Multi-effect reinforced high-performance water-based drilling fluid and preparation method thereof

Abstract

The invention relates to a multi-effect reinforced high-performance water-based drilling fluid. The drilling fluid is characterized by comprising the following components in percentage by weight: 0.3-5% of a high-temperature-resistant salt-resistant polymer filtrate reducer; 0.5-3% of a binary copolymerization low molecular weight polyamine inhibitor; 1-3% of a nano film-embedded emulsion lubricant; 2-5% of a nano polymer blocking agent; 1-4% of a bridging agent; 2-4% of bentonite; 5-10% of an inorganic salt; 0.1%-1% of a tackifier; 0.5-4% of polymeric alcohol; and the balance of water. The preparation method comprises the following steps: adding the high-temperature-resistant salt-resistant polymer filtrate reducer into pre-hydrated bentonite slurry, sequentially adding the tackifier and the inorganic salt, after the inorganic salt is dissolved, sequentially adding the remaining treating agent, and after one of the treating agents is fully dissolved or dispersed, adding the next one of the treating agents until the materials are uniformly mixed. The drilling fluid can meet the drilling requirement in a complex stratum, is excellent in comprehensive performance and wide in application range, and can replace an oil-based drilling fluid.

Description

Technical Field:

[0001] The present invention relates to the technical field of oilfield drilling, and particularly to a multi-effect enhanced high-performance water-based drilling fluid and a preparation method thereof, which are applicable to the horizontal well drilling of unconventional oil and gas reservoirs such as tight oil, tight gas and shale gas. Background Art:

[0002] In recent years, the exploration and development of unconventional oil and gas fields have developed rapidly, and the number of unconventional wells such as extended-reach horizontal wells and tight oil horizontal wells has also increased significantly. Moreover, the occurrence of complex accidents during the drilling process of these complex-structured wells has become increasingly prominent. Among them, wellbore stability, wellbore cleaning and lubrication and sticking prevention are the main technical difficulties faced in the drilling construction of complex-structured wells. Especially when drilling through formations with high content of strongly water-sensitive mud shale, large changes in formation pressure, relatively developed fractures and relatively complex lithology, when using a drilling fluid system added with traditional inhibitors such as KCl, sulfonated asphalt, potassium humate and various quaternary ammonium salts, problems such as lost circulation, collapse, and hole shrinkage often occur due to insufficient inhibition, resulting in problems such as bit balling, sticking, and poor cementing quality, greatly increasing the drilling complexity rate, extending the drilling cycle, increasing the construction difficulty, and raising the drilling cost. Therefore, the performance requirements for the drilling fluid also need to be further improved.

[0003] Especially in the upper formation of the northern Songliao Basin in China, the content of clay minerals is relatively high, mainly montmorillonite, illite and illite / smectite mixed layer, and microfractures are extremely developed. During the construction of horizontal wells and extended-reach wells, problems such as hole shrinkage, spalling and falling of wellbore wall, collapse, bit balling, and sticking often occur. It is difficult to control the comprehensive performance of the drilling fluid, and the drilling construction difficulty is further increased. In foreign countries, such as the Rumaila Oilfield in Iraq, the formation shale is well-developed, with strong sludging property, and the formation fluid has a high salt content, which is easy to pollute the drilling fluid and cause downhole complexity.

[0004] At present, various inhibitory water-based drilling fluids have been formed at home and abroad, such as polyamine drilling fluid, silicate drilling fluid, potassium-calcium-based drilling fluid, organic salt drilling fluid, cationic polymer drilling fluid and polyalcohol drilling fluid, etc. These drilling fluids can all effectively inhibit the hydration swelling of mud shale in conventional wells, but when drilling in large sections of strongly water-sensitive mud shale formations, they often show insufficient inhibition, and wellbore instability still occurs. Therefore, the existing inhibitory drilling fluid systems still have certain limitations, usually manifested in poor comprehensive performance, unable to combine multiple performances such as inhibition, plugging, lubrication, and salt resistance. Many complex-structured wells still rely on oil-based drilling fluid for drilling construction. Although the oil-based drilling fluid has stable performance and good lubricity and can effectively solve the problem of wellbore instability caused by the easy hydration swelling of mud shale, it has defects such as high cost, great environmental protection pressure, and poor safety. Therefore, in order to better meet the needs of drilling in complex formations, it is necessary to study a high-performance water-based drilling fluid system with excellent comprehensive performance, wide application range and capable of replacing oil-based drilling fluid. Summary of the Invention:

[0005] The object of the present invention is to overcome the problems existing in the background art, and to provide a multi-effect enhanced high-performance water-based drilling fluid. This multi-effect enhanced high-performance water-based drilling fluid can meet the requirements of drilling in complex formations, has excellent comprehensive performance, a wide range of applications, and can replace oil-based drilling fluids. The present invention also provides a preparation method for the multi-effect enhanced high-performance water-based drilling fluid.

[0006] To achieve the above object, in the first aspect of the present invention, a multi-effect enhanced high-performance water-based drilling fluid is provided, and the components and their ratios are as follows by weight percentage: 0.3-5% of a high-temperature and high-salt resistant polymer filtration reducer; 0.5-3% of a binary copolymer low-molecular-weight polyamine inhibitor; 1-3% of a nano-embedded film emulsifying lubricant; 2-5% of a nano-polymer plugging agent; 1-4% of a bridging agent; 2-4% of bentonite; 5-10% of inorganic salts; 0.1%-1% of a viscosifier; 0.5-4% of polyhydric alcohol; and the balance is water.

[0007] Preferably, the high-temperature and high-salt resistant polymer filtration reducer is a carboxyhydroxyalkene copolymer Redu200.

[0008] Preferably, the preparation method of the binary copolymer low-molecular-weight polyamine inhibitor can be found in the invention patent ZL 2019 11378233.4.

[0009] Preferably, the preparation method of the nano-embedded film emulsifying lubricant can be found in the invention patent ZL 2013 1 0342598.8.

[0010] Preferably, the viscosifier is an XC biopolymer.

[0011] Preferably, the bridging agent is a sulfonated asphalt-based plugging agent FT-Ⅰ.

[0012] Preferably, the nano-polymer plugging agent is an emulsion-type nano-polymer plugging agent SFD-Ⅰ with a particle size distribution of 50nm-200nm.

[0013] Preferably, the polyhydric alcohol is a solid polyhydric alcohol PGCS-Ⅰ.

[0014] Preferably, the inorganic salt is potassium chloride.

[0015] In the second aspect of the present invention, a preparation method for the multi-effect enhanced high-performance water-based drilling fluid is provided, including the following steps:

[0016] Weigh the amounts of each component of the reaction proportionally; add bentonite into water, and use a high-speed stirrer to stir at 8000 rpm for 20 min. After ensuring that the bentonite is fully dispersed, conduct pre-hydration treatment at room temperature for 24 hours; slowly add the high-temperature and high-salt resistant polymer filtrate reducer into the pre-hydrated bentonite slurry at a rotation speed of 8000 rpm, and stir for 20 min to ensure no caking or wall sticking; add a viscosifier, fully stir and disperse it evenly, then add the inorganic salt potassium chloride. After the inorganic salt is stirred and dissolved, slowly add the binary copolymer low-molecular-weight polyamine inhibitor, nano-embedded film emulsified lubricant, bridging agent, nano-polymer plugging agent, and polyalcohol in sequence. All the above treatment agents are stirred at 8000 rpm. When one treatment agent is fully dissolved or dispersed, then add the next treatment agent until all are added and mixed evenly.

