Temperature-resistant salt-resistant long-acting low-friction coiled tubing drilling and grinding fluid and preparation method thereof

Abstract

The invention provides a temperature-resistant salt-resistant long-acting low-friction coiled tubing drilling and grinding fluid and a preparation method thereof. The method comprises the following steps: preparing a thickening agent for drilling and grinding and a shear-resistant reinforcing agent in proportion to obtain the drilling and grinding fluid; wherein the mass fraction of the thickening agent for drilling and grinding is 0.05-0.3%, the mass fraction of the shear-resistant reinforcing agent is 0.1-0.6%, and the balance is solvent water. According to the prepared drilling and grinding fluid, the supermolecular acting force between molecules is accurately controlled by adding the composite supermolecular acting monomer in a specific proportion, so that temperature resistance and salt resistance are achieved, and long-acting shear resistance of the drilling and grinding fluid is achieved through the positive synergistic effect between the composite supermolecular acting monomer and the specific surfactant along with the change of shear strength; the temperature-resistant, salt-resistant, long-acting and low-friction effects are realized.

Description

Technical Field

[0001] This invention relates to the field of petroleum engineering technology, and more specifically, to a temperature- and salt-resistant, long-lasting, low-friction coiled tubing drilling fluid and its preparation method. Background Technology

[0002] Currently, the main challenges facing deep shale gas drilling fluids are: after prolonged use at high temperatures, the drag reduction effect decreases significantly; and due to repeated use of the working fluid, the mineralization and metal ion content of the liquid increase, so even with the addition of drag-reducing agents, the drag reduction effect remains unsatisfactory. Therefore, it is necessary to develop long-lasting, low-friction drilling fluids suitable for deep shale gas drilling. Summary of the Invention

[0003] The purpose of this invention is to address at least one of the aforementioned deficiencies in the prior art. For example, one objective of this invention is to provide a method for preparing a temperature- and salt-resistant, long-lasting, low-friction coiled tubing drilling fluid; another objective of this invention is to provide a temperature- and salt-resistant, long-lasting, low-friction coiled tubing drilling fluid.

[0004] To achieve the above objectives, the present invention provides a method for preparing a temperature- and salt-resistant, long-lasting, low-friction coiled tubing drilling fluid, the method comprising:

[0005] A drilling fluid is prepared by mixing a thickener for drilling and a shear-resistant enhancer in a certain proportion; wherein the mass fraction of the thickener for drilling is 0.05-0.3%, the mass fraction of the shear-resistant enhancer is 0.1-0.6%, and the remainder is water as a solvent.

[0006] Alternatively, the thickener for drilling is a quaternary polymer prepared from multiple monomers using a segmented initiation process.

[0007] Alternatively, the plurality of monomers may include hydrophilic monomers, anionic monomers, and supramolecularly interacting monomers.

[0008] Alternatively, the hydrophilic monomer may include acrylamide, accounting for 63.5% to 68.5% of the total mass of the various monomers.

[0009] Alternatively, the anionic monomer may include sodium acrylate and 2-acrylamide-2-methylpropanesulfonic acid, accounting for 24.5%–26.0% and 5.0%–7.0% of the total mass of the various monomers, respectively.

[0010] Alternatively, the supramolecular monomer may include a mixture of hexadecyl dimethyl allyl ammonium chloride and octadecyl dimethyl allyl ammonium chloride in a mass ratio of 4:1, accounting for 3.5% to 6.5% of the total mass of the various monomers.

[0011] Alternatively, the structure of the segmented initiation process includes:

[0012] The azo initiator includes azobisisobutyramidine hydrochloride, used in amounts of 0.02% to 0.035% of the total mass of the various monomers; the redox initiator may include sodium hypophosphite, sodium metabisulfite, and sodium persulfate, used in amounts of 0.02% to 0.035%, 0.005% to 0.015%, and 0.015% to 0.03% of the total mass of the various monomers, respectively.

[0013] Alternatively, the method for preparing the drilling thickener includes:

[0014] The various monomers are added to the reactor in proportion; urea is added, the amount of which is 5.5% to 12% of the total mass of the various monomers; sodium hypophosphite is added; an azo initiator is added; an aqueous solution with a total monomer mass fraction of 26% to 29.5% is added and the pH value is adjusted to 6.95 to 7.35.

[0015] Control the reactor to 19–21°C and introduce an inert gas to remove oxygen;

[0016] Add a redox reaction initiator;

[0017] Continue passing the inert gas until no more can be passed through;

[0018] Insulate the temperature and then begin making granules;

[0019] Add 2.5%–5% sodium hydroxide aqueous solution by weight of the colloidal particles, mix well, and hydrolyze at 85–95°C;

[0020] After drying, the powder is sieved to obtain a thickener for drilling and grinding.

[0021] Optionally, the inert gas includes nitrogen; the time for introducing the inert gas to remove oxygen is 35–65 minutes.

[0022] Optionally, the heat preservation time is 3.5 to 4.5 hours, and the hydrolysis time is 1.5 to 2.5 hours.

[0023] Alternatively, the shear-strengthening agent is prepared by uniformly mixing 50% aqueous solution of alkyl glycoside APG1214 and 50% aqueous solution of alkyl glycoside APG1216 at a mass ratio of 2:1 to 2.5:1.

[0024] Another aspect of the present invention provides a temperature- and salt-resistant, long-lasting, low-friction continuous tubing drilling fluid.

[0025] The drilling fluid can be prepared by the above method.

[0026] Compared with the prior art, the beneficial effects of the present invention include at least one of the following:

[0027] (1) The temperature resistance of the deep shale gas temperature and salt resistant long-term low friction coiled tubing drilling fluid of the present invention is increased from 150℃ to more than 180℃. The drag reduction rate of the drilling fluid prepared after the thickener is aged at 180℃ for 1 hour is still more than 70%.

[0028] (2) The salt resistance of the deep shale gas temperature and salt resistance long-term low friction coiled tubing drilling fluid of the present invention can reach 75% in 100,000 ppm salt water, while the resistance reduction rate of conventional drilling fluid in 100,000 ppm salt water is less than 65%.

[0029] (3) The deep shale gas temperature- and salt-resistant, long-lasting, low-friction coiled tubing drilling fluid of the present invention maintains a viscosity above 50 MPa·s after shearing at 180°C for 2 hours; and maintains a viscosity above 50 MPa·s after 6000 seconds. -1 Under these conditions, the resistance reduction rate remained above 70% after 10 minutes of testing. Attached Figure Description

[0030] The above and other objects and / or features of the present invention will become clearer from the following description taken in conjunction with the accompanying drawings, in which:

[0031] Figure 1 The temperature resistance of the thickener for drilling prepared in Example 1 of the present invention is shown;

[0032] Figure 2 The drag reduction capability of the drilling fluid prepared in Example 1 of the present invention in 100,000 ppm brine is shown;

[0033] Figure 3 The shear resistance of the drilling fluid prepared by the drilling thickener of Example 1 of the present invention after crosslinking is shown. Detailed Implementation

[0034] In the following description, a temperature- and salt-resistant, long-lasting, low-friction coiled tubing drilling fluid and its preparation method will be explained in detail with reference to exemplary embodiments.

[0035] Exemplary Example 1

[0036] This exemplary embodiment provides a method for preparing a temperature- and salt-resistant, long-lasting, low-friction coiled tubing drilling fluid, the method comprising:

[0037] A drilling fluid is prepared by mixing a thickener for drilling and a shear-resistant enhancer in a certain proportion; wherein the mass fraction of the thickener for drilling is 0.05-0.3%, such as 0.05%, 0.09%, 0.1%, 0.15%, 0.2%, 0.29%, etc., and the mass fraction of the shear-resistant enhancer is 0.1-0.6%, such as 0.1%, 0.15%, 0.2%, 0.26%, 0.3%, 0.58%, etc., and the remainder is water as a solvent.

[0038] In this embodiment, the thickener for drilling is a quaternary polymer prepared from multiple monomers using a segmented initiation process.

[0039] In this embodiment, the plurality of monomers includes hydrophilic monomers, anionic monomers, and supramolecular interaction monomers, wherein the total mass fraction of the plurality of monomers is 1.

[0040] In this embodiment, the hydrophilic monomer may include acrylamide, accounting for 63.5% to 68.5% of the total mass of the various monomers, such as 63.5%, 64.2%, 65%, 66.7%, 68.5%, etc.

[0041] In this embodiment, the anionic monomer may include sodium acrylate and 2-acrylamide-2-methylpropanesulfonic acid, with mass fractions of 24.5% to 26.0% and 5.0% to 7.0% of the total mass of the various monomers, such as 24.5%, 24.7%, 25.2%, 25.6%, 25.9%, and 5%, 5.2%, 5.5%, 6.5%, 6.9%.

[0042] In this embodiment, the supramolecular monomer may include a mixture of hexadecyl dimethyl allyl ammonium chloride and octadecyl dimethyl allyl ammonium chloride in a mass ratio of 4:1, and the mass fraction of the total mass of the various monomers is 3.5% to 6.5%, such as 3.5%, 4.2%, 5%, 5.5%, 6.4%, etc.

[0043] In this embodiment, the segmented initiation process comprises:

[0044] Azo initiators include azobisisobutyramidine hydrochloride, used in amounts ranging from 0.02% to 0.035% of the total mass of the various monomers, such as 0.02%, 0.029%, 0.03%, 0.031%, 0.034%, etc.; redox initiators may include sodium hypophosphite, sodium metabisulfite, and sodium persulfate; sodium hypophosphite is used in amounts ranging from 0.02% to 0.035% of the total mass of the various monomers, such as 0.02%, 0.029%, etc. 0.03%, 0.031%, 0.034%, etc.; the amount of sodium metabisulfite is 0.005% to 0.015% of the total mass of the various monomers, such as 0.005%, 0.006%, 0.008%, 0.01%, 0.014%, etc.; the amount of sodium persulfate is 0.015% to 0.03% of the total mass of the monomers, such as 0.015%, 0.02%, 0.023%, 0.025%, 0.029%, etc.

[0045] In this embodiment, the preparation method of the drilling thickener includes:

[0046] The various monomers are added to the reactor in proportion; urea is added, the amount of which is 5.5% to 12% of the total mass of the various monomers; sodium hypophosphite is added; an azo initiator is added; an aqueous solution with a total monomer mass fraction of 26% to 29.5% is added and the pH value is adjusted to 6.95 to 7.35.

[0047] Control the reactor to 19–21°C and introduce an inert gas to remove oxygen;

[0048] Add a redox reaction initiator;

[0049] Continue passing the inert gas until no more can be passed through;

[0050] Insulate the temperature and then begin making granules;

[0051] Add 2.5% to 5% of the mass of the colloidal particles in a 48% sodium hydroxide aqueous solution, mix well, and hydrolyze in an oven at 85 to 95°C for 2 hours;

[0052] After drying, the powder is sieved to obtain a thickener for drilling and grinding.

[0053] In this embodiment, the inert gas includes nitrogen; the time for introducing the inert gas to remove oxygen is 35 to 65 minutes.

[0054] In this embodiment, the heat preservation time is 3.5 to 4.5 hours, and the hydrolysis time is 1.5 to 2.5 hours.

[0055] In this embodiment, the shear-strengthening agent is prepared by uniformly mixing 50% aqueous solution of alkyl glycoside APG1214 and 50% aqueous solution of alkyl glycoside APG1216 at a mass ratio of 2:1 to 2.5:1, such as 2:1, 2.05:1, 2.1:1, 2.16:1, 2.3:1, 2.48:1, etc.

[0056] Exemplary Example 2

[0057] This exemplary embodiment provides a method for preparing a temperature- and salt-resistant, long-lasting, low-friction coiled tubing drilling fluid. The thickener molecular structure of the drilling fluid is designed to precisely control the supramolecular forces between molecules by adding a specific proportion of composite supramolecular interaction monomers, thereby achieving temperature and salt resistance. The long-lasting shear resistance of the drilling fluid is achieved through the positive synergistic effect between the composite supramolecular interaction monomers and a specific surfactant, which varies with shear strength.

