Well drilling settling agent as well as preparation method and application thereof

Abstract

The invention provides a well drilling settling agent as well as a preparation method and application thereof, and belongs to the technical field of drilling. The well drilling settling agent is prepared from the following raw materials in parts by mass: 30 to 50 parts of acrylamide monomers, 3 to 12 parts of cationic monomers, 0.02 to 0.12 part of an initiator, 6 to 12 parts of fatty acid, 1 to 3 parts of sodium acrylate, 0.05 to 0.2 part of sodium ethylene diamine tetracetate, 5 to 10 parts of a surfactant, 2 to 5 parts of trifluoroethyl methacrylate, 20 to 50 parts of base oil and 20 to 50 parts of water. The well drilling settling agent disclosed by the invention is excellent in settling effect, can effectively settle an inferior solid phase in an oil-based drilling fluid, and overcomes the problem that the viscous cutting of the oil-based drilling fluid is too high due to the fact that the effect of removing the inferior solid phase in the oil-based drilling fluid is not ideal in an existing method; the problems of slowing down during drilling, overlarge tripping excitation pressure, lubricating property deterioration, filter loss increase and the like are avoided, and meanwhile, the problems of borehole instability accidents and the like are avoided.

Description

Technical Field

[0001] The present invention relates to the field of drilling technology, and in particular to a drilling sedimentation agent and a preparation method and application thereof. Background Art

[0002] During the drilling process, the solid phase materials in the formation that are broken by the drill bit are mainly carried to the ground by the circulation of the drilling fluid and removed by the vibrating screen. The composition of these solid phase materials is related to the formation, and is usually composed of a mixture of sand, flint, limestone, dolomite, certain shales and many minerals. These solid phase materials produced in the formation are usually inert and useless in the drilling fluid, so they are also called useless solid phases. During the drilling process, due to the accumulation of rock cuttings at the bottom of the well and the hydration and dispersion of inferior soil such as mud shale, the solid phase content of the drilling fluid will become higher and higher, especially the submicron rock cuttings and inferior soil in the drilling fluid. Since most of the particles are below 2μm, the solid control equipment cannot effectively remove them, and these useless submicron solid phases will increase the viscosity and shear force of the drilling fluid, deteriorate the rheological properties of the drilling fluid, reduce the mechanical drilling speed, and increase the drilling cost.

[0003] During the operation using oil-based drilling fluid, due to the long horizontal section, poor rock carrying capacity of oil-based drilling fluid, limited performance of solid control equipment and other reasons, some solid phases cause the solid phase content in the oil-based drilling fluid system to be generally too high and difficult to remove, resulting in excessive viscosity and shear of the oil-based drilling fluid, which in turn leads to problems such as slow drilling time, excessive pressure during drilling and drilling, deterioration of lubricity, increased filtration loss, and in severe cases, well wall instability accidents. Summary of the invention

[0004] The object of the present invention is to provide a drilling sedimentation agent and a preparation method and application thereof. The drilling sedimentation agent has excellent sedimentation effect and can effectively sediment inferior solid phases in oil-based drilling fluid.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a drilling sedimentation agent, comprising the following raw materials in parts by weight:

[0007] 30-50 parts of acrylamide monomer, 3-12 parts of cationic monomer, 0.02-0.12 parts of initiator, 6-12 parts of fatty acid, 1-3 parts of sodium acrylate, 0.05-0.2 parts of sodium ethylenediaminetetraacetate, 5-10 parts of surfactant, 2-5 parts of trifluoroethyl methacrylate, 20-50 parts of base oil, and 20-50 parts of water.

[0008] Preferably, the acrylamide monomer includes at least one of acrylamide and 2-acrylamide-2-methylpropanesulfonic acid.

[0009] Preferably, the cationic monomer includes one or more of diallyldimethylammonium chloride, vinylpyridine, acryloyloxyethyltrimethylammonium chloride, methacryloyloxyethyltrimethylammonium chloride and diallylmethylbenzylammonium chloride.

[0010] Preferably, the initiator is azobisisobutyronitrile or benzoyl peroxide.

[0011] Preferably, the fatty acid comprises stearic acid or oleic acid.

