:2、1:2.2、1:2.4、1:2.6、1:2.8、1:3，或者也可以为上述任意两个比值构成的范围，或该范围中的任意中间比值。
优选地，每100mL的所述钻井液中，乳化剂的用量为3-8g，优选为4-6g。
例如，每100mL的所述钻井液中，乳化剂的用量可以为4g、4.2g、4.4g、4.6g、4.8g、5g、5.2g、5.4g、5.6g、5.8g、6g，或者也可以为上述任意两个值构成的范围，或该范围中的任意中间值。
优选地，每100mL的所述钻井液中，封堵剂的用量为2-10g，优选为3-7g。
例如，每100mL的所述钻井液中，封堵剂的用量可以为3g、3.1g、3.2g、3.3g、3.4g、3.5g、3.6g、3.7g、3.8g、3.9g、4g、4.2g、4.5g、4.8g、5g、5.2g、5.5g、5.8g、6g、6.2g、6.5g、6.8g、7g，或者也可以为上述任意两个值构成的范围，或该范围中的任意中间值。
钻井液中采用本发明提供的封堵剂和上述优选乳化剂时，具有良好抗高温效果，且能够实现底层微裂隙的多尺度广谱强封堵，从而更利于维持井壁稳定。
根据本发明的优选实施方式，其中，所述钻井液体系中含有可膨胀石墨、膨胀石墨、疏水改性的纳米级二氧化硅、疏水改性的微米级二氧化硅、低聚脂肪酸盐和含烷基的磺酸盐，且可膨胀石墨、膨胀石墨、疏水改性的纳米级二氧化硅、疏水改性的微米级二氧化硅、低聚脂肪酸盐和含烷基的磺酸盐的重量比为1:0.1-5:0.1-5:0.1-5:0.5-4:0.1-2。
根据本发明的优选实施方式，其中，所述钻井液中还含有基础油、分散剂、降滤失剂、润湿剂、有机土、加重剂和提切剂中的至少一种。上述组分可以为本领域常规选用的对应成分，通常可以通过商购途径获得相应的成品材料。
优选地，所述分散剂选自烷基磺酸盐、烷基聚氧乙烯醚、烷基酰胺丙基甜菜碱中的至少一种。
根据本发明的一些优选实施方式，其中，所述钻井液中，以钻井液的总重量计，可膨胀石墨的含量为0.5-8重量％。
根据本发明的优选实施方式，其中，所述钻井液中还可以含有本领域中常用的其他封堵成分，例如疏水超钙、油溶性树脂和沥青等。
优选地，所述疏水超钙的粒径不低于1μm，优选为5-50μm。
例如，所述疏水超钙的粒径可以为5μm、5.5μm、6μm、6.5μm、7μm、7.5μm、8μm、8.5μm、9μm、9.5μm、10μm、15μm、20μm、25μm、30μm、35μm、40μm、45μm、50μm，或者也可以为上述任意两个值构成的范围，或该范围中的任意中间值。
优选地，所述沥青的软化点不低于180℃。
更优选地，每100mL的钻井液中，疏水超钙的含量可以为0-3g。
根据本发明的优选实施方式，其中，所述钻井液中还可以含有流型调节剂、碱(优选CaO)、氯化钙。上述组分可以为本领域常规选用的对应成分，通常可以通过商购途径获得相应的成品材料。
根据本发明的一些优选实施方式，其中，每100mL的钻井液中，润湿剂的含量为1-2g，流型调节剂的含量为0.3-0.8g，有机土的含量为3-5g，碱的含量为3-5g，降滤失剂的含量为4-6g。
根据本发明的优选实施方式，其中，所述钻井液中的各组分可以各自独立包装保存，在使用时再将其混匀。例如，可以将封堵剂、乳化剂(以及基础油、分散剂、降滤失剂、润湿剂、有机土、加重剂和提切剂等)按照前述用量分别单独包装，在使用时将各组分加入到基础油中混匀，即可得到本发明提供的钻井液。
本发明进一步提供上述钻井液的制备方法，该方法可以包括在基础油存在下，将封堵剂和乳化剂混合。所述基础油、封堵剂和乳化剂的特征如前所述，在此不再赘述。
根据本发明的一些优选实施方式，其中，所述方法还包括制备封堵剂中采用的可膨胀石墨、膨胀石墨以及微纳米二氧化硅(分散体系)的步骤。
根据本发明的优选实施方式，其中，可膨胀石墨的制备可以包括：将鳞片石墨与预氧化剂接触得到预氧化石墨，再将所述预氧化石墨与插层剂和氧化剂接触，得到可膨胀石墨。该可膨胀石墨的制备方法具体可参考CN202410001951.4，或可采用如前所述的方法制备该可膨胀石墨。
根据本发明的优选实施方式，其中，所述可膨胀石墨的制备方法包括：
(1)氧化剂和插层剂经混合I，得到混合溶液；
(2)鳞片石墨与预氧化剂经混合II，得到预氧化石墨；
(3)预氧化石墨与混合溶液经混合III，发生氧化插层，得到氧化插层的石墨溶液；
(4)所述氧化插层的石墨溶液与辅助插层剂经混合IV，发生强化插层，得到所述可膨胀石墨。
