阅读说明：本技术 一种页岩气井用水基钻井液及其生产方法 (Water-based drilling fluid for shale gas well and production method thereof ) 是由 郑�和 王亚宁 龚厚平 蔡巍 陈文可 张晓红 于 2019-10-08 设计创作，主要内容包括：本发明涉及一种页岩气井用水基钻井液及其生产方法,依次包括如下步骤,⑴准备原料,水1000份；钠基膨润土45～50份；水溶性抑制加重剂Ⅱ型500份；水溶性抑制加重剂Ⅲ型100份；抑制防塌剂无荧光白沥青15～20份；固体聚合醇10～20份；降滤失剂10～20份；聚胺抑制剂0.5～1份；超细碳酸钙20～30份；极压润滑剂10～25份；包被抑制剂0.5～1份；⑵将钠基膨润土与水混合并搅拌,常温下养护至少24小时；⑶在搅拌下先加入水溶性抑制加重剂Ⅱ型和Ⅲ型,再加入抑制防塌剂无荧光白沥青和固体聚合醇,再加入降滤失剂和聚胺抑制剂,再加入超细碳酸钙和极压润滑剂,最后加入包被抑制剂,再调节pH值和密度。该钻井液具有高封堵性、强抑制性和极好的润滑性,可以满足页岩气水平井的安全钻井需求。(The invention relates to a water-based drilling fluid for a shale gas well and a production method thereof, which sequentially comprises the following steps of preparing raw materials and 1000 parts of water; 45-50 parts of sodium bentonite; 500 parts of water-soluble weight-inhibiting additive II; 100 parts of water-soluble weight-inhibiting weighting agent III; 15-20 parts of non-fluorescent white asphalt serving as an anti-collapse agent; 10-20 parts of solid polymeric alcohol; 10-20 parts of a filtrate reducer; 0.5-1 part of polyamine inhibitor; 20-30 parts of superfine calcium carbonate; 10-25 parts of an extreme pressure lubricant; 0.5-1 part of coating inhibitor; mixing and stirring sodium bentonite and water, and curing at normal temperature for at least 24 hours; the water-soluble inhibition weighting agents II and III are added under stirring, the inhibition anti-collapse agent non-fluorescent white asphalt and solid polymeric alcohol are added, the filtrate reducer and the polyamine inhibitor are added, the superfine calcium carbonate and the extreme pressure lubricant are added, the coating inhibitor is added, and the pH value and the density are adjusted. The drilling fluid has high plugging property, strong inhibition property and excellent lubricity, and can meet the requirement of safe drilling of a shale gas horizontal well.)

1. The water-based drilling fluid for the shale gas well is characterized by comprising the following components in parts by weight: the water-based drilling fluid for the shale gas well comprises the following raw materials in parts by weight: 1000 parts of (A); sodium bentonite: 45-50 parts of a solvent; water soluble inhibitor weighting agent type ii: 500 parts; water soluble inhibitor weighting agent type iii: 100 parts of (A); non-fluorescent white asphalt for inhibiting anti-collapse agent: 15-20 parts of a solvent; solid polymeric alcohol: 10-20 parts; fluid loss additive: 10-20 parts; polyamine inhibitors: 0.5-1 part; ultra-fine calcium carbonate: 20-30 parts of a solvent; extreme pressure lubricant: 10-25 parts; coating inhibitor: 0.5-1 part.

2. The water-based drilling fluid for shale gas wells as claimed in claim 1, wherein: the water-based drilling fluid for the shale gas well comprises the following raw materials in parts by weight: 1000 parts of (A); sodium bentonite: 45 parts of (1); water soluble inhibitor weighting agent type ii: 500 parts; water soluble inhibitor weighting agent type iii: 100 parts of (A); non-fluorescent white asphalt for inhibiting anti-collapse agent: 15 parts of (1); solid polymeric alcohol: 10 parts of (A); fluid loss additive: 10 parts of (A); polyamine inhibitors: 0.5 part; ultra-fine calcium carbonate: 20 parts of (1); extreme pressure lubricant: 10 parts of (A); coating inhibitor: 0.5 part.

