A solid-free low frictional resistance foam drilling fluid and a preparation method thereof

Abstract

The application discloses a solid-phase-free low-friction foam drilling fluid, which comprises water, a foaming agent, a viscosity increasing agent, a lubricant, a filtrate reducer and a foam stabilizer; the foaming agent is zinc dialkyldithiophosphate, and a molecular formula of the zinc dialkyldithiophosphate is shown as formula (1); wherein R1 and R2 are the same or different, and are selected from at least one of C1-C8 alkyl groups. The solid-phase-free low-friction foam drilling fluid has the characteristics of strong foam stability, strong high-temperature resistance and good lubricity.

Description

TECHNICAL FIELD

[0001] The application provides a solid-phase-free low-friction foam drilling fluid as well as a preparation method and application thereof, and relates to the technical field of drilling fluids. BACKGROUND

[0002] The foam drilling fluid is an underbalanced drilling technology taking foam as a drilling fluid, and is suitable for the exploration and development of low-pressure and low-permeability oil and gas reservoirs and pressure-depleted strata. The foam drilling fluid has the characteristics of significantly improving the mechanical drilling speed, effectively reducing or eliminating the filtration of drilling fluid filtrate to the reservoir, small formation pollution, strong rock-carrying capacity and the like.

[0003] The existing foam drilling fluid technologies CN201210310014.4, CN201410448547.8 and CN201610821642.7 and the like report the preparation and use of foam drilling fluids.

[0004] When drilling with the foam drilling fluid, the drilling speed is high, and there are more drill cuttings in the wellbore, which increases the friction coefficient between the drill pipe and the well wall and the drill pipe and the casing, and there are risks such as serious erosion of the drilling tool and fatigue of the drilling tool.

[0005] The patent CN201610821642.7 discloses a foam drilling fluid, which comprises a first foaming agent (alkyl sulfate, alkyl betaine and carboxylate), a second foaming agent (alkyl sulfonate and alkyl ammonium bromide), inorganic fiber and water.

[0006] Patent CN201210310014.4 discloses a kind of foam drilling fluid, including foaming agent is 0.5%~2.0%, foam stabilizer is 0.2%~0.5%, shale inhibitor is 2%~10%, shale stabilizer is 0.2%~1.0%, the rest is water;And the pH value of foam drilling fluid is 8~10.The foaming agent of this foam drilling fluid is at least one of sodium dodecyl polyoxyethylene ether sulfate, dodecyl dimethyl betaine or hexadecyl trimethyl ammonium bromide, half-life is up to 26.9min at room temperature, after 130 DEG C hot rolling 16h, half-life is only up to 8.3min, after high temperature aging, half-life attenuation is fast, and very low.

[0007] Patent CN201310078767.1 discloses a kind of high oil microfoam drilling fluid, and each component content is by weight parts: water 100;Bentonite 2.5-3;Sodium carbonate 0.1-0.15;pH value regulator 0.1-0.15;Inhibiting anti-sloughing agent 0.2-0.25;Fluid loss additive 0.4-0.5;Anti-sloughing agent 1.5-2;High temperature resistant fluid loss additive 0.8-1.0;Flow pattern regulator 0.1-0.15;Oil 47-113;Oil-water compatible foaming agent DRfoam-Ⅱ 3-4, this microfoam drilling fluid is by light crude oil to improve the lubricity of drilling fluid by adding, but foaming volume is small.

[0008] In summary, the prior art lacks a kind of foam drilling fluid that can improve the lubricity of drilling fluid and has good foaming property. SUMMARY

[0009] In view of the above problems existing in the prior art, the present application provides a kind of solid phase-free low friction foam drilling fluid, zinc dialkyldithiophosphate is introduced as foaming agent, with the characteristics of strong foam stability, strong high temperature resistance, good lubricity.The present application also provides a kind of solid phase-free low friction foam drilling fluid preparation method.