优选地，步骤(1)中，所述氧化剂选自双氧水、浓硫酸、发烟硝酸、硝酸钠(酸性)和高锰酸钾中的至少一种。
优选地，步骤(1)中，所述插层剂选自浓硫酸、高氯酸和浓硝酸中至少一种。
更优选地，氧化剂与鳞片石墨的质量比为0.1-2。
更优选地，插层剂与鳞片石墨的质量比为2-15。
优选地，步骤(2)中，所述预氧化剂为双氧水。
更优选地，预氧化剂与鳞片石墨的质量比为5-20。
优选地，步骤(4)中，辅助插层剂选自冰乙酸、硝酸铵和醋酸中的至少一种。
更优选地，辅助插层剂与鳞片石墨的质量比为1-15。
根据本发明的优选实施方式，其中，膨胀石墨的制备包括：将鳞片石墨与氧化剂、插层剂接触，得到可膨胀石墨，然后将可膨胀石墨进行膨胀处理。该膨胀石墨的制备方法具体可参考CN202410785481.5。
根据本发明的优选实施方式，其中，所述膨胀石墨的制备方法包括：
(1)将鳞片石墨与氧化剂和插层剂混合进行氧化插层后得到可膨胀石墨；
(2)将可膨胀石墨进行膨胀得到膨胀石墨。
优选地，所述氧化剂选自过氧化氢、硫酸、硝酸、硝酸钠、高锰酸钾中的至少一种，更优选为高锰酸钾。
优选地，所述插层剂选自硫酸、高氯酸、硝酸中的至少一种，更优选为高氯酸。
更优选地，所述氧化剂与鳞片石墨的质量比为0.2-0.5:1。
更优选地，所述插层剂与鳞片石墨的质量比为6-12:1。
优选地，步骤(1)中，氧化插层的温度为30-50℃。
优选地，步骤(2)中，膨胀的温度为900-1000℃，时间30-180s。
优选地，所述方法还包括对步骤(2)得到的膨胀石墨进行粉碎的步骤。优选所述粉碎使得其具备前述粒径特征。
根据本发明的优选实施方式，其中，纳微米二氧化硅分散体系的制备包括：依次将纳米级二氧化硅和微米级二氧化硅在分散剂的存在下与分散介质进行混合。该纳微米二氧化硅分散体系的制备方法可参考CN202310894527.2。
根据本发明的一些优选实施方式，其中，纳微米二氧化硅分散体系的制备方法包括：
(1)将分散剂和分散介质进行第一混合，得到分散液相；
(2)将纳米级二氧化硅与分散液相进行第二混合，得到纳米二氧化硅分散液；
(3)将微米级二氧化硅与纳米二氧化硅分散液进行第三混合，得到纳微米二氧化硅分散体系。
优选地，步骤(1)中，所述分散介质为油相I。油相I的具体特征如前所述，在此不再赘述。
优选地，步骤(1)中，所述分散剂选自烷基磺酸盐、烷基聚氧乙烯醚、烷基酰胺丙基甜菜碱中的至少一种。
优选地，步骤(2)中还包括在第二混合之前先对疏水改性的纳米级二氧化硅按照D50进行进一步分级。优选纳米级二氧化硅按照D50大小划分为2-5个亚级。更优选相邻两个亚级的纳米级二氧化硅的D50相差30-500nm，不同亚级的纳米二氧化硅与其相邻的亚级之间D50差值可以相同也可以不同。
更优选地，步骤(2)包括按照D50从小到大的顺序依次将各亚级的纳米级二氧化硅与分散液进行混合。
为了方便理解，以将纳米级二氧化硅分为三个亚级(按照D50从小到大依次命名为第一亚级、第二亚级和第三亚级纳米二氧化硅)为例，步骤(2)可以包括：
(2-1)将第一亚级纳米二氧化硅与分散液相进行第二混合-1；
(2-2)将第二亚级纳米二氧化硅与步骤(2-1)的产物进行第二混合-2；
(2-3)将第三亚级纳米二氧化硅与步骤(2-2)的产物进行第二混合-3，得到纳米二氧化硅分散液。
在一些优选实施方式中，第一亚级、第二亚级和第三亚级纳米二氧化硅的D50可以分别为20-40nm、80-150nm、500-600nm。
优选地，步骤(3)中还包括在第三混合之前先对疏水改性的微米级二氧化硅按照D50进行进一步分级。优选微米级二氧化硅按照D50大小划分为2-4个亚级。更优选相邻两个亚级的微米级二氧化硅的D50相差2-20μm。不同亚级的微米二氧化硅与其相邻的亚级之间D50差值可以相同也可以不同。
更优选地，步骤(3)包括按照D50从小到大的顺序依次将各亚级的微米级二氧化硅与纳米二氧化硅分散液进行混合。
为了方便理解，以将微米级二氧化硅分为两个亚级(按照D50从小到大依次命名为第一亚级和第二亚级微米二氧化硅)为例，步骤(3)可以包括：
(3-1)将第一亚级微米二氧化硅与纳米二氧化硅分散液相进行第三混合-1；
(3-2)将第二亚级微米二氧化硅与步骤(3-1)的产物进行第三混合-2，得到纳微米二氧化硅分散液。
在一些优选实施方式中，第一亚级和第二亚级微米二氧化硅的D50可以分别为2-5μm、6-10μm。