[0012] Preferably, the surfactant includes one or more of Tween 80, sorbitan fatty acid ester, polyoxyethylene sorbitan monooleate, polyoxyethylene octylphenol ether-10, sodium α-olefin sulfonate, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate and hexadecyltrimethylammonium chloride.

[0013] Preferably, the base oil comprises one or more of aliphatic hydrocarbons, isoparaffins, cyclohexane, white oil and kerosene.

[0014] The present invention provides a method for preparing the drilling sedimentation agent described in the above technical solution, comprising the following steps:

[0015] Mixing an aqueous solution of acrylamide monomers, a cationic monomer, a fatty acid, trifluoroethyl methacrylate, sodium acrylate and sodium ethylenediaminetetraacetate to obtain a reaction solution;

[0016] The base oil is mixed with the surfactant, the obtained mixture is mixed with the reaction liquid under a nitrogen atmosphere, an initiator is added, and after reaction, a drilling sedimentation agent is obtained.

[0017] Preferably, the reaction temperature is 50-100° C. and the reaction time is 3-5 h.

[0018] The present invention provides the application of the drilling sedimentation agent described in the above technical solution or the drilling sedimentation agent prepared by the preparation method described in the above technical solution in the field of drilling.

[0019] The present invention provides a drilling sedimentation agent, comprising the following raw materials in parts by weight: 30-50 parts of acrylamide monomers, 3-12 parts of cationic monomers, 0.02-0.12 parts of initiators, 6-12 parts of fatty acids, 1-3 parts of sodium acrylate, 0.05-0.2 parts of sodium ethylenediaminetetraacetate, 5-10 parts of surfactants, 2-5 parts of trifluoroethyl methacrylate, 20-50 parts of base oil, and 20-50 parts of water. The drilling sedimentation agent of the present invention can be quickly dissolved and dispersed in an oil-based drilling fluid system, and efficiently flocculates tiny solid phases in the oil-based drilling fluid, so that the solid phase particles in the drilling fluid are destabilized, agglomerated, and settled. The flocculation time is short and the effect is good. The problem that the existing method of removing inferior solid phases in the oil-based drilling fluid is not ideal can be overcome, and the problems of high solid phase content and difficult maintenance of the drilling fluid can be effectively solved.

[0020] The drilling sedimentation agent of the present invention has excellent sedimentation effect and can effectively sediment inferior solid phase in oil-based drilling fluid, thereby overcoming the problem of excessively high solid phase content in the oil-based drilling fluid system and difficulty in removing the solid phase in the existing method, which results in excessive viscosity of the oil-based drilling fluid, and avoids the problems of slow drilling time, excessive drilling pressure, deterioration of lubricity, increased filtration loss, and the like, while also avoiding the problems of well wall instability accidents.

[0021] The drilling sedimentation agent of the present invention can significantly increase the particle size of the inferior solid phase in the oil-based drilling fluid, significantly reduce the plastic viscosity and final shear value of the drilling fluid, and after further treatment with centrifugal measures, can significantly reduce the content of the inferior solid phase in the oil-based drilling fluid.

[0022] The sedimentation agent of the present invention has good compatibility with oil-based drilling fluid and does not affect the performance of the drilling fluid. The treated old slurry can be recycled to achieve the purpose of reducing costs. DETAILED DESCRIPTION

[0023] The present invention provides a drilling sedimentation agent, comprising the following raw materials in parts by weight:

[0024] 30-50 parts of acrylamide monomer, 3-12 parts of cationic monomer, 0.02-0.12 parts of initiator, 6-12 parts of fatty acid, 1-3 parts of sodium acrylate, 0.05-0.2 parts of sodium ethylenediaminetetraacetate, 5-10 parts of surfactant, 2-5 parts of trifluoroethyl methacrylate, 20-50 parts of base oil, and 20-50 parts of water.

[0025] Unless otherwise specified, the reagents or raw materials used in the present invention are commercially available products well known in the art.