3. The water-based drilling fluid for shale gas wells as claimed in claim 1, wherein: the water-based drilling fluid for the shale gas well comprises the following raw materials in parts by weight: 1000 parts of (A); sodium bentonite: 48 parts of a mixture; water soluble inhibitor weighting agent type ii: 500 parts; water soluble inhibitor weighting agent type iii: 100 parts of (A); non-fluorescent white asphalt for inhibiting anti-collapse agent: 18 parts of a mixture; solid polymeric alcohol: 15 parts of (1); fluid loss additive: 15 parts of (1); polyamine inhibitors: 0.8 part; ultra-fine calcium carbonate: 25 parts of (1); extreme pressure lubricant: 18 parts of a mixture; coating inhibitor: 0.7 part.

4. The water-based drilling fluid for shale gas wells as claimed in claim 1, wherein: the water-based drilling fluid for the shale gas well comprises the following raw materials in parts by weight: 1000 parts of (A); sodium bentonite: 50 parts of a mixture; water soluble inhibitor weighting agent type ii: 500 parts; water soluble inhibitor weighting agent type iii: 100 parts of (A); non-fluorescent white asphalt for inhibiting anti-collapse agent: 20 parts of (1); solid polymeric alcohol: 20 parts of (1); fluid loss additive: 20 parts of (1); polyamine inhibitors: 1 part; ultra-fine calcium carbonate: 30 parts of (1); extreme pressure lubricant: 25 parts of (1); coating inhibitor: 1 part.

5. The shale gas well water-based drilling fluid as claimed in any one of claims 1 to 4, wherein: the pH value of a mixed system formed by mixing the raw materials is 8.5-9.5.

6. The shale gas well water-based drilling fluid as claimed in any one of claims 1 to 4, wherein: and limestone or barite for regulating the density of the mixed system.

7. A production method of water-based drilling fluid for a shale gas well is characterized by comprising the following steps of preparing raw materials and water according to the following components and weight contents: 1000 parts of (A); sodium bentonite: 45-50 parts of a solvent; water soluble inhibitor weighting agent type ii: 500 parts; water soluble inhibitor weighting agent type iii: 100 parts of (A); non-fluorescent white asphalt for inhibiting anti-collapse agent: 15-20 parts of a solvent; solid polymeric alcohol: 10-20 parts; fluid loss additive: 10-20 parts; polyamine inhibitors: 0.5-1 part; ultra-fine calcium carbonate: 20-30 parts of a solvent; extreme pressure lubricant: 10-25 parts; coating inhibitor: 0.5-1 part;

mixing sodium bentonite and water, continuously stirring for 30-60 minutes under the stirring condition of 1000-4000 rpm, then increasing the stirring speed to 6000-10000 rpm, continuously stirring for 30-40 minutes, and then curing for at least 24 hours at normal temperature;

the water-soluble inhibition weighting agent II and the water-soluble inhibition weighting agent III are added into the mixture formed in the second step at a stirring speed of 6000-10000 rpm, the inhibition anti-collapse agent non-fluorescent white asphalt and the solid polymer alcohol are added after stirring for 10-20 minutes, the filtrate reducer and the polyamine inhibitor are added after stirring for 15-20 minutes, the superfine calcium carbonate and the extreme pressure lubricant are added after stirring for 15-25 minutes, the coating inhibitor is added after stirring for 10-15 minutes, and the stirring is continued for 30 minutes.

8. The method for producing the water-based drilling fluid for the shale gas well, according to claim 7, is characterized by further comprising the following steps: fourthly, adjusting the pH value of the mixed system formed in the third step by using NaOH to enable the pH value to be 8.5-9.5, and then maintaining at normal temperature for more than 16 hours; and fifthly, adding limestone or barite into the mixed system obtained in the fourth step, and stirring for 15-25 minutes to form uniform drilling fluid colloid meeting the density requirement.