根据本发明的优选实施方式，其中，本发明提供的钻井液的制备方法包括：分别提供前述封堵剂和乳化剂以及其他可选成分(如分散剂、降滤失剂、润湿剂、有机土、加重剂和提切剂等)；在基础油存在下，将封堵剂、乳化剂以及其他可选成分混合。
根据本发明的一些优选实施方式，其中，所述封堵剂的制备方法包括：
1)提供纳微米二氧化硅分散体系；
2)在纳微米二氧化硅分散体系中加入可膨胀石墨和膨胀石墨。
步骤1)可采用前述方法进行纳微米二氧化硅分散体系的制备，具体过程在此不再赘述。
步骤2)中，任意能够将可膨胀石墨和膨胀石墨在纳微米二氧化硅分散体系中混匀的方法均可适用于本发明。例如可以采用搅拌的方式将可膨胀石墨和膨胀石墨在纳微米二氧化硅分散体系中混匀。
优选地，步骤2)还包括加入鳞片石墨。
上述方法中采用的可膨胀石墨、膨胀石墨以及鳞片石墨的具体特征如前所述，在此不再赘述。
上述方法中，步骤2)中可以同时将可膨胀石墨、膨胀石墨和鳞片石墨加入纳微米二氧化硅分散体系中，也可以将可膨胀石墨、膨胀石墨和鳞片石墨分步加入纳微米二氧化硅分散体系中。本发明对于具体的添加方式和顺序等均无特别要求，只要添加后将体系混匀即可。
前述乳化剂可采用202410760399.7的方法制备得到，该申请的内容通过引用全部引入本申请中。
根据本发明的一些优选实施方式，其中，所述乳化剂的制备方法包括：
在油相II和含烷基的磺酸盐的存在下，将低聚脂肪酸和碱性物质接触并反应，所述低聚脂肪酸的总碳数不超过108。
优选地，所述碱性物质选自碱金属氢氧化物和/或碱土金属氢氧化物，优选氧化钙、氧化钠、氧化钾、氢氧化钙、氢氧化钠、氢氧化钾和氢氧化锂中的至少一种。
本发明提供的上述方法中，所述低聚脂肪酸和碱性物质反应形成所述乳化剂中的低聚脂肪酸盐。本领域技术人员能够根据实际情况，并根据前述乳化剂中低聚脂肪酸盐的特征选定该方法中采用的低聚脂肪酸和碱性物质的种类和用量，具体不再赘述。该方法制备得到的乳化剂的特征如前所述，在此不再赘述。
本发明第三方面提供第一方面所述的封堵剂，或者，第二方面所述的钻井液在提高钻井过程中的微裂隙封堵效果，和/或降低钻井过程中的滤失量，和/或提高钻井过程中的井壁稳定性中的应用。
根据本发明的优选实施方式，其中，所述钻井过程在高温高压环境下进行。
优选地，所述高温高压环境的温度不低于180℃，优选为200-260℃，压力不低于100MPa。
优选地，降低滤失量包括降低高温高压滤失量和降低PPA滤失量。PPA滤失量是指在使用钻井液封堵性能评价仪(PPA)进行测试时，一定时间内钻井液在压差作用下向有孔隙的地层渗透的滤液体积。具体的检测过程和操作可参考PPA供应商提供的说明书进行。
本发明第四方面提供第一方面所述的封堵剂，或者，第二方面所述的钻井液体系在提高钻井过程中的井壁稳定性中的应用。
实施例
以下将通过实施例对本发明的内容进行进一步解释和说明。应当能够理解的是，以下实施例仅用于示例性地进一步解释和说明本发明的内容，而不用于限制本发明。
未做特殊说明的情况下，以下实施例中采用的鳞片石墨(即天然鳞片石墨)的厚度为1.5±0.5nm，宽度为1±0.5μm；0#柴油的凝固点为0℃；3#白油的凝固点为-30℃，5#白油的凝固点为-25℃，10#白油的凝固点为-10℃。
制备例
(一)可膨胀石墨的制备
参考CN202410001951.4的方法，进行可膨胀石墨制备。具体方法如下：
(1)称取鳞片石墨与双氧水混合(A、B、C为10g鳞片石墨+100g双氧水；D为10g鳞片石墨+120g双氧水)，在35℃下250rpm搅拌15min，进行预氧化；
(2)将按照表1用量称取的高锰酸钾与高氯酸搅拌混匀后，加入预氧化产物，在35℃下350rpm搅拌10min，进行氧化插层；
(3)将氧化插层产物与50g冰乙酸混合，进行强化插层，在40℃下150rpm搅拌8min后，依次进行抽滤、水洗和烘干，其中，水洗温度为25℃，烘干温度为65℃，烘干时间为4.5h。得到可膨胀石墨。
取适量得到的可膨胀石墨加入到白油5号中(可膨胀石墨：白油的重量比为1:20)，200℃加热16h，检测可膨胀石墨的体积膨胀倍数；采用纳米激光粒度仪检测可膨胀石墨膨胀前后的粒径分布，结果详见表1。
表1
(二)膨胀石墨的制备
参考CN202410785481.5的方法，进行膨胀石墨制备。具体方法如下：
(1)按照表2中的用量称取高锰酸钾、高氯酸，先将高锰酸钾和高氯酸混匀，再加入10g天然鳞片石墨，然后在40℃下，以350rpm的搅拌速度搅拌15min，进行氧化插层；