[0026] In terms of mass fraction, the raw materials for preparing the drilling settlement agent provided by the present invention include 30 to 50 parts of acrylamide monomers. In the present invention, the acrylamide monomers preferably include at least one of acrylamide and 2-acrylamide-2-methylpropane sulfonic acid. When the acrylamide monomers are two of the above, the present invention has no special restrictions on the ratio of different types of acrylamide monomers, which can be adjusted according to actual needs.

[0027] Based on the mass fraction of the acrylamide monomer, the raw material for preparing the drilling settlement agent provided by the present invention includes 3 to 12 parts of cationic monomers. In the present invention, the cationic monomer preferably includes one or more of diallyldimethylammonium chloride, vinylpyridine, acryloyloxyethyltrimethylammonium chloride, methacryloyloxyethyltrimethylammonium chloride and diallylmethylbenzylammonium chloride. When the cationic monomer is two or more of the above, the present invention has no special limitation on the ratio of different types of cationic monomers, and can be adjusted according to actual needs.

[0028] Based on the mass fraction of the acrylamide monomer, the raw material for preparing the drilling sedimentation agent provided by the present invention includes 0.02 to 0.12 parts of an initiator, and the initiator is preferably azobisisobutyronitrile or benzoyl peroxide.

[0029] Based on the mass fraction of the acrylamide monomer, the raw material for preparing the drilling sedimentation agent provided by the present invention includes 6 to 12 parts of fatty acid, and the fatty acid includes stearic acid or oleic acid.

[0030] Based on the mass fraction of the acrylamide monomer, the raw materials for preparing the drilling sedimentation agent provided by the present invention include 1 to 3 parts of sodium acrylate.

[0031] Based on the mass fraction of the acrylamide monomer, the raw materials for preparing the drilling sedimentation agent provided by the present invention include 0.05 to 0.2 parts of sodium ethylenediaminetetraacetate,

[0032] Based on the mass fraction of the acrylamide monomer, the raw materials for preparing the drilling settlement agent provided by the present invention include 5 to 10 parts of a surfactant. In the present invention, the surfactant preferably includes one or more of Tween 80, sorbitan fatty acid ester, polyoxyethylene sorbitan monooleate, polyoxyethylene octylphenol ether-10, sodium α-olefin sulfonate, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate and hexadecyltrimethylammonium chloride. When the surfactant is two or more of the above, the present invention has no special limitation on the ratio of different types of surfactants, and can be adjusted according to actual needs.

[0033] Based on the mass fraction of the acrylamide monomer, the raw material for preparing the drilling sedimentation agent provided by the present invention includes 2 to 5 parts of trifluoroethyl methacrylate.

[0034] Based on the mass fraction of the acrylamide monomer, the raw material for preparing the drilling sedimentation agent provided by the present invention includes 20 to 50 parts of base oil. In the present invention, the base oil preferably includes one or more of aliphatic hydrocarbons, isoparaffins, cyclohexane, white oil and kerosene. When the base oil is two or more of the above, the present invention has no special limitation on the ratio of different types of base oils, and can be adjusted according to actual needs.

[0035] Based on the mass fraction of the acrylamide monomer, the raw material for preparing the drilling sedimentation agent provided by the present invention includes 20 to 50 parts of water.

[0036] The present invention provides a method for preparing the drilling sedimentation agent described in the above technical solution, comprising the following steps:

[0037] Mixing an aqueous solution of acrylamide monomers, a cationic monomer, a fatty acid, trifluoroethyl methacrylate, sodium acrylate and sodium ethylenediaminetetraacetate to obtain a reaction solution;

[0038] The base oil is mixed with the surfactant, the obtained mixture is mixed with the reaction liquid under a nitrogen atmosphere, an initiator is added, and after reaction, a drilling sedimentation agent is obtained.

[0039] The aqueous solution of acrylamide monomers of the present invention is prepared by mixing acrylamide monomers with water.

[0040] The invention is to stir the base oil and the surfactant at 25-35°C for 40-50 minutes to mix them uniformly, and mix the obtained mixture with the reaction liquid at 25-35°C for 40-60 minutes under a nitrogen atmosphere.

[0041] In the present invention, the reaction temperature is preferably 50-100° C., and the reaction time is preferably 3-5 h.

