A releasing agent for drilling fluid and a preparation method thereof

Abstract

The present application relates to a kind of drilling fluid with releasing agent and its preparation method, belong to petroleum additive technical field.The component of the releasing agent is: synthetic ester 11-16.5wt%, self-adapting emulsifier 5.7-8.2wt%, water-soluble salt 0.5-2wt%, filtrate reducer 2.7-3.3wt% and tackifier 0.65-0.8wt%, the rest is water;The molecular main chain of self-adapting emulsifier is low molecular weight polyester chain, wherein the structure of disulfide bond sensitive to heat is embedded, and the side chain is short chain alkyl quaternary ammonium group, and most of the synthetic ester used for lubrication has good emulsification effect;In the process of releasing in deep well, the emulsified shell structure formed by self-adapting emulsifier disintegrates, and synthetic ester is fully released for lubrication, while the decomposition fragment promotes the decomposition of the mud cake at the stuck position, and efficient releasing is realized.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of petroleum additives, and particularly relates to a drilling fluid releasing agent and a preparation method thereof. BACKGROUND

[0002] In the drilling process, the pipe sticking accident is one of the common downhole complex conditions, which seriously affects the drilling efficiency and safety. The releasing agent as a key additive for treating the pipe sticking accident mainly functions to reduce the frictional resistance by penetrating into the adhesion interface between the drilling tool and the well wall, and to prevent the channeling of the drilling fluid by matching the density of the releasing fluid with the drilling fluid, so as to safely and efficiently release the pipe sticking. Especially in the complex working conditions such as high-pressure oil and gas water layer, easy-collapsing formation and ultra-deep well, the performance of the releasing agent is directly related to the success or failure of the accident treatment.

[0003] Traditionally, the oil-based releasing agent is widely used due to its excellent lubricating performance and penetration capacity. The oil-based releasing agent takes mineral oil or synthetic oil as the base, effectively reduces the friction between the drilling tool and the formation through the good spreading property and extreme pressure wear resistance of the oil phase. However, the oil-based system has obvious environmental protection defects: the use of a large amount of mineral oil and oil-soluble additives may cause soil and groundwater pollution, which does not meet the increasingly stringent environmental protection regulations, and especially the application in offshore drilling and ecologically sensitive areas is greatly limited.

[0004] To overcome the environmental protection problem of the oil-based releasing agent, the water-based releasing agent has gradually become the focus of research and application. The water-based releasing agent takes water as the continuous phase, and realizes the releasing function by adding lubricants, emulsifiers, penetrants and other additives. The core mechanism is to disperse the oily lubricating components (such as synthetic esters, vegetable oils, etc.) in water through emulsification to form an emulsion, and the emulsion particles release the lubricating components at the friction interface after being injected into the wellbore, thereby playing a role in reducing friction and releasing. However, the existing water-based releasing agent still faces many challenges: first, its lubricating effect is usually not as good as that of the oil-based system, especially in high temperature and high pressure environments; second, in order to realize effective penetration and releasing, a large amount of penetrants and other chemical additives are often needed, resulting in complex formula and high cost; more importantly, the addition of high content of additives not only increases the environmental burden, but also reduces the biodegradability and environmental compatibility of the system, so that the environmental protection advantage of the water-based releasing agent cannot be fully realized. SUMMARY

[0005] In order to solve the technical problems mentioned in the background art, the purpose of the present application is to provide a drilling fluid releasing agent and a preparation method thereof.

[0006] The purpose of the present application can be achieved by the following technical solutions:

[0007] A kind of drilling fluid with the fish agent, its specific component is: synthetic ester 11-16.5wt%, self-adapting emulsifier 5.7-8.2wt%, water-soluble salt 0.5-2wt%, filtrate reducer 2.7-3.3wt% and tackifier 0.65-0.8wt%, the rest is water.