(2)氧化插层产物依次进行抽滤、水洗和烘干，水洗温度为25±5℃，时间1h，烘干温度65±5℃。时间6h，得到可膨胀石墨；
(3)可膨胀石墨置于960±10℃下膨胀60s，然后将膨胀产物进行气体粉碎(粉碎时间45min)，得到膨胀石墨。
检测得到的膨胀石墨的膨胀系数；采用纳米激光粒度仪检测膨胀石墨的粒径特征。结果详见表2。
表2
(三)纳微米二氧化硅分散体系的制备
参考CN202310894527.2的方法，进行纳微米二氧化硅分散体系的制备。具体方法如下：
(1)将纳米级二氧化硅和微米级二氧化硅分别加入甲苯中，升温至60℃，通氮气25min，继续升温至90℃，加入疏水改性剂(相对于10g二氧化硅，疏水改性剂用量为0.75±0.25g)，反应5h后，依次进行蒸馏、洗涤、过滤和真空干燥，得到疏水改性二氧化硅颗粒；
(2)按照表4的用量称取分散剂(十五烷基磺酸钠盐)并加入到基础油(油相I)中进行第一混合(搅拌速度150rpm，温度30℃，时间15min)，得到分散液；
(3)从步骤(1)得到的改性纳米二氧化硅中分别取不同D50的纳米级改性二氧化硅颗粒(具体纳米二氧化硅的选择和用量配比见表3)，依次加入到步骤(2)得到的分散液中，进行第二混合(每加入一次二氧化硅，在搅拌速度250rpm，温度30℃的条件下搅拌25min)，得到纳米分散液；
(4)在步骤(3)得到的纳米分散液中依次加入步骤(1)得到的微米级D50的改性二氧化硅颗粒(具体微米二氧化硅的选择和用量配比见表3)，进行第三混合(每加入一次二氧化硅，在搅拌速度350rpm，温度30℃的条件下搅拌35min)，得到纳微米二氧化硅分散体系。
表3
采用如下方法对得到的纳微米二氧化硅分散体系的特征进行检测，并观察其溶解度，结果详见表4。
采用激光粒度法检测分散体系中纳微米二氧化硅的粒径分布和粒度分布；
分散度计算方法如下：
分散度(wt％)＝(体系中二氧化硅总重量/纳微米二氧化硅分散体系总重量)×100％
表4
*1#至4#纳微米二氧化硅分散体系采用的疏水改性剂分别为KH540、KH550、KH570和KH570；3#白油的密度为0.86g/cm3；5#白油的密度为0.82g/cm3。
(四)乳化剂的制备
参考202410760399.7的方法，进行乳化剂的制备。具体方法如下：
将低聚脂肪酸和基础油(油相II)混合后加热至60±5℃，搅拌充分溶解，加入碱性化合物(即低聚脂肪酸盐中所含碱金属对应的氢氧化物)，在90±5℃下反应约2h，再加入含烷基的磺酸盐，在90±5℃下继续反应约3h，冷却后即得所述乳化剂。
得到的乳化剂成分详见表5。含量是指在乳化剂中该成分所占的重量百分比(根据投料计算获得)。
表5
实施例1
本实施例用于说明本发明提供的封堵剂的制备。
参照表6的配方，分别量取或称取制备例中得到的纳微米二氧化硅分散体系、可膨胀石墨、膨胀石墨和鳞片石墨。在搅拌条件下(250rpm搅拌15min)，向纳微米二氧化硅分散体系中一同加入可膨胀石墨、膨胀石墨和鳞片石墨。各组分混匀后所得到的油相悬浮液即为封堵剂。注：表6中的纳微米二氧化硅分散体系的用量是以其中的油相含量计的。
表6
*a9为在基础油(3#白油，100mL)中按照上述方法直接添加可膨胀石墨、膨胀石墨和鳞片石墨制成的封堵剂，其中不含二氧化硅成分。
配制的各封堵剂分别取样1mL，在240℃下加热16h，采用激光粒度仪分别测量加热前后封堵剂中封堵材料的D50，并通过如下式III计算加热后D50的增加值(％)，结果详见表7。
D50增加值(％)＝(加热后D50-加热前D50)/加热前D50×100％   式III
表7
配制的各封堵剂分别取样1mL，采用激光粒度仪检测其粒径分布和粒度分布情况。结果详见表8。
表8
实施例2
本实施例用于说明本发明提供的钻井液体系的制备。
制备方法：按照表9中的配方，先量取基础油置于高速搅拌机物料杯中，加入乳化剂和润湿剂，以12000r/min速度搅拌15min；量取氯化钙溶液加入物料杯中，12000r/min继续搅拌20min；称取有机土缓慢加入到物料杯中，12000r/min搅拌20min；继续称取提切剂加入到物料杯中，12000r/min搅拌20min；将降滤失剂加入到物料杯中，12000r/min搅拌10min；将碱加入到物料杯中，12000r/min搅拌10min；再将封堵剂加入到物料杯中，搅拌10min；最后加入270g加重剂(重晶石)，12000r/min搅拌20min。
表9钻井液配方