9. The production method of the water-based drilling fluid for the shale gas well, which is characterized in that the water-based drilling fluid for the shale gas well comprises the following raw materials in percentage by weight: 1000 parts of (A); sodium bentonite: 48 parts of a mixture; water soluble inhibitor weighting agent type ii: 500 parts; water soluble inhibitor weighting agent type iii: 100 parts of (A); non-fluorescent white asphalt for inhibiting anti-collapse agent: 18 parts of a mixture; solid polymeric alcohol: 15 parts of (1); fluid loss additive: 15 parts of (1); polyamine inhibitors: 0.8 part; ultra-fine calcium carbonate: 25 parts of (1); extreme pressure lubricant: 18 parts of a mixture; coating inhibitor: 0.7 part.

10. The production method of the water-based drilling fluid for the shale gas well, which is characterized in that the water-based drilling fluid for the shale gas well comprises the following raw materials in percentage by weight: 1000 parts of (A); sodium bentonite: 50 parts of a mixture; water soluble inhibitor weighting agent type ii: 500 parts; water soluble inhibitor weighting agent type iii: 100 parts of (A); non-fluorescent white asphalt for inhibiting anti-collapse agent: 20 parts of (1); solid polymeric alcohol: 20 parts of (1); fluid loss additive: 20 parts of (1); polyamine inhibitors: 1 part; ultra-fine calcium carbonate: 30 parts of (1); extreme pressure lubricant: 25 parts of (1); coating inhibitor: 1 part.

Technical Field

The invention relates to a water-based drilling fluid for a shale gas well and a production method of the water-based drilling fluid for the shale gas well, belongs to the technical field of oil and gas drilling, and can meet the requirement of shale gas well construction to replace an oil-based drilling fluid.

Background

Since the 21 st century, represented by the united states, the shale gas revolution was raised through horizontal well drilling and multi-stage hydraulic fracturing development technologies, and the wave soon rolled the world, and about 30 countries currently added shale gas exploration and development lines. In China, shale gas development is also developed successively in Sichuan Changning, Wingyuan, Chongqing Fuling, Pengshui, Yunnan Shogtong and the like, and commercial development of shale gas is realized in Chongqing Fuling in 2014.

In the construction of the shale gas well, due to the particularity and complexity of a shale stratum, the shale microcracks and the bedding development are realized, the water sensitivity is high, the problems of well leakage, collapse and the like are easy to occur in the drilling of a long horizontal section, and the problems of friction, rock carrying, reservoir pollution and the like are caused due to the longer horizontal section, so that the probability of underground complex faults in the construction is increased. The oil-based drilling fluid technology is mostly preferred in the drilling process of shale gas horizontal wells at home and abroad to solve the problems of borehole instability and high friction resistance of long-interval horizontal wells. However, oil-based drilling fluids suffer from several disadvantages: (1) the cost of oil-based drilling fluids is too high due to the low cost pressure of drilling; (2) in force of increasingly strict environmental regulations, oil-based drilling fluids are not conducive to formation and environmental protection. The traditional strong-inhibition water-based drilling fluid is difficult to meet the requirements of shale gas construction. Therefore, aiming at the technical problems and the environmental protection requirements of shale gas horizontal wells, various large drilling fluid companies at home and abroad develop water-based drilling fluid for shale gas wells, which can partially replace oil-based drilling fluid and synthetic-based drilling fluid in the aspects of performance, cost, environmental protection and the like, and the requirements of shale gas well construction in new times are met.

Aiming at the technical problems and the environmental protection requirements of shale gas horizontal wells, various large drilling fluid companies abroad develop water-based drilling fluid for shale gas wells, which can replace oil-based drilling fluid in the aspects of performance, cost, environmental protection and the like, form representative water-based drilling fluid technology and products for shale gas wells, and have case reports of successful application in some wells. M-I Swaco corporation developed various environmentally friendly water-based drilling fluid systems for shale gas wells, including ULTRADRIL systems, KLA-SHIELD systems, and HydraGlyde systems. The system can provide good inhibitive performance, lubricity, well hole purification capacity and high mechanical drilling speed, and the non-toxicity of the system enables drill cuttings generated by drilling operation to be directly discharged, and drilling fluid can be recycled after drilling, so that the drilling cost is greatly reduced; the system is successfully used for high-activity shale drilling and deep water drilling in environmentally sensitive areas at present.

