CN107663446B - Blocking remover for oil-based drilling fluid and preparation method thereof - Google Patents
Blocking remover for oil-based drilling fluid and preparation method thereof Download PDFInfo
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Abstract
The invention discloses a blocking remover for an oil-based drilling fluid, which comprises the following components in percentage by weight: 10-20% of acid liquor, 4-6% of emulsifier, 2-4.5% of dispersant, 1-3% of solubilizer, 1-3% of waterproof locking agent, 1-2% of chelating agent, 0.1-0.3% of cleanup additive and the balance of water; wherein the acid solution is selected from hydrochloric acid, nitric acid, phosphoric acid and composite acid; the waterproof locking agent is composed of fatty alcohol-polyoxyethylene ether, alkyl sodium sulfonate, polyoxyethylene ester and water. The blocking remover for the oil-based drilling fluid disclosed by the invention has the following beneficial effects: (1) the comprehensive performance is good, the cost is low, the waterproof locking agent in the blockage removing system can effectively protect an oil layer, and the secondary damage to the oil layer is reduced. (2) The preparation is simple, other treating agents are not needed to be added on site, and only water is needed to be added to dilute the mixture into the designed concentration.
Description
Technical Field
The invention relates to an oil-based drilling fluid blocking remover and a preparation method thereof, belonging to the technical field of drilling fluid blocking removal.
Background
The oil-based drilling fluid is applied from the last 20 years, has the advantages of high temperature resistance, salt and calcium erosion resistance, good collapse resistance, good lubricating property, small damage to oil and gas reservoirs and the like compared with water-based drilling fluid, and is an important means for drilling high-difficulty high-temperature deep wells, large-inclination directional wells, horizontal wells and various complex strata at present. However, the filter cake formed by the oil-based drilling fluid is easy to cause the permeability of the reservoir to be blocked, so that the reservoir is damaged. At present, more research methods are used for unblocking water-based drilling fluid, and relatively less research is used for effectively unblocking oil-based drilling fluid.
At present, the known unblocking agent for oil-based drilling fluid and the preparation method thereof mainly comprise the following steps: the brave et al propose a compound blocking remover JDJ in the strong blocking oil-based drilling fluid drilling reservoir blocking removing technology, which is an oil-in-water emulsion prepared by compounding organic acid, inorganic acid, nonionic surfactant, organic solvent and the like. When in application, the blocking remover and seawater are mixed into water-based blocking remover according to the ratio of 1:4, and inorganic salt such as KCl is used for adjusting the density (see drilling fluid and completion fluid, 2013, 30 (2)). In the application of an oil-based mud damage blockage removal process in a WZAA-X1 well, the Liangyukai et al provides a blockage removal agent NH-JDJ, which comprises the following components in percentage by weight: 2O% of cleaning penetrant, 12% of solvent type organic matter, 6% of emulsion breaker, 2.5% of clay stabilizer, 15% of organic acid, 1.5% of corrosion inhibitor, 3% of iron ion stabilizer and the balance of seawater (see the book 2015,28(5) of the college and universities of petrochemical industry). Patent document CN 201110326605.6 (grant No. CN 103074046B) discloses a completion fluid for removing filter cake of oil-based drilling fluid and a preparation method thereof, the components include a base fluid, a primary emulsifier, a secondary emulsifier, an inter-solvent and a high-efficiency blocking remover, wherein the weight percentage of the base fluid is 85-92%, the weight percentage of the primary emulsifier is 2-4%, the weight percentage of the secondary emulsifier is 2-3%, the weight percentage of the inter-solvent is 1-3% and the weight percentage of the high-efficiency blocking remover is 3-5%. Patent document CN 201410535641.7 (publication number: CN 104263339 a) discloses a well completion cleaning solution for an oil-based drilling fluid well and a preparation method thereof, wherein the well completion cleaning solution for the oil-based drilling fluid well comprises the following raw materials in percentage by weight: 25 to 30 percent of organic acid solution, 1 to 3 percent of emulsifier, 0.5 to 0.7 percent of organic solvent, 0.5 to 2 percent of rapid penetrating agent, 0.05 to 0.1 percent of corrosion inhibitor and the balance of base oil.
In the well-known oil-based drilling fluid blockage removing systems listed above, the first two oil-based drilling fluid blockage removing systems are water-based blockage removing fluids, so the cost is low, but the systems do not contain a waterproof locking agent, so that water locking damage to a reservoir stratum is easily caused; the latter two oil-based drilling fluid blockage relieving systems are oil-based blockage relieving liquids, contain no aqueous phase, can prevent water from polluting the oil-based drilling fluid, prevent formation of water lock damage to a reservoir, but are high in cost.
Disclosure of Invention
Aiming at the prior art, the invention provides an oil-based drilling fluid blocking remover and a preparation method thereof, aiming at solving the problems of poor blocking removing effect, high cost and the like of oil-based drilling fluid in oil fields in the prior art. The blocking remover disclosed by the invention is good in comprehensive performance and low in cost, the water-proof locking agent in the blocking remover system can effectively protect an oil layer and reduce secondary damage to the oil layer, and the blocking remover effect is 5 times that of conventional earth acid. The emulsifier in the blockage removal system has excellent emulsifying capacity; the discharge assistant in the blockage removal system has the capability of reducing the surface interface more strongly, the discharge assistant rate can reach over 36 percent, the filtration loss can be reduced, the water contact angle is increased, and the problem of large adsorption of the cationic surfactant is effectively solved; the on-site preparation is simple, other treating agents are not needed to be added, and only water is needed to be added for dilution to the designed concentration.
The invention is realized by the following technical scheme:
the blockage remover for the oil-based drilling fluid comprises the following components in percentage by weight: 10-20% of acid liquor, 4-6% of emulsifier, 2-4.5% of dispersant, 1-3% of solubilizer, 1-3% of waterproof locking agent, 1-2% of chelating agent, 0.1-0.3% of cleanup additive and the balance of water; wherein,
the acid solution is selected from hydrochloric acid, nitric acid, phosphoric acid and composite acid; preferably a complex acid; the composite acid is prepared by mixing hydrochloric acid (the concentration is 9.87g/mol), hydrofluoric acid and nitric acid according to the volume ratio of 1:3: 0.5.
The emulsifier is selected from AE1910, alkylphenol ether sulfosuccinate sodium salt, isomeric alcohol and ethylene oxide condensate, fatty acid polyoxyethylene ester, polyoxyethylene fatty acid ester and stearic acid polyoxyethylene ether; the sodium alkylphenol ether sulfosuccinate is preferably selected, the sodium alkylphenol ether sulfosuccinate is of a trimerization type phthalic amine structure, and the organic amine surfactant can form a clay-amine complex structure with organic soil and has excellent emulsifying capacity.
The dispersing agent is selected from sodium polyacrylate, modified polycarboxylate, polyepoxy sodium succinate, sodium polyaspartate, acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer, maleic acid-acrylic acid copolymer and carboxylate-sulfonate-nonionic terpolymer; acrylic acid-2-acrylamido-2-methylpropanesulfonic acid copolymer is preferred.
The solubilizer is selected from N- (2-hydroxyethyl) -N- (2-ethylhexyl) - β -alanine monosodium salt, N- (2-hydroxyethyl) -N- (octyl) - β -alanine monosodium salt, tallow dihydroxyethyl betaine, phenol ether phosphate and alkyl betaine, preferably phenol ether phosphate which is an associated long-chain alkane structure.
The waterproof locking agent is a self-made waterproof locking agent FSH and consists of fatty alcohol-polyoxyethylene ether, alkyl sodium sulfonate, polyoxyethylene ester and water, wherein the mass fractions of the fatty alcohol-polyoxyethylene ether, the alkyl sodium sulfonate and the polyoxyethylene ester are respectively 0.45-0.55%, 0.04-0.06% and 0.025-0.035%, and the balance of the water (in preparation, the four raw materials are directly mixed and stirred uniformly).
The chelating agent is selected from acetic acid, sodium dimethyldithiocarbamate, dithiocarbamate, sodium methyldithiocarbamate and sodium thiosulfate; sodium methyldithiocarbamate, which is an ionic compound synthesized from an ammonium ion and an acid ion, is preferable.
The cleanup additive is a self-made microemulsion active cleanup additive and is prepared by the following method: adding a surfactant (octadecylamine polyoxypropyleneoxyethylene ether dicarboxylate), sodium salicylate, kerosene and water (the mass percentage of the four is 25-35 percent, 10-15 percent, 8-10 percent and 45-50 percent, preferably 30 percent, 12 percent, 10 percent and 48 percent) into a test tube in sequence for mixing, fully vibrating and standing to obtain emulsions with different compositions, wherein the emulsions are in different phase states, namely homogeneous emulsions, two-phase (upper phase and lower phase) emulsions and three-phase (middle phase) emulsions; and separating out the oil phase part of the emulsion, and adding water to dilute by 100-1000 times to obtain the microemulsion active cleanup additive.
The discharge aiding agent has stronger discharge aiding capacity, and the discharge aiding rate can reach over 36 percent; in addition, the filtration loss can be reduced, the water-wetting contact angle can be increased, and the problem of large adsorption of the cationic surfactant can be effectively solved.
The substances not described in detail above are all available from the market in general.