[0058] The technical solution adopted in this invention includes: the drilling fluid is mainly composed of two core additives, a drilling thickener and a shear-resistant enhancer, formulated in a specific ratio. The formula is as follows: drilling thickener mass fraction 0.05%–0.3%, shear-resistant enhancer mass fraction 0.1%–0.6%, and the remainder is water for mixing.

[0059] The thickener for drilling is a quaternary copolymer with a specific monomer ratio and a segmented initiation process. The monomers include hydrophilic monomers, anionic monomers, and a specific ratio of supramolecular interaction monomers: the hydrophilic monomer is acrylamide, which accounts for 63.5% to 68.5% of the total monomer mass; the anionic monomers are sodium acrylate and 2-acrylamido-2-methylpropanesulfonic acid, which account for 24.5% to 26.0% and 5.0% to 7.0% of the total monomer mass, respectively; the supramolecular interaction monomer is a mixture of hexadecyl dimethyl allyl ammonium chloride and octadecyl dimethyl allyl ammonium chloride in a mass ratio of 4:1, which accounts for 3.5% to 6.5% of the total monomer mass; the total mass fraction of the four monomers is 1.

[0060] The segmented initiation system consists of an azo initiator, azobisisobutyramidine hydrochloride, added at 0.02%–0.035% of the total monomer mass. Redox initiators are sodium hypophosphite, sodium metabisulfite, and sodium persulfate, with mass percentages of 0.02%–0.035%, 0.005%–0.015%, and 0.015%–0.03%, respectively.

[0061] The preparation method of the thickener for drilling and grinding is as follows:

[0062] 1) Add the four monomers to the reactor in the following proportions; add urea at a rate of 5.5% to 12% of the total monomer mass; add sodium hypophosphite; add an azo initiator; add an aqueous solution that has been fully dissolved in pure water to form a total monomer mass fraction of 26% to 29.5%, and precisely adjust the pH value to 6.95 to 7.35;

[0063] 2) Heat the reactor to 19-21°C and purge with nitrogen for 35-60 minutes to remove oxygen;

[0064] 3) Add sodium metabisulfite and sodium persulfate as redox initiators;

[0065] 4) Increase the nitrogen flow rate and continue purging nitrogen until no more can be introduced;

[0066] 5) After holding at the temperature for 4 hours, begin granulation;

[0067] 6) Add 2.5% to 5% sodium hydroxide aqueous solution by weight of the colloid particles, mix well, and hydrolyze in an oven at 85 to 95°C for 2 hours;

[0068] 7) After drying, the powder can be passed through a 120-mesh sieve to obtain the product.

[0069] The shear-strengthening agent is prepared by mixing 50% alkyl glycoside APG1214 aqueous solution with 50% alkyl glycoside APG1216 aqueous solution in a ratio of 2:1 to 2.5:1.

[0070] Exemplary Example 3

[0071] This exemplary embodiment provides a temperature- and salt-resistant, long-lasting, low-friction continuous tubing drilling fluid.

[0072] The drilling fluid can be prepared by the method described in Exemplary Example 1 or Exemplary Example 2.

[0073] To better understand the exemplary embodiments described above, further explanation is provided below with specific examples.