[0017] Compared with the above-mentioned background technology, the present invention may have the following beneficial effects:

[0018] 1). The drilling fluid system of the present invention takes the binary copolymer low-molecular-weight polyamine inhibitor as the core. By utilizing the adsorption effect of the amino group, it tightly binds to the clay layer, inhibits the clay from adsorbing water, and weakens the hydration effect; introducing the inorganic salt potassium chloride, with the help of its inlay inhibition effect, together with the binary copolymer low-molecular-weight polyamine inhibitor, realizes the synergistic inhibition of the drilling fluid, improves the inhibition ability for shale, and can meet the strong inhibition requirements of the drilling fluid for safe drilling in large sections of shale and strongly water-sensitive formations.

[0019] 2). The present invention uses a high-temperature and high-salt resistant polymer filtrate reducer to solve the problem that clay particles are prone to thickening under high-salt conditions in the brine system. This filtrate reducer is a medium- and low-molecular-weight polymer filtrate reducer, which plays a protective role for clay particles through the adsorption effect of the amide group and the adsorption solvation water film formed by the hydration of the polymer group, and further improves the stability of the drilling fluid system.

[0020] 3). The present invention realizes the effective plugging of micro-fractures with a slit width of 10 - 200 μm by using the cloud point effect of alcohol materials in cooperation with rigid nano- and micro-meter materials and deformable materials to form a synergistic plugging. And a micro-fracture plugging evaluation method is established for the nano-plugging material, which can simulate the morphology of nano- and micro-meter scale fractures in hard and brittle formations, improve the accuracy of plugging experiment data, and further conduct better qualitative and quantitative evaluations on the plugging materials.

[0021] 4). The lubricant adopted in the present invention is a nano-embedded film emulsified lubricant, which can reduce the extreme pressure lubrication coefficient by more than 80%, and can effectively solve the problems of large friction and easy pipe sticking in long horizontal sections and large-displacement horizontal wells.

[0022] 5). The drilling fluid of the present invention integrates various excellent performances such as inhibiting shale hydration, stabilizing the drilling fluid system, plugging micro-fractures, lubricating and preventing sticking, etc., and can achieve the purpose of replacing oil-based drilling fluid for safe construction in the drilling of complex structure wells. Specific implementation mode:

[0023] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods.

[0024] Unless otherwise specified, the materials, reagents, etc. used in the following examples can all be obtained through commercial channels.

[0025] A multi-effect enhanced high-performance water-based drilling fluid, and the components and their ratios are as follows by weight percentage: high-temperature and salt-resistant polymer filtration reducer 0.3-5%; binary copolymer low-molecular-weight polyamine inhibitor 0.5-3%; nano-embedded film emulsified lubricant 1-3%; nano-polymer plugging agent 2-5%; bridging agent 1-4%; bentonite 2-4%; inorganic salt 5-10%; viscosifier 0.1%-1%; polyhydric alcohol 0.5-4%; the balance is water.

[0026] The high-temperature and salt-resistant polymer filtration reducer is carboxyhydroxyalkene copolymer Redu200; for the preparation method of the binary copolymer low-molecular-weight polyamine inhibitor, see invention patent ZL 2019 1 1378233.4; for the preparation method of the nano-embedded film emulsified lubricant, see invention patent ZL 2013 1 0342598.8.

[0027] The viscosifier is XC biopolymer; the bridging agent is sulfonated asphalt-based plugging agent FT-Ⅰ.

[0028] The nano-polymer plugging agent is emulsion-type nano-polymer plugging agent SFD-Ⅰ with a particle size distribution of 50nm-200nm; the polyhydric alcohol is solid polyhydric alcohol PGCS-Ⅰ; the inorganic salt is potassium chloride.