[0010] The first aspect of the present application provides a kind of solid phase-free low friction foam drilling fluid, including water, foaming agent, tackifier, lubricant, fluid loss additive and foam stabilizer;

[0011] The foaming agent is zinc dialkyldithiophosphate, and its molecular formula is shown as formula (1):

[0012]

[0013] Wherein, R1 and R2 are the same or different, and are selected from at least one of C1-C8 alkyl.

[0014] According to some embodiments of the present application, R1 and R2 are selected from at least one of methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl and octyl.

[0015] According to some embodiments of the present application, the foaming agent is at least one of zinc butyl octyl dithiophosphate, zinc dioctyl dithiophosphate, zinc butyl hexyl dithiophosphate, zinc isopropyl isooctyl dithiophosphate, zinc di-sec-pentyl dithiophosphate.

[0016] According to some embodiments of the present application, the water is included in an amount of 80wt%-99wt%, based on the total weight of the drilling fluid.

[0017] 0.2wt%-0.5wt% foaming agent, 0.5wt%-1.0wt% viscosity increasing agent, 1.0wt%-3.0wt% lubricant, 0.2wt%-0.5wt% foam stabilizer, 1.5wt%-3.0wt% fluid loss additive.

[0018] According to some embodiments of the present application, the foaming agent is included in an amount of 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt% and any value therebetween.

[0019] According to some embodiments of the present application, the viscosity increasing agent is included in an amount of 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, 1.0wt% and any value therebetween.

[0020] According to some embodiments of the present application, the lubricant is included in an amount of 1.0wt%, 1.5wt%, 2.0wt%, 2.5wt%, 3.0wt% and any value therebetween.

[0021] According to some embodiments of the present application, the viscosity increasing agent is at least one of high viscosity carboxymethyl cellulose, biopolymer, high viscosity polyanionic cellulose, hydroxyethyl cellulose.

[0022] According to some embodiments of the present application, the lubricant is phosphate ester lubricant.

[0023] According to some embodiments of the present application, the phosphate ester lubricant is at least one of trimethylphenyl phosphate, dibutyl phosphite.

[0024] According to some embodiments of the present application, the fluid loss additive is at least one of lignite resin, carboxymethyl starch, sulfonated phenol formaldehyde resin, sulfonate copolymer.

[0025] According to some embodiments of the present application, the foam stabilizer is at least one of potassium silicate or sodium silicate.

[0026] According to some embodiments of the present application, the pH adjusting agent is further included.

[0027] According to some embodiments of the present application, the pH adjusting agent is used to adjust the pH value of the drilling fluid to be 8-10.

[0028] According to some embodiments of the present application, the pH regulator is NaOH or KOH.

[0029] The second aspect of the present application provides a preparation method of the drilling fluid of the first aspect, comprising mixing a foaming agent, a tackifier, a lubricant, a fluid loss additive, a foam stabilizer, water and an optional pH regulator to obtain the solid-free low friction foaming drilling fluid.

[0030] According to some embodiments of the present application, the specific method of mixing comprises sequentially adding the foaming agent, the tackifier, the lubricant, the fluid loss additive, the foam stabilizer and the optional pH regulator into water.

[0031] According to some embodiments of the present application, the mixing process is carried out under stirring, and the stirring rate is preferably 10000 r / min-12000 r / min.

[0032] According to some embodiments of the present application, the stirring time is 1-5 min, preferably 1-3 min.

[0033] According to some embodiments of the present application, the preparation method comprises the following steps:

[0034] (1) adding water into a high-stirring cup, and starting a stirrer to stir at a rate of 10000 r / min-12000 r / min;

[0035] (2) adding the foaming agent, stirring to dissolve it completely; adding the tackifier, continuing to stir to dissolve it completely; then adding the phosphate lubricant, continuing to stir to dissolve it completely; adding the fluid loss additive, continuing to stir to dissolve it completely, and finally adding the foam stabilizer, continuing to stir to dissolve it completely; continuing to stir for 1-3 min to prepare the solid-free low friction foaming drilling fluid.