[0042] After the reaction is completed, the present invention preferably cools the obtained product to room temperature to obtain a drilling sedimentation agent.

[0043] The present invention provides the application of the drilling sedimentation agent described in the above technical solution or the drilling sedimentation agent prepared by the preparation method described in the above technical solution in the field of drilling. The present invention has no special limitation on the application method, and the application can be carried out according to the method well known in the art.

[0044] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0045] Example 1

[0046] The drilling sedimentation agent provided in this embodiment includes the following raw materials in parts by weight:

[0047] 30 parts of acrylamide monomer (acrylamide), 5 parts of cationic monomer (methacryloyloxyethyl trimethyl ammonium chloride and diallyl methyl benzyl ammonium chloride, mass ratio 1:1), 0.06 parts of initiator (azobisisobutyronitrile), 6 parts of fatty acid (stearic acid), 1 part of sodium acrylate, 0.08 parts of sodium ethylenediaminetetraacetate, 6 parts of surfactant (polyoxyethylene sorbitan monooleate), 2 parts of trifluoroethyl methacrylate, 20 parts of base oil (white oil), 25 parts of water;

[0048] The preparation method of the drilling sedimentation agent:

[0049] Mixing an aqueous solution of acrylamide monomers, a cationic monomer, a fatty acid, trifluoroethyl methacrylate, sodium acrylate and sodium ethylenediaminetetraacetate to obtain a reaction solution;

[0050] The base oil and the surfactant were stirred and mixed at 25°C for 50 minutes, the obtained mixture was mixed with the reaction liquid at 25°C for 60 minutes under a nitrogen atmosphere, and then an initiator was added and reacted at 50°C for 5 hours to obtain a drilling sedimentation agent.

[0051] Example 2

[0052] The drilling sedimentation agent provided in this embodiment includes the following raw materials in parts by weight:

[0053] 50 parts of acrylamide monomer (2-acrylamide-2-methylpropanesulfonic acid), 12 parts of cationic monomer (diallyldimethylammonium chloride and diallylmethylbenzylammonium chloride, mass ratio 1:1), 0.12 parts of initiator (azobisisobutyronitrile), 12 parts of fatty acid (oleic acid), 3 parts of sodium acrylate, 0.2 parts of sodium ethylenediaminetetraacetate, 10 parts of surfactant (polyoxyethylene octylphenol ether-10 and hexadecyltrimethylammonium chloride, mass ratio 1:1), 5 parts of trifluoroethyl methacrylate, 50 parts of base oil (white oil and kerosene, volume ratio 1:1), 50 parts of water;

[0054] The preparation method of the drilling sedimentation agent:

[0055] Mixing an aqueous solution of acrylamide monomers, a cationic monomer, a fatty acid, trifluoroethyl methacrylate, sodium acrylate and sodium ethylenediaminetetraacetate to obtain a reaction solution;

[0056] The base oil and the surfactant were stirred and mixed at 35°C for 40 minutes, the obtained mixture was mixed with the reaction liquid at 35°C for 40 minutes under a nitrogen atmosphere, and then an initiator was added and reacted at 100°C for 3 hours to obtain a drilling sedimentation agent.

[0057] Example 3

[0058] The drilling sedimentation agent provided in this embodiment includes the following raw materials in parts by weight:

[0059] 35 parts of acrylamide monomer (acrylic acid), 5 parts of cationic monomer (diallyl dimethyl ammonium chloride), 0.05 parts of initiator (azobisisobutyronitrile), 8 parts of fatty acid (stearic acid), 2 parts of sodium acrylate, 0.1 parts of sodium ethylenediaminetetraacetate, 8 parts of surfactant (Tween 80 and hexadecyl trimethyl ammonium chloride, mass ratio 1:1), 3 parts of trifluoroethyl methacrylate, 30 parts of base oil (white oil), 30 parts of water;

[0060] The preparation method of the drilling sedimentation agent:

[0061] Mixing an aqueous solution of acrylamide monomers, a cationic monomer, a fatty acid, trifluoroethyl methacrylate, sodium acrylate and sodium ethylenediaminetetraacetate to obtain a reaction solution;

[0062] The base oil and the surfactant were stirred and mixed at 30°C for 45 minutes, the obtained mixture was mixed with the reaction liquid at 30°C for 50 minutes under a nitrogen atmosphere, and then an initiator was added and reacted at 80°C for 4 hours to obtain a drilling sedimentation agent.