[0029] A preparation method of a multi-effect enhanced high-performance water-based drilling fluid includes the following steps:

[0030] Weigh the amounts of the reaction components in proportion; add bentonite to water, and use a high-speed stirrer to stir at 8000 rpm for 20 min. After ensuring that the bentonite is fully dispersed, conduct pre-hydration treatment at room temperature for 24 hours; slowly add the high-temperature and salt-resistant polymer filtration reducer to the pre-hydrated bentonite slurry at a rotation speed of 8000 rpm, and stir for 20 min to ensure no caking or sticking to the wall; add the viscosifier, stir evenly and disperse fully, then add potassium chloride as the inorganic salt. After the inorganic salt is stirred and dissolved, sequentially and slowly add the binary copolymer low-molecular-weight polyamine inhibitor, nano-embedded film emulsified lubricant, bridging agent, nano-polymer plugging agent, and polyhydric alcohol. All the above treatment agents are stirred at 8000 rpm. When one treatment agent is fully dissolved or dispersed, then add the next treatment agent until all are added and mixed evenly.

[0031] The following further illustrates the present invention with specific examples.

[0032] Prepare a drilling fluid system in accordance with the conventional method for preparing water-based drilling fluids. The examples are as follows:

[0033] Example 1

[0034] Prepare the multi-effect enhanced high-performance water-based drilling fluid DQFI from the following components

[0035] 4% bentonite + 2% high-temperature and high-salt resistant polymer filtrate reducer + 0.5% viscosifier XC + 10% potassium chloride + 2% binary copolymer low-molecular-weight polyamine inhibitor + 1% nano-embedded film emulsifying lubricant + 3% bridging agent FT-I + 2% nano-polymer plugging agent SFD-I + 2% polyhydric alcohol.

[0036] Among them: the bentonite is the bentonite for preparing drilling fluid for testing required by the petroleum and natural gas industry standard SY / T 5490-2016 "Soil for Drilling Fluid Tests" of China National Petroleum Corporation;

[0037] The high-temperature and high-salt resistant polymer filtrate reducer is the carboxyhydroxyalkene copolymer Redu200 produced by Beijing Peikang Jiaye Technology Development Co., Ltd.;

[0038] The binary copolymer low-molecular-weight polyamine inhibitor is prepared according to the preparation method described in the invention patent ZL 2019 11378233.4;

[0039] The viscosifier is the XC biopolymer - xanthan gum series produced by Renqiu City Runde Chemical Industry Co., Ltd.;

[0040] The nano-embedded film emulsifying lubricant is a fatty alcohol derivative, and the preparation method is described in the invention patent ZL 2013 10342598.8;

[0041] The nano-polymer plugging agent is the emulsion-type nano-polymer plugging agent SFD-I with a particle size distribution of 50nm - 200nm produced by Heilongjiang Yirui Chemical Industry Co., Ltd.;

[0042] The bridging agent is the sulfonated asphalt-based plugging agent FT-I produced by the No. 7 Chemical Industry Co., Ltd. of Xinxiang City, Henan Province;

[0043] The polyhydric alcohol is the solid polyhydric alcohol PGCS-I produced by Beijing Peikang Jiaye Technology Development Co., Ltd.;

[0044] The preparation method of the multi-effect enhanced high-performance water-based drilling fluid DQFI is as follows: Weigh bentonite at 4% by mass percentage and add it to water. Use a high-speed stirrer to stir at 8000 rpm for 20 min. After ensuring that the bentonite is fully dispersed, conduct pre-hydration treatment at room temperature for 24 hours. Weigh the high-temperature and high-salt resistant polymer filtrate reducer Redu200 at 2% by mass percentage and slowly add it to the pre-hydrated bentonite slurry at a rotation speed of 8000 rpm, and stir for 20 min to ensure no lumping or sticking to the wall. Then add 0.5% by mass percentage of the viscosifier XC. After fully stirring and uniformly dispersing, add 10% of the inorganic salt potassium chloride. After the inorganic salt is stirred and dissolved, sequentially add 2% by mass percentage of the binary copolymer low-molecular-weight polyamine inhibitor, 1% by mass percentage of the nano-embedded film emulsified lubricant, 3% by mass percentage of the bridging agent FT-I, 2% by mass percentage of the nano-polymer plugging agent SFD-I, and 2% by mass percentage of the polyhydric alcohol PGCS-I at the component ratio. All the above treatment agents are stirred at 8000 rpm. When one treatment agent is fully dissolved or dispersed, then add the next treatment agent until all are added and mixed evenly.

