Water-based drilling fluid, preparation method thereof and horizontal well drilling construction method

Abstract

The application provides a water-based drilling fluid, a preparation method thereof and a horizontal well drilling construction method. The water-based drilling fluid comprises 1.0-3.0% of a shielding temporary plugging agent, 2.0-3.0% of an inert particle plugging agent, 1.0-5.0% of a deformable polymer plugging agent, 1.0-3.0% of an organic amine anti-sloughing agent, 2.0-5.0% of a solid lubricant, 3.0-5.0% of a liquid lubricant, 1.0-3.0% of a anti-mud ball cleaning agent, 10-25% of inorganic salts and organic salts, 0.1-0.5% of an alkali substance, 1.0-4.0% of a fluid loss additive, 0.2-0.5% of a flow type regulator, a weighting agent and clean water, with the total weight of the clean water being 100%. The water-based drilling fluid has excellent plugging, anti-sloughing, lubricating, fluid loss reducing and rheological properties and has a good effect on preventing and plugging leakage.

Description

Technical Field

[0001] This invention relates to a water-based drilling fluid and its preparation method, as well as a horizontal well drilling method, belonging to the field of oil and gas extraction technology, and more specifically to the field of drilling fluid technology used in the oil and gas extraction process. Background Technology

[0002] With the large-scale construction of shale gas horizontal wells, the application of oil-based drilling fluids is becoming increasingly widespread. Compared with traditional water-based drilling fluids, oil-based drilling fluids are widely used in shale gas drilling due to their superior inhibition, lubrication, and rheological properties. However, oil-based drilling fluids generally pose significant environmental risks, involve complex cuttings treatment, and have high operating costs. Compared to oil-based drilling fluids, water-based drilling fluids offer advantages such as lower pollution and lower cost. In recent years, shale gas horizontal wells have become increasingly deeper, drawing attention to deep shale gas resources.

[0003] Shale gas horizontal wells with a vertical depth of less than 3500m are generally referred to as deep shale gas horizontal wells. Compared with conventional shale gas horizontal wells, deep shale gas horizontal wells have higher requirements for drilling fluids, and the key is to ensure wellbore stability, lubrication, anti-sticking, and leak prevention and plugging.

[0004] Compared to oil-based drilling fluids, water-based drilling fluids have weaker anti-collapse properties. Applying water-based drilling fluids to shale gas horizontal wells necessitates significantly enhancing their anti-collapse performance. For water-based drilling fluids, ensuring wellbore stability hinges on providing effective plugging capabilities. Based on past shale gas horizontal well drilling practices, conventional plugging agents (such as bituminous plugging agents) have large particle sizes, far exceeding the pore size of shale and mudstone, making it difficult to seal micropores and microfractures. This allows filtrate to enter the formation, causing wellbore instability. The presence of numerous high-angle fractures within shale and mudstone microfractures further exacerbates wellbore instability under stress. Therefore, wellbore collapse is a primary challenge that drilling fluids for deep shale gas horizontal wells need to address.

[0005] In the past, when wellbore instability occurred during shale gas horizontal well construction, the first approach was usually to increase the drilling fluid density. However, higher-density drilling fluids are more likely to penetrate formation micropores and microfractures, accelerating the formation of microfractures and leading to wellbore spalling, collapse, and instability. When the drilling fluid's plugging capacity is insufficient, a vicious cycle can easily occur: "wellbore instability → increased density → temporary stability → increased filtrate intrusion → worsening collapse." Consequently, the density of the drilling fluid used on-site increases, but wellbore stability deteriorates, resulting in prominent problems such as wellbore spalling and stuck pipe.

[0006] In summary, the following problems currently exist in the construction of shale gas horizontal wells and need to be overcome:

[0007] 1. Commonly used plugging agents have large particle sizes, while shale pores are mostly at the nanoscale. Conventional plugging agents used in the past had large particle sizes, much larger than the shale pore size, making it difficult to seal micropores and microcracks. This caused the filtrate to enter the formation, resulting in wellbore instability.

[0008] 2. In the past, the problem of wellbore instability during the construction of shale gas horizontal wells was solved by simply increasing the density of the drilling fluid. However, the higher density of the drilling fluid makes it easier to penetrate the formation micropores and microfractures, thereby accelerating the formation of formation microfractures and causing wellbore spalling and collapse.

[0009] 3. Deep shale has well-developed micro-fractures, which are often at both the nanometer and micrometer levels. Both types of micro-fractures can be encountered during horizontal well construction. If only nano-sealing agents are used, micrometer-level micro-fractures are difficult to seal effectively, leading to wellbore collapse.

[0010] 4. Deep shale gas horizontal wells have greater depths than conventional shale gas horizontal wells, resulting in higher friction and greater torque during drilling. While conventionally used solid lubricants are inexpensive, their lubrication effect is not ideal. Liquid lubricants often provide better lubrication, but their action time is shorter. Therefore, a single type of lubricant is insufficient to meet the requirements for lubrication and drag reduction.

[0011] 5. Deep shale is more prone to hydration and dispersion than conventional shale, and it absorbs water and expands, causing downhole complications.

[0012] 6. Deep shale gas horizontal wells often use rotary steerable tools for directional drilling. However, the small annular clearance of the rotary steerable tool and the small annular clearance between the drill string and the wellbore makes it difficult for conventional plugging materials to pass through these gaps in case of well leakage, making well leakage difficult to manage. Typically, it is necessary to trip the drill string to remove the rotary steerable tool and then run the drill string back down for pressure plugging. However, this operation is time-consuming and inefficient. Deep shale formations can collapse due to a decrease in drilling fluid column pressure caused by well leakage.

[0013] Therefore, providing a novel water-based drilling fluid and its preparation method, as well as a horizontal well drilling method, to enable the water-based drilling fluid to possess excellent plugging, lubrication, and inhibition properties, while also exhibiting good leakage prevention and plugging effects for deep shale wells, and meeting the high requirements of deep shale gas horizontal wells, shale oil horizontal wells, carbonaceous mudstone horizontal wells, coal-bearing formation horizontal wells, fractured zones, complex fault zones, and other formations for the plugging and anti-collapse performance of water-based drilling fluids, has become an urgent technical problem to be solved in this field. Summary of the Invention

[0014] In view of the problems often encountered in drilling horizontal wells for deep shale gas, such as well collapse, well leakage, and poor lubricity and insufficient inhibition of the drilling fluid used, one objective of the present invention is to provide a water-based drilling fluid.

