Low electrical conductivity inhibitor and preparation method therefor, and drilling fluid containing low electrical conductivity inhibitor

Abstract

The present invention provides a low electrical conductivity inhibitor and a preparation method therefor, and a drilling fluid containing the low electrical conductivity inhibitor. The preparation method for the low electrical conductivity inhibitor comprises: mixing tertiary amine and an epoxy coupling agent, carrying out a first heating reaction, cooling and then adding a terminator, and carrying out second heating and then adding a conditioning agent to obtain a low electrical conductivity inhibitor. The drilling fluid containing the inhibitor can solve the technical problem that existing brine drilling fluids have high electrical conductivity and thus affect the evaluation results of low resistivity oil layers from array induction logging in the oil layers, and meet the requirements for the low electrical conductivity of the drilling fluid, collapse prevention, and environmental friendliness.

Description

A low conductivity inhibitor and its preparation method and drilling fluid containing the low conductivity inhibitor

[0001] Cross-reference information

[0002] This application claims priority to the Chinese patent application filed with the Patent Office of China on December 13, 2023, with application number 202311714558.1 and invention name “A drilling fluid inhibitor, a preparation method thereof and a drilling fluid containing the inhibitor”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The invention relates to a low conductivity inhibitor and a preparation method thereof and a drilling fluid containing the low conductivity inhibitor, belonging to the technical field of water-based drilling fluids. Background Art

[0004] With the continuous expansion of exploration and development, reservoirs in new areas and new strata have gradually become important strata for increasing reserves and production and resource succession in oil fields. Obtaining complete and accurate logging data for detailed evaluation is an important guarantee for subsequent increases in reserves and production.

[0005] Due to the difficulties in interpreting and evaluating reservoirs such as complex lithology, complex water properties, and complex oil-gas-water relationships in unconventional and new types of oil and gas reservoirs, the use of conventional logging series (natural gamma, compensated neutron, lithology density, etc.) to interpret and evaluate reservoirs from the aspects of lithology, porosity and permeability can no longer meet the geological needs of exploration and development. The main problems are as follows: (1) The γ value of low-resistance reservoirs and water layers is very close (50-60), and the use of conventional logging series is likely to miss oil and gas layers; (2) It is not conducive to accurately identifying gas-water co-layer reservoirs, affecting the subsequent transformation methods and process parameter decisions, and easily causing gas well flooding in the later stage.

[0006] Array induction logging can accurately determine the true resistivity of the formation and is an effective means of identifying low-resistivity reservoirs. Array induction logging is an inversion of multiple resistivity curves at different detection depths. It has the characteristics of high vertical resolution, uniform resolution, large detection depth, and high measurement accuracy. It is an important means of discovering and identifying low-resistivity reservoirs and gas-water co-layer reservoirs. Array induction logging requires that the resistivity of the drilling fluid be no less than 0.3Ω·m. Salts are commonly used as inhibitors in current drilling fluids, and the main ions present in the drilling fluid are K + 、Na +Plasma resistivity is generally less than 0.15Ω·m, with more than half of the wells with composite salt drilling fluid systems having resistivities less than 0.1Ω·m. This distorts array measurement curves, fails to accurately reflect formation information, and fails to meet the demand for detailed evaluation data for unconventional and emerging oil and gas reservoirs. Existing drilling fluid inhibitors are primarily salts, and some drilling fluid treatment agents are prone to dissociating into charged particles within the drilling fluid system, resulting in high conductivity and failing to meet the low conductivity requirements of array induction logging. To meet the drilling fluid resistivity requirements of array induction logging, the field approach is to replace the wellbore drilling fluid with a newly formulated, salt-free, low-solids drilling fluid before electrical logging. However, this approach significantly increases drilling fluid costs and is less effective due to pre-existing mud cake formation downhole and the adsorption and migration of salt ions into the formation during drilling. Furthermore, the fluctuations in wellbore system performance caused by the mud replacement significantly increase the risk of wellbore instability and collapse.

[0007] There is an urgent need to develop a strong inhibition drilling fluid system with low conductivity to meet the requirements of array induction logging for low conductivity of drilling fluid and assist in the identification and discovery of new areas and new layers. Summary of the Invention

[0008] In order to solve the above technical problems, one object of the present invention is to provide a method for preparing a low conductivity inhibitor. The prepared low conductivity inhibitor has the technical characteristics of low conductivity and strong inhibitory effect.

[0009] Another object of the present invention is to provide a low conductivity inhibitor, which is an inhibitor for drilling fluid.

[0010] Another object of the present invention is to provide a drilling fluid containing a low-conductivity inhibitor. This drilling fluid overcomes the technical problem of high conductivity in existing brine drilling fluids, which affects the evaluation results of array induction logging in low-resistivity oil reservoirs. It also meets the requirements for low conductivity, anti-slump, and environmental performance of the drilling fluid.

[0011] To achieve the above object, the present invention provides a method for preparing a low conductivity inhibitor, which comprises:

[0012] The tertiary amine and the epoxy coupling agent are mixed, and a first heating reaction is carried out. After cooling, a terminator is added. After a second heating, a blending agent is added to prepare an inhibitor for drilling fluid.

[0013] The mass ratio of the tertiary amine, the epoxy coupling agent, the terminator and the regulator is (1-20): (1-10): (1-9): (1-10).

[0014] According to a specific embodiment of the present invention, preferably, the mass ratio of the tertiary amine, epoxy coupling agent, terminator and modifier is (2-8): (1-2): (1-2): (2-8), more preferably 4:1:1:4.

[0015] According to a specific embodiment of the present invention, preferably, the tertiary amine is selected from one or a combination of two or more of N,N-dimethylaniline, N,N-dipropyl-1-propylamine, triethylamine, trimethylammonium chloride, and octadecyldimethylbenzylammonium chloride; preferably, the tertiary amine is selected from one or a combination of two or more of 1-3 parts by mass of N,N-dimethylaniline, 1-5 parts by mass of N,N-dipropyl-1-propylamine, 1-3 parts by mass of triethylamine, 1-4 parts by mass of trimethylammonium chloride, and 1-5 parts by mass of octadecyldimethylbenzylammonium chloride.

[0016] According to a specific embodiment of the present invention, preferably, the epoxy coupling agent is selected from one or a combination of two or more of trichloroethylene oxide, tetrachloroethylene oxide, and epichlorohydrin; preferably, the epoxy coupling agent is selected from one or a combination of two or more of 1-3 parts by mass of trichloroethylene oxide, 1-3 parts by mass of tetrachloroethylene oxide, and 1-4 parts by mass of epichlorohydrin.

[0017] According to a specific embodiment of the present invention, preferably, the terminator is selected from one or a combination of sodium lauryl sulfate and cetyltrimethylammonium bromide; preferably, the terminator is selected from one or a combination of 2-3 parts by mass of sodium lauryl sulfate and 2-6 parts by mass of cetyltrimethylammonium bromide.

[0018] According to a specific embodiment of the present invention, preferably, the conditioning agent is selected from one or a combination of two or more of potassium silicate, oleic acid, and sodium oleate; preferably, the conditioning agent is selected from one or a combination of two or more of 1-2 parts by mass of potassium silicate, 1-3 parts by mass of oleic acid, and 1-5 parts by mass of sodium oleate.

[0019] According to a specific embodiment of the present invention, preferably, the reaction temperature of the first heating reaction is 85-95°C, and the reaction time is 2-5h; further preferably, the reaction temperature of the first heating reaction is 90-95°C (more preferably 95°C), and the reaction time is 2-5h (more preferably 3h).

[0020] According to a specific embodiment of the present invention, preferably, the temperature of the second heating is 70-85°C, and the time is 10-60 min; further preferably, the reaction temperature of the second heating reaction is 70-85°C (more preferably 80°C), and the reaction time is 10-20 min (more preferably 20 min).

[0021] According to a specific embodiment of the present invention, preferably, according to the mass ratio of tertiary amine, epoxy coupling agent, terminator and conditioning agent of 4:1:1:4, the raw materials tertiary amine, epoxy coupling agent and terminator are first added to the reactor at room temperature, stirred at a certain speed for 10 minutes, the temperature is set to 95°C, and the temperature is stabilized, and the timing is started for 3 hours; after the reaction for 3 hours, the heating system is turned off and stirring is continued until it is cooled to room temperature, and then the terminator is added and fully mixed, the water bath temperature is 80°C, stirred for 20 minutes, and then the conditioning agent is added to be mixed evenly, and the product is cooled to room temperature and sealed for storage.

[0022] In another aspect, the present invention provides a low conductivity suppressor prepared according to the preparation method of the present invention.

[0023] In another aspect, the present invention provides a drilling fluid comprising the low conductivity suppressor of the present invention.

[0024] According to a specific embodiment of the present invention, preferably, based on the mass of water as 100%, the raw material composition of the drilling fluid includes:

[0025] 0.01%-0.05% soda ash, 0.01%-0.25% caustic soda, 3.0%-5.0% bentonite, 1.0%-3.0% low conductivity inhibitor, 0.2%-0.5% viscosity enhancer, 0.2%-1.0% film-forming agent, 0.3%-0.5% shear enhancer, 1.0%-4.0% fluid loss additive, 1.0%-3.0% anti-collapse agent, 1.0%-3.0% plugging agent.

[0026] According to a specific embodiment of the present invention, preferably, the viscosity enhancing agent includes one or a combination of two or more of the following: drilling fluid preparation soil, high viscosity polyanionic cellulose, carboxymethyl cellulose, and hydroxyethyl cellulose.

[0027] According to a specific embodiment of the present invention, preferably, the film-forming agent includes one or a combination of two or more of brown algae oligosaccharide, fucoidan, soy gum, and polyol (cloud point between 60-110° C.).

[0028] According to a specific embodiment of the present invention, preferably, the shearing agent includes one or a combination of two of xanthan gum and hydroxypropyl guar gum.

[0029] According to a specific embodiment of the present invention, preferably, the fluid loss additive includes one or a combination of two or more of low-viscosity polyanionic cellulose, temperature-resistant modified starch, and sulfonated phenolic resin.

[0030] According to a specific embodiment of the present invention, preferably, the anti-collapse agent includes one or a combination of two or more of ethylene glycol-propylene glycol copolymer, organic amine inhibitor, and polyethylene glycol.

[0031] According to a specific embodiment of the present invention, preferably, the plugging agent includes one or a combination of two or more of ultrafine calcium carbonate (2000 mesh), barite, emulsified asphalt, and emulsified paraffin (particle size less than 300 microns).

[0032] According to a specific embodiment of the present invention, preferably, the drilling fluid of the present invention further comprises a weighting material, a lubricant, a bactericide, and a defoaming agent.

[0033] According to a specific embodiment of the present invention, preferably, the conductivity of the drilling fluid of the present invention is ≤0.65 μs / m.

[0034] According to a specific embodiment of the present invention, preferably, the EC of the drilling fluid of the present invention is 50 Value ≥30000mg / L.

[0035] In another aspect, the present invention provides a method for preparing a drilling fluid containing the low conductivity inhibitor of the present invention, comprising the following steps:

[0036] (1) preparing the components according to the above weight percentages, adding soda ash and caustic soda into water and stirring thoroughly until completely dissolved to obtain an alkaline solution;

[0037] (2) adding bentonite powder to the alkaline solution obtained in step (1), stirring and hydrating for at least 24 hours to obtain a mixed solution;

[0038] (3) adding a viscosity enhancer, a fluid loss additive, a plugging agent, a film former, an anti-slump agent and a low conductivity inhibitor to the mixed solution obtained in step (2) and stirring for at least 1 hour to obtain a drilling fluid containing the inhibitor of the present invention.

[0039] The low-conductivity, strong inhibition and anti-collapse drilling fluid provided by the present invention is a water-based system. In addition to water, alkali, clay, and weighting materials, it also includes main treatment agents such as lubricants, bactericides, and defoamers. It has the effect of strengthening the inhibition of hydration and expansion of mud shale on the well wall, maintaining the stability of the drilling fluid colloid and low filtration loss, and reducing formation hydration.

[0040] The technical solution of the present invention can overcome the technical difficulty that the existing brine drilling fluid system uses a large amount of inorganic salt inhibitors, resulting in high drilling fluid conductivity and being unable to meet the low conductivity requirement of array induction logging for drilling fluid. It can also solve the problem that the existing drilling fluid inhibitors are salts and some drilling fluid treatment agents are also easily dissociated into charged particles in the drilling fluid system, resulting in high conductivity of the drilling fluid system and being unable to meet the low conductivity requirement of array induction logging for drilling fluid. The present invention forms a low-conductivity, strong-inhibition, and anti-collapse drilling fluid system through an optimal combination of low-conductivity inhibitors and matching drilling fluid treatment agents, thereby meeting the low conductivity, anti-collapse and environmental protection performance requirements of the drilling fluid system.

[0041] Compared with the prior art, the drilling fluid provided by the present invention has the following beneficial effects:

[0042] (1) The low-conductivity, strong-inhibition drilling fluid prepared by the present invention has the technical characteristics of low conductivity and strong inhibition. Compared with existing composite salt drilling fluid systems, this drilling fluid system has low conductivity, overcoming the limitation that conventional drilling fluids require a large amount of salt to improve inhibition, resulting in high conductivity of the drilling fluid and an inability to meet the requirements of low-resistance reservoir array induction logging.

[0043] (2) The low-conductivity, highly inhibitive drilling fluid system prepared by the present invention combines low conductivity with environmental performance and lower biological toxicity. Compared with traditional inorganic and organic salt inhibitors, the inhibitor of the present invention does not cause residual sodium and potassium ions and localized enrichment. Moreover, the on-site inhibitor dosage is only 1%-2% of that of conventional salt inhibitors, which can significantly reduce the use of industrial salt on the job site and has a good environmental protection effect. DETAILED DESCRIPTION

[0044] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be understood as limiting the scope of implementation of the present invention.

[0045] The present invention will be further described with reference to the following embodiments:

[0046] Composite salt system (by weight percentage): 3% bentonite for drilling fluid (Weifang Damei Bentonite Co., Ltd.) + 0.5% polyanionic cellulose PAC-L (Rongsheng Chemical Co., Ltd.) + 0.4% xanthan gum XCD (Hebei Hengju Chemical Co., Ltd.) + 2% phenolic resin SMP (Hebei Yanxing Chemical Co., Ltd.) + 1% white asphalt NAT-25 (Beijing Peikang Jiaye Technology Development Co., Ltd.) + 5% KCL (Henan Weiding Chemical Products Co., Ltd.) + 10% sodium formate (Jinan Xuzhikun Chemical Co., Ltd.) + 30% barite (Changqing Chemical Group Co., Ltd.) + balance water.

[0047] Example 1:

[0048] This embodiment provides a low conductivity inhibitor and a drilling fluid containing the low conductivity inhibitor, as follows:

[0049] (1) The preparation of low conductivity inhibitor is carried out according to the following steps and dosage:

[0050] Add 200g of raw tertiary amine (50g of N,N-dimethylaniline, 50g of N,N-dipropyl-1-propylamine, 50g of triethylamine, and 50g of trimethylammonium chloride) to the reactor at room temperature, and then add 50g of raw epoxy coupling agent (25g of trichloroethylene oxide and 25g of tetrachloroethylene oxide). Stir at a certain speed for 10min, set the temperature to 30°C, then heat until the temperature is stable, and then set the temperature to 95°C. When it reaches 95°C, start timing for 3h (that is, when the temperature in the reactor reaches 95°C, start timing for 3h). After reacting for 3h, turn off the heating system and continue stirring until it cools to room temperature. Take 50g of terminator (25g of sodium lauryl sulfate and 25g of hexadecyltrimethylammonium bromide) and mix thoroughly. Lower the water bath temperature to 70°C and stir for 20min. Finally, add 200g of tonic agent (100g of potassium silicate and 100g of oleic acid) and stir again for 20-30min. After mixing evenly to obtain a strong low-conductivity inhibitor, the product was cooled to room temperature and then sealed for storage. The conductivity of the strong low-conductivity inhibitor at different aqueous solution concentrations (1%, 2%, and 3% low-conductivity inhibitor, i.e., 1g, 2g, and 3g of low-conductivity inhibitor added to 100ml of aqueous solution) was measured using a DDS drilling fluid conductivity meter produced by Qingdao Shande Petroleum Instruments. The conductivity data for different inhibitor concentrations are shown in Table 1.

[0051] Table 1 Conductivity of low conductivity inhibitors

[0052] (2) The low conductivity inhibitor drilling fluid is prepared according to the following weight percentages (based on the mass of water as 100%), specifically: 400 ml of water, 0.01% soda ash, 0.01% caustic soda, 3% bentonite, 1.0% low conductivity inhibitor, 0.2% viscosity enhancer high viscosity polyanionic cellulose, 0.2% film-forming agent brown algae oligosaccharide, 0.3% shear enhancer xanthan gum, 1.0% fluid loss reducer low viscosity polyanionic cellulose, 1.0% anti-collapse agent ethylene glycol-propylene glycol copolymer, 1.0% plugging agent ultrafine calcium carbonate (2000 mesh), and 40% weighting agent barite are added under high stirring to obtain a low conductivity inhibitor drilling fluid.

[0053] The properties (density, water loss, six-speed viscosity, and linear expansion reduction rate) of the prepared low-conductivity, strong-inhibition, anti-collapse drilling fluid were measured in accordance with SY-T 5621-1993 "Drilling Fluid Test Procedure" and SY / T 6787-2010 "Technical Requirements for Environmental Protection of Water-Soluble Oilfield Chemicals." The conductivity and resistivity were measured using a DDS drilling fluid conductivity meter produced by Qingdao Shande Petroleum Instruments. The properties and basic information of the low-conductivity, strong-inhibition drilling fluid are shown in Table 2.

[0054] Table 2 Performance and basic information of low conductivity strong inhibition drilling fluid

[0055] The prepared low-conductivity, strong-inhibition, anti-collapse drilling fluid was then heated at 90°C for 16 hours, cooled to room temperature, and tested for its performance and basic characteristics. Specific performance and basic characteristics are shown in Table 3.

[0056] Table 3 Performance and basic conditions of low conductivity strong inhibition drilling fluid after hot rolling

[0057] Example 2:

[0058] This embodiment provides a low conductivity inhibitor and a drilling fluid containing the low conductivity inhibitor, as follows:

[0059] (1) The preparation of low conductivity inhibitor is carried out according to the following steps and dosage:

[0060] Add 200g of the raw tertiary amine (100g of N,N-dimethylaniline and 100g of trimethylammonium chloride) to a reactor at room temperature, then add 50g of the raw epoxy coupling agent (25g of trichloroethylene oxide and 25g of epichlorohydrin). Stir at a constant speed for 10 minutes. Set the temperature to 30°C, then increase the temperature until it stabilizes. Then set the temperature to 95°C. When it reaches 95°C, start the 3h timer (i.e., when the temperature in the reactor reaches 95°C, start the 3h timer). After 3 hours of reaction, turn off the heating system and continue stirring until it cools to room temperature. Take 50g of the terminator (25g of sodium lauryl sulfate and 25g of hexadecyltrimethylammonium bromide) and mix thoroughly. Lower the water bath temperature to 70°C and stir for 20 minutes. Finally, add 200g of the tonic agent (100g of potassium silicate and 100g of sodium oleate) and stir thoroughly again for 20-30 minutes. Once mixed evenly, a low-conductivity strong inhibitor is obtained. Let the product cool to room temperature and store in a sealed container. The conductivity of the low conductivity strong inhibitor (1%, 2%, 3% low conductivity inhibitor, i.e., 1g, 2g, 3g low conductivity inhibitor added to 100ml aqueous solution) at different aqueous solution concentrations was measured using a DDS drilling fluid conductivity meter produced by Qingdao Shande Petroleum Instruments. The conductivity data of the inhibitors at different concentrations are shown in Table 4.

[0061] Table 4 Conductivity of low conductivity inhibitors

[0062] (2) The low conductivity inhibitor drilling fluid is prepared according to the following weight percentage components (based on the mass of water as 100%), specifically: 400 ml of water, under high-speed stirring, 0.03% soda ash, 0.15% caustic soda, 4% bentonite, 2.0% low conductivity inhibitor, 0.3% viscosity enhancer hydroxyethyl cellulose, 0.5% film-forming agent soy gum, 0.3% shear enhancer xanthan gum, 2.0% fluid loss reducer temperature-resistant modified starch, 2.0% anti-slump agent organic amine inhibitor, 2.0% plugging agent emulsified paraffin (particle size less than 300 microns), 40% weighting agent barite, and 0.05%-0.1% fungicide to obtain a low conductivity inhibitor drilