Method for rapid detection of barium ions in oil-based drilling fluid and method for avoiding drill pipe plugging

Abstract

The application provides a method for rapid detection of barium ions in oil-based drilling fluid and a method for preventing drill pipe blockage, the method for rapid detection of barium ions comprising the steps of: mixing an oil-based drilling fluid sample and a demulsification solvent, stirring uniformly to obtain a mixed solution; mixing the mixed solution with distilled water, stirring and then standing until oil and water are separated; filtering the lower water phase to obtain a colorless and clear liquid, adding a sodium chromate solution, and observing whether a yellow precipitate appears, if a yellow precipitate appears, it indicates that the oil-based drilling fluid contains barium ions, and if no yellow precipitate appears, it indicates that the oil-based drilling fluid does not contain barium ions. The method for preventing drill pipe blockage comprises: taking an oil-based drilling fluid sample to be detected to detect whether it contains barium ions; and taking preventive measures in advance to prevent the internal circulation channel of the drill pipe from being blocked in the case that it is determined that the oil-based drilling fluid contains barium ions. The application has the advantages of simple and rapid operation, low cost, and the result can be obtained within 30 min without special instruments, equipment and medicines.

Description

Technical Field

[0001] This invention relates to the field of oil and gas drilling technology, specifically to a method for rapid detection of barium ions in oil-based drilling fluids and a method for preventing drill string blockage. Background Technology

[0002] During drilling, oil-based drilling fluids may encounter formations containing soluble barium salts, causing the barium salts to dissolve and barium ions to enter the aqueous phase of the oil-based drilling fluid. Once in the fluid, barium ions form ring-shaped crystalline scale within the drill string's water channels, clogging the fluid circulation channels, causing pump stalling, and even leading to stuck pipe, lost circulation, and blowouts. To balance formation activity, oil-based drilling fluids often contain more than 20% calcium chloride in their aqueous phase. Since calcium and barium ions have similar precipitation properties, ions that can react with calcium ions to form precipitates generally have the same effect as barium ions. Therefore, it is difficult to quickly and easily qualitatively analyze the presence of barium ions in high concentrations of calcium ions. Furthermore, oil-based drilling fluids have complex compositions and are dark black in color. Current barium ion detection technology for oil-based drilling fluids can only be carried out through indoor precision analytical instruments, with a testing cycle of at least one week and a single testing cost of over 5,000 yuan. The long cycle and high cost make it impossible to conduct large-scale testing and analysis on the drilling site. Because there is currently no simple and rapid qualitative detection method for barium ions, the scale can only be removed after the dissolved barium salts have formed ring-shaped crystalline scale inside the drill string. The specific composition of the scale can then be determined through relevant analysis using indoor precision instruments before appropriate treatment measures can be taken. This results in the inability to detect the dissolution and intrusion of barium salts into the oil-based drilling fluid in advance, posing a significant safety hazard.

[0003] In view of this, it is necessary to design a rapid qualitative detection method for barium ions in oil-based drilling fluids to effectively overcome the interference of high concentrations of calcium ions. Without the need for precision analytical instruments, it is possible to quickly and qualitatively detect whether barium ions are present in oil-based drilling fluids at the drilling site, thereby taking preventive measures in advance to effectively avoid the formation of barium salt crystals and scale that block the drilling fluid circulation channels. Summary of the Invention

[0004] The purpose of this invention is to address at least one of the aforementioned shortcomings of the prior art. For example, one objective of this invention is to provide a rapid qualitative detection method for barium ions in oil-based drilling fluids that is simple, fast, and inexpensive, yielding results within 30 minutes, and requiring no special instruments or reagents. Another objective of this invention is to provide a method that can determine the presence of barium ions under extremely low concentration conditions, take preventative measures to remove barium ions, and avoid the blockage of drilling fluid circulation channels inside the drilling tools by preventing barium salt crystallization and precipitation that could lead to blockage of drilling fluid flow channels after a high concentration of barium ions has accumulated.

[0005] To achieve the above objectives, one aspect of the present invention provides a rapid qualitative detection method for barium ions in oil-based drilling fluids, the rapid qualitative detection method comprising the following steps:

[0006] The oil-based drilling fluid sample and the demulsifier were mixed and stirred until a homogeneous solution was obtained.

[0007] Mix the mixture with distilled water or deionized water, stir, and let stand until the oil and water separate into layers;

[0008] The lower aqueous phase was filtered until a colorless and clear liquid was obtained.

[0009] Add sodium chromate solution to the colorless and clear liquid and observe whether a yellow precipitate appears. If a yellow precipitate appears, it indicates that the oil-based drilling fluid contains barium ions. If no yellow precipitate appears, it indicates that the oil-based drilling fluid does not contain barium ions.

[0010] In one exemplary embodiment of this invention, the lower aqueous phase may be a grayish-white turbid liquid, and the filter paper used for filtration may be a rapid qualitative filter paper.

[0011] In one exemplary embodiment of this invention, the absence of barium ions in the oil-based drilling fluid means that the concentration of barium ions in the oil-based drilling fluid is less than 500 mg / L.

[0012] In one exemplary embodiment of one aspect of the present invention, the oil-based drilling fluid sample may contain calcium ions and barium ions, both of which can react with sodium chromate to generate calcium chromate and barium chromate. Under the same conditions, the solubility of calcium chromate is much greater than that of barium chromate.

[0013] In one exemplary embodiment of one aspect of the present invention, the solubility of the calcium chromate can be 4110 to 20650 times that of the barium chromate within the range of 10 to 30°C.

[0014] In one exemplary embodiment of this invention, the rapid qualitative detection method can detect whether barium ions are present in oil-based drilling fluid within 30 minutes.

[0015] In one exemplary embodiment of this invention, the oil-based drilling fluid sample and the demulsifying solvent are mixed in a volume ratio of 1:25 to 1:100 ml:ml.

[0016] In one exemplary embodiment of this invention, the mixed solution is mixed with distilled water or deionized water in a volume ratio of 1:1 to 1:2 ml:ml.

[0017] In one exemplary embodiment of this invention, the concentration of the sodium chromate solution may be 0.05–0.2 mol / L.

[0018] In one exemplary embodiment of one aspect of the present invention, the demulsifying solvent may include 0-50% by volume propylene glycol n-propyl ether, 0-50% xylene, and 0-50% isopropanol. Another aspect of the present invention provides a method for preventing blockage of drilling fluid circulation channels inside drill bits. This method can be implemented using the rapid qualitative detection method for barium ions in oil-based drilling fluids as described in any of the above claims, and includes the following steps:

[0019] Take a sample of the oil-based drilling fluid to be tested and use a rapid qualitative detection method for barium ions in oil-based drilling fluid to determine whether it contains barium ions;

[0020] If barium ions are confirmed to be present, preventative measures should be taken in advance to avoid the formation of barium salt crystals and scale that can clog the internal circulation channels of the drill bit.

[0021] In another exemplary embodiment of the present invention, the preventive measures may include: adding a barium ion remover to the oil-based drilling fluid to remove barium ions therein.

[0022] Compared with the prior art, the beneficial effects of the present invention include at least one of the following:

[0023] (1) The rapid qualitative detection method for barium ions in oil-based drilling fluid of the present invention is simple, fast and inexpensive to operate, and can obtain results within 30 minutes. It does not require special instruments and reagents, and is convenient to be detected at the drilling site, and can quickly guide the on-site response measures.

[0024] (2) The detection method of the present invention can effectively avoid the interference of high concentrations of calcium ions in oil-based drilling fluids on the detection results. When the barium ion concentration is greater than 500 mg / L (the minimum crystallization concentration of barium ions in the wellbore environment is 3.04 × 10⁻⁶), the detection results are obtained even when the barium ion concentration is greater than 500 mg / L (the minimum crystallization concentration of barium ions in the wellbore environment is 3.04 × 10⁻⁶). 5 The presence of barium ions can be detected with a concentration of mg / L, which is a reliable method and provides accurate test results.

[0025] (3) Barium salt crystallization is impossible at a concentration of 500 mg / L. Therefore, this test method can determine the presence of barium ions under extremely low concentration conditions and take measures to remove barium ions in advance to avoid the precipitation of barium salt crystals after the barium ion concentration accumulates to a high level, which would block the drilling fluid flow channel. Detailed Implementation

[0026] The following will describe in detail the rapid detection method for barium ions in oil-based drilling fluids and the method for preventing drill string blockage of the present invention with reference to exemplary embodiments. In a first exemplary embodiment of the present invention, the rapid qualitative detection method for barium ions in oil-based drilling fluids mainly includes the following steps:

[0027] The oil-based drilling fluid sample and the demulsifying solvent are mixed and stirred until homogeneous to obtain a mixed solution. Here, the oil-based drilling fluid sample and the demulsifying solvent are mixed in a volume ratio of 1:25 to 1:100 ml:ml. The mixed solution is then mixed with distilled water or deionized water, stirred, and allowed to stand until the oil and water separate into layers. Here, the mixed solution is mixed with distilled water or deionized water in a volume ratio of 1:1 to 1:2 ml:ml.

[0028] Filter the lower aqueous phase until a colorless, clear liquid is obtained. Here, the lower aqueous phase can be a grayish-white, turbid liquid, and the filter paper used for filtration can be rapid qualitative filter paper. If the liquid is still not clear enough after one filtration, the filter paper can be replaced and the filtration can be repeated, or three sheets of filter paper can be stacked for filtration.

[0029] Add sodium chromate solution to the colorless, clear liquid and observe whether a yellow precipitate appears. If a yellow precipitate appears, it indicates that the oil-based drilling fluid sample contains barium ions; if no yellow precipitate appears, it indicates that the oil-based drilling fluid sample does not contain barium ions. Here, the concentration of the sodium chromate solution can be 0.05–0.2 mol / L.

[0030] In this exemplary embodiment, the absence of barium ions in the oil-based drilling fluid means that the barium ion concentration in the oil-based drilling fluid is less than 500 mg / L. Specifically, this detection method effectively avoids the interference of high concentrations of calcium ions in the oil-based drilling fluid on the detection results. When the barium ion concentration is greater than or equal to 500 mg / L (the minimum crystallization concentration of barium ions in the wellbore environment is 3.04 × 10⁻⁶), the detection results are obtained. 5 The presence of barium ions can be detected by a concentration of mg / L, which is a reliable method and provides accurate test results.

[0031] In this exemplary embodiment, the oil-based drilling fluid sample may contain calcium ions and barium ions. Both calcium and barium ions can react with sodium chromate to form calcium chromate and barium chromate, respectively. Under the same conditions, the solubility of calcium chromate is much greater than that of barium chromate. Furthermore, within the temperature range of 10–30°C, the solubility of calcium chromate can be 4110–20650 times that of barium chromate. See Table 1 below for details.

[0032] Table 1 Solubility of Barium Chromate and Calcium Chromate

[0033]

[0034] In this exemplary embodiment, the rapid qualitative detection method can detect whether barium ions are present in oil-based drilling fluid within 30 minutes. Specifically, the qualitative detection method for barium ions in oil-based drilling fluid of the present invention is simple, rapid, and inexpensive to operate, and can obtain results within 30 minutes. It requires no special instruments or reagents, making it convenient for on-site detection and quickly guiding on-site countermeasures.

[0035] In this exemplary embodiment, the demulsifying solvent may include 0-50% by volume propylene glycol propyl ether, 0-50% by volume xylene, and 0-50% by volume isopropanol. In a second exemplary embodiment of the present invention, the method for preventing blockage of the drilling fluid circulation channels inside the drill string can be implemented by the rapid qualitative detection method for barium ions in oil-based drilling fluid described in the first exemplary embodiment above, and includes the following steps:

[0036] Take a sample of the oil-based drilling fluid to be tested and use a rapid qualitative detection method for barium ions in oil-based drilling fluid to determine whether it contains barium ions;

[0037] If barium ions are confirmed to be present, preventative measures should be taken in advance to avoid the formation of barium salt crystals and scale that can clog the internal circulation channels of the drill bit.

[0038] In this exemplary embodiment, the preventive measures may include adding a barium ion remover to the oil-based drilling fluid to remove barium ions. Here, the barium ion remover is mainly various sulfates, such as potassium sulfate, sodium sulfate, etc.

[0039] To better understand the exemplary embodiments of the present invention described above, further explanation is provided below with reference to specific examples.

[0040] Example 1

[0041] Oil-based drilling fluids and prepared drilling muds (prepared without barium ions) from three actual drilled wells (A, B, and C) were tested. Well A encountered a soluble barium salt formation, resulting in barium salt crystallization within the drill string and clogging of the drilling fluid flow channels. Wells B and C did not exhibit this problem. The oil-based drilling fluids and prepared drilling muds from wells A, B, and C were tested according to the testing method of this invention.

[0042] 1. Add 100 mL of demulsifying solvent to each of the four 500 mL Erlenmeyer flasks.

[0043] 2. Using four 5mL syringes, draw up at least 3mL of oil-based drilling fluid samples from wells A, B, and C, as well as a prepared well slurry sample, and transfer 2.0mL of each sample into four titration containers.

[0044] 3. Stir the sample and demulsifying solvent for 5 minutes until they are evenly mixed. Add 200 mL of distilled water (or deionized water) to each titration vessel, stir for 10 minutes, and then let stand.

[0045] 4. Add the stirred liquid mixture to four pear-shaped separatory funnels and let it stand until the oil and water separate (generally no more than 5 minutes). Take out about 60-70 mL of the lower aqueous phase and place it in four beakers.

[0046] 5. Due to the presence of oil-based drilling fluid, the extracted lower aqueous phase is a grayish-white turbid liquid. Filter the grayish-white turbid liquid with rapid qualitative filter paper until the grayish-white turbid liquid becomes a colorless and clear liquid (if the liquid is still not clear enough after filtration, the filter paper can be replaced and filtered repeatedly or three filter papers can be stacked for filtration).

[0047] 6. Take approximately 50 mL of the filtered colorless and clear liquid and place it into four beakers. Add 3–5 drops of 0.1 mol / L sodium chromate solution to each beaker and observe whether a yellow precipitate appears. The test results are shown in Table 2 below:

[0048] Table 2. Test results of oil-based drilling fluid samples from three actual drilled wells A, B, and C.

[0049]

[0050]

[0051] Example 2

[0052] The basic formula for preparing 7 cups of oil-based drilling fluid is as follows:

[0053] 240mL white oil + 6g primary emulsifier + 3g secondary emulsifier + 6g calcium oxide + 0.9g organic clay + 3g plugging agent + 1.5g filtration reducer + 4.5g wetting agent + 80mL calcium chloride brine (dissolve 20g anhydrous calcium chloride in 100mL distilled water, then measure out 80mL and add to oil-based drilling fluid) + 800g barite.

[0054] Different amounts of barium nitrate were added to seven cups of oil-based drilling fluid to form oil-based drilling fluids with different barium ion concentrations. The testing method of this invention (see Example 1 for specific steps) was used to test these seven cups of oil-based drilling fluids. The test results are shown in Table 3 below:

[0055] Table 3. Test results of oil-based drilling fluids with different barium ion concentrations

[0056] Serial Number Barium ion concentration mg / L Analytical liquid sample Barium ion detection results Remark 1 0 No sediment Barium ion-free - 2 100 No sediment Barium ion-free - 3 300 No sediment Barium ion-free - 4 500 Slightly cloudy Barium ion - 5 800 turbid Barium ion - 6 1000 turbid Barium ion - 7 5000 turbid Barium ion -

[0057] As shown in Table 3, the detection method of the present invention can detect barium ion concentrations of 500 mg / L or higher.

[0058] Example 3

[0059] Various types of oil-based drilling fluids are available:

[0060] A. Water-in-oil white oil-based drilling fluid (slurry);

[0061] B. Water-in-oil diesel-based drilling fluid (slurry);

[0062] C. All-oil-based drilling fluid (prepared with white oil, well slurry);

[0063] D. All-oil-based drilling fluid (prepared with diesel oil, formula as follows: diesel oil + 3% emulsifier + 4% organic clay + 1% plugging agent + 2% filtration reducer + 2% wetting agent + 1% flow pattern modifier + 800g barite);

[0064] E. Water-in-oil synthetic drilling fluid (prepared with synthetic base oil, formula as follows: 240mL synthetic base oil + 6g primary emulsifier + 3g secondary emulsifier + 6g calcium oxide + 0.9g organo-earth + 3g plugging agent + 1.5g filtration reducer + 4.5g wetting agent + 80mL calcium chloride brine + 800g barite);

[0065] F. Oil-in-water low oil-water ratio oil-based drilling fluid (prepared with white oil, formula as follows: 180mL white oil + 6g primary emulsifier + 3g secondary emulsifier + 6g calcium oxide + 0.9g organic clay + 3g plugging agent + 1.5g filtration reducer + 4.5g wetting agent + 120mL calcium chloride brine + 800g barite).

[0066] First, the barium ion detection method of the present invention was used to detect barium ions in the above six oil-based drilling fluids. The detection results are shown in Table 4 below:

[0067] Table 4 Test results of different oil-based drilling fluids

[0068] Serial Number Analytical liquid sample Barium ion detection results A No sediment Barium ion-free B No sediment Barium ion-free C No sediment Barium ion-free D No sediment Barium ion-free E No sediment Barium ion-free F No sediment Barium ion-free

[0069] As shown in Table 4, none of the six oil-based drilling fluids contained barium ions. To verify this detection method, different concentrations of barium ions were added to the six oil-based drilling fluids, and the barium ion concentration was measured again. The specific results are shown in Table 5 below:

[0070] Table 5. Test results of adding different concentrations of barium ions to different oil-based drilling fluids.

[0071]

[0072] As shown in Table 5, the rapid qualitative detection method for barium ion concentration of the present invention yields consistent results for water-in-oil, all-oil-based drilling fluids, various formulated base oils (white oil, diesel oil, synthetic base oil), and oil-based drilling fluids with different oil-water ratios (100:0 to 60:40). This indicates that the detection method is applicable to all types of oil-based drilling fluids, has good reproducibility, and provides stable detection results.

[0073] Example 4

[0074] The results of the rapid qualitative detection method for barium ions in drilling fluid selected at the drilling site were compared with those of existing laboratory tests. Specific results are shown in Table 6 below.

[0075] Table 6 Comparison of Drilling Site Testing and Laboratory Testing Results

[0076] As shown in Table 6, the field test results are completely consistent with the laboratory test results, indicating that the rapid qualitative testing method of this invention is highly accurate. Comparative tests were conducted on well slurries from more than 20 wells using the rapid qualitative testing method of this invention and the laboratory testing method. The test results show that the field drilling test results are completely consistent with the laboratory results.

[0077] Table 7 Comparison of the detection method of the present invention with existing similar technologies

[0078] Test methods The test method of the present invention Existing similar technologies cycle 30min More than 7 working days cost Less than 100 yuan / time More than 5000 yuan / time Place Drilling site professional laboratory Instruments and equipment Conventional glass instruments at drilling sites, etc. Precision analytical instruments personnel Drilling Fluid Engineer professional analysts Personnel training requirements Training takes 2-3 hours. Professional and technical training, long duration Test Results Qualitative analysis Quantitative analysis

[0079] As shown in Table 7, compared with similar technologies currently in widespread use, this testing method has advantages such as shorter testing cycle, simpler instruments and equipment, lower cost, lower personnel requirements and faster training, and the ability to perform analysis directly on-site.

[0080] Oil-based drilling fluids are a primary technology for unconventional oil and gas development, such as shale gas and tight gas. In China, at least 500 wells are drilled annually using oil-based drilling fluids (each well using over 200 cubic meters), and the operation cycle is relatively long, generally 15-60 days or even longer. If barium-containing formations are encountered, the oil-based drilling fluid will contain barium ions. Barium ion crystallization can clog drill strings, causing a series of downhole complications. Barium ions are highly toxic substances, posing significant harm to the environment and humans. When barium ions infiltrate oil-based drilling fluids, the fluid, waste fluids, and drill cuttings will all contain barium ions, posing safety and environmental risks. To address this issue, a method is needed for rapid, repeated detection of barium ions in oil-based drilling fluids to guide appropriate countermeasures.

[0081] Existing methods for detecting barium ions in oil-based drilling fluids are time-consuming, and during the waiting period, barium ions may crystallize in the oil-based drilling fluid, causing a series of complications. Furthermore, existing methods are expensive, and multiple tests on all wells would incur huge costs, making them impractical. This invention provides a rapid qualitative detection method for barium ions, solving the technical challenge of quickly and accurately detecting the presence of barium ions in oil-based drilling fluids at a low cost. It provides rapid results and allows for targeted barium removal measures. This method can be used in conjunction with barium removal measures, conducting multiple tests until barium ions are completely removed from the oil-based drilling fluid. This effectively avoids downhole complications caused by barium ion crystallization in oil-based drilling fluids, and resolves the downhole complications and safety and environmental risks that may result from barium ion intrusion into oil-based drilling fluids. It has significant social benefits and aligns with national policies and the operational and technological development needs of the petroleum industry.

[0082] In summary, the beneficial effects of the present invention include at least one of the following:

[0083] (1) The rapid qualitative detection method for barium ions in oil-based drilling fluid of the present invention is simple, fast and inexpensive to operate, and can obtain results within 30 minutes. It does not require special instruments and reagents, and is convenient to be detected at the drilling site, and can quickly guide the on-site response measures.

[0084] (2) The detection method of the present invention can effectively avoid the interference of high concentrations of calcium ions in oil-based drilling fluids on the detection results. When the barium ion concentration is greater than 500 mg / L (the minimum crystallization concentration of barium ions in the wellbore environment is 3.04 × 10⁻⁶), the detection results are obtained even when the barium ion concentration is greater than 500 mg / L (the minimum crystallization concentration of barium ions in the wellbore environment is 3.04 × 10⁻⁶). 5 The presence of barium ions can be detected with a concentration of mg / L, which is a reliable method and provides accurate test results.

[0085] (3) Barium salt crystallization is impossible at a concentration of 500 mg / L. Therefore, this test method can determine the presence of barium ions under extremely low concentration conditions and take measures to remove barium ions in advance to avoid the precipitation of barium salt crystals after the barium ion concentration accumulates to a high level, which would block the drilling fluid flow channel.

[0086] Although the present invention has been described above in conjunction with exemplary embodiments, it should be clear to those skilled in the art that various modifications can be made to the above embodiments without departing from the spirit and scope of the claims.

Claims

1. A rapid qualitative detection method for barium ions in oil-based drilling fluids, characterized in that, The rapid qualitative detection method includes the following steps: The oil-based drilling fluid sample and the demulsifier were mixed at a volume ratio of 1:25ml to 1:100ml and stirred until homogeneous to obtain a mixed solution. The demulsifying solvent comprises 0-50% by volume propylene glycol n-propyl ether, 0-50% xylene, and 0-50% isopropanol; Mix the mixture with distilled water or deionized water at a volume ratio of 1:1ml to 1:2ml, stir, and let stand until the oil and water separate into layers. The lower aqueous phase was filtered until a colorless and clear liquid was obtained. Add 0.05–0.2 mol / L sodium chromate solution to the colorless and clear liquid and observe whether a yellow precipitate appears. If a yellow precipitate appears, it indicates that the barium ion concentration in the oil-based drilling fluid is ≥500 mg / L. If no yellow precipitate appears, it indicates that the barium ion concentration in the oil-based drilling fluid is <500 mg / L. The detection method can be completed within 30 minutes; The detection method requires no special instruments or reagents, making it convenient to conduct detection at the drilling site.

2. The rapid qualitative detection method for barium ions in oil-based drilling fluid according to claim 1, characterized in that, The lower aqueous phase is a grayish-white turbid liquid, and the filter paper used for filtration is a rapid qualitative filter paper.

3. The rapid qualitative detection method for barium ions in oil-based drilling fluid according to claim 1, characterized in that, The oil-based drilling fluid sample contains calcium ions and barium ions. Both calcium ions and barium ions can react with sodium chromate to form calcium chromate and barium chromate. Under the same conditions, the solubility of calcium chromate is much greater than that of barium chromate.

4. The rapid qualitative detection method for barium ions in oil-based drilling fluid according to claim 3, characterized in that, Within the temperature range of 10 to 30°C, the solubility of the calcium chromate is 4110 to 20650 times that of the barium chromate.

5. The rapid qualitative detection method for barium ions in oil-based drilling fluid according to claim 1, characterized in that, The rapid qualitative detection method can detect whether barium ions are present in oil-based drilling fluid within 30 minutes.

6. A method for preventing blockage of drilling fluid circulation channels inside drilling tools, characterized in that, The method for preventing blockage of the drilling fluid circulation channels inside the drilling tool is implemented by the rapid qualitative detection method for barium ions in oil-based drilling fluid as described in any one of claims 1 to 5, and includes the following steps: Take a sample of the oil-based drilling fluid to be tested, and use a rapid qualitative detection method for barium ions in oil-based drilling fluid to detect whether it contains barium ions; If barium ions are confirmed to be present, preventative measures should be taken in advance to avoid the formation of barium salt crystals and scale that can clog the internal circulation channels of the drill bit.

7. The method for avoiding blockage of the drilling fluid circulation channel inside the drill string according to claim 6, characterized in that, The preventive measures include adding a barium ion remover to the oil-based drilling fluid to remove barium ions.

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