注：22号和24号中采用的商购封堵剂成分为不同粒径疏水超钙的混合物(该混合物中，D50为5μm、
10μm和15μm的疏水超钙的重量比为1:1:1)
测试例1
本测试例用于说明本发明提供的封堵剂的均匀性、稳定性和配伍性特点。
(一)均匀性和稳定性
分别取实施例1中配制的封堵剂，采用如下方法进行稳定性测试，结果详见表10：
取6g封堵剂样品置于10mL离心管中，以100g的离心力离心10min，以离心后的离心管内液面的中间位置(1/2液面处)为分界线，用移液枪从分界线以上的液体(记作“上部液体”)和分界线以下的液体(记作“下部液体”)分别取1mL称重，并计算其密度(g/cm3)，比较上部液体和下部液体的密度差。
按照如下式II计算上部液体和下部液体的密度比：
密度比(％)＝上部液体密度/下部液体密度×100％式II
表10
(二)配伍性
分别检测实施例1中配制的封堵剂a1、a6-a13以及实施例2中配制的钻井液1号、6-15号的塑性黏度(PV)和动切力(YP)，具体检测结果详见表11。
以上各参数的均参照中华人民共和国国家标准GB/T16783.2-2012《石油天然气工业钻井液现场测试第2部分：油基钻井液》中记载的相关方法进行检测。
表11
测试例2
本实施例用于测试制备例中制备得到的钻井液的流变性和滤失性。
依据中华人民共和国国家标准GB/T16783.2-2012《石油天然气工业钻井液现场测试第2部分：油基钻井液》，分别对制备例得到的钻井液在240℃加热16h，加热后进行流变性、滤失性和破乳电压测试，实验结果如表12所示。其中，AV-表观黏度，单位mPa·s；PV-塑性黏度，单位mPa·s；YP-动切力，单位Pa；API-中压滤失量，单位mL；HTHP-高温高压滤失量(240℃，500psi)，单位mL；ES-破乳电压，单位V。
表12
测试例3
本实施例用于测试制备例中制备得到的钻井液的封堵性能。
分别将制备例中制备得到的钻井液在240℃加热16h，然后通过钻井液封堵性能评价实验装置(渗透封堵仪(PAA)，购自Fann，型号：Model 389A)测试加热后的钻井液在180℃的砂盘滤失量(PPA滤失量)，该测试采用20μm砂盘进行，测试压差为500psi，测试时间为30min。测试结果如表13所示。
表13