The oil-based drilling fluid blocking remover is preferably composed of the following components in percentage by weight: 20% of acid liquor, 6% of emulsifier, 4.5% of dispersant, 2.5% of solubilizer, 3% of waterproof locking agent, 2% of chelating agent, 0.2% of cleanup additive and the balance of water.
The preparation method of the blocking remover for the oil-based drilling fluid comprises the following steps: adding acid liquor, emulsifier, dispersant, solubilizer, water-proof locking agent, chelating agent and cleanup additive into a container in sequence, finally adding water, and stirring uniformly to obtain the product.
The blocking remover for the oil-based drilling fluid disclosed by the invention has the following beneficial effects:
(1) the blocking remover for the oil-based drilling fluid disclosed by the invention is good in comprehensive performance and low in cost, a waterproof locking agent in a blocking removing system can effectively protect an oil layer, secondary damage to the oil layer is reduced, and the blocking removing effect is 5 times that of the conventional earth acid.
(2) In the blocking remover for the oil-based drilling fluid, the emulsifier is of a trimerization type phthalein amine structure, and the organic amine surfactant can form a clay-amine complex structure with organic soil, has excellent emulsifying capacity, and enhances the emulsifying capacity of a system.
(3) In the blockage remover for the oil-based drilling fluid, the cleanup additive is a micro-emulsion active cleanup additive, and compared with a conventional cleanup additive, the micro-emulsion active cleanup additive has stronger cleanup capability, and the cleanup rate can reach over 36%; in addition, the filtration loss can be reduced, the water-wetting contact angle can be increased, and the problem of large adsorption of the cationic surfactant can be effectively solved.
(4) The blocking remover for the oil-based drilling fluid is simple in preparation, other treating agents do not need to be added on site, and the blocking remover only needs to be diluted into a designed concentration by adding water.
Drawings
FIG. 1: corrosion curve of composite acid with different preparation proportions to mud.
FIG. 2: and (3) microemulsion structure.
FIG. 3: schematic diagram of the wetting reversal.
Detailed Description
The present invention will be further described with reference to the following examples.
The instruments, reagents, materials and the like used in the following examples are conventional instruments, reagents, materials and the like in the prior art and are commercially available in a normal manner unless otherwise specified. Unless otherwise specified, the experimental methods, detection methods, and the like described in the following examples are conventional experimental methods, detection methods, and the like in the prior art.
Experimental example 1: the main acid is preferably
Inorganic substances in oil-based mud, mainly clay (mainly montmorillonite), are removed, and in an acid solution system, under the conditions that the temperature is 60 ℃ and the experimental time is 5 hours, hydrochloric acid, composite acid (hydrochloric acid: hydrofluoric acid: nitric acid according to the volume ratio of 1:3:0.5), nitric acid and phosphoric acid with the mass fraction of 10% are selected to respectively have the corrosion rates of 14.6%, 62.5%, 12.8% and 14.3% on the mud, wherein the composite acid has the best corrosion effect on the mud. For this reason, the main acid for slurry erosion is determined to be a complex acid.
The results of the corrosion test of the composite acid with different preparation ratios on the slurry under the conditions that the test temperature is 60 ℃ and the test time is 5h are shown in figure 1. The experimental results show that: the corrosion rate of the composite acid to the slurry is gradually enhanced along with the increase of the mass fraction of the composite acid, and when the weight fraction of the composite acid is increased to more than 20%, the corrosion rate is reduced on the contrary, mainly because secondary precipitation is generated, and the optimal proportion of the composite acid is 20%.
Experimental example 2: the emulsifier is preferably
The organic matter in oil-based mud is mainly white oil. Because the blockage relieving system is water-based, an emulsifier is required for relieving oily matters, and the oily matters such as white oil and the like can be fully emulsified only by selecting a proper emulsifier and then discharged out of a near-wellbore area and a wellbore. The experimental method comprises the following steps: mixing oil and acid (6% emulsifier is added) according to a certain proportion (30:20), stirring uniformly, and measuring the demulsification amount at a certain temperature so as to measure the demulsification capacity. The results are shown in Table 1. As can be seen from Table 1, the demulsification rate of the emulsifier alkylphenol ether sulfosuccinate sodium salt reaches 100% at 10min, and the effect is the best. The emulsifier is preferably alkylphenol ether sulfosuccinate sodium salt. The emulsifier is of a trimerization type phthalic amine structure, the organic amine surfactant can form a clay-amine complex structure with organic soil, and the emulsifying capacity of the system is enhanced due to the excellent emulsifying capacity of the emulsifier.
And the demulsification rate of the emulsifier alkylphenol ether sulfosuccinate sodium salt under the condition of different concentrations is compared, and the experimental result is shown in table 2. As can be seen from Table 2, the emulsion breaking rate of the emulsifier reaches 100% at 6% concentration for 10min, and the emulsifier concentration is preferably 6%.