[0036] Compared with the prior art, the present application has the following beneficial effects:

[0037] (1) The present application uses zinc dialkyldithiophosphate (ZDDP) as a foaming agent, which can improve the foaming volume and stability of the foaming drilling fluid because ZDDP can be decomposed into sulfophosphate when it comes into contact with water.

[0038] (2) Zn, S and P in the zinc dialkyldithiophosphate (ZDDP) can form an intercalation effect with metal ions on the surface of the drilling tool, and can form a physical or chemical adsorption film on the friction surface in cooperation with the phosphate, thereby improving the lubricity of the drilling fluid and reducing the erosion of the drilling cuttings on the drilling tool. Meanwhile, the sulfur and phosphorus in the ZDDP product are the main active components of the extreme pressure anti-wear agent, which has strong extreme pressure and wear resistance, and can greatly improve the lubricity of the phosphate.

[0039] (3) The solid-free low frictional resistance foam drilling fluid of the present application applies additives in the lubricating oil field to the drilling fluid field, enriching the product types of the foaming agent.

[0040] (4) The solid-free low frictional resistance foam drilling fluid of the present application has strong foam stability, and the longest foam half-life can reach 120 min.

[0041] (5) The solid-free low frictional resistance foam drilling fluid of the present application has strong temperature resistance, and still has strong foam stability after aging at 120℃ for 16h.

[0042] (6) The solid-free low frictional resistance foam drilling fluid of the present application has good lubricity, with an extreme pressure lubrication coefficient of ≤0.40, which is conducive to reducing the erosion of drill cuttings to the drilling tool. DETAILED DESCRIPTION

[0043] In order to make the present application easier to understand, the present application will be described in detail below in combination with examples, which are only illustrative and do not limit the application scope of the present application.

[0044] In the present application, zinc butyl octyl dithiophosphate is purchased from Wuxi Nanfang Petroleum Additive Company, with a brand of T202;

[0045] Zinc dioctyl dithiophosphate is purchased from Wuxi Nanfang Petroleum Additive Company, with a brand of T203;

[0046] Zinc butyl hexyl dithiophosphate is purchased from Wuxi Nanfang Petroleum Additive Company, with a brand of T205;

[0047] Isopropyl isooctyl zinc dithiophosphate is purchased from Lanlian-Lubrizol Additive Company, with a brand of LAN204;

[0048] Zinc di-sec-pentane dithiophosphate is purchased from Lanlian-Lubrizol Additive Company, with a brand of LAN205;

[0049] Sodium dodecyl benzene sulfonate is analytical pure, purchased from National Pharmaceutical Group Chemical Reagent Co., Ltd.;

[0050] Biopolymer is biopolymer XC, with a molecular formula (C2H6O2) n , n is 1210-1350, purchased from Shandong Deshunyuan Petroleum Technology Co., Ltd.;

[0051] Trimethylphenol phosphate is analytical pure, purchased from National Pharmaceutical Group Chemical Reagent Co., Ltd.;

[0052] Sulfonated phenolic resin is an industrial product, from Shandong Deshunyuan Petroleum Technology Co., Ltd.;

[0053] Potassium silicate is analytical pure, purchased from National Pharmaceutical Group Chemical Reagent Co., Ltd.

[0054] Sodium silicate was purchased from National Pharmaceutical Group Chemical Reagent Co., Ltd. and was of analytical purity;

[0055] High viscosity carboxymethyl cellulose (HV-CMC) was purchased from Shengda Cellulose Factory in Dongying, Shandong Province and had a molecular weight of 9-10 million;

[0056] Hydroxyethyl cellulose (HEC) was purchased from Fuyin Biological Technology Co., Ltd. in Shandong Province and had a molecular weight of 8-11 million;

[0057] Dibutyl phosphite was purchased from National Pharmaceutical Group Chemical Reagent Co., Ltd.;

[0058] Sulfonate copolymer (DSP) was an industrial product purchased from Shandong Deshengyuan Petroleum Technology Co., Ltd. and had a molecular weight of 3-4 million;

[0059] Lignite resin was an industrial product purchased from Shandong Deshengyuan Petroleum Technology Co., Ltd.;

[0060] High viscosity polyanionic cellulose (HV-PAC) was purchased from Shengda Cellulose Factory in Dongying, Shandong Province and had a molecular weight of 9-10 million;

[0061] Carboxymethyl starch (CMS) was an industrial product purchased from Henan Qiangan Industry Co., Ltd.