[0008] Wherein, self-adapting emulsifier is prepared by the following method:

[0009] Step A1: N, N-dimethyl ethanolamine, triphenylphosphine and acetone are premixed, water bath temperature is controlled at 40-50 DEG C, neopentyl glycol diglycidyl ether is slowly added and stirred for 2.5-3.3 h, finally acetone is removed by evaporation under reduced pressure, to obtain modified alcohol monomer;

[0010] Further, the amount ratio of neopentyl glycol diglycidyl ether, N, N-dimethyl ethanolamine, triphenylphosphine and acetone is 0.1 mol:0.2 mol:30-40 mg:120-150 mL, N, N-dimethyl ethanolamine is grafted with neopentyl glycol diglycidyl ether to form a compound containing alcohol hydroxyl.

[0011] Step A2: the modified alcohol monomer, mercaptoacetic acid and anhydrous toluene are premixed, then p-toluenesulfonic acid is added, heated to 80-90 DEG C and stirred for 6-7.5 h, cooled to 50 DEG C, then water bath is kept constant, hydrogen peroxide is slowly added and stirred for 2.5-3.5 h, finally toluene and moisture are removed by rotary evaporation under reduced pressure, to obtain modified ester matrix;

[0012] Further, the amount ratio of modified alcohol monomer, mercaptoacetic acid, p-toluenesulfonic acid, hydrogen peroxide and anhydrous toluene is 0.1 mol:0.2 mol:0.42-0.5 g:16-22 mL:200-250 mL, mercaptoacetic acid is esterified with modified alcohol monomer, and the mercapto group of esterified product is condensed to form disulfide under oxidation.

[0013] Step A3: the modified ester matrix, bromoethanol and isopropyl alcohol are mixed, heated to 60-70 DEG C and stirred for 10-15 h, finally isopropyl alcohol and excess bromoethanol are removed by rotary evaporation under reduced pressure, to obtain self-adapting emulsifier;

[0014] Further, the amount ratio of modified ester matrix, bromoethanol and isopropyl alcohol is 10 g:4-5 mL:35-45 mL, bromoethanol is quaternized with dimethylamino on the modified ester matrix, to generate hydroxyl-containing quaternary ammonium structure on the side chain.

[0015] Preferably, water-soluble salt includes one or more of calcium chloride, sodium chloride, magnesium chloride and potassium chloride, which can be adjusted according to geological environment to balance downhole osmotic pressure.

[0016] Preferably, the filtration loss reducer is iron-chromium lignin sulfonate, which has good thermal stability and is suitable for high-temperature deep well unblocking systems.

[0017] Preferably, the thickener is an aqueous polymer formulation that maintains a stable thickening effect during the high-temperature unblocking process in deep wells, and works synergistically with the filtration loss reducer to reduce the permeation and loss of the unblocking agent.

[0018] A method for preparing a drilling fluid unblocking agent includes: emulsifying a synthetic ester, an adaptive emulsifier, and water by shearing and stirring; then adding a water-soluble salt for mixing; and finally adding a filtration loss reducer and a viscosity enhancer sequentially to obtain the unblocking agent.

[0019] The beneficial effects of this invention are:

[0020] This invention, based on a water-based unblocking agent system, synthesizes an emulsifier with adaptive release properties, effectively solving the cost and environmental problems caused by the insufficient unblocking efficiency of existing water-based unblocking agents and their reliance on high-content additives. The main molecular chain of this adaptive emulsifier is a low-molecular-weight polyester chain with embedded heat-sensitive disulfide bonds, and the side chains are short-chain alkyl quaternary ammonium groups. Compared with existing emulsification technologies, the advantages are as follows: Stuck pipe often occurs in deep wells, where the drilling fluid temperature is high. The disulfide bonds in the main chain of the adaptive emulsifier molecules break, and the emulsion shell structure formed disintegrates. On the one hand, the synthetic ester is fully released and adheres to the stuck pipe location, improving lubrication. On the other hand, the broken bonds form a large number of small-molecule quaternary ammonium cation fragments that penetrate into the deep layer of the filter cake, destroying the colloidal material of the cake through charge reversal. At the same time, the decomposed fragments of the small-molecule ester structure act as a lubricant, reducing the frictional resistance between particles in the cake, enabling efficient crushing and decomposition of the cake, thereby improving the unsticking efficiency. It realizes an integrated adaptive unsticking process of "emulsification-release-neutralization", which not only reduces the dependence on additional permeants and other additives, reducing the complexity of the formulation and the environmental impact, but also shows dual unsticking advantages in high-temperature environments, taking into account both high efficiency and environmental protection. It is especially suitable for complex drilling conditions such as ultra-deep wells and high-temperature and high-pressure wells. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Fig. 1 This is a surface morphology diagram of the mud cake after unblocking in Embodiment 4 of the present invention;