Claims (15)

  1. 一种封堵剂，其特征在于，所述封堵剂包括油相以及分散于油相I中的封堵材料，所述封堵材料包括可膨胀石墨、膨胀石墨和二氧化硅，
    其中，所述封堵材料的粒径分布为1nm-50μm，所述封堵剂在240℃下加热16h后，封堵材料的D50值相比于加热前增加至少10％。
  2. 根据权利要求1所述的封堵剂，其中，所述封堵剂在100g的离心力作用下离心10min，上部液体的密度为下部液体密度的70-100％，优选为80-100％；
    和/或，所述封堵剂中，封堵材料的粒度分布为D10为50-1500nm、D50为1-10μm、D90为1-15μm；
    优选地，所述封堵剂中，封堵材料的粒度分布为D10为300-1500nm、D50为1-5μm、D90为5-15μm。
  3. 根据权利要求1或2所述的封堵剂，其中，所述二氧化硅的粒度分布为D10为20-40nm、D50为230-280nm、D90为1200-1500nm；
    优选地，所述二氧化硅的粒度分布为D10为25-40nm、D50为240-275nm、D90为1200-1450nm；
    和/或，所述二氧化硅表面接枝有疏水改性剂，优选所述疏水改性剂选自硅烷偶联剂。
  4. 根据权利要求1-3中任一项所述的封堵剂，其中，所述可膨胀石墨经240℃加热16h后的膨胀倍数为1-10倍，优选为1.5-3倍；
    和/或，所述可膨胀石墨的D50为1-100μm，优选为1-20μm，更优选为1-5μm；
    优选地，所述可膨胀石墨的D10为1-3μm，D50为1-5μm，D90为4-7μm。
  5. 根据权利要求1-4中任一项所述的封堵剂，其中，所述膨胀石墨的D50为1-5μm，优选为1-3μm。
  6. 根据权利要求1-5中任一项所述的封堵剂，其中，所述油相I由柴油、白油、C原子数在5以上的直链或支链α-烯烃、精炼矿物油中的至少一种提供。
  7. 根据权利要求1-6中任一项所述的封堵剂，其中，所述封堵剂中，可膨胀石墨、膨胀石墨和二氧化硅的重量比为1:0.1-5:0.1-5，优选为1:0.2-2:0.2-2；
    优选地，所述封堵剂中，相对于100mL的油相I，封堵材料的含量为20-200g，优选为30-100g。
  8. 根据权利要求1-7中任一项所述的封堵剂，其中，所述封堵剂还包括鳞片石墨，优选所述鳞片石墨的厚度不超过2nm，宽度不超过2μm；
    优选地，所述封堵剂中，相对于100mL的油相I，鳞片石墨的含量为0.5-150g，优选为1-50g。
  9. 一种钻井液，其特征在于，所述钻井液包含权利要求1-8中任一项所述的封堵剂。
  10. 根据权利要求9所述的钻井液，其中，所述钻井液中还含有乳化剂，优选所述乳化剂包括低聚脂肪酸盐和含烷基的磺酸盐，所述低聚脂肪酸盐的总碳数不超过108；
    优选地，所述乳化剂中还含有油相II，优选所述油相II由柴油、白油、C原子数在5以上的直链或支链α-烯烃、精炼矿物油中的至少一种提供；
    优选地，所述乳化剂中，低聚脂肪酸盐与含烷基的磺酸盐的重量比为0.5-20:1，优选为0.5-15:1；
    更优选地，所述乳化剂中，以乳化剂的总重量为基准，低聚脂肪酸盐的含量为10-50重量％，含烷基的磺酸盐的含量为5-25重量％，余量为油相II。
  11. 根据权利要求9或10所述的钻井液，其中，所述低聚脂肪酸盐的聚合度为2-5；
    优选地，所述低聚脂肪酸盐选自低聚油酸盐、低聚亚油酸盐、低聚亚麻酸盐、低聚妥尔油脂肪酸盐中的至少一种；
    更优选地，所述低聚脂肪酸盐选自低聚油酸钙、低聚油酸钠、低聚油酸钾、低聚亚油酸钙、低聚亚油酸钠、低聚亚油酸钾、低聚亚麻酸钙、低聚亚麻酸钠、低聚亚麻酸钾、低聚妥尔油脂肪酸钙、低聚妥尔油脂肪酸钠、低聚妥尔油脂肪酸钾中的至少一种；
    进一步优选地，所述低聚脂肪酸盐的脂肪酸部分由二聚油酸、二聚亚油酸、二聚妥尔油酸、三聚油酸、三聚亚麻酸、三聚亚油酸、三聚妥尔油酸、四聚亚油酸、四聚油酸、五聚亚油酸、五聚妥尔油酸中的至少一种提供。
  12. 根据权利要求9-11中任一项所述的钻井液，其中，所述含烷基的磺酸盐选自烷基苯磺酸盐、烷基磺酸盐、烷基萘磺酸盐中的至少一种；优选为烷基苯磺酸钾、烷基苯磺酸钠、烷基苯磺酸钙、烷基磺酸钾、烷基磺酸钙、烷基磺酸钠、烷基萘磺酸钾、烷基萘磺酸钠和烷基萘磺酸钙中的至少一种；
    优选地，所述含烷基的磺酸盐中的烷基选自C6-C40的烷基；
    更优选地，所述含烷基的磺酸盐选自十二烷基磺酸钠、十二烷基磺酸钙、十八烷基苯磺酸钙、辛基萘磺酸钙、癸基萘磺酸钙、十六烷基苯磺酸钾、二十烷基磺酸钠和十八烷基磺酸钙中的至少一种。
  13. 根据权利要求9-12中任一项所述的钻井液，其中，所述钻井液中，乳化剂和封堵剂的重量比为1:0.5-5，优选为1:0.6-3；
    优选地，每100mL的所述钻井液中，乳化剂的用量为3-8g，优选为4-6g；
    优选地，每100mL的所述钻井液中，封堵剂的用量为2-10g，优选为3-7g。
  14. 权利要求1-8中任一项所述的封堵剂，或者，权利要求9-13中任一项所述的钻井液在提高钻井过程中的微裂隙封堵效果，和/或降低钻井过程中的滤失量，和/或提高钻井过程中的井壁稳定性中的应用。
  15. 根据权利要求14所述的应用，其中，所述钻井过程在高温高压环境下进行，优选所述高温高压环境的温度不低于180℃，压力不低于100MPa。
PCT/CN2025/095385 2024-06-13 2025-05-16 封堵剂、油基钻井液及其应用 Pending WO2025256345A1 (zh)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
CN202410760399.7 2024-06-13
CN202410760399.7A CN121136690A (zh) 2024-06-13 2024-06-13 具有乳化功能的组合物及其制备方法和应用
CN202410785481.5 2024-06-18
CN202410785481.5A CN121162212A (zh) 2024-06-18 2024-06-18 钻井方法和油基钻井液及其应用