[0015] Another object of the present invention is to provide a method for preparing the water-based drilling fluid described above.

[0016] Another object of the present invention is to provide a horizontal well drilling method that uses the water-based drilling fluid described above.

[0017] To achieve the above objectives, in one respect, the present invention provides a water-based drilling fluid, wherein, based on 100% of the total weight of clean water used in preparing the water-based drilling fluid, the water-based drilling fluid comprises:

[0018] 1.0-3.0% shielding and temporary plugging agent, 2.0-3.0% inert particulate plugging agent, 1.0-5.0% deformable polymer plugging agent, 1.0-3.0% organic amine inhibitor, 2.0-5.0% solid lubricant, 3.0-5.0% liquid lubricant, 1.0-3.0% anti-mud bag cleaner, 10-25% inorganic and organic salts, 0.1-0.5% alkaline substances, 1.0-4.0% filtration loss reducer, 0.2-0.5% flow pattern regulator, weighting agent, and water.

[0019] As a specific embodiment of the water-based drilling fluid described above in this invention, the water-based drilling fluid further includes a plugging agent.

[0020] In this invention, when well leakage occurs, a plugging agent needs to be added to the water-based drilling fluid.

[0021] As a specific embodiment of the water-based drilling fluid described above in this invention, the plugging agent comprises, based on 100% of the total weight of clean water used in preparing the water-based drilling fluid, the plugging agent includes:

[0022] Permeability-free treatment agent: 1.0-3.0%, wellbore film-forming agent: 1.0-2.0%, ultrafine calcium carbonate: 1.0-2.0%, graphite powder: 1.0-2.0%, mica powder: 1.0-2.0%, unidirectional pressure sealant: 1.0-2.0%, modified polymer fiber: 0.05-0.1%, deformable polymer plugging agent: 0.5-1.5%.

[0023] In one specific embodiment of the water-based drilling fluid described above in this invention, the ultrafine calcium carbonate has a mesh size of 1250 mesh.

[0024] In one specific embodiment of the water-based drilling fluid described above in this invention, the impermeable treatment agent includes powders whose main component is plant fiber. In some embodiments of this invention, the impermeable treatment agent may be, for example, impermeable treatment agent G362, manufactured by Xi'an Chuanqin Petroleum Technology Co., Ltd.

[0025] The non-permeable treatment agent used in this invention is used to prevent and plug leaks during the drilling of horizontal wells such as deep shale gas wells, thereby effectively reducing the consumption of water-based drilling fluid.

[0026] In some embodiments of the present invention, the deformable polymer plugging agent may be G308, a micro-crosslinked nano-deformable polymer plugging agent for drilling fluid, manufactured by Xi'an Chuanqin Petroleum Technology Co., Ltd.; the wellbore film-forming agent may be DF-NIN, manufactured by Jingzhou Xuecheng Co., Ltd.; the graphite powder may be SH-2, manufactured by Henan Jinma Co., Ltd.; the unidirectional pressure sealing agent may be DF-A, manufactured by Xi'an Tianzheng Co., Ltd.; and the modified polymer fiber may be CQ-SCF, manufactured by Xi'an Chuanqin Petroleum Technology Co., Ltd.

[0027] The plugging agent used in this invention is a plugging agent formulation that can be guided by a rotary tool. The modified polymer fibers and deformable polymer plugging agents contained in the plugging agent can significantly improve the plugging effect of the water-based drilling fluid.

[0028] As a specific embodiment of the water-based drilling fluid described above in this invention, the shielding and plugging agent is a micron-sized shielding and plugging agent with a size of 1-8 μm;

[0029] The inert particle plugging agent is a nano-sized inert particle plugging agent with a size of 10-300 nm;

[0030] The deformable polymer plugging agent is a nanoscale deformable polymer plugging agent with a size of 200-800 nm.

[0031] As a specific embodiment of the water-based drilling fluid described above in this invention, the shielding plugging agent includes drilling fluid shielding plugging agent G325 (whose main component is modified paraffin, such as emulsified paraffin), the inert particle plugging agent includes drilling fluid plugging agent G314, and the deformable polymer plugging agent includes drilling fluid micro-crosslinked nano-deformable polymer plugging agent G308, etc., all of which are manufactured by Xi'an Chuanqin Petroleum Technology Co., Ltd.

[0032] As a specific embodiment of the water-based drilling fluid described above in this invention, the organic amine-based anti-collapse agent includes one or a combination of several of polyether diamine, polyamine, polyhydroxyalkylammonium salt, and hexamethylenediamine. In some embodiments of this invention, the organic amine-based anti-collapse agent may be, for example, drilling fluid anti-collapse inhibitor G319, which is a mixture of polyether diamine and polyhydroxyalkylammonium salt, manufactured by Xi'an Chuanqin Petroleum Technology Co., Ltd.

[0033] As a specific embodiment of the water-based drilling fluid described above in this invention, the solid lubricant includes one or a combination of two of graphite powder and elastic graphite.

[0034] As a specific embodiment of the water-based drilling fluid described above in this invention, the liquid lubricant includes one or a combination of chemically modified vegetable oils and polymeric alcohols. In some embodiments of this invention, the liquid lubricant may be, for example, drilling fluid lubricant G316, manufactured by Xi'an Chuanqin Petroleum Technology Co., Ltd.

[0035] As a specific embodiment of the water-based drilling fluid described above in this invention, the anti-mud bag cleaner includes drilling fluid anti-mud bag cleaner G383, etc., which is manufactured by Xi'an Chuanqin Petroleum Technology Co., Ltd.

[0036] As a specific embodiment of the water-based drilling fluid described above in this invention, the inorganic salt includes one or a combination of potassium chloride, sodium chloride, potassium nitrate, etc., and the organic salt includes one or a combination of sodium acetate, sodium formate, potassium formate, etc.

[0037] The inorganic salts used in this invention are mainly used to improve the salinity of water-based drilling fluid, thereby improving its inhibition and anti-collapse performance. The organic salts are used to improve the temperature resistance of the entire water-based drilling fluid by improving the temperature resistance of the flow modifier in the water-based drilling fluid, thereby reducing the consumption of the flow modifier and lowering the cost of the water-based drilling fluid.