[0074] Example 1

[0075] Preparation of thickener for drilling and grinding: Add 550 kg of water to a reactor, then add 129 kg of acrylamide, 50 kg of sodium acrylate, 14 kg of 2-acrylamido-2-methylpropanesulfonic acid, and 7 kg of a mixture of hexadecyl dimethyl allyl ammonium chloride and octadecyl dimethyl allyl ammonium chloride in a 4:1 mass ratio. Add 12 kg of urea, 0.04 kg of sodium hypophosphite, and 0.04 kg of azobisisobutyramidine hydrochloride. Adjust the pH to 7.05. Heat the reactor to 20°C and purge with nitrogen for 45 min to remove oxygen. Add redox initiators: 0.018 kg of sodium metabisulfite and 0.036 kg of sodium persulfate. Increase the nitrogen flow and continue purging until no more nitrogen can be introduced. After maintaining the temperature for 4 hours, begin granulation. Add a 3% sodium hydroxide aqueous solution (by weight of the granules), mix thoroughly, and hydrolyze in an 80°C oven for 2 h. After drying and granulation, pulverize through a 120-mesh sieve to obtain the product. Drilling fluids formulated with a 0.3% (w / w) thickener (hereinafter referred to as "0.3% drilling thickener") can withstand temperatures up to 194℃ (e.g., Figure 1 As shown), after crosslinking with 0.3% drilling thickener, it was subjected to 100s at 180°C. -1 Shearing for 2 hours, viscosity 89 mPa·s (e.g.) Figure 3 (As shown).

[0076] Preparation of shear-resistant reinforcing agent: 150 kg of shear-resistant reinforcing agent was prepared by mixing 100 kg of 50% alkyl glycoside APG1214 aqueous solution with 50 kg of 50% alkyl glycoside APG1216 aqueous solution.

[0077] Preparation of a temperature- and salt-resistant, long-lasting, low-friction coiled tubing drilling fluid: 0.05% drilling thickener + 0.1% shear-strengthening agent, with the remainder being water, to prepare a deep shale gas temperature- and salt-resistant, long-lasting, low-friction coiled tubing drilling fluid. The drilling fluid prepared after the thickener is aged at 180℃ for 1 hour exhibits a drag reduction rate of 74.5%; in 100,000 ppm brine, the drag reduction rate can reach 77% (e.g., ...). Figure 2 (As shown); at 6000s -1 Under shear conditions, after 10 minutes of testing, the drag reduction rate remained above 70% (e.g. Figure 2 (As shown).

[0078] Example 2

[0079] Preparation of thickener for drilling and grinding: Add 520 kg of water to the reactor, then add 130 kg of acrylamide, 50 kg of sodium acrylate, 12 kg of 2-acrylamido-2-methylpropanesulfonic acid, and 8 kg of a mixture of hexadecyl dimethyl allyl ammonium chloride and octadecyl dimethyl allyl ammonium chloride in a 4:1 mass ratio. Add 16 kg of urea, 0.06 kg of sodium hypophosphite, and 0.06 kg of azobisisobutyramidine hydrochloride. Adjust the pH to 7.11. Heat the reactor to 21°C and purge with nitrogen for 40 min to remove oxygen. Add redox initiators: 0.02 kg of sodium metabisulfite and 0.04 kg of sodium persulfate. Increase the nitrogen flow and continue purging until no more nitrogen can be introduced. After maintaining the temperature for 4 hours, begin granulation. Add a 4.5% sodium hydroxide aqueous solution (by weight of the granules), mix thoroughly, and hydrolyze in an 80°C oven for 2 h. After drying and granulation, pulverize through a 120-mesh sieve to obtain the product. A 0.3% thickener for drilling and grinding can withstand temperatures up to 196℃. After cross-linking, a 0.3% thickener for drilling and grinding can withstand temperatures up to 180℃ for 100 seconds. -1 After 2 hours of shearing, the viscosity was 94.32 mPa·s.

[0080] Preparation of shear-resistant reinforcing agent: 170 kg of shear-resistant reinforcing agent was prepared by mixing 120 kg of 50% alkyl glycoside APG1214 aqueous solution with 50 kg of 50% alkyl glycoside APG1216 aqueous solution.

[0081] Preparation of a temperature- and salt-resistant, long-lasting, low-friction coiled tubing drilling fluid: 0.1% drilling thickener + 0.2% shear-strengthening agent, the remainder being water, to prepare a deep shale gas temperature- and salt-resistant, long-lasting, low-friction coiled tubing drilling fluid. The drilling fluid prepared after the thickener is aged at 180℃ for 1 hour exhibits a drag reduction rate of 75.5%; in 100,000 ppm brine, the drag reduction rate reaches 75.3%; and at 6000 s... -1 Under shear conditions, the drag reduction rate remained above 70% after 10 minutes of testing.