Publications (1)

Publication Number Publication Date
WO2025256345A1 true WO2025256345A1 (zh) 2025-12-18

Family

ID=98050106

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2025/095385 Pending WO2025256345A1 (zh) 2024-06-13 2025-05-16 封堵剂、油基钻井液及其应用

Country Status (1)

Country Link
WO (1) WO2025256345A1 (zh)

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107073877A (zh) * 2014-11-13 2017-08-18 贝克休斯公司 增强复合材料、制造方法及其制品
CN107446559A (zh) * 2017-07-11 2017-12-08 中石化石油工程技术服务有限公司 一种封堵型钻井液及其应用于井壁加固的方法
CN107556990A (zh) * 2017-09-20 2018-01-09 中国石油集团渤海钻探工程有限公司 一种强化抑制和封堵性能的有机盐钻井液
CN109097013A (zh) * 2018-09-06 2018-12-28 中国海洋石油集团有限公司 一种抗高温型油基钻井液承压封堵剂及其制备方法
CN110105941A (zh) * 2019-05-20 2019-08-09 中国石油大学(华东) 碳微球作为高温水基钻井液用封堵剂的应用及高温水基钻井液
CN113502146A (zh) * 2021-07-09 2021-10-15 西南石油大学 一种膨胀型堵漏材料的制备及其应用
CN115029112A (zh) * 2022-07-13 2022-09-09 中海石油(中国)有限公司湛江分公司 一种复合基钻井液及其制备方法和应用