The Harlibertn company develops the HYDRO-GUADRTM shale gas well water-based drilling fluid, the inhibitive performance of the system is improved through polyamine salt and an aluminic acid complex, a fast drilling agent is adopted to prevent bit balling, and a deformable polymer plugging agent is adopted to tightly fill shale microcracks. Has been successfully applied to active shale formations and deep water drilling in Saudi, Egypt, Africa, gulf of Mexico, etc.

Related units and research institutions in China also have research on the aspect, for example, Zhang Yangxi and the like research a water-based drilling fluid system suitable for shale oil gas large-section shale, the system takes polymer, organic amine and other treating agents with strong inhibition as main materials, takes nano emulsion, polyalcohol, aluminum amine polymer and asphalt products as auxiliary materials with strong plugging property, and is added with efficient lubricant to form an aluminum amine polymer lubricating anti-collapse system. The multi-silicon-based strong plugging water-based drilling fluid technology developed by the Shengli oil field drilling research institute is successfully applied to the three-section of the Dongping 1 well of the horizontal well of the shale oil and gas reservoir. Aiming at the problems of shale collapse, large friction resistance and the like, China oil group companies successfully develop two sets of shale gas water-based drilling fluid systems CQH-M1 and DRHPW-1, and successfully apply a plurality of shale gas horizontal wells in the Sichuan Changning-Weiyuan block and Zhaotong block, but the oil-based drilling fluid in the Weiyuan block is still the main drilling fluid system at present.

The technical levels of the water-based drilling fluids for the shale gas wells in China are different, and due to the particularity and complexity of shale strata, some of the water-based drilling fluids have continuous underground complex faults in the construction process; in addition, the differences of the blocks of the shale are large, and any formula cannot meet the requirements of any block. In particular to a shale gas well with a long horizontal section, the well wall is stable, and problems exist in the aspects of lubrication and anti-blocking. The concrete points are as follows: the method has the advantages that the inhibition and blocking performance are poor, the problem of borehole wall instability is serious, and the construction requirement of a long horizontal section cannot be met; the anti-blocking lubricating device has the advantages of poor lubrication and anti-blocking performance, frictional resistance torque beating in construction and large drilling blocking risk. Some application wells have to be converted into oil-based drilling fluid again in the later construction period, some drilling construction has no problem, but complex faults of the later completion operation occur frequently, and the oil-based drilling fluid also has to be converted into the oil-based drilling fluid.

Inhibition, plugging and lubrication are technical keys of the water-based drilling fluid, and the formula of a plurality of research institutions has single research on the treatment agents in the three aspects, and the requirement of simultaneous consideration cannot be met, so that complex underground faults can frequently occur as long as one treatment agent cannot meet the requirement in construction.

Disclosure of Invention

The invention aims to overcome the problems in the prior art, and provides the water-based drilling fluid for the shale gas well, which has high plugging property, strong inhibition property and excellent lubricity, can meet the requirement of safe drilling of the shale gas horizontal well, can replace an oil-based drilling fluid to meet the requirement of environmental protection, and improves the overall benefit of shale gas development.

In order to solve the technical problems, the water-based drilling fluid for the shale gas well comprises the following raw material components in percentage by weight: 1000 parts of (A); sodium bentonite: 45-50 parts of a solvent; water soluble inhibitor weighting agent type ii: 500 parts; water soluble inhibitor weighting agent type iii: 100 parts of (A); non-fluorescent white asphalt for inhibiting anti-collapse agent: 15-20 parts of a solvent; solid polymeric alcohol: 10-20 parts; fluid loss additive: 10-20 parts; polyamine inhibitors: 0.5-1 part; ultra-fine calcium carbonate: 20-30 parts of a solvent; extreme pressure lubricant: 10-25 parts; coating inhibitor: 0.5-1 part.