[0038] As a specific embodiment of the water-based drilling fluid described above in this invention, the alkaline substances include sodium hydroxide and / or potassium hydroxide, etc.

[0039] As a specific embodiment of the water-based drilling fluid described above in this invention, the filtration loss reducing agent includes drilling fluid anti-high temperature micro-nano filtration loss reducing agent G352, etc., which is manufactured by Xi'an Chuanqin Petroleum Technology Co., Ltd.

[0040] As a specific embodiment of the water-based drilling fluid described above in this invention, the flow pattern regulator includes one or a combination of several of xanthan gum, guar gum, guar gum, hydroxypropyl guar gum, hydroxypropyl guar gum, carboxymethyl guar gum, and carboxymethyl guar gum.

[0041] As a specific embodiment of the water-based drilling fluid described above in this invention, the amount of the weighting agent is determined according to the target density of the water-based drilling fluid, wherein the weighting agent includes one or a combination of several of barite, iron ore powder and limestone.

[0042] The G325, G314, G308, G319, G316, G383, G352 and G362 used in this invention are all commercially available conventional products.

[0043] On the other hand, the present invention also provides a method for preparing the water-based drilling fluid described above, wherein the preparation method includes:

[0044] Under high-speed stirring conditions, a shielding and plugging agent, an inert particle plugging agent, a deformable polymer plugging agent, an organic amine anti-collapse agent, a solid lubricant, a liquid lubricant, a mud-pack cleaner, inorganic and organic salts, alkaline substances, a filtration loss reducer, a flow pattern regulator, and a weighting agent are added to clean water according to the specified ratio. After stirring evenly, the water-based drilling fluid is obtained.

[0045] This invention does not impose specific requirements on the order of addition of each component in the preparation of water-based drilling fluid or the stirring speed of high-speed stirring, etc., which can be reasonably adjusted according to the actual needs of on-site operations.

[0046] In another aspect, the present invention also provides a horizontal well drilling construction method, wherein the horizontal well drilling construction method uses the water-based drilling fluid described above.

[0047] As a specific embodiment of the horizontal well drilling construction method described above in this invention, the horizontal well includes a deep shale gas horizontal well, a shale oil horizontal well, a carbonaceous mudstone horizontal well, a coal-bearing formation horizontal well, a fractured zone horizontal well, or a complex fault zone horizontal well.

[0048] Compared with existing technologies, the beneficial technical effects that the water-based drilling fluid provided by this invention can achieve include:

[0049] (1) The water-based drilling fluid provided by the present invention uses three different types of plugging agents, namely shielding temporary plugging agent, inert particle plugging agent and deformable polymer plugging agent. These three different types of plugging agents are not simply superimposed, but are specifically designed for the micro-fracture characteristics of different formations such as deep shale. The three have different functions and work closely together, so as to effectively solve the problem of collapse of formations such as deep shale.

[0050] Specifically, the inert particle plugging agent and the deformable polymer plugging agent are nano-scale inert particle plugging agent and nano-scale deformable polymer plugging agent, respectively, used to plug the large proportion of nano-scale microfractures in deep shale and other formations. During drilling, the nano-scale inert particle plugging agent in the water-based drilling fluid can quickly enter the formation fractures to form an inner plugging layer, rapidly reducing the intrusion of filtrate into the rock formation. Based on the inner plugging layer formed by the nano-scale inert particle plugging agent, the nano-scale deformable polymer plugging agent itself undergoes micro-crosslinking and deformable plugging under certain temperature conditions to form an outer plugging layer, enhancing the plugging strength and strengthening the plugging effect. By utilizing the time difference between the action of the nano-scale inert particle plugging agent and the nano-scale deformable polymer plugging agent, two different plugging layers can be formed. The nano-scale inert particle plugging agent forms the inner plugging layer through the accumulation effect, with rapid plugging effect, mainly through physical action. The nano-scale deformable polymer plugging agent forms the outer plugging layer through micro-crosslinking, which takes slightly longer but has high plugging strength, mainly through chemical action. Micron-level shielding and temporary plugging agents are mainly used to seal micron-level cracks in deep shale and other strata.

[0051] As shown above, the three different types of plugging agents used in water-based drilling fluids have a synergistic effect, which effectively improves the plugging performance of water-based drilling fluids, especially their plugging performance on micro-fractures and micropores, reduces the permeability of the plugging layer, and thus improves the anti-collapse plugging performance of water-based drilling fluids. That is, it plays an anti-collapse role by effectively plugging micro-fractures and micropores, solving the problem of wellbore instability in shale gas and other horizontal wells with micro-fracture development that currently restricts the exploration and development of deep shale gas and other products, and meeting the needs of safe and rapid drilling of shale gas and other horizontal wells.

[0052] (2) Deep shale gas horizontal wells have greater depths than conventional shale gas horizontal wells, resulting in higher friction and torque during drilling. Solid lubricants used in water-based drilling fluids are low-cost but have unsatisfactory lubrication effects, while liquid lubricants have good lubrication effects but short action time. It is clear that a single type of lubricant is insufficient to meet the requirements for lubrication and drag reduction. Therefore, the water-based drilling fluid provided by this invention combines solid and liquid lubricants. The solid and liquid lubricants work together to give the water-based drilling fluid excellent lubrication and drag reduction properties, thereby significantly reducing torque and friction during drilling operations. This solves the problem of lubrication and drag reduction in long horizontal sections of deep shale gas horizontal wells, allowing for a significant extension of the horizontal section length to meet geological requirements.

[0053] (3) The water-based drilling fluid provided by the present invention uses three types of inhibitors: inorganic salts, organic salts and organic amines. The synergistic inhibitory effect of these three types of inhibitors can achieve a good inhibitory and anti-collapse effect, so that the water-based drilling fluid has excellent inhibitory performance, especially for deep shale and mudstone, limestone and coal seams that are often encountered in deep shale gas horizontal wells. It can effectively prevent mudstone and shale from absorbing water and swelling, hydration and dispersion, and reduce downhole complexity.