[0023] Fig. 2 This is a surface morphology diagram of the mud cake after unpacking in Comparative Example 1 of the present invention;

[0024] Fig. 3 This is a surface morphology diagram of the mud cake after unblocking in Comparative Example 2 of the present invention. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Example 1: Preparation of a drilling fluid unblocking agent. The specific implementation process is as follows:

[0027] (1) Preparation of adaptive emulsifier

[0028] Step A1: N,N-dimethylethanolamine, triphenylphosphine, and acetone were premixed and the water bath temperature was controlled at 40℃. Neopentyl glycol diglycidyl ether was slowly added and the mixture was stirred for 3.3 h. The ratio of neopentyl glycol diglycidyl ether, N,N-dimethylethanolamine, triphenylphosphine, and acetone was 0.1 mol: 0.2 mol: 30 mg: 120 mL. The mixture was then left to stand under reduced pressure overnight to evaporate and remove acetone, yielding the modified alcohol monomer.

[0029] Step A2: Take the modified alcohol monomer, mercaptoacetic acid and anhydrous toluene, premix them, then add p-toluenesulfonic acid and mix. Heat to 80℃ and stir for 7.5h. Cool down to 50℃ and keep at a constant temperature in a water bath. Slowly add hydrogen peroxide and stir for 3.5h. The ratio of the amount of modified alcohol monomer, mercaptoacetic acid, p-toluenesulfonic acid, hydrogen peroxide and anhydrous toluene is 0.1mol:0.2mol:0.42g:16mL:200mL. The hydrogen peroxide is an industrial raw material with a mass fraction of 30%. Finally, remove toluene and water by rotary evaporation under reduced pressure to obtain the modified ester matrix.

[0030] Step A3: Mix the modified ester matrix, bromoethanol and isopropanol, heat to 60℃ and stir for 15 hours. The ratio of the amount of modified ester matrix, bromoethanol and isopropanol is 10g:4mL:35mL. Finally, remove isopropanol and excess bromoethanol by rotary evaporation under reduced pressure to obtain the adaptive emulsifier.

[0031] (2) Prepare the card release agent

[0032] Raw materials are calculated by weight percentage as follows: 11 wt% synthetic ester, using commercially available Staradd LB616; 5.7 wt% adaptive emulsifier, prepared in-house in this embodiment; 0.5 wt% water-soluble salt, using calcium chloride and sodium chloride mixed in equal weight ratio; 3.3 wt% filtration loss reducer, using commercially available iron-chromium lignin sulfonate; 0.8 wt% tackifier, using AQUAVIS® CF type waterborne polymer tackifier; the balance being water.

[0033] The synthetic ester, adaptive emulsifier, and water were mixed and emulsified by high-speed shearing at 6000 rpm for 10 min. Then, water-soluble salt was added and stirred to dissolve. Finally, filtration loss reducer and thickener were added in sequence and mixed to obtain the unblocking agent.

[0034] Example 2: Preparation of a drilling fluid unblocking agent. The specific implementation process is as follows:

[0035] (1) Preparation of adaptive emulsifier

[0036] Step A1: N,N-dimethylethanolamine, triphenylphosphine, and acetone were premixed and the water bath temperature was controlled at 50℃. Neopentyl glycol diglycidyl ether was slowly added and the mixture was stirred for 2.5 h. The ratio of neopentyl glycol diglycidyl ether, N,N-dimethylethanolamine, triphenylphosphine, and acetone was 0.1 mol: 0.2 mol: 40 mg: 150 mL. The mixture was then left to stand under reduced pressure overnight to evaporate and remove acetone, yielding the modified alcohol monomer.