[0045] Comparative Example 1

[0046] Prepare a cationic polymer drilling fluid from the following components

[0047] 3% bentonite + 0.6% polyamine + 0.2% cationic polyacrylamide + 0.5% cationic starch + 5% cationic glycoside + 0.2% xanthan gum.

[0048] Comparative Example 2

[0049] Prepare a potassium silicate polyhydric alcohol water-based drilling fluid from the following components

[0050] 4% bentonite + 4% potassium silicate FP-V + 0.6% viscosifier HV-CMC + 0.4% filtrate reducer + 2% polyhydric alcohol + 3% KCl + 4% NaOH.

[0051] Comparative Example 3

[0052] Prepare a polyamine drilling fluid from the following components

[0053] 3% bentonite + 0.6% polyamine + 2% sulfonated phenolic resin SMP-1 + 0.8% hydrolyzed polyacrylonitrile potassium salt KHPAN + 2% zwitterionic polymer + 2.5% polyacrylamide + 3% modified asphalt + 0.2% xanthan gum + 0.5% polyhydric alcohol.

[0054] Test the basic performance parameters of the products in the above examples and comparative examples, and the test results are shown in Table 1.

[0055] Table 1

[0056]

[0057] As can be seen from Table 1, before and after hot rolling at 120°C, the rheological parameters of the multi-effect enhanced high-performance water-based drilling fluid DQFI, such as apparent viscosity, plastic viscosity, dynamic / static shear force, etc., are stable, and the API filtration loss < 2 mL. It has better rheological stability and filtration wall-building property compared with the other three drilling fluid systems such as cationic polymers.

[0058] I. Performance evaluation of the multi-effect enhanced high-performance water-based drilling fluid of the present invention

[0059] 1. Inhibiting property evaluation

[0060] Prepare an oil-based drilling fluid: The oil-based drilling fluid is prepared from the following components and ratios:

[0061] 80% diesel + 3% main emulsifier + 1% auxiliary emulsifier + 5% organophilic clay + 4% water-in-oil filtration reducer + 3% water-in-oil plugging agent + 20% CaCI2(30%) + 4% CaO + 3% non-permeable plugging agent + 0.2% KOH.

[0062] Test the rolling recovery rate of shale, conduct an inhibiting property evaluation. By adding 20 g of shale cuttings with a mesh size of 6 - 10 to the drilling fluid, hot roll in an aging tank (about 350 mL) at 120°C for 16 h, then recover the cuttings with a 40-mesh sieve, wash, dry, and weigh. The ratio of the weight of the recovered cuttings to the weight of the initial cuttings is the cuttings recovery rate. The higher the recovery rate, the stronger the inhibiting property of the drilling fluid and the lower the dispersion degree of the cuttings. The experimental test results are shown in Table 2.

[0063] Table 2

[0064] Drilling fluid system Rolling recovery rate Multi-effect enhanced high-performance water-based drilling fluid DQFI 96.8％ Oil-based drilling fluid 98.6％ Clear water 38.5％

[0065] As can be seen from Table 2, the rolling recovery rate of the multi-effect enhanced high-performance water-based drilling fluid DQFI is as high as 96.8%, far higher than that of clear water (38.5%), and close to that of the oil-based drilling fluid, indicating that the multi-effect enhanced high-performance water-based drilling fluid DQFI has excellent inhibiting performance and is close to that of the oil-based drilling fluid.

[0066] 2. Lubricity evaluation

[0067] The experimental test results of the lubricity are shown in Table 3 below.