Compared with the prior art, the invention has the following beneficial effects: the sodium bentonite is used as a basic slurry preparation material, provides an adsorption medium for the interaction of other treating agents, and simultaneously improves the functions of viscosity cutting and barite suspension; the water-soluble inhibition weighting agent II can improve the liquid phase density, improve the activity and improve the inhibition of the drilling fluid; the water-soluble inhibition weighting agent III can improve the activity and improve the inhibition of the drilling fluid; the non-fluorescent white asphalt for inhibiting the anti-collapse agent can improve the plugging property, so that the drilling fluid has good anti-collapse capability; the solid polymer alcohol can synergistically improve the mud cake lubricity; the filtrate reducer can reduce the high-temperature and high-pressure filtrate loss; the coating inhibitor is used as a shear strength improving agent, and can meet the requirement of effective suspension of high-density drilling fluid on barite; the superfine calcium carbonate can improve the quality and plugging capability of mud cakes; the extreme pressure lubricant can reduce the lubricating coefficient of the drilling fluid, effectively reduce the friction resistance and the torque, and ensure that the drilling fluid has good lubricating capability; polyamine inhibitors can synergistically improve drilling fluid inhibition. The invention utilizes the water-soluble weight inhibitor to improve the system inhibition and the density of the base slurry, realizes the purpose of high density and low solid phase, greatly improves the blocking property and the inhibition property by utilizing the dual functions of the non-fluorescent white asphalt of the anti-collapse agent and the polyamine inhibitor, and realizes the purpose of stabilizing the well wall. The cloud point effect of the solid polyalcohol is utilized, and the extreme pressure lubricant is matched to ensure the good lubricating anti-sticking effect of the system, and various treating agents are mutually cooperated, so that the comprehensive performance of the system is better. Compared with the prior similar products, the drilling fluid has the following advantages: the drilling fluid effectively solves three contradictions of 'high density and rheological property, filtration loss control and rheological property, inhibition and dispersion' inherent in the conventional high-density drilling fluid, realizes low solid phase and high density, and has good suspension performance, high plugging property, strong inhibition property, high lubricity and strong temperature and pollution resistance. The formula of the invention is more matched with the stratum microcracks of the shale gas well, can effectively inhibit the hydration dispersion of the shale and block the microcracks in the construction of the shale gas well, effectively delay the instability of the well wall caused by the entering of the filtrate into the stratum and maintain the stability of the well wall; the shale stratum collapse period can be prolonged, and the stability of the well wall is equivalent to that of the oil-based drilling fluid. The good lubricity can effectively solve the difficult problem of the lubricity of the drilling fluid of the shale gas horizontal well at the long horizontal section, ensure that the shale gas well at the long horizontal section can be safely and efficiently constructed, and the drilling fluid is not required to be replaced by oil-based drilling fluid at the later stage.

As a preferable scheme of the invention, the water-based drilling fluid for the shale gas well comprises the following raw materials in parts by weight: 1000 parts of (A); sodium bentonite: 45 parts of (1); water soluble inhibitor weighting agent type ii: 500 parts; water soluble inhibitor weighting agent type iii: 100 parts of (A); non-fluorescent white asphalt for inhibiting anti-collapse agent: 15 parts of (1); solid polymeric alcohol: 10 parts of (A); fluid loss additive: 10 parts of (A); polyamine inhibitors: 0.5 part; ultra-fine calcium carbonate: 20 parts of (1); extreme pressure lubricant: 10 parts of (A); coating inhibitor: 0.5 part.

As a preferable scheme of the invention, the water-based drilling fluid for the shale gas well comprises the following raw materials in parts by weight: 1000 parts of (A); sodium bentonite: 48 parts of a mixture; water soluble inhibitor weighting agent type ii: 500 parts; water soluble inhibitor weighting agent type iii: 100 parts of (A); non-fluorescent white asphalt for inhibiting anti-collapse agent: 18 parts of a mixture; solid polymeric alcohol: 15 parts of (1); fluid loss additive: 15 parts of (1); polyamine inhibitors: 0.8 part; ultra-fine calcium carbonate: 25 parts of (1); extreme pressure lubricant: 18 parts of a mixture; coating inhibitor: 0.7 part.