TABLE 1 demulsification experiment data table for different emulsifiers
TABLE 2 demulsification rate experiment table for alkylphenol ether sulfosuccinate sodium salt with different concentrations
Experimental example 3: the dispersant is preferably
Because the oil-based mud is a mixture of oil, inorganic clay and various additives, and a dispersant is added into the blockage removing system, the products after blockage removal form a stable dispersion body, secondary aggregation is not easy to occur, and blockage removing residual liquid can be well and thoroughly discharged.
The experimental method comprises the following steps: 0# diesel oil and acid liquor are mixed, different types of dispersants are added respectively, the concentration of the dispersant is 4%, the interfacial tension is measured by a JYW-200X type interfacial tension meter, and the experimental data are shown in Table 3.
TABLE 3 dispersant screening Experimental data
| Serial number | Dispersing agent | Average interfacial tension, mN/m |
| 1 | Polyacrylamide sodium salt | 1.8 |
| 2 | Modified polycarboxylates | 5.2 |
| 3 | Polyepoxysuccinic acid sodium salt | 6.0 |
| 4 | Polyaspartic acid sodium salt | 3.0 |
| 5 | Acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer | 1.3 |
| 6 | Maleic acid-acrylic acid copolymer | 1.6 |
| 7 | Carboxylate-sulfonate-nonionic terpolymers | 2.0 |
As can be seen from table 3: the dispersant acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer is optimal, and the average interfacial tension is 1.3 mN/m. The acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer is a polyoxyethylene ether surfactant, and in order to further determine the optimal use concentration of the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer, the interfacial tension of the acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer with different concentrations is measured, and the experimental results are shown in table 4. As can be seen from table 4, the interfacial tension did not change much when the concentration exceeded 4.5%, so 4.5% was selected as the optimum concentration for use.
TABLE 4 determination of interfacial tension test data for acrylic acid-2-acrylamido-2-methylpropanesulfonic acid copolymers at various concentrations
Experimental example 4: the solubilizer is preferably
When the water-based emulsification system is usually adopted to remove the blockage of organic matters, in order to enhance the dissolving capacity of the organic matters, a solubilizer is usually added to enhance the blockage removing effect.
The experimental method comprises the following steps: 0# diesel oil and acid liquor are mixed, different types of solubilizing agents are respectively added, the concentration of the solubilizing agents is 2.5%, the interfacial tension of the mixture is measured by a JYW-200X type interfacial tension meter, and the experimental data are shown in Table 5.
TABLE 5 solubilizer screening test data
| Serial number | Solubilizer | Average interfacial tension, mN/m |
| 1 | N- (2-hydroxyethyl) -N- (2-ethylhexyl) - β -alanine monosodium salt | 3.6 |
| 2 | N- (2-hydroxyethyl) -N- (octyl) - β -alanine monosodium salt | 4.1 |
| 3 | Tallow dihydroxyethyl betaine | 2.5 |
| 4 | Phenol ether phosphate esters | 0.8 |
| 5 | Alkyl betaines | 1.9 |
As seen from Table 5, the solubilizing agent phenolether phosphate was most effective in solubilizing, and therefore, the solubilizing agent was selected as the solubilizing agent for experiments. The phenol ether phosphate as a solubilizing agent is an associative long-chain alkane structure, and the solubilizing agent is initially solubilized while increasing the amount of the solubilizing substance in water while maintaining a certain surfactant concentration, but when the maximum solubilizing amount is exceeded, the solubilizing substance begins to become a second phase. This is more favorable for the dissolution of organic matters. To further determine the optimum concentration of phenol ether phosphate for use, measurements of the interfacial tension of the phenol ether phosphate at various concentrations were made and the results are shown in Table 6. As can be seen from table 6, the interfacial tension does not change much when the concentration exceeds 2.5%, so 2.5% is selected as the optimum concentration for use.
TABLE 6 determination of interfacial tension of phenol ether phosphate at various concentrations
Experimental example 5: the water-proof locking agent is preferably
The oil-based mud is mainly used for protecting an oil layer to the maximum extent and mainly avoiding water damage. The blockage relieving system of the invention is water-based, so a waterproof locking agent should be added. The FSH waterproof locking agent developed by the invention consists of fatty alcohol-polyoxyethylene ether, alkyl sodium sulfonate, polyoxyethylene ester and water, wherein the mass fractions of the fatty alcohol-polyoxyethylene ether, the alkyl sodium sulfonate and the polyoxyethylene ester are respectively 0.5%, 0.05% and 0.03%, and the balance is water (in preparation, the four raw materials are directly mixed and stirred uniformly).
The developed FSH waterproof locking agent has lower surface interfacial tension, the milk prevention rate is more than or equal to 98 percent, the FSH waterproof locking agent resists high temperature, and the flowback pressure is obviously reduced (the performance index is shown in a table 7).
TABLE 7 FSH Water-lock Performance index
| Performance of | Index (I) |
| Surface tension | ≤28×10-3N/m |
| Interfacial tension | ≤0.6×10-3N/m |
| Milk prevention rate | ≥98％ |
| Temperature resistant | 150℃ |
| Reducing the amplitude of the back pressure | ≥50％ |
TABLE 8 Water-proof Lock test results
The core of 2 wells is taken to perform a waterproof lock experiment, and the experimental result table 8 shows that the developed FSH waterproof locking agent has an obvious effect on preventing the damage of low-permeability core caused by pre-waterproof invasion, is used for low-permeability oil reservoirs, and has a good effect on preventing the damage caused by water invasion.
Experimental example 6: the chelating agent is preferably
In order to prevent iron hydroxide precipitation generated in the acidification process from causing formation blockage and reducing the formation permeability, a chelating agent needs to be added.
The experimental method comprises the following steps: different chelating agents with the concentration of 2.0% are added into the acid, the residual acid is taken after the reaction with the rock debris, the pH value of the residual acid when precipitates appear in the residual acid is measured by titration with NaOH solution, and the experimental results are shown in Table 9.
As can be seen from the results in Table 9, the chelating agent sodium methyldithiocarbamate was selected because the pH of the precipitate produced after addition of the chelating agent sodium methyldithiocarbamate was the highest. The chelating agent sodium methyldithiocarbamate is an ionic compound synthesized by ammonium ions and acid radical ions and is a white solid.
As can be seen from table 9, after the chelating agent sodium methyldithiocarbamate is added to the acid, no precipitate is generated before the pH is 6.5, indicating that the chelating agent sodium methyldithiocarbamate has good complexing ability for iron ions, because the ionic chelating agent sodium methyldithiocarbamate generates a synergistic effect after being compounded with other components, the polarity of polar groups of complexing agent molecules and the complexing distribution coefficient in acid solution are increased, and thus the complexing effect is improved. To further determine the optimum chelating agent concentration for use, a preferred experiment was conducted with different concentrations of sodium methyldithiocarbamate and the results are shown in Table 10. As can be seen from Table 10, the complexing ability was substantially unchanged when the chelating agent was used at a concentration exceeding 2%, and therefore the optimal chelating agent concentration of 2% was selected.
TABLE 9 Experimental data for various chelating agents
| Serial number | Chelating agents | pH value of the resulting precipitate |
| 1 | Acetic acid | 4.5 |
| 2 | Dimethyldithiocarbamate sodium salt | 4.9 |
| 3 | Dithiocarbamate salts | 4.8 |
| 4 | Sodium methyldithiocarbamate | 6.5 |
| 5 | Sodium thionate | 5.5 |
TABLE 10 Experimental data sheet for sodium methyldithiocarbamate as chelating agent at different concentrations
Experimental example 7: the discharge assistant is preferably
In order to more thoroughly discharge the blockage removing residual liquid, a discharge assistant is added into the system, and the flow-back efficiency is improved by reducing the interfacial tension.
The traditional cleanup additive is generally prepared by singly or compounding nonionic and anionic surfactants, has the action mechanism of directional arrangement and adsorption on an interface, has better surface interface reducing capability, and has limited improvement on contact angles. The cationic surfactant has a function of improving the wetting angle, but cannot be applied due to large adsorption. The discharge aiding rate of the common discharge aiding agent is less than 19 percent.
The cleanup additive used in the invention is a self-made microemulsion active cleanup additive, and is prepared by the following method: sequentially adding surfactant (octadecyl amine polyoxypropyleneoxyethylene ether dicarboxylate), sodium salicylate, kerosene and water (the mass percentage of the four is 30 percent to 12 percent to 10 percent to 48 percent) into a test tube, mixing, fully shaking and standing to obtain emulsion, separating out the oil phase part of the emulsion, and adding water to dilute by 500 times to obtain the microemulsion active cleanup additive.
The micro-emulsion active cleanup additive is composed of a surfactant, water, oil and an auxiliary agent, is a thermodynamically stable system (the structure is shown in figure 2), namely a homogeneous transparent system under general conditions, has the functions of the traditional cleanup additive, has good functions of improving and increasing the water-lubricated contact angle (shown in figure 3) due to the adsorption of an oil phase, and effectively reduces capillary force and improves flowback efficiency compared with the traditional cleanup additive (shown in table 11). The micro-emulsion active cleanup additive has a cleanup rate of over 36 percent. Due to the special composition of the microemulsion and the special surfactant and auxiliary agent, the structure is formed under higher concentration, and the water phase is diluted without layering or turbidity and still can keep a certain shape with a nano-scale structure.