[0063] Example 4

[0064] The drilling sedimentation agent provided in this embodiment includes the following raw materials in parts by weight:

[0065] 45 parts of acrylamide monomer (acrylamide), 8 parts of cationic monomer (methacryloyloxyethyl trimethyl ammonium chloride and diallyl methyl benzyl ammonium chloride), 0.1 parts of initiator (azobisisobutyronitrile), 10 parts of fatty acid (stearic acid), 2.5 parts of sodium acrylate, 0.15 parts of sodium ethylenediaminetetraacetate, 8 parts of surfactant (polyoxyethylene octylphenol ether-10 and sodium dodecyl sulfate, mass ratio 1:1), 4 parts of trifluoroethyl methacrylate, 40 parts of base oil (cyclohexane and kerosene, volume ratio 1:1), 40 parts of water;

[0066] The preparation method of the drilling sedimentation agent:

[0067] Mixing an aqueous solution of acrylamide monomers, a cationic monomer, a fatty acid, trifluoroethyl methacrylate, sodium acrylate and sodium ethylenediaminetetraacetate to obtain a reaction solution;

[0068] The base oil and the surfactant were stirred and mixed at 35°C for 45 minutes, the obtained mixture was mixed with the reaction liquid at 35°C for 450 minutes under a nitrogen atmosphere, and then an initiator was added and reacted at 80°C for 4 hours to obtain a drilling sedimentation agent.

[0069] Example 5

[0070] The drilling sedimentation agent provided in this embodiment includes the following raw materials in parts by weight:

[0071] 35 parts of acrylamide monomer (2-acrylamide-2-methylpropanesulfonic acid), 5 parts of cationic monomer (diallyldimethylammonium chloride, methacryloyloxyethyltrimethylammonium chloride and diallylmethylbenzylammonium chloride, mass ratio 1:1:1), 0.06 parts of initiator (azobisisobutyronitrile), 7 parts of fatty acid (stearic acid), 1.5 parts of sodium acrylate, 0.16 parts of sodium ethylenediaminetetraacetate, 6 parts of surfactant (sodium dodecylbenzenesulfonate and hexadecyltrimethylammonium chloride, mass ratio 1:1), 3.5 parts of trifluoroethyl methacrylate, 35 parts of base oil (kerosene), 35 parts of water;

[0072] The preparation method of the drilling sedimentation agent:

[0073] Mixing an aqueous solution of acrylamide monomers, a cationic monomer, a fatty acid, trifluoroethyl methacrylate, sodium acrylate and sodium ethylenediaminetetraacetate to obtain a reaction solution;

[0074] The base oil and the surfactant were stirred and mixed at 25°C for 50 minutes, the obtained mixture was mixed with the reaction liquid at 25°C for 60 minutes under a nitrogen atmosphere, and then an initiator was added and reacted at 90°C for 3.5 hours to obtain a drilling sedimentation agent.

[0075] Performance Testing

[0076] 1) Take a certain amount of oil-based drilling fluid, add 1.5% of the sedimentation agent prepared in different cases, stir at 3000r / min for 20min, test the rheological properties (apparent viscosity AV, plastic viscosity PV, dynamic shear force YP) and demulsification voltage; then age the drilling fluid in a roller furnace at 180℃ for 16h, and test the rheological properties and demulsification voltage of the oil-based drilling fluid after aging.

[0077] Oil-based drilling fluid formula: 255mL 3# white oil + 45mL calcium chloride brine (20%) + 1% main emulsion (oleic acid) + 4% auxiliary emulsion (oleic acid amide) + 5% wetting agent (lecithin) + 1% organic soil + 3% oxidized asphalt + 4% 2500 mesh calcium carbonate + 3% calcium oxide + 20% 11μm kaolin + 250% 2500 mesh barite (drilling fluid density is 2.2g / cm 3 ).