[0054] (4) When using the water-based drilling fluid provided by this invention for drilling deep shale gas and other horizontal wells, the well leakage problem in these wells can be solved. The drilling process is simple to operate, has a short processing time, is quick to take effect, and provides good plugging performance, especially excellent plugging performance for micro-fractures. It can meet the plugging requirements of water-based drilling fluid for deep shale gas and other horizontal wells, effectively solving the well leakage problem that restricts the construction of deep shale gas and other horizontal wells. It can also avoid the collapse of deep shale formations caused by a decrease in the liquid column pressure of the water-based drilling fluid due to well leakage. It has low equipment requirements and does not require adjustment of the water-based drilling fluid system formula. Only the appropriate plugging material and concentration need to be selected according to the fracture conditions and leakage rate of the drilled formation. The target amount of plugging material can be directly added to the existing water-based drilling fluid system. Furthermore, during the drilling process, it is not necessary to trip the drill string to handle wells with a leakage rate of 10m / s. 3 This method can plug leaks of / h, replacing the previous process that required first pulling out the drill bit to remove the rotary guide tool and then drilling down to perform pressure plugging.

[0055] In summary, the water-based drilling fluid provided by this invention still exhibits excellent sealing and anti-collapse performance, inhibition performance, lubrication performance, filtration loss reduction performance, and rheological properties under conditions such as deep shale and carbonaceous mudstone with a vertical depth of less than 3500 meters and / or high temperature conditions. At the same time, it has a good anti-leakage and plugging effect on well leakage in deep shale and other formations. It can be applied to drilling operations in deep shale gas horizontal wells, shale oil horizontal wells, carbonaceous mudstone horizontal wells, coal-bearing formation horizontal wells, as well as horizontal wells encountering other easily collapsible formations, complex exploration wells, fracture zones, complex fault zones, and other formations where the sealing and anti-collapse performance of water-based drilling fluids is highly demanding. Attached Figure Description

[0056] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0057] Figure 1 This is a schematic diagram showing the comparison of the sealing performance of sample slurry 1 and base slurry 0-3 in Test Example 1 of the present invention.

[0058] Figures 2a-2b This is a schematic diagram of the dual-layer sealing mechanism of nanoscale inert particle plugging agent and nanoscale deformable polymer plugging agent used in the water-based drilling fluid provided in Embodiment 1 of the present invention.

[0059] Figures 3a-3b This is a schematic diagram showing the comparison of the ceramic filter cake of sample slurry 1 and base slurry 0 in Test Example 1 of the present invention.

[0060] Figure 4 This is a schematic diagram showing the comparison of the lubrication performance of sample slurry 1 and base slurry 14 in Test Example 2 of the present invention.

[0061] Figure 5 This is a schematic diagram showing the comparison of the on-site torque of sample slurry 1 and base slurry 14 in test example 2 of the present invention.

[0062] Figure 6 This is a schematic diagram showing the comparison of on-site friction resistance between sample slurry 1 and base slurry 14 in test example 2 of the present invention.

[0063] Figure 7 This is a schematic diagram showing the comparison of the linear expansion rates of sample slurry 2 and base slurry 21 in test example 3 of the present invention.

[0064] Figure 8 This is a schematic diagram showing the comparison of rock cuttings recovery rates between sample slurry 2 and base slurry 21 in test example 3 of the present invention.

[0065] Figure 9 This is a schematic diagram showing the comparison of the sealing leakage of sample slurry 3 and sample slurry 4 in test example 3 of the present invention.

[0066] Figure 10 This is a schematic diagram showing the comparison of water loss between sample slurry 3 and sample slurry 4 in test example 3 of the present invention. Detailed Implementation

[0067] It should be noted that the term "comprising" and any variations thereof in the specification, claims, and accompanying drawings of this invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0068] The "range" disclosed in this invention is given in the form of a lower limit and an upper limit. It can be one or more lower limits and one or more upper limits, respectively. A given range is defined by selecting a lower limit and an upper limit. The selected lower and upper limits define the boundaries of the particular range. All ranges defined in this way are composable, meaning that any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for specific parameters, it is also expected that ranges of 60-110 and 80-120 are also expected. Furthermore, if the listed minimum range values ​​are 1 and 2, and the listed maximum range values ​​are 3, 4, and 5, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5.

[0069] In this invention, unless otherwise specified, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this invention, and "0-5" is simply a shortened representation of these numerical combinations.

[0070] In this invention, unless otherwise specified, all embodiments and preferred embodiments mentioned in this invention can be combined with each other to form new technical solutions.

[0071] In this invention, unless otherwise specified, all technical features and preferred features mentioned in this invention can be combined with each other to form new technical solutions.

[0072] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying tables, drawings, and embodiments. The embodiments described below are some, but not all, embodiments of this invention, and are only used to illustrate the invention, and should not be considered as limiting the scope of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0073] Example 1

[0074] This embodiment provides a water-based drilling fluid, wherein, based on the total weight of clean water used in preparing the water-based drilling fluid as 100%, the water-based drilling fluid comprises:

[0075] Drilling fluid shielding and temporary plugging agent G325: 1.0%, drilling fluid plugging agent G314: 2.0%, drilling fluid micro-crosslinked nano-deformable polymer plugging agent G308: 3.0%;

[0076] Drilling fluid anti-collapse inhibitor G319: 1.0%, solid lubricant graphite powder: 2.0%, drilling fluid lubricant G316: 3.0%, drilling fluid anti-mud bag cleaner G383: 1.0%, potassium chloride: 5.0%, sodium formate: 5.0%, sodium hydroxide: 0.1%, drilling fluid high temperature resistant micro-nano filtration loss reducer G352: 1.0%, flow pattern regulator xanthan gum: 0.2%, barite: 5%, and water.

[0077] The water-based drilling fluid provided in this embodiment is prepared by a method including the following specific steps:

[0078] Under high-speed stirring conditions, drilling fluid shielding and plugging agent G325, drilling fluid plugging agent G314, drilling fluid micro-crosslinked nano-deformable polymer plugging agent G308, drilling fluid anti-collapse inhibitor G319, solid lubricant graphite powder, drilling fluid lubricant G316, drilling fluid anti-mud bag cleaner G383, potassium chloride, sodium formate, sodium hydroxide, well fluid high-temperature resistant micro-nano filtration loss reducer G352, flow pattern regulator xanthan gum and barite were added to clean water in sequence according to the formula. After stirring evenly, the water-based drilling fluid was prepared and denoted as sample slurry 1.