When the microemulsion contacts the rock surface, the oil phase is adsorbed on the rock surface due to the special micelle structure, so that the rock wettability is improved, the improvement degree is related to the oil phase and the surfactant structure in the microemulsion and is closely related to the use concentration, and according to the formation condition, the ideal water-wetting contact angle can be achieved by adjusting the microemulsion composition and the use concentration, so that the capillary force is effectively reduced.
TABLE 11 microemulsion active cleanup additive vs. traditional cleanup additive
| Surface active agent | Nonionic surfactant | Anionic surfactants | Microemulsion active cleanup additive |
| Surface tension, mN/ |
30 | 31 | 31 |
| cosθ | 1.0 | 1.0 | 0.5 |
The microemulsion active cleanup additive has the advantages that:
(1) the surfactant in the microemulsion has the capability of reducing the surface interfacial tension of the conventional cleanup additive;
(2) has the ability to reduce fluid loss;
(3) has the capability of increasing the contact angle of water wetting;
(4) due to the adsorption of the oil phase, the problem of large adsorption of the cationic surfactant is solved.
Example 1 formulation of oil-based drilling fluid unblocking agent
The formula is as follows: 20% of acid liquor, 6% of emulsifier, 4.5% of dispersant, 2.5% of solubilizer, 3% of waterproof locking agent, 2% of chelating agent, 0.2% of cleanup additive and the balance of water; wherein the acid solution is a composite acid (hydrochloric acid with the concentration of 9.87 g/mol: hydrofluoric acid: nitric acid are mixed according to the volume percentage of 1:3:0.5), the emulsifier is alkylphenol ether sulfosuccinate sodium salt, the dispersant is acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer, the solubilizer is phenol ether phosphate, the waterproof locking agent is FSH, the cleanup additive is microemulsion active cleanup additive ME, and the chelating agent is sodium methyldithiocarbamate.
The waterproof locking agent is composed of fatty alcohol-polyoxyethylene ether, alkyl sodium sulfonate, polyoxyethylene ester and water, wherein the mass fractions of the fatty alcohol-polyoxyethylene ether, the alkyl sodium sulfonate and the polyoxyethylene ester are respectively 0.5%, 0.05% and 0.03%, and the balance is water (in preparation, the four raw materials are directly mixed and stirred uniformly).
The cleanup additive is prepared by the following method: adding surfactant (octadecyl amine polyoxypropyleneoxyethylene ether dicarboxylate), sodium salicylate, kerosene and water (the mass percentage of the four is 30% to 12% to 10% to 48%) into a test tube in sequence, mixing, fully shaking and standing to obtain emulsion, separating out the oil phase part of the emulsion, and adding water to dilute by 500 times.
The preparation method comprises the following steps: sequentially adding acid liquor, emulsifier, dispersant, solubilizer, water-proof locking agent, chelating agent and cleanup additive, finally adding water, and stirring uniformly to obtain the product.
Application examples of the blocking remover for the oil-based drilling fluid are as follows:
the 129-flat 10-well is positioned in a wet sunken pile west hidden mountain covering structure with north piles 129-inclined 10 blocks, is a large displacement deep horizontal well, and finishes the drilling depth of 4740.97 m. Three openings are completed by adopting an oil-based drilling fluid system and a perforated sieve tube, and the length of the sieve tube is 367.93 m. The oil of formulation example 1The plugging agent is prepared according to the preparation amount meeting the on-site requirement, and is injected into a 129-flat 10-well borehole of a pile according to the requirement, and the test liquid amount of the well after use is 36m3And d is 3 times of that of the adjacent horizontal well, and shows that the blocking remover for removing the filter cake of the oil-based drilling fluid can effectively remove the filter cake of the oil-based drilling fluid, effectively protect an oil layer and reduce secondary damage to the oil layer.
Example 2 formulation of oil-based drilling fluid unblocking agent
The formula is as follows: 10% of acid liquor, 6% of emulsifier, 2% of dispersant, 3% of solubilizer, 1% of waterproof locking agent, 2% of chelating agent, 0.1% of cleanup additive and the balance of water; wherein
The acid solution is selected from hydrochloric acid (the concentration is 9.87 g/mol).
The emulsifier is selected from polyoxyethylene fatty acid ester.
The dispersant is selected from sodium polyacrylate.
The solubilizer is selected from N- (2-hydroxyethyl) -N- (2-ethylhexyl) - β -alanine monosodium salt.
The chelating agent is selected from sodium thiosulfate.
The waterproof locking agent is composed of fatty alcohol-polyoxyethylene ether, alkyl sodium sulfonate, polyoxyethylene ester and water, wherein the mass fractions of the fatty alcohol-polyoxyethylene ether, the alkyl sodium sulfonate and the polyoxyethylene ester are respectively 0.45%, 0.06% and 0.025%, and the balance is water (in preparation, the four raw materials are directly mixed and stirred uniformly).
The cleanup additive is prepared by the following method: sequentially adding surfactant (octadecyl amine polyoxypropyleneoxyethylene ether dicarboxylate), sodium salicylate, kerosene and water (the mass percentage of the four components is 25: 15: 10: 50%) into a test tube, mixing, fully shaking and standing to obtain emulsion, separating out the oil phase part of the emulsion, and adding water to dilute by 100 times to obtain the emulsion.
The preparation method comprises the following steps: sequentially adding acid liquor, emulsifier, dispersant, solubilizer, water-proof locking agent, chelating agent and cleanup additive, finally adding water, and stirring uniformly to obtain the product.
Example 3 formulation of oil-based drilling fluid unblocking agent
The formula is as follows: 20% of acid liquor, 4% of emulsifier, 4.5% of dispersant, 1% of solubilizer, 3% of waterproof locking agent, 1% of chelating agent, 0.3% of cleanup additive and the balance of water; wherein
The acid solution is selected from nitric acid.
The emulsifier is selected from polyoxyethylene fatty acid ester.
The dispersant is selected from sodium polyepoxysuccinate.
The solubilizer is selected from tallow dihydroxyethyl betaine.
The chelating agent is selected from acetic acid.
The waterproof locking agent consists of fatty alcohol-polyoxyethylene ether, alkyl sodium sulfonate, polyoxyethylene ester and water, wherein the mass fractions of the fatty alcohol-polyoxyethylene ether, the alkyl sodium sulfonate and the polyoxyethylene ester are respectively 0.55%, 0.04% and 0.025%, and the balance is water (in preparation, the four raw materials are directly mixed and stirred uniformly).
The cleanup additive is prepared by the following method: sequentially adding surfactant (octadecylamine polyoxypropyleneoxyethylene ether dicarboxylate), sodium salicylate, kerosene and water (the mass percentage of the four is 35 percent to 10 percent to 45 percent) into a test tube, mixing, fully shaking and standing to obtain emulsion, separating out the oil phase part of the emulsion, and adding water to dilute 1000 times to obtain the emulsion.
The preparation method comprises the following steps: sequentially adding acid liquor, emulsifier, dispersant, solubilizer, water-proof locking agent, chelating agent and cleanup additive, finally adding water, and stirring uniformly to obtain the product.
Example 4 formulation of oil-based drilling fluid unblocking agent
The formula is as follows: 15% of acid liquor, 5% of emulsifier, 3.5% of dispersant, 2% of solubilizer, 2% of waterproof locking agent, 1.5% of chelating agent, 0.2% of cleanup additive and the balance of water; wherein
The acid solution is selected from phosphoric acid.
The emulsifier is selected from polyoxyethylene stearate.
The dispersant is selected from sodium polyaspartate.
The solubilizer is selected from alkyl betaine.
The chelating agent is selected from sodium dimethyldithiocarbamate.
The waterproof locking agent is composed of fatty alcohol-polyoxyethylene ether, alkyl sodium sulfonate, polyoxyethylene ester and water, wherein the mass fractions of the fatty alcohol-polyoxyethylene ether, the alkyl sodium sulfonate and the polyoxyethylene ester are respectively 0.5%, 0.05% and 0.03%, and the balance is water (in preparation, the four raw materials are directly mixed and stirred uniformly).
The cleanup additive is prepared by the following method: adding surfactant (octadecyl amine polyoxypropyleneoxyethylene ether dicarboxylate), sodium salicylate, kerosene and water (the mass percentage of the four is 31: 13: 8: 48%) into a test tube in sequence, mixing, fully shaking and standing to obtain emulsion, separating out the oil phase part of the emulsion, and adding water to dilute by 800 times.
The preparation method comprises the following steps: sequentially adding acid liquor, emulsifier, dispersant, solubilizer, water-proof locking agent, chelating agent and cleanup additive, finally adding water, and stirring uniformly to obtain the product.
Although the specific embodiments of the present invention have been described with reference to the examples, the scope of the present invention is not limited thereto, and those skilled in the art will appreciate that various modifications and variations can be made without inventive effort by those skilled in the art based on the technical solution of the present invention.
Claims (4)
1. The blocking remover for the oil-based drilling fluid is characterized by comprising the following components in parts by weight: the paint consists of the following components in percentage by weight: 10-20% of acid liquor, 4-6% of emulsifier, 2-4.5% of dispersant, 1-3% of solubilizer, 1-3% of waterproof locking agent, 1-2% of chelating agent, 0.1-0.3% of cleanup additive and the balance of water; wherein,
the acid solution is a composite acid formed by mixing hydrochloric acid, hydrofluoric acid and nitric acid according to the volume ratio of 1:3: 0.5;
the emulsifier is selected from sodium alkyl phenol ether sulfosuccinate;
the dispersant is selected from acrylic acid-2-acrylamide-2-methylpropanesulfonic acid copolymer;
the solubilizer is selected from phenol ether phosphate;
the waterproof locking agent consists of fatty alcohol-polyoxyethylene ether, alkyl sodium sulfonate, polyoxyethylene ester and water, wherein the mass fractions of the fatty alcohol-polyoxyethylene ether, the alkyl sodium sulfonate and the polyoxyethylene ester are respectively 0.45-0.55%, 0.04-0.06%, 0.025-0.035%, and the balance of water;
the chelating agent is selected from sodium methyldithiocarbamate;
the cleanup additive is a microemulsion active cleanup additive and is prepared by the following method: adding surfactant octadecylamine polyoxypropylene polyoxyethylene ether dicarboxylate, sodium salicylate, kerosene and water into a test tube to mix, wherein the mass percentages of the surfactant octadecylamine polyoxypropylene polyoxyethylene ether dicarboxylate, the surfactant sodium salicylate, the kerosene and the water are 25-35 percent, 10-15 percent, 8-10 percent and 45-50 percent; adding the mixture into a test tube in sequence, mixing, fully shaking and standing to obtain emulsion, separating out an oil phase part of the emulsion, and adding water to dilute 100-1000 times to obtain the emulsion.
2. The oil-based drilling fluid unblocking agent of claim 1, wherein: the waterproof locking agent consists of fatty alcohol-polyoxyethylene ether, alkyl sodium sulfonate, polyoxyethylene ester and water, wherein the mass fractions of the fatty alcohol-polyoxyethylene ether, the alkyl sodium sulfonate and the polyoxyethylene ester are respectively 0.5%, 0.05% and 0.03%, and the balance is water.
3. The oil-based drilling fluid unblocking agent of claim 1, wherein: the cleanup additive is prepared by the following method: adding surfactant octadecylamine polyoxypropylene polyoxyethylene ether dicarboxylate, sodium salicylate, kerosene and water into a test tube to mix, wherein the surfactant octadecylamine polyoxypropylene polyoxyethylene ether dicarboxylate, the sodium salicylate, the kerosene and the water are 30 to 12 to 10 to 48 mass percent; and (3) fully shaking and standing to obtain emulsion, separating out an oil phase part of the emulsion, and adding water to dilute by 100-1000 times to obtain the emulsion.
4. The oil-based drilling fluid unblocking agent of claim 1, wherein: the paint consists of the following components in percentage by weight: 20% of acid liquor, 6% of emulsifier, 4.5% of dispersant, 2.5% of solubilizer, 3% of waterproof locking agent, 2% of chelating agent, 0.2% of cleanup additive and the balance of water.
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| CN108929666B (en) * | 2018-06-25 | 2020-11-03 | 西南石油大学 | A high-efficiency plug removing agent for sour gas wells |
| CN108913112B (en) * | 2018-08-10 | 2019-06-14 | 宁夏朔光石油科技有限公司 | Cleaning antiscale and preparation method thereof |
| CN109575894B (en) * | 2018-12-29 | 2020-04-21 | 黑龙江益瑞化工有限公司 | Neutral blocking remover for chemical oil extraction in oil field and preparation method thereof |
| CN110821461B (en) * | 2019-10-28 | 2021-11-30 | 中国石油化工股份有限公司 | Composite water lock releasing process for low-permeability oil well |
| CN111961541A (en) * | 2020-08-24 | 2020-11-20 | 上海斯瑞文特种油品科技有限公司 | Environment-friendly metal surface cleaning agent and preparation method thereof |
| CN112745820A (en) * | 2021-02-01 | 2021-05-04 | 西南石油大学 | Barium sulfate scale dissolving agent |
| CN113429951B (en) * | 2021-08-02 | 2023-02-28 | 浙江砉润科技有限公司 | Biomass pollution-free oilfield blocking remover |
| CN115141616B (en) * | 2022-07-18 | 2024-10-29 | 洲际海峡能源科技有限公司 | Acid soaking and unclamping agent, preparation method thereof and acid soaking and unclamping method |
| CN115353869A (en) * | 2022-08-17 | 2022-11-18 | 扬州润达油田化学剂有限公司 | Neutral composite blocking remover |
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| CN103074046B (en) * | 2011-10-25 | 2015-05-13 | 中国石油化工股份有限公司 | Completion fluid used for removing filter cake formed by oil-based drilling fluid and preparation method thereof |
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