As a preferable scheme of the invention, the water-based drilling fluid for the shale gas well comprises the following raw materials in parts by weight: 1000 parts of (A); sodium bentonite: 50 parts of a mixture; water soluble inhibitor weighting agent type ii: 500 parts; water soluble inhibitor weighting agent type iii: 100 parts of (A); non-fluorescent white asphalt for inhibiting anti-collapse agent: 20 parts of (1); solid polymeric alcohol: 20 parts of (1); fluid loss additive: 20 parts of (1); polyamine inhibitors: 1 part; ultra-fine calcium carbonate: 30 parts of (1); extreme pressure lubricant: 25 parts of (1); coating inhibitor: 1 part.

In a preferred embodiment of the present invention, the pH of a mixed system formed by mixing the above raw materials is 8.5 to 9.5.

In a preferred embodiment of the invention, the water-based drilling fluid for shale gas wells further comprises limestone or barite for adjusting the density of the mixed system. Generally, when the density is required to be below 1.3g/cm in heavy plantation, only limestone needs to be added; if the density requirement is more than 1.3g/c m, barite is usually added to ensure that the density of the drilling fluid meets the design requirement.

The invention also aims to overcome the problems in the prior art and provide a production method of the water-based drilling fluid for the shale gas well, and the produced water-based drilling fluid for the shale gas well has high plugging property, strong inhibition property and excellent lubricating property, can meet the requirement of safe drilling of the shale gas horizontal well, can also replace oil-based drilling fluid to meet the requirement of environmental protection, and improves the overall benefit of shale gas development.

In order to solve the technical problems, the production method of the water-based drilling fluid for the shale gas well sequentially comprises the following steps of: 1000 parts of (A); sodium bentonite: 45-50 parts of a solvent; water soluble inhibitor weighting agent type ii: 500 parts; water soluble inhibitor weighting agent type iii: 100 parts of (A); non-fluorescent white asphalt for inhibiting anti-collapse agent: 15-20 parts of a solvent; solid polymeric alcohol: 10-20 parts; fluid loss additive: 10-20 parts; polyamine inhibitors: 0.5-1 part; ultra-fine calcium carbonate: 20-30 parts of a solvent; extreme pressure lubricant: 10-25 parts; coating inhibitor: 0.5-1 part; mixing sodium bentonite and water, continuously stirring for 30-60 minutes under the stirring condition of 1000-4000 rpm, then increasing the stirring speed to 6000-10000 rpm, continuously stirring for 30-40 minutes, and then curing for at least 24 hours at normal temperature; the water-soluble inhibition weighting agent II and the water-soluble inhibition weighting agent III are added into the mixture formed in the second step at a stirring speed of 6000-10000 rpm, the inhibition anti-collapse agent non-fluorescent white asphalt and the solid polymer alcohol are added after stirring for 10-20 minutes, the filtrate reducer and the polyamine inhibitor are added after stirring for 15-20 minutes, the superfine calcium carbonate and the extreme pressure lubricant are added after stirring for 15-25 minutes, the coating inhibitor is added after stirring for 10-15 minutes, and the stirring is continued for 30 minutes.

Compared with the prior art, the invention has the following beneficial effects: the invention has simple and reasonable process and convenient production, and the produced drilling fluid has the technical effect in shale gas well construction as described above. The various materials must be added in the exact order of the present invention or otherwise interact with each other to the extent that the desired performance requirements are not met. Adding a water-soluble inhibition weighting agent II type and a water-soluble inhibition weighting agent III type, stirring to promote the dissolution of the water-soluble inhibition weighting agent, adding the inhibition anti-collapse agent non-fluorescent white asphalt and solid polyalcohol after the water-soluble inhibition weighting agent is completely dissolved, and stirring for 15-20 minutes to ensure that the slurry has no undissolved substances or treatment agent inclusion is not standard; continuously adding the filtrate reducer and the polyamine inhibitor, and stirring for 15-25 minutes to ensure that the slurry has no undissolved substances or treatment agent is not standard; and then adding superfine calcium carbonate and an extreme pressure lubricant, stirring for 10-15 minutes, finally adding a coating inhibitor and stirring to fully dissolve the coating inhibitor, so that branched chains in macromolecules can stretch and can be mutually adsorbed and fused with other treating agents to form uniform colloid.