[0079] Comparative Example 1

[0080] This comparative example provides a blank water-based drilling fluid without the addition of three plugging agents: G325, G314, and G308. The blank water-based drilling fluid comprises, based on 100% of the total weight of clean water used in its preparation, the following components:

[0081] Drilling fluid anti-collapse inhibitor G319: 1.0%, solid lubricant graphite powder: 2.0%, drilling fluid lubricant G316: 3.0%, drilling fluid anti-mud bag cleaner G383: 1.0%, potassium chloride: 5.0%, sodium formate: 5.0%, sodium hydroxide: 0.1%, drilling fluid high temperature resistant micro-nano filtration loss reducer G352: 1.0%, flow pattern regulator xanthan gum: 0.2%, barite: 5%, and water.

[0082] The blank water-based drilling fluid provided in this comparative example was prepared by a method including the following specific steps:

[0083] Under high-speed stirring conditions, drilling fluid anti-collapse inhibitor G319, solid lubricant graphite powder, drilling fluid lubricant G316, drilling fluid anti-mud bag cleaner G383, potassium chloride, sodium formate, sodium hydroxide, well fluid anti-high temperature micro-nano filtration loss reducer G352, flow pattern regulator xanthan gum and barite are added to clean water in sequence according to the formula. After stirring evenly, the blank water-based drilling fluid is prepared and is denoted as base slurry 10.

[0084] Comparative Example 2

[0085] This comparative example provides a water-based drilling fluid containing only one sealing material, G325. The water-based drilling fluid comprises, based on 100% of the total weight of clean water used in its preparation, the following components:

[0086] Drilling fluid shielding and plugging agent G325: 1.0%, drilling fluid anti-collapse inhibitor G319: 1.0%, solid lubricant graphite powder: 2.0%, drilling fluid lubricant G316: 3.0%, drilling fluid anti-mud bag cleaner G383: 1.0%, potassium chloride: 5.0%, sodium formate: 5.0%, sodium hydroxide: 0.1%, drilling fluid high temperature resistant micro-nano filtration loss reducer G352: 1.0%, flow pattern regulator xanthan gum: 0.2%, barite: 5%, and water.

[0087] The water-based drilling fluid provided in this comparative example was prepared by a method including the following specific steps:

[0088] Under high-speed stirring conditions, drilling fluid shielding and plugging agent G325, drilling fluid anti-collapse inhibitor G319, solid lubricant graphite powder, drilling fluid lubricant G316, drilling fluid anti-mud bag cleaner G383, potassium chloride, sodium formate, sodium hydroxide, well fluid high-temperature resistant micro-nano filtration loss reducer G352, flow pattern regulator xanthan gum and barite are added to clean water in sequence according to the formula. After stirring evenly, the water-based drilling fluid is prepared and is referred to as base slurry 11.

[0089] Comparative Example 3

[0090] This comparative example provides a water-based drilling fluid containing only one sealing material, G314. The water-based drilling fluid comprises, based on 100% of the total weight of clean water used in its preparation, the following components:

[0091] Drilling fluid plugging agent G314: 2.0%, drilling fluid anti-collapse inhibitor G319: 1.0%, solid lubricant graphite powder: 2.0%, drilling fluid lubricant G316: 3.0%, drilling fluid anti-mud bag cleaner G383: 1.0%, potassium chloride: 5.0%, sodium formate: 5.0%, sodium hydroxide: 0.1%, drilling fluid high temperature resistant micro-nano filtration loss reducer G352: 1.0%, flow pattern regulator xanthan gum: 0.2%, barite: 5%, and water.

[0092] The water-based drilling fluid provided in this comparative example was prepared by a method including the following specific steps:

[0093] Under high-speed stirring conditions, drilling fluid plugging agent G314, drilling fluid anti-collapse inhibitor G319, solid lubricant graphite powder, drilling fluid lubricant G316, drilling fluid anti-mud bag cleaner G383, potassium chloride, sodium formate, sodium hydroxide, well fluid high-temperature resistant micro-nano filtration loss reducer G352, flow pattern regulator xanthan gum, and barite are added to clean water in sequence according to the formula. After stirring evenly, the water-based drilling fluid is prepared and is referred to as base slurry 12.

[0094] Comparative Example 4

[0095] This comparative example provides a water-based drilling fluid containing only one sealing material, G308. The water-based drilling fluid comprises, based on 100% of the total weight of clean water used in its preparation, the following components:

[0096] Drilling fluid micro-crosslinked nano-deformable polymer plugging agent G308: 3.0%, drilling fluid anti-collapse inhibitor G319: 1.0%, solid lubricant graphite powder: 2.0%, drilling fluid lubricant G316: 3.0%, drilling fluid anti-mud bag cleaner G383: 1.0%, potassium chloride: 5.0%, sodium formate: 5.0%, sodium hydroxide: 0.1%, drilling fluid high temperature resistant micro-nano filtration loss reducer G352: 1.0%, flow pattern regulator xanthan gum: 0.2%, barite: 5%, and water.

[0097] The water-based drilling fluid provided in this comparative example was prepared by a method including the following specific steps:

[0098] Under high-speed stirring conditions, drilling fluid micro-crosslinked nano-deformable polymer plugging agent G308, drilling fluid anti-collapse inhibitor G319, solid lubricant graphite powder, drilling fluid lubricant G316, drilling fluid anti-mud bag cleaner G383, potassium chloride, sodium formate, sodium hydroxide, well fluid high-temperature resistant micro-nano filtration loss reducer G352, flow pattern regulator xanthan gum and barite are added to clean water in sequence according to the formula. After stirring evenly, the water-based drilling fluid is prepared and is referred to as base slurry 13.

[0099] Comparative Example 5

[0100] This comparative example provides a water-based drilling fluid without the addition of solid and liquid lubricants, wherein, based on 100% of the total weight of clean water used in preparing the water-based drilling fluid, the water-based drilling fluid comprises:

[0101] Drilling fluid shielding and temporary plugging agent G325: 1.0%, drilling fluid plugging agent G314: 2.0%, drilling fluid micro-crosslinked nano-deformable polymer plugging agent G308: 3.0%;

[0102] Drilling fluid anti-collapse inhibitor G319: 1.0%, drilling fluid anti-mud bag cleaner G383: 1.0%, potassium chloride: 5.0%, sodium formate: 5.0%, sodium hydroxide: 0.1%, drilling fluid high temperature resistant micro-nano filtration loss reducer G352: 1.0%, flow pattern regulator xanthan gum: 0.2%, barite: 5%, and water.

[0103] The water-based drilling fluid provided in this comparative example was prepared by a method including the following specific steps:

[0104] Under high-speed stirring conditions, drilling fluid shielding and plugging agent G325, drilling fluid plugging agent G314, drilling fluid micro-crosslinked nano-deformable polymer plugging agent G308, drilling fluid anti-collapse inhibitor G319, drilling fluid anti-mud bag cleaner G383, potassium chloride, sodium formate, sodium hydroxide, well fluid high-temperature resistant micro-nano filtration loss reducer G352, flow pattern regulator xanthan gum, and barite are added to clean water in sequence according to the formula. After stirring evenly, the water-based drilling fluid is obtained and is referred to as base slurry 14.

[0105] Example 2

[0106] This embodiment provides a water-based drilling fluid, wherein, based on the total weight of clean water used in preparing the water-based drilling fluid as 100%, the water-based drilling fluid comprises:

[0107] Drilling fluid shielding and temporary plugging agent G325: 2.0%, drilling fluid plugging agent G314: 2.0%, drilling fluid micro-crosslinked nano-deformable polymer plugging agent G308: 4.0%;

[0108] Drilling fluid anti-collapse inhibitor G319: 3.0%, solid lubricant graphite powder: 3.0%, drilling fluid lubricant G316: 3.0%, drilling fluid anti-mud bag cleaner G383: 1.0%, potassium chloride: 10.0%, sodium formate: 10.0%, sodium hydroxide: 0.1%, drilling fluid high temperature resistant micro-nano filtration loss reducer G352: 2.0%, flow pattern regulator xanthan gum: 0.3%, barite: 5%, and water.

[0109] The water-based drilling fluid provided in this embodiment is prepared by a method including the following specific steps:

[0110] Under high-speed stirring conditions, drilling fluid shielding and plugging agent G325, drilling fluid plugging agent G314, drilling fluid micro-crosslinked nano-deformable polymer plugging agent G308, drilling fluid anti-collapse inhibitor G319, solid lubricant graphite powder, drilling fluid lubricant G316, drilling fluid anti-mud bag cleaner G383, potassium chloride, sodium formate, sodium hydroxide, well fluid high-temperature resistant micro-nano filtration loss reducer G352, flow pattern regulator xanthan gum and barite were added to clean water in sequence according to the formula. After stirring evenly, the water-based drilling fluid was prepared and denoted as sample slurry 2.

[0111] Comparative Example 6

[0112] This comparative example provides a blank water-based drilling fluid without added inhibitors, wherein, based on 100% of the total weight of clean water used in preparing the water-based drilling fluid, the water-based drilling fluid comprises:

[0113] Drilling fluid shielding and temporary plugging agent G325: 2.0%, drilling fluid plugging agent G314: 2.0%, drilling fluid micro-crosslinked nano-deformable polymer plugging agent G308: 4.0%;

[0114] Solid lubricant graphite powder: 3.0%, drilling fluid lubricant G316: 3.0%, drilling fluid anti-mud bag cleaner G383: 1.0%, sodium hydroxide: 0.1%, drilling fluid high temperature resistant micro-nano filtration loss reducer G352: 2.0%, flow pattern regulator xanthan gum: 0.3%, barite: 5%, and water.

[0115] The water-based drilling fluid provided in this comparative example was prepared by a method including the following specific steps:

[0116] Under high-speed stirring conditions, drilling fluid shielding and plugging agent G325, drilling fluid plugging agent G314, drilling fluid micro-crosslinked nano-deformable polymer plugging agent G308, solid lubricant graphite powder, drilling fluid lubricant G316, drilling fluid anti-mud bag cleaner G383, sodium hydroxide, well fluid high-temperature resistant micro-nano filtration loss reducer G352, flow pattern regulator xanthan gum and barite are added to clean water in sequence according to the formula ratio. After stirring evenly, the water-based drilling fluid is obtained and is referred to as base slurry 21.

[0117] Example 3

[0118] This embodiment provides a water-based drilling fluid, wherein, based on the total weight of clean water used in preparing the water-based drilling fluid as 100%, the water-based drilling fluid comprises:

[0119] Drilling fluid shielding and temporary plugging agent G325: 3.0%, drilling fluid plugging agent G314: 3.0%, drilling fluid micro-crosslinked nano-deformable polymer plugging agent G308: 5.0%;

[0120] Drilling fluid anti-collapse inhibitor G319: 3.0%, solid lubricant graphite powder: 5.0%, drilling fluid lubricant G316: 3.0%, drilling fluid anti-mud bag cleaner G383: 1.0%, potassium chloride: 10.0%, sodium formate: 10.0%, sodium hydroxide: 0.3%, drilling fluid high temperature resistant micro-nano filtration loss reducer G352: 3.0%, flow pattern regulator xanthan gum: 0.5%, barite: 25%, and water.

[0121] The water-based drilling fluid provided in this embodiment is prepared by a method including the following specific steps:

[0122] Under high-speed stirring conditions, drilling fluid shielding and plugging agent G325, drilling fluid plugging agent G314, drilling fluid micro-crosslinked nano-deformable polymer plugging agent G308, drilling fluid anti-collapse inhibitor G319, solid lubricant graphite powder, drilling fluid lubricant G316, drilling fluid anti-mud bag cleaner G383, potassium chloride, sodium formate, sodium hydroxide, well fluid high-temperature resistant micro-nano filtration loss reducer G352, flow pattern regulator xanthan gum and barite were added to clean water in sequence according to the formula. After stirring evenly, the water-based drilling fluid was prepared and denoted as sample slurry 3.

[0123] Example 4

[0124] This embodiment provides a water-based drilling fluid containing a plugging agent, which is obtained by adding the plugging agent to the sample slurry 3 provided in Example 3. The plugging agent comprises, based on 100% of the total weight of the clean water used in preparing the sample slurry 3, the plugging agent comprising:

[0125] Permeability-free treatment agent (G362): 2.0%, wellbore film-forming agent (DF-NIN): 2.0%, 1250-mesh ultrafine calcium carbonate: 2.0%, graphite powder (SH-2): 1.0%, mica powder: 1.0%, one-way pressure sealant (DF-A): 2.0%, modified polymer fiber (CQ-SCF): 0.1%, deformable polymer plugging agent (G308): 1.0%. The water-based drilling fluid provided in this example is designated as sample slurry 4.