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107073877A (zh) * 2014-11-13 2017-08-18 贝克休斯公司 增强复合材料、制造方法及其制品
CN107446559A (zh) * 2017-07-11 2017-12-08 中石化石油工程技术服务有限公司 一种封堵型钻井液及其应用于井壁加固的方法
CN107556990A (zh) * 2017-09-20 2018-01-09 中国石油集团渤海钻探工程有限公司 一种强化抑制和封堵性能的有机盐钻井液
CN109097013A (zh) * 2018-09-06 2018-12-28 中国海洋石油集团有限公司 一种抗高温型油基钻井液承压封堵剂及其制备方法
CN110105941A (zh) * 2019-05-20 2019-08-09 中国石油大学(华东) 碳微球作为高温水基钻井液用封堵剂的应用及高温水基钻井液
CN113502146A (zh) * 2021-07-09 2021-10-15 西南石油大学 一种膨胀型堵漏材料的制备及其应用
CN115029112A (zh) * 2022-07-13 2022-09-09 中海石油(中国)有限公司湛江分公司 一种复合基钻井液及其制备方法和应用

Similar Documents

Publication Publication Date Title
Sargam et al. Effects of anionic and nonionic surfactants on the dispersion and stability of nanoSiO2 in aqueous and cement pore solutions
Luo et al. Polymer nanocomposite ADA@ SM as a high-temperature filtrate reducer for water-based drilling fluids and its filtration loss mechanism
Mao et al. Hydrophobic associated polymer based silica nanoparticles composite with core–shell structure as a filtrate reducer for drilling fluid at utra-high temperature
Vargas et al. Effects of montmorillonite (Mt) and two different organo-Mt additives on the performance of asphalt
Edgehouse et al. Stabilization of oil-in-water emulsions with graphene oxide and cobalt oxide nanosheets and preparation of armored polymer particles
Dorosti et al. Preparation and characterization of water-based magnetorheological fluid using wormlike surfactant micelles
US11286411B2 (en) Synergist for water-based drilling fluid and preparation method therefor, water-based drilling fluid and application thereof
Ni et al. Modified Laponite synthesized with special wettability as a multifunctional additive in oil-based drilling fluids
JP2010527395A (ja) 複合粒子及びその調製のための方法
EP0002368A1 (en) Rapidly dissolved water-soluble polymer compositions and a method for dissolving them without agglomeration
Zhao et al. Design and characterization of oil-in-water nanoemulsion for enhanced oil recovery stabilized by amphiphilic copolymer, nonionic surfactant, and LAPONITE® RD
CN104610946B (zh) 用于高温高压超深井的超微油基钻井液及其制备方法
Luo et al. Polymer-laponite composites as filtrate reducer for high temperature and salt resistant drilling fluid: Characterization and performance evaluation
Gao et al. Preparation of PET/LDH composite materials and their mechanical properties and permeability for O2
Manoj et al. II. Steady-state rheological investigations
Choi et al. Effect of reduced graphene oxide and MnFe2O4 nanoparticles on carbonyl iron for magnetorheological fluids
Jia et al. The synthesis of novel amphiphilic GOJS-Cn nanoparticles and their further application in stabilizing pickering emulsion and enhancing oil recovery
Liu et al. Cellulose nanocrystals as sustainable additives in water-based cutting fluids
Shi et al. Controllable assembly and application of janus smart nanosheets for oil displacement
Jiao et al. Surface‐coated thermally expandable microspheres with a composite of polydisperse graphene oxide sheets
CN103788402A (zh) 一种碳量子点/锂皂石乳液稳定体系及制备石蜡乳液的方法
Mikhaylov et al. Magnetically controlled liquid paraffin oil-in-water Pickering emulsion stabilized by magnetite/cellulose nanocrystals: Formation and Cr (VI) adsorption
Zhao et al. CO 2 responsive reversible aggregation of nanoparticles and formation of nanocapsules with an aqueous core
Yan et al. Environmentally friendly bio-based additives in oil-based drilling fluids: Efficient synthesis, well-ordered self-assembly, exceptional ultra-high-temperature resistance, and excellent anti-settling properties
Minakov et al. Experimental study of the effect of crystalline aluminum oxide nanofibers on the properties of oil-based drilling fluids

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 25821023

Country of ref document: EP

Kind code of ref document: A1