[0068] Table 3

[0069]

[0070] As can be seen from Table 3, both the extreme pressure lubrication coefficient and the mud cake viscosity coefficient of the multi-effect enhanced high-performance water-based drilling fluid DQFI are < 0.1, indicating that it has good lubricity and can reduce the frictional resistance between the drill string and the wellbore wall.

[0071] 3. Plugging Evaluation

[0072] First, prepare potassium chloride polysulfonate drilling fluid:

[0073] Prepare potassium chloride polysulfonate drilling fluid from the following components:

[0074] 3% bentonite + 0.5% macromolecular coating agent PAC-141 + 1% SK-2 + 7% KCl + 3% SMP + 1% XY-27 + 3% sulfonated asphalt + 0.3% KOH.

[0075] Use a non-permeable drilling fluid filter loss instrument for plugging evaluation. Pour 500 mL of drilling fluid into a cylindrical transparent drilling fluid cup filled with 20 - 40 mesh and 40 - 60 mesh quartz sand, and test the penetration of the drilling fluid at 0.69 MPa. The lower the penetration intrusion depth of the sand bed, the higher the plugging performance. The test results of the plugging experiment are shown in Table 4.

[0076] Table 4:

[0077]

[0078] As can be seen from Table 4, the penetration depth of the multi-effect enhanced high-performance water-based drilling fluid DQFI into the 20 - 40 mesh sand bed is 4.2 cm, and the penetration depth into the 40 - 60 mesh sand bed is 2.3 cm. Its plugging performance is better than that of potassium chloride polysulfonate drilling fluid, indicating that it has good plugging effect.

[0079] II. Field Application of the Multi-Effect Enhanced High-Performance Water-Based Drilling Fluid of the Present Invention

[0080] The present invention has been popularized and applied in more than 200 wells in the tight oil horizontal wells of Daqing Oilfield and Rumaila Oilfield, creating an accumulated economic benefit of more than 200 million yuan.

[0081] The multi-effect enhanced high-performance water-based drilling fluid DQFI of the present invention has been popularized and applied in the Rumaila Oilfield in Iraq, improving the inhibition of shale formations and the anti-pollution ability of formation water in this area, reducing the complex time rate, shortening the drilling cycle, and achieving remarkable results. It has realized that no short trips (10-15 drill strings) are required in the first spud, no reaming is needed by pulling out and running in the whole string, and the casing cementing operation can be directly carried out after pulling out the drill string after drilling completion, saving an average of 0.5 days. It has realized that no short trips (10-15 drill strings) are required in the second spud, no reaming is needed by pulling out and running in the whole string, and the logging, casing running, and cementing operations can be directly carried out after pulling out the drill string after drilling completion, saving an average of 1.6 days. It has realized that no short trips (10-15 drill strings) are required in the third spud. After the third spud is completed, the drill string is pulled up to the bottom of the technical casing. After pulling out all the drill strings, the logging, casing running, and cementing operations can be directly carried out, saving 2 times of pulling out and running in the whole string and 4-5 times of short trips (10-15 drill strings), saving a total of 3.3 days. At the same time, the good drilling fluid performance has greatly reduced the occurrence of downhole complications, indirectly saving a large amount of time and cost. In the construction of Well R-682, a new record of 20.73 days for the drilling and completion cycle was created.

[0082] The multi-effect enhanced high-performance water-based drilling fluid DQFI of the present invention has been popularized and applied to 142 horizontal wells in tight oil blocks such as F198 and YH1 in the Daqing Oilfield on a large scale. The on-site construction was carried out smoothly without any complications. Compared with conventional water-based drilling fluids, this system has remarkable effects in stabilizing the wellbore, preventing bit balling, preventing pipe sticking, and improving cementing quality. This technology has achieved many good results, such as the longest horizontal section of 2033 meters drilled with water-based drilling fluid in tight oil horizontal wells, the longest footage of 3375 meters in the shale open hole section of horizontal wells, and the highest excellent rate of 91.62% in the cementing of the horizontal section of tight oil horizontal wells.