[0126] Test Example 1

[0127] This test example uses an OFITE permeability plugging instrument (a conventional device in this field) to test the high-temperature and high-pressure filtration loss of the test slurry and base slurries 10, 11, 12, and 13, respectively, and examines the high-temperature and high-pressure filtration loss at different time periods to analyze and compare the plugging performance of water-based drilling fluids before and after the addition of different plugging agents. The comparison of the plugging performance of sample slurry 1 with base slurries 10-13 is as follows: Figure 1 As shown. From Figure 1As can be seen, compared with the high-temperature and high-pressure filtration loss of sample slurry 1 obtained by adding three sealing materials (G308, G314 and G325) in Example 1, the high-temperature and high-pressure filtration loss of base slurry 10-base slurry 13 obtained by Comparative Examples 1-4 without adding the three sealing agents G325, G314 and G308, adding only G325, adding only G314 and adding only G308 respectively is significantly higher, and the high-temperature and high-pressure filtration loss of base slurry 10 is the highest.

[0128] from Figure 1 It can also be seen that the high-temperature and high-pressure filtration loss of the base slurry 12 with only G314 (inert particles) on the 35μm ceramic filter plate is significantly less in the initial stage than that of the base slurry 13 with only G308 (nanopolymer) and the base slurry 11 with only G325. The lower high-temperature and high-pressure filtration loss of the base slurry 12 with only G314 (inert particles) in the initial stage indicates that the inert particles quickly form a cake and achieve instantaneous sealing. At 30 min, the high-temperature and high-pressure filtration loss of the base slurry 13 with only G308 (nanopolymer) is the lowest, indicating that although the sealing layer formed by the nanopolymer takes longer (presumably because micro-crosslinking requires a certain amount of time), the sealing layer formed by it is more dense.

[0129] A schematic diagram of the dual-layer plugging mechanism of the nanoscale inert particle plugging agent and the nanoscale deformable polymer plugging agent used in sample slurry 1 is shown below. Figures 2a-2b As shown, from Figures 2a-2b As can be seen, the nano-scale inert particle plugging agent in the water-based drilling fluid can quickly enter the formation fractures to form an inner plugging layer, rapidly reducing the intrusion of the filtrate into the rock formation; on the basis of the inner plugging layer formed by the nano-scale inert particle plugging agent, the nano-scale deformable polymer plugging agent undergoes micro-crosslinking and deformable plugging to form an outer plugging layer, enhancing the plugging strength and strengthening the plugging effect.

[0130] The experimental results above show that the high-temperature and high-pressure filtration loss of sample slurry 1 is much smaller than that of base slurry 10-13. Base slurry 10 has the largest high-temperature and high-pressure filtration loss on the 35μm ceramic filter, indicating that the sealing performance of water-based drilling fluid has been significantly improved after adding the three sealing agents.

[0131] Additionally, the comparison of the ceramic filter cake of sample slurry 1 and base slurry 10 is as follows: Figures 3a-3bAs shown in the comparison, the mud cake formed by water-based drilling fluid with added plugging agent is smooth and dense, while the mud cake formed by water-based drilling fluid without added plugging agent is rough and loose. This indicates that the plugging material in sample slurry 1 can significantly reduce the instantaneous filtrate loss of water-based drilling fluid. The instantaneous filtrate loss of water-based drilling fluid with added plugging material is much smaller than that of water-based drilling fluid without added plugging agent. The plugging material can quickly form a mud cake on the surface of the grinding disc, reducing filtrate intrusion and helping to inhibit the generation, expansion, and connection of secondary micro-fractures, thereby playing a role in preventing collapse.

[0132] Test Example 2

[0133] This test example, following the SY-T 6094-1994 evaluation procedure for lubricants used in drilling fluids, tested the lubrication performance of base slurry 14 and sample slurry 1. The tested parameters included the slider friction coefficient and extreme pressure lubrication coefficient, thereby analyzing and comparing the lubrication performance of the water-based drilling fluid before and after the addition of lubricant. The comparison of the lubrication performance of sample slurry 1 and base slurry 14 is as follows: Figure 4 As shown, the comparison of the field torque (taken from field drilling parameters) of sample slurry 1 and base slurry 14 is as follows: Figure 5 As shown, the field friction (taken from field drilling parameters) of sample slurry 1 and base slurry 14 are compared as follows. Figure 6 As shown.

[0134] from Figure 4 As can be seen, compared to base slurry 14, the lubrication performance of the water-based drilling fluid obtained by adding liquid and solid lubricants in Example 1, i.e., sample slurry 1, is significantly improved, specifically manifested in a substantial reduction in both the slider friction coefficient and the extreme pressure lubrication coefficient. From Figure 5 and Figure 6 The field test results shown show that, compared with the base slurry 14, the drilling torque, idling torque, lifting friction and lowering friction of the water-based drilling fluid obtained by adding liquid lubricant and solid lubricant in Example 1, namely the sample slurry 1, are significantly reduced.

[0135] Test Example 3

[0136] This test example uses conventional methods in the art to test the inhibition performance of sample slurry 2, base slurry 21, and water, respectively. The comparison of the linear expansion rates of sample slurry 2 and base slurry 21 is shown below. Figure 7 As shown, the comparison of cuttings recovery rates between sample slurry 2 and base slurry 21 is as follows: Figure 8 As shown.

[0137] Will Figure 7 and Figure 8Comparison of experimental data in Example 2 shows that the inhibition performance of sample slurry 2, prepared with three inhibitors (drilling fluid anti-collapse inhibitor G319, potassium chloride, and sodium formate), is significantly higher than that of the water-based drilling fluid prepared without inhibitors in Comparative Example 6, namely base slurry 21 and water. Furthermore, if only one or two of the three inhibitors are added, the anti-collapse performance of the resulting water-based drilling fluid is also substandard, posing a risk of well collapse. Specifically, compared to base slurry 21, the linear expansion rate of sample slurry 2 is significantly reduced, and the cuttings recovery rate is significantly increased. This indicates that the water-based drilling fluid prepared in Example 2 has strong inhibition performance.

[0138] Test Example 4

[0139] This test example uses conventional methods in the field to test the plugging performance of sample slurry 3 and sample slurry 4 respectively. The comparison of the sealing leakage of sample slurry 3 and sample slurry 4 is as follows. Figure 9 As shown, the comparison of water loss between sample slurry 3 and sample slurry 4 is as follows: Figure 10 As shown.