[0037] Step A2: Take the modified alcohol monomer, mercaptoacetic acid and anhydrous toluene, premix them, then add p-toluenesulfonic acid and mix. Heat to 90℃ and stir for 6 hours. Cool down to 50℃ and keep at a constant temperature in a water bath. Slowly add hydrogen peroxide and stir for 2.5 hours. The ratio of the amount of modified alcohol monomer, mercaptoacetic acid, p-toluenesulfonic acid, hydrogen peroxide and anhydrous toluene is 0.1mol:0.2mol:0.5g:22mL:250mL. The hydrogen peroxide is an industrial raw material with a mass fraction of 30%. Finally, remove toluene and water by rotary evaporation under reduced pressure to obtain the modified ester matrix.

[0038] Step A3: Mix the modified ester matrix, bromoethanol and isopropanol, heat to 70℃ and stir for 10 h. The ratio of the amount of modified ester matrix, bromoethanol and isopropanol is 10 g: 5 mL: 45 mL. Finally, remove isopropanol and excess bromoethanol by rotary evaporation under reduced pressure to obtain the adaptive emulsifier.

[0039] (2) Prepare the card release agent

[0040] Raw materials are calculated by weight percentage as follows: 16.5 wt% synthetic ester, using commercially available Staradd LB616; 8.2 wt% adaptive emulsifier, prepared in-house in this embodiment; 2 wt% water-soluble salt, using calcium chloride and magnesium chloride mixed in equal weight ratio; 2.7 wt% filtrate loss reducer, using commercially available iron-chromium lignin sulfonate; 0.65 wt% tackifier, using AQUAVIS® CF type waterborne polymer tackifier; the balance being water.

[0041] The synthetic ester, adaptive emulsifier, and water were mixed and emulsified by high-speed shearing at 6000 rpm for 10 min. Then, water-soluble salt was added and stirred to dissolve. Finally, filtration loss reducer and thickener were added in sequence and mixed to obtain the unblocking agent.

[0042] Example 3: Preparation of a drilling fluid unblocking agent. The specific implementation process is as follows:

[0043] (1) Preparation of adaptive emulsifier

[0044] Step A1: N,N-dimethylethanolamine, triphenylphosphine, and acetone were premixed and the water bath temperature was controlled at 45℃. Neopentyl glycol diglycidyl ether was slowly added and the mixture was stirred for 2.8 h. The ratio of neopentyl glycol diglycidyl ether, N,N-dimethylethanolamine, triphenylphosphine, and acetone was 0.1 mol: 0.2 mol: 35 mg: 130 mL. The mixture was then left to stand under reduced pressure overnight to evaporate and remove acetone, yielding the modified alcohol monomer.

[0045] Step A2: Take the modified alcohol monomer, mercaptoacetic acid and anhydrous toluene, premix them, then add p-toluenesulfonic acid and mix. Heat to 85℃ and stir for 6.5h. Cool down to 50℃ and keep at a constant temperature in a water bath. Slowly add hydrogen peroxide and stir for 3h. The ratio of the amount of modified alcohol monomer, mercaptoacetic acid, p-toluenesulfonic acid, hydrogen peroxide and anhydrous toluene is 0.1mol:0.2mol:0.45g:20mL:220mL. The hydrogen peroxide is an industrial raw material with a mass fraction of 30%. Finally, remove toluene and water by rotary evaporation under reduced pressure to obtain the modified ester matrix.

[0046] Step A3: Mix the modified ester matrix, bromoethanol and isopropanol, heat to 65℃ and stir for 12 hours. The ratio of the amount of modified ester matrix, bromoethanol and isopropanol is 10g:5mL:40mL. Finally, remove isopropanol and excess bromoethanol by rotary evaporation under reduced pressure to obtain the adaptive emulsifier.

[0047] (2) Prepare the card release agent

[0048] Raw materials are calculated by weight percentage as follows: 13 wt% synthetic ester, using commercially available Staradd LB616; 6.4 wt% adaptive emulsifier, prepared in-house in this embodiment; 1.1 wt% water-soluble salt, using calcium chloride and potassium chloride mixed in equal weight ratio; 2.9 wt% filtrate reducer, using commercially available iron-chromium lignin sulfonate; 0.75 wt% thickener, using AQUAVIS® CF type waterborne polymer thickener; the balance is water.

[0049] The synthetic ester, adaptive emulsifier, and water were mixed and emulsified by high-speed shearing at 6000 rpm for 10 min. Then, water-soluble salt was added and stirred to dissolve. Finally, filtration loss reducer and thickener were added in sequence and mixed to obtain the unblocking agent.

[0050] Example 4: Preparation of a drilling fluid unblocking agent. The specific implementation process is as follows:

[0051] (1) Preparation of adaptive emulsifier

[0052] Step A1: N,N-dimethylethanolamine, triphenylphosphine, and acetone were premixed and the water bath temperature was controlled at 50℃. Neopentyl glycol diglycidyl ether was slowly added and the mixture was stirred for 3 hours. The ratio of neopentyl glycol diglycidyl ether, N,N-dimethylethanolamine, triphenylphosphine, and acetone was 0.1 mol: 0.2 mol: 40 mg: 140 mL. The mixture was then left to stand under reduced pressure overnight to evaporate and remove acetone, yielding the modified alcohol monomer.

[0053] Step A2: Take the modified alcohol monomer, mercaptoacetic acid and anhydrous toluene, premix them, then add p-toluenesulfonic acid and mix. Heat to 80℃ and stir for 7 hours. Cool down to 50℃ and keep at a constant temperature in a water bath. Slowly add hydrogen peroxide and stir for 3.2 hours. The ratio of the amount of modified alcohol monomer, mercaptoacetic acid, p-toluenesulfonic acid, hydrogen peroxide and anhydrous toluene is 0.1mol:0.2mol:0.45g:20mL:200mL. The hydrogen peroxide is an industrial raw material with a mass fraction of 30%. Finally, remove toluene and water by rotary evaporation under reduced pressure to obtain the modified ester matrix.

[0054] Step A3: Mix the modified ester matrix, bromoethanol and isopropanol, heat to 70℃ and stir for 13 hours. The ratio of the amount of modified ester matrix, bromoethanol and isopropanol is 10g:5mL:45mL. Finally, remove isopropanol and excess bromoethanol by rotary evaporation under reduced pressure to obtain the adaptive emulsifier.

[0055] (2) Prepare the card release agent

[0056] Raw materials are calculated by weight percentage as follows: 14 wt% synthetic ester, using commercially available Staradd LB616; 7.1 wt% adaptive emulsifier, prepared in-house in this embodiment; 0.9 wt% water-soluble salt, using calcium chloride and sodium chloride mixed in equal weight ratio; 3.1 wt% filtrate reducer, using commercially available iron-chromium lignin sulfonate; 0.72 wt% tackifier, using AQUAVIS® CF type waterborne polymer tackifier; the balance being water.

[0057] The synthetic ester, adaptive emulsifier, and water were mixed and emulsified by high-speed shearing at 6000 rpm for 10 min. Then, water-soluble salt was added and stirred to dissolve. Finally, filtration loss reducer and thickener were added in sequence and mixed to obtain the unblocking agent.

[0058] Comparative Example 1, referring to the implementation process of Example 4 and the existing implementation scheme, replaced the adaptive emulsifier with 6.4 wt% of PE6400 type emulsifier and 0.7 wt% of polysiloxane quaternary ammonium salt-8, wherein polysiloxane quaternary ammonium salt-8 and water-soluble salt were added together, and the rest of the implementation process was exactly the same.

[0059] Comparative Example 2: Similar to Comparative Example 1, add 0.9 wt% of JFC-1 permeate, and adjust the balance to 100 wt% with water. Add JFC-1 permeate before the filtration loss reducer. The rest of the implementation process is exactly the same.

[0060] Samples were taken from the unblocking agent prepared above and relevant tests were conducted, specifically:

[0061] Preparation of base slurry: Take 4wt% bentonite, 4wt% bentonite, 1wt% iron-chromium lignin sulfonate, 0.1wt% sodium carboxymethyl cellulose and the balance water. Mix the components and let them stand for 24 hours to homogenize. Then stir at high speed to form a uniform mixture, which is the base slurry.