[0083] The multi-effect enhanced high-performance water-based drilling fluid DQFI of the present invention has the advantages of strong temperature and salt resistance, stable rheology, outstanding wellbore stability ability, good effect in preventing bit balling and pipe sticking, and is beneficial to improving cementing quality. It can meet the drilling requirements of conventional horizontal wells, as well as unconventional wells such as tight oil horizontal wells and shale gas wells, solving the problems of high cost and poor environmental protection of oil-based drilling fluids, and having broad application prospects.

[0084] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of them. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention. Although the specific implementation manners of the present invention have been described above, it does not limit the protection scope of the present invention. Those skilled in the art should understand that various modifications or deformations that can be made without creative labor on the basis of the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A multi-effect enhanced high-performance water-based drilling fluid, characterized in that: The components and their proportions are as follows by weight percentage: high-temperature and salt-resistant polymer filtration loss reducer 0.3 - 5%; binary copolymer low-molecular-weight polyamine inhibitor 0.5 - 3%; nano-embedded film emulsified lubricant 1 - 3%; nano-polymer plugging agent 2 - 5%; bridging agent 1 - 4%; bentonite 2 - 4%; inorganic salt 5 - 10%; viscosifier 0.1% - 1%; polyhydric alcohol 0.5 - 4%; and the balance is water.

2. The poly-effect enhanced high-performance water-based drilling fluid according to claim 1, characterized in that: The high-temperature and salt-resistant polymer filtration loss reducer is carboxyhydroxyalkene copolymer Redu200.

3. A multi-effect enhanced high-performance water-based drilling fluid according to claim 1, characterized in that: For the preparation method of the binary copolymer low-molecular-weight polyamine inhibitor, see the invention patent ZL 2019 1 1378233.

4.

4. A multi-effect enhanced high-performance water-based drilling fluid according to claim 1, characterized in that: For the preparation method of the nano-embedded film emulsified lubricant, see the invention patent ZL 2013 1 0342598.

8.

5. The multi-effect enhanced high-performance water-based drilling fluid according to claim 1, wherein: The viscosifier is XC biopolymer.

6. The multi-effect enhanced high-performance water-based drilling fluid according to claim 1, wherein: The bridging agent is sulfonated asphalt plugging agent FT-Ⅰ.

7. The multi-effect enhanced high-performance water-based drilling fluid according to claim 1, characterized in that: The nano-polymer plugging agent is emulsion-type nano-polymer plugging agent SFD-Ⅰ with a particle size distribution of 50nm - 200nm.

8. A multi-effect enhanced high-performance water-based drilling fluid according to claim 1, characterized in that: The polyhydric alcohol is solid polyhydric alcohol PGCS-Ⅰ.

9. The multi-effect enhanced high-performance water-based drilling fluid according to claim 1, wherein: The inorganic salt is potassium chloride.

10. A method for preparing a multi-effect enhanced high-performance water-based drilling fluid according to any one of claims 1 to 9, characterized in that: It includes the following steps: Weigh the amounts of the reaction components in proportion; add bentonite to water, and use a high-speed stirrer to stir at 8000 rpm for 20 min. After ensuring that the bentonite is fully dispersed, conduct pre-hydration treatment at room temperature for 24 hours; slowly add the high-temperature and salt-resistant polymer filtration loss reducer to the pre-hydrated bentonite slurry at a rotation speed of 8000 rpm, and stir for 20 min to ensure no caking or wall sticking; add the viscosifier, stir evenly and disperse fully, then add the inorganic salt potassium chloride. After the inorganic salt is stirred and dissolved, sequentially and slowly add the binary copolymer low-molecular-weight polyamine inhibitor, nano-embedded film emulsified lubricant, bridging agent, nano-polymer plugging agent, and polyhydric alcohol. All the above treating agents are stirred at 8000 rpm. When one treating agent is fully dissolved or dispersed, then add the next treating agent until all are added and mixed evenly.

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