As a preferable scheme of the invention, the method further comprises the following steps: fourthly, adjusting the pH value of the mixed system formed in the third step by using NaOH to enable the pH value to be 8.5-9.5, and then maintaining at normal temperature for more than 16 hours; and fifthly, adding limestone or barite into the mixed system obtained in the fourth step, and stirring for 15-25 minutes to form uniform drilling fluid colloid meeting the density requirement. The water-based drilling fluid disclosed by the invention is sensitive to a pH value, especially when the water-based drilling fluid is high in density, the rheological property becomes poor and is thickened after the pH value exceeds 9.5, and the pH value is maintained at 8.5-9.5, so that the water-based drilling fluid is beneficial to underground safe construction. After all the treating agents are added, the curing is carried out for more than 16 hours at normal temperature, and the full hydration of all the treating agents is ensured.

As a preferable scheme of the invention, the water-based drilling fluid for the shale gas well comprises the following raw materials in parts by weight: 1000 parts of (A); sodium bentonite: 48 parts of a mixture; water soluble inhibitor weighting agent type ii: 500 parts; water soluble inhibitor weighting agent type iii: 100 parts of (A); non-fluorescent white asphalt for inhibiting anti-collapse agent: 18 parts of a mixture; solid polymeric alcohol: 15 parts of (1); fluid loss additive: 15 parts of (1); polyamine inhibitors: 0.8 part; ultra-fine calcium carbonate: 25 parts of (1); extreme pressure lubricant: 18 parts of a mixture; coating inhibitor: 0.7 part. The aged water-based drilling fluid has the apparent viscosity AV of 54-55 mPa.s, the plastic viscosity Pv of 42-46 mPa.s, the yield value Yp of 9-12 Pa, the dynamic-plastic ratio Yp/Pv of 0.20-0.29, the flow pattern index n of 0.83, the consistency coefficient K of 0.17Pa.sn, GEL10 '/GEL 10' of 3.5/8, the medium-pressure filtration loss API of 5.4ml, the high-temperature and high-pressure filtration loss HTHP of 10ml, the lubrication coefficient of 0.0699 and the sand bed filtration loss of 0.

As a preferable scheme of the invention, the water-based drilling fluid for the shale gas well comprises the following raw materials in parts by weight: 1000 parts of (A); sodium bentonite: 50 parts of a mixture; water soluble inhibitor weighting agent type ii: 500 parts; water soluble inhibitor weighting agent type iii: 100 parts of (A); non-fluorescent white asphalt for inhibiting anti-collapse agent: 20 parts of (1); solid polymeric alcohol: 20 parts of (1); fluid loss additive: 20 parts of (1); polyamine inhibitors: 1 part; ultra-fine calcium carbonate: 30 parts of (1); extreme pressure lubricant: 25 parts of (1); coating inhibitor: 1 part. The aged water-based drilling fluid has the apparent viscosity AV of 61-62 mPa.s, the plastic viscosity Pv of 48-49 mPa.s, the yield value Yp of 13Pa, the dynamic-plastic ratio Yp/Pv of 0.27, the flow pattern index n of 0.8, the consistency coefficient K of 0.23Pa.sn, GEL10 '/GEL 10' of 4.5/13, the medium-pressure filtration loss API of 4.8ml, the high-temperature and high-pressure filtration loss HTHP of 9ml, the lubrication coefficient of 0.0612 and the sand bed filtration loss of 0.

Detailed Description