[0062] Example 1

[0063] A solid-free low friction foam drilling fluid was prepared, which included, based on the weight of water:

[0064] 0.2wt% zinc butyloctyl dithiophosphate (T202), 0.5wt% biopolymer (XC), 2.0wt% trimethylphenyl phosphite, 0.2wt% potassium silicate, 1.0wt% carboxymethyl starch, 2.0wt% sulfonated phenolic resin.

[0065] The pH value of the foam drilling fluid system was adjusted to 8 using NaOH.

[0066] The preparation method of the solid-free low friction foam drilling fluid of the present example included the following steps:

[0067] (1) 100 mL of water was added to a high-speed stirring cup, and the stirrer was turned on and stirred at 10,000 r / min;

[0068] (2) add 0.2wt% zinc butyl octyl dithiophosphate (T202), continue to stir to fully dissolve; add 0.5wt% biopolymer (XC), continue to stir to fully dissolve, add 2.0wt% trimethylphenyl phosphate, continue to stir to fully dissolve, add 1.0wt% carboxymethyl starch, 2.0wt% sulfonated phenolic resin, continue to stir to fully dissolve; finally add 0.2wt% potassium silicate, continue to stir to fully dissolve; continue to stir for 3min to prepare the foam drilling fluid.

[0069] Example 2

[0070] A solid-free low friction foam drilling fluid is prepared, which includes, based on the weight of water:

[0071] 0.5wt% zinc dioctyl dithiophosphate (T203), 0.4wt% high viscosity carboxymethyl cellulose (HV-CMC, molecular weight 900,000), 0.3wt% hydroxyethyl cellulose (HEC, molecular weight 1,100,000); 3.0wt% dibutyl phosphite; 0.3wt% sodium silicate; 0.5wt% sulfonate copolymer (DSP, molecular weight 400,000), 1.0wt% lignite resin.

[0072] The pH value of the foam drilling fluid system is adjusted to 9 using NaOH.

[0073] The preparation method of the solid-free low friction foam drilling fluid of the present embodiment includes the following steps:

[0074] (1) add 100mL water to a high-speed stirring cup, start the stirrer and stir at 12000r / min;

[0075] (2) add 0.5wt% zinc dioctyl dithiophosphate (T203), continue to stir to fully dissolve; add 0.4wt% high viscosity carboxymethyl cellulose (HV-CMC, molecular weight 900,000), 0.3wt% hydroxyethyl cellulose (HEC, molecular weight 1,100,000), continue to stir to fully dissolve; add 3.0wt% dibutyl phosphite, continue to stir to fully dissolve, add 0.5wt% sulfonate copolymer (DSP, molecular weight 400,000), 1.0wt% lignite resin, continue to stir to fully dissolve; finally add 0.3wt% sodium silicate, continue to stir to fully dissolve; continue to stir for 1min to prepare the foam drilling fluid.

[0076] Example 3

[0077] A solid-free low friction foam drilling fluid is prepared, which includes, based on the weight of water:

[0078] 0.3wt% zinc butyl hexyl dithiophosphate (T205), 0.3wt% high viscosity anionic cellulose (HV-CMC, molecular weight 900,000), 0.4wt% biopolymer (XC), 1.5wt% trimethylphenyl phosphate, 0.5wt% potassium silicate, 0.5wt% sulfonate copolymer (DSP, molecular weight 300,000), 2.0wt% sulfonated phenolic resin.

[0079] The pH value of the foam drilling fluid system is adjusted to 9 using KOH.