[0082] Although the present invention has been described above in conjunction with exemplary embodiments and accompanying drawings, those skilled in the art should understand that various modifications can be made to the above embodiments without departing from the spirit and scope of the claims.

Claims

1. A method for preparing a temperature- and salt-resistant, long-lasting, low-friction coiled tubing drilling fluid, characterized in that, The method includes: A drilling fluid is prepared by mixing a thickener and a shear-resistant enhancer in a specific ratio; wherein... The thickener used for drilling and grinding has a mass fraction of 0.05-0.3%, the shear-resistant reinforcing agent has a mass fraction of 0.1-0.6%, and the remainder is water as a solvent.

2. The method for preparing drilling fluid according to claim 1, characterized in that, The thickener for drilling is a quaternary polymer prepared from multiple monomers using a segmented initiation process.

3. The method for preparing drilling fluid according to claim 2, characterized in that, The various monomers include hydrophilic monomers, anionic monomers, and supramolecular interaction monomers.

4. The method for preparing drilling fluid according to claim 3, characterized in that, The hydrophilic monomer includes acrylamide, accounting for 63.5% to 68.5% of the total mass of the various monomers.

5. The method for preparing drilling fluid according to claim 3, characterized in that, The anionic monomers include sodium acrylate and 2-acrylamide-2-methylpropanesulfonic acid, accounting for 24.5%–26.0% and 5.0%–7.0% of the total mass of the various monomers, respectively.

6. The method for preparing drilling fluid according to claim 3, characterized in that, The supramolecular monomer comprises a mixture of hexadecyl dimethyl allyl ammonium chloride and octadecyl dimethyl allyl ammonium chloride in a mass ratio of 4:1, and accounts for 3.5% to 6.5% of the total mass of the various monomers.

7. The method for preparing drilling fluid according to claim 2, characterized in that, The segmented initiation process comprises the following components: The azo initiator is azobisisobutyramidine hydrochloride, used in an amount of 0.02% to 0.035% of the total mass of the various monomers; the redox initiators include sodium hypophosphite, sodium metabisulfite, and sodium persulfate, used in amounts of 0.02% to 0.035%, 0.005% to 0.015%, and 0.015% to 0.03% of the total mass of the various monomers, respectively.

8. The method for preparing drilling fluid according to claim 2, characterized in that, The preparation method of the drilling thickener includes: The various monomers are added to the reactor in proportion; urea is added, the amount of which is 5.5% to 12% of the total mass of the various monomers; sodium hypophosphite is added; an azo initiator is added; an aqueous solution with a total monomer mass fraction of 26% to 29.5% is added and the pH value is adjusted to 6.95 to 7.

35. Control the reactor to 19–21°C and introduce an inert gas to remove oxygen; Add a redox reaction initiator; Continue passing the inert gas until no more can be passed through; Insulate the temperature and then begin making granules; Add 2.5%–5% sodium hydroxide aqueous solution by weight of the colloidal particles, mix well, and hydrolyze at 85–95°C; After drying, the powder is sieved to obtain a thickener for drilling and grinding.

9. The method for preparing drilling fluid according to claim 8, characterized in that, The inert gas includes nitrogen or an inert gas; the time for introducing the inert gas to remove oxygen is 35 to 65 minutes.

10. The method for preparing drilling fluid according to claim 8, characterized in that, The heat preservation time is 3.5 to 4.5 hours, and the hydrolysis time is 1.5 to 2.5 hours.

11. The method for preparing drilling fluid according to claim 1, characterized in that, The shear-strengthening agent is prepared by uniformly mixing 50% aqueous solution of alkyl glycoside APG1214 and 50% aqueous solution of alkyl glycoside APG1216 at a mass ratio of 2:1 to 2.5:

1.

12. A temperature- and salt-resistant, long-lasting, low-friction coiled tubing drilling fluid, characterized in that, The drilling fluid is prepared by the method described in any one of claims 1-11.

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