[0062] Unblocking test: The base slurry is injected into an unblocking instrument containing filter paper. The pressure in the base slurry is increased to 500 psi and filtered for 5 min, forming a thin mud layer on the filter paper. Then, the suspension weight is fixed on the mud layer and the filtration continues for 30 min. After that, the base slurry is extracted and the unblocking agent prepared above is injected and sealed. The instrument is placed in an oil bath at 160℃ and a load of 5 kg is applied to the suspension weight. The time it takes for the suspension weight to detach from the mud cake is recorded as the unblocking time.

[0063] Mud cake decomposition and permeation test: After filtration for 30 minutes as described above, the base slurry was extracted, rinsed with a water distributor, and allowed to stand for 12 hours to form a mud cake. The cake was weighed, injected with an unblocking agent and sealed. It was placed in a 160℃ oil bath and allowed to stand for 30 minutes. The unblocking agent was poured out, and the cake was rinsed again with a water distributor. After standing for 6 hours, the cake was weighed. The surface morphology of the unblocked mud cake was observed and the weight loss rate of the mud cake before and after unblocking was calculated.

[0064] The specific test results are shown in Table 1:

[0065] Table 1

[0066]

[0067] As shown in Table 1, the unblocking time of the unblocking agent in this embodiment is significantly shorter than that in the comparative example. During the unblocking process, the mud cake exhibits a high weight loss rate and dense, deep network cracks. Specifically, as shown in Table 1... Figs. 1-3 The images show the surface morphology of the mud cake after the unblocking test in Example 4, Comparative Example 1, and Comparative Example 2, respectively.

[0068] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

Claims

1. A drilling fluid unblocking agent, characterized in that, The specific components are: 11-16.5 wt% synthetic ester, 5.7-8.2 wt% adaptive emulsifier, 0.5-2 wt% water-soluble salt, 2.7-3.3 wt% filtration loss reducer, and 0.65-0.8 wt% thickener, with the balance being water; The adaptive emulsifier is prepared by the following method: Step A1: Premix N,N-dimethylethanolamine, triphenylphosphine, and acetone in a water bath at 40-50℃, slowly add neopentyl glycol diglycidyl ether and stir for 2.5-3.3 hours to prepare a modified alcohol monomer. The ratio of neopentyl glycol diglycidyl ether, N,N-dimethylethanolamine, triphenylphosphine, and acetone is 0.1mol:0.2mol:30-40mg:120-150mL. Step A2: Premix the modified alcohol monomer, mercaptoacetic acid, and anhydrous toluene, then add p-toluenesulfonic acid and mix. Heat to 80-90℃ and stir for 6-7.5h. Cool to 50℃ and maintain the temperature in a water bath. Slowly add hydrogen peroxide and stir for 2.5-3.5h to prepare the modified ester matrix. The ratio of the modified alcohol monomer, mercaptoacetic acid, p-toluenesulfonic acid, hydrogen peroxide, and anhydrous toluene is 0.1mol:0.2mol:0.42-0.5g:16-22mL:200-250mL. Step A3: Mix the modified ester matrix, bromoethanol and isopropanol, heat to 60-70℃ and stir for 10-15 hours to prepare an adaptive emulsifier. The ratio of the modified ester matrix, bromoethanol and isopropanol is 10g:4-5mL:35-45mL. The water-soluble salt includes one or more of calcium chloride, sodium chloride, magnesium chloride, and potassium chloride.

2. The drilling fluid unblocking agent according to claim 1, characterized in that, The filtration loss reducer is iron-chromium lignin sulfonate.

3. The drilling fluid unblocking agent according to claim 1, characterized in that, The thickener is an aqueous polymer formulation.

4. A method for preparing an unblocking agent for drilling fluid according to any one of claims 1-3, characterized in that, Specifically, the synthetic ester, adaptive emulsifier, and water are sheared and emulsified, then water-soluble salt is added and mixed, and finally a filtration loss reducer and a thickener are added sequentially and mixed to obtain an unblocking agent.

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