[0080] The preparation method of the solid-free low friction foam drilling fluid described in this embodiment includes the following steps:

[0081] (1) 100 mL of water is added to a high-speed stirring cup, and the stirrer is turned on for stirring at 11000 r / min;

[0082] (2) 0.3wt% zinc butyl hexyl dithiophosphate (T205) is added, and stirring is continued to fully dissolve it; 0.3wt% high viscosity anionic cellulose (HV-CMC, molecular weight 900,000), 0.4wt% biopolymer (XC) are added, and stirring is continued to fully dissolve them; 1.5wt% trimethylphenyl phosphate is added, and stirring is continued to fully dissolve it; 0.5wt% sulfonate copolymer (DSP, molecular weight 300,000), 2.0wt% sulfonated phenolic resin are added, and stirring is continued to fully dissolve them; finally, 0.5wt% potassium silicate is added, and stirring is continued to fully dissolve it; stirring is continued for 3 min to prepare the foam drilling fluid.

[0083] Example 4

[0084] The solid-free low friction foam drilling fluid is prepared, and based on the weight of water, it includes:

[0085] 0.4wt% zinc isopropyl isooctyl dithiophosphate (LAN204), 0.5wt% hydroxymethyl cellulose (HEC, molecular weight 900,000), 1.0wt% dibutyl phosphite, 0.4wt% sodium silicate, 1.0wt% lignite resin, 2.0wt% sulfonated phenolic resin.

[0086] The pH value of the foam drilling fluid system is adjusted to 9 using NaOH.

[0087] The preparation method of the solid-free low friction foam drilling fluid described in this embodiment includes the following steps:

[0088] (1) 100 mL of water is added to a high-speed stirring cup, and the stirrer is turned on for stirring at 12000 r / min;

[0089] (2) add 0.4wt% zinc isopropyl isooctyl dithiophosphate (LAN204), continue to stir until it is fully dissolved; add 0.5wt% hydroxymethyl cellulose (HEC, molecular weight 900,000), continue to stir until it is fully dissolved, add 1.0wt% dibutyl phosphite, continue to stir until it is fully dissolved, add 1.0wt% lignum vitreum resin, 2.0wt% sulfonated phenol aldehyde resin, continue to stir until it is fully dissolved; finally add 0.4wt% sodium silicate, continue to stir until it is fully dissolved; continue to stir for 1min to prepare the foam drilling fluid.

[0090] Example 5

[0091] A solid-free low friction foam drilling fluid is prepared, which includes, based on the weight of water:

[0092] 0.5wt% zinc di-sec-pentane dithiophosphate (LAN205), 0.5wt% high viscosity carboxymethyl cellulose (HV-CMC, molecular weight 1,000,000), 0.5wt% high viscosity poly anionic cellulose (HV-PAC, molecular weight 1,000,000), 2.0wt% trimethyl phenol phosphate, 0.5wt% sodium silicate, 0.5wt% sulfonate copolymer (DSP, molecular weight 300,000), 2.0wt% carboxymethyl starch (CMS).

[0093] The pH value of the foam drilling fluid system is adjusted to 9 using NaOH.

[0094] The preparation method of the solid-free low friction foam drilling fluid described in this example includes the following steps:

[0095] (1) add 100mL water to a high stirring cup, turn on the stirrer and stir at 12,000r / min;

[0096] (2) add 0.5wt% zinc di-sec-pentane dithiophosphate (LAN205), continue to stir until it is fully dissolved; add 0.5wt% high viscosity carboxymethyl cellulose (HV-CMC, molecular weight 1,000,000), 0.5wt% high viscosity poly anionic cellulose (HV-PAC, molecular weight 1,000,000); continue to stir until it is fully dissolved, add 2.0wt% trimethyl phenol phosphate, continue to stir until it is fully dissolved; add 0.5wt% sulfonate copolymer (DSP, molecular weight 300,000), 2.0wt% carboxymethyl starch (CMS), continue to stir until it is fully dissolved; finally add 0.5wt% sodium silicate, continue to stir until it is fully dissolved; continue to stir for 3min to prepare the foam drilling fluid.