[0078] The rheological properties of the sedimentation agents prepared in Examples 1 to 5 were tested before and after aging at 65° C. according to standard GBT16783.2. The test results are shown in Table 1.

[0079] Table 1 Performance evaluation results of the sedimentation agents prepared in Examples 1 to 5

[0080]

[0081] As can be seen from Table 1, the sedimentation agent provided by the present invention has good temperature resistance. After adding the sedimentation agent, the demulsification voltage of the oil-based drilling fluid is significantly improved compared with that before adding the sedimentation agent, which indicates that the sedimentation agent of the present invention has the effect of improving the stability of the oil-based drilling fluid emulsion.

[0082] 2) Evaluation of poor quality solid phase removal performance

[0083] Take a certain amount of the drilling fluid described in 1) above, add 1.5% of the sedimentation agent of Examples 1 to 5 respectively, stir at 3000r / min for 20min, and age in a roller furnace at 180°C for 16h; after aging, sieve the drilling fluid with a 400-mesh sieve, filter out the sieved solid phase, and obtain the sieved oil-based drilling fluid. Take 5mL of the sieved oil-based drilling fluid, dry it, and weigh it, and calculate the solid content. The results are shown in Table 2.

[0084] Table 2 Comparison of solid content of sedimentation agents added to Examples 1 to 5

[0085]

[0086]

[0087] As shown in Table 2, after the sedimentation agent was added, the drilling fluid was hot rolled and sieved, the solid content of the drilling fluid was reduced, indicating that the sedimentation agent of the present invention has an excellent inferior solid removal effect.

[0088] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A drilling sedimentation agent, characterized in that: The preparation comprises the following raw materials in parts by weight: 30-50 parts of acrylamide monomer, 3-12 parts of cationic monomer, 0.02-0.12 parts of initiator, 6-12 parts of fatty acid, 1-3 parts of sodium acrylate, 0.05-0.2 parts of sodium ethylenediaminetetraacetate, 5-10 parts of surfactant, 2-5 parts of trifluoroethyl methacrylate, 20-50 parts of base oil, and 20-50 parts of water.

2. The drilling sedimentation agent according to claim 1, characterized in that: The acrylamide monomer includes at least one of acrylamide and 2-acrylamide-2-methylpropane sulfonic acid.

3. The drilling sedimentation agent according to claim 1, characterized in that: The cationic monomer includes one or more of diallyldimethylammonium chloride, vinylpyridine, acryloyloxyethyltrimethylammonium chloride, methacryloyloxyethyltrimethylammonium chloride and diallylmethylbenzylammonium chloride.

4. The drilling sedimentation agent according to claim 1, characterized in that: The initiator is azobisisobutyronitrile or benzoyl peroxide.

5. The drilling sedimentation agent according to claim 1, characterized in that: The fatty acid includes stearic acid or oleic acid.

6. The drilling sedimentation agent according to claim 1, characterized in that: The surfactant includes one or more of Tween 80, sorbitan fatty acid ester, polyoxyethylene sorbitan monooleate, polyoxyethylene octylphenol ether-10, sodium α-olefin sulfonate, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate and hexadecyltrimethylammonium chloride.

7. The drilling sedimentation agent according to claim 1, characterized in that: The base oil includes one or more of aliphatic hydrocarbons, isoparaffins, cyclohexane, white oil and kerosene.

8. The method for preparing the drilling sedimentation agent according to any one of claims 1 to 7, characterized in that: The following steps are involved: Mixing an aqueous solution of acrylamide monomers, a cationic monomer, a fatty acid, trifluoroethyl methacrylate, sodium acrylate and sodium ethylenediaminetetraacetate to obtain a reaction solution; The base oil is mixed with the surfactant, the obtained mixture is mixed with the reaction liquid under a nitrogen atmosphere, an initiator is added, and after reaction, a drilling sedimentation agent is obtained.

9. The preparation method according to claim 8, characterized in that: The reaction temperature is 50-100° C. and the reaction time is 3-5 hours.

10. Use of the drilling sedimentation agent according to any one of claims 1 to 7 or the drilling sedimentation agent prepared by the preparation method according to any one of claims 8 to 9 in the field of drilling.

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