[0140] By comparison Figure 9 and Figure 10 As shown in the experimental results, compared to sample slurry 3, sample slurry 4, containing a plugging agent, exhibits superior leak-proof and plugging performance. In particular, the plugging materials in the aforementioned plugging agent can pass through the inner annular space of the rotary directional tool and the outer annular space between the drill string and the wellbore. This solves the problem that existing medium and coarse-grained plugging materials, while effective, cannot pass through the annular space, while fine-grained plugging materials can pass through the annular space but have poor plugging effect. Furthermore, using sample slurry 4 for plugging eliminates the need to trip the drill string and change the drill string, improving efficiency and preventing collapse of deep shale formations due to reduced drilling fluid column pressure during well leakage.

[0141] In summary, the water-based drilling fluid provided in this invention exhibits excellent sealing and anti-collapse performance, inhibition performance, lubrication performance, filtration loss reduction performance, and rheological properties even under conditions such as deep shale and carbonaceous mudstone with a vertical depth of less than 3500 meters and / or high temperature conditions. It also provides good leakage prevention and plugging effects for wells with lost circulation in deep shale formations. This fluid is suitable for drilling operations in deep shale gas horizontal wells, shale oil horizontal wells, carbonaceous mudstone horizontal wells, coal-bearing formation horizontal wells, as well as horizontal wells encountering other easily collapsible formations, complex exploration wells, fractured zones, complex fault zones, and other formations where high sealing and anti-collapse performance of water-based drilling fluids is required.

[0142] The above description is merely a specific embodiment of the present invention and should not be construed as limiting the scope of the invention. Therefore, any substitution of equivalent components or equivalent changes and modifications made within the scope of protection of this patent should still fall within the scope of this patent. Furthermore, the technical features, technical features and technical inventions, and technical inventions in this invention can be freely combined and used.

Claims

1. A water-based drilling fluid, characterized in that, Based on the total weight of clean water used in preparing the water-based drilling fluid as 100%, the water-based drilling fluid comprises: 1.0-3.0% shielding and temporary plugging agent, 2.0-3.0% inert particulate plugging agent, 1.0-5.0% deformable polymer plugging agent, 1.0-3.0% organic amine inhibitor, 2.0-5.0% solid lubricant, 3.0-5.0% liquid lubricant, 1.0-3.0% anti-mud bag cleaner, 10-25% inorganic and organic salts, 0.1-0.5% alkaline substances, 1.0-4.0% filtration loss reducer, 0.2-0.5% flow pattern modifier, weighting agent, leak plugging agent, and water; The shielding plugging agent includes drilling fluid shielding plugging agent G325, the inert particle plugging agent includes drilling fluid plugging agent G314, and the deformable polymer plugging agent includes drilling fluid micro-crosslinked nano-deformable polymer plugging agent G308. The solid lubricant includes one or a combination of graphite powder and elastic graphite, and the liquid lubricant includes one or a combination of chemically modified vegetable oil and polyol. The organic amine inhibitors include one or a combination of several of polyether diamine, polyamine, polyhydroxyalkylammonium salt and hexamethylenediamine; The fluid loss reducer includes G352, a high-temperature resistant micro-nano fluid loss reducer for drilling fluids.

2. The water-based drilling fluid according to claim 1, characterized in that, Based on 100% of the total weight of clean water used in preparing the water-based drilling fluid, the plugging agent comprises: Permeability-free treatment agent: 1.0-3.0%, wellbore film-forming agent: 1.0-2.0%, ultrafine calcium carbonate: 1.0-2.0%, graphite powder: 1.0-2.0%, mica powder: 1.0-2.0%, one-way pressure sealant: 1.0-2.0%, modified polymer fiber: 0.05-0.1%, deformable polymer plugging agent: 0.5-1.5%.

3. The water-based drilling fluid according to claim 2, characterized in that, The non-permeable treatment agent comprises a powder whose main component is plant fiber.

4. The water-based drilling fluid according to any one of claims 1-3, characterized in that, The shielding and plugging agent is a micron-sized shielding and plugging agent with a size of 1-8 μm; The inert particle plugging agent is a nano-sized inert particle plugging agent with a size of 10-300 nm; The deformable polymer plugging agent is a nanoscale deformable polymer plugging agent with a size of 200-800 nm.

5. The water-based drilling fluid according to any one of claims 1-3, characterized in that, The mud-packing cleaner includes drilling fluid mud-packing cleaner G383.

6. The water-based drilling fluid according to any one of claims 1-3, characterized in that, The inorganic salt includes one or a combination of potassium chloride, sodium chloride, and potassium nitrate, and the organic salt includes one or a combination of sodium acetate, sodium formate, and potassium formate.

7. The water-based drilling fluid according to any one of claims 1-3, characterized in that, The alkaline substances include sodium hydroxide and / or potassium hydroxide.

8. The water-based drilling fluid according to any one of claims 1-3, characterized in that, The flow pattern regulator includes one or a combination of xanthan gum, guar gum, guar gum, hydroxypropyl guar gum, hydroxypropyl guar gum, carboxymethyl guar gum, and carboxymethyl guar gum.

9. The water-based drilling fluid according to any one of claims 1-3, characterized in that, The amount of weighting agent is determined according to the target density of the water-based drilling fluid, wherein the weighting agent includes one or a combination of barite, iron ore powder and limestone.

10. The method for preparing the water-based drilling fluid according to any one of claims 1-9, characterized in that, The preparation method includes: Under high-speed stirring conditions, a shielding and plugging agent, an inert particle plugging agent, a deformable polymer plugging agent, an organic amine anti-collapse agent, a solid lubricant, a liquid lubricant, a mud-pack cleaner, inorganic and organic salts, alkaline substances, a filtration loss reducer, a flow pattern regulator, and a weighting agent are added to clean water according to the specified ratio. After stirring evenly, the water-based drilling fluid is obtained.

11. A method for drilling horizontal wells, characterized in that, The horizontal well drilling method uses the water-based drilling fluid described in any one of claims 1-9.

12. The horizontal well drilling method according to claim 11, characterized in that, The horizontal wells include deep shale gas horizontal wells, shale oil horizontal wells, carbonaceous mudstone horizontal wells, coal-bearing formation horizontal wells, fractured zone horizontal wells, or complex fault zone horizontal wells.

Images