[0097] Comparative Example 1

[0098] A foamed drilling fluid was prepared, the formulation and preparation method were the same as Example 1, the only difference was that "0.2wt% zinc butyl octyl dithiophosphate (T202)" was replaced by "0.2wt% sodium dodecyl benzene sulfonate".

[0099] Comparative Example 2

[0100] A foamed drilling fluid was prepared, the formulation and preparation method were the same as Example 1, the only difference was that "0.2wt% zinc butyl octyl dithiophosphate (T202)" was replaced by "0.1wt% zinc butyl octyl dithiophosphate (T202)".

[0101] Comparative Example 3

[0102] A foamed drilling fluid was prepared, the formulation and preparation method were the same as Example 1, the only difference was that "0.2wt% zinc butyl octyl dithiophosphate (T202)" was replaced by "1.0wt% zinc butyl octyl dithiophosphate (T202)".

[0103] Comparative Example 4

[0104] A foamed drilling fluid was prepared, the formulation and preparation method were the same as Example 4, the only difference was that "0.5wt% hydroxymethyl cellulose (HEC, molecular weight 900,000)" was replaced by "1.5wt% hydroxymethyl cellulose (HEC, molecular weight 900,000)".

[0105] Comparative Example 5

[0106] A foamed drilling fluid was prepared, the formulation and preparation method were the same as Example 4, the only difference was that "1.0wt% dibutyl phosphite" was replaced by "0.5wt% dibutyl phosphite".

[0107] Test Example 1

[0108] Drilling fluid foam half-life and basic performance test.

[0109] 500mL of the foamed drilling fluid prepared in Examples 1-5 and Comparative Examples 1-5 was immediately poured into 5 1000mL measuring cylinders, respectively, and the timing was started, and the foam half-life was recorded. Another 500mL of the foamed drilling fluid prepared in Examples 1-5 and Comparative Example 1 was immediately poured into a 1000mL measuring cylinder, and the timing was started, and the foam half-life was recorded. The rheological properties and extreme pressure lubrication properties of the foamed drilling fluid prepared in Examples 1-5 and Comparative Example 1 were determined according to GB 16783.1-2014 "Petroleum and Natural Gas Industry Drilling Fluids Field Test Part 1: Water-based Drilling Fluids". The same extreme pressure lubrication coefficient test was performed on clean water as a control, and the test results are shown in Table 1.

[0110] Table 1

[0111]

[0112] According to the test results in Table 1, the foam half-life of the solid-free low friction foam drilling fluid prepared in Examples 1-5 is more than 95 min, which is obviously higher than that of the drilling fluids in Comparative Examples 1 and 2, indicating that the solid-free low friction foam drilling fluid of the present application has good foam stability. The foam half-life of the drilling fluid in Comparative Example 3 is not obviously increased, although the amount of the foaming agent is 1.0 wt%. The drilling fluid prepared in Examples 1-5 has suitable rheological properties, while the viscosity of the drilling fluid in Comparative Example 4 is too high and the shear force is too large, because the amount of the thickening agent HEC is 1.5 wt%. The solid-free low friction foam drilling fluid prepared in Examples 1-5 greatly reduces the lubrication coefficient of the drilling fluid, reduces the frictional resistance of the drilling fluid, and improves the lubricity of the drilling fluid. Compared with Comparative Example 1, the foaming agent sodium dodecyl benzene sulfonate in Comparative Example 1 does not have synergistic effect with trimethyl phosphate, and the lubricity is greatly reduced. Compared with Comparative Example 5, when the amount of dibutyl phosphite is reduced to 0.5 wt%, the synergistic effect with other treatment agents is also reduced, and the lubricity is poor.

[0113] Test Example 2

[0114] Temperature resistance test of the drilling fluid.

[0115] The foam drilling fluids prepared in Examples 1-5 and Comparative Examples 1-5 were taken and placed in an aging tank, and after constant temperature rolling at 120℃ for 16 h, the foam drilling fluids were taken out, cooled to room temperature, and stirred at high speed for 2 min at 11000 r / min, and then the basic properties and rheological properties of the foam drilling fluids were determined. The same extreme pressure lubrication coefficient test was performed on water as a control, and the test results are shown in Table 2.

[0116] Table 2

[0117]

[0118] According to the test results in Table 2, after the foam drilling fluids prepared in Examples 1-5 were aged at 120℃ for 16 h, the half-life and viscosity were slightly reduced, but the lubricity of the drilling fluid was improved, indicating that the solid-free low friction foam drilling fluid of the present application has good temperature resistance, and can still stably maintain the foam half-life, rheological properties and lubricity after high temperature aging.

[0119] In summary, the solid-free low friction foam drilling fluid provided by the present application uses ZDDP as a foaming agent, which improves the foam stability and lubricity of the drilling fluid, and reduces the friction of the drilling fluid.

[0120] The above only describes the preferred examples of the present application. It should be noted that for those skilled in the art, under the technical inspiration provided by the present application, other equivalent variants and improvements as common knowledge in the art can also be made, and should be considered as the protection scope of the present application.

Claims

1. A solid-free low friction foamed drilling fluid, comprising water, a foaming agent, a viscosifier, a lubricant, a fluid loss additive, and a foam stabilizer; the foaming agent is zinc dialkyldithiophosphate, and the molecular formula is shown as formula (1) : R 1-S-S-R 2 (1) wherein R 1 and R 2 are the same or different, and each is selected from at least one of C 1-C 8 alkyl; wherein the solid-free low friction foamed drilling fluid comprises, by weight of water, 0.2 wt%-0.5 wt% of the foaming agent, 0.5 wt%-1.0 wt% of the viscosifier, 1.0 wt%-3.0 wt% of the lubricant, 0.2 wt%-0.5 wt% of the foam stabilizer, and 1.5 wt%-3.0 wt% of the fluid loss additive; the lubricant is a phosphate ester lubricant. R 1 and R 2 are each selected from at least one of methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, and octyl.

2. The drilling fluid of claim 1, wherein, the foaming agent is at least one of zinc butyloctyl dithiophosphate, zinc dioctyl dithiophosphate, zinc butylhexyl dithiophosphate, zinc isopropyl isooctyl dithiophosphate, and zinc di-sec-pentyl dithiophosphate.

3. The drilling fluid of claim 1, wherein, the viscosifier is at least one of high viscosity carboxymethyl cellulose, biopolymer, high viscosity anionic cellulose, and hydroxyethyl cellulose.

4. The drilling fluid of any one of claims 1-3, wherein, the phosphate ester lubricant is at least one of trimethylphenyl phosphate and dibutyl phosphite.

5. The drilling fluid of any one of claims 1-3, wherein, the fluid loss additive is at least one of lignite resin, carboxymethyl starch, sulfonated phenol-formaldehyde resin, and sulfonate copolymer; and / or 6. The drilling fluid of any one of claims 1-3, wherein, the foam stabilizer is at least one of potassium silicate or sodium silicate. a pH regulator is further included.

7. The drilling fluid of any one of claims 1-3, wherein, the pH regulator is used to adjust the pH value of the drilling fluid to 8-10.

8. The drilling fluid of claim 7, wherein, the pH regulator is NaOH or KOH.

9. The drilling fluid of claim 7, wherein, a method for preparing the solid-free low friction foamed drilling fluid is provided, comprising mixing the foaming agent, the viscosifier, the lubricant, the fluid loss additive, the foam stabilizer, water, and the optional pH regulator.

10. A method of preparing the drilling fluid according to any one of claims 1 to 9, characterized in that, the mixing method specifically comprises sequentially adding the foaming agent, the viscosifier, the lubricant, the fluid loss additive, the foam stabilizer, and the optional pH regulator into water.

11. The method of claim 10, wherein, the mixing process is performed under stirring; and / or 12. The production method according to claim 10 or 11, characterized by, the stirring time is 1-5 min. the stirring rate is 10 000 r / min-12 000 r / min; and / or 13. The method of claim 12, wherein, the stirring time is 1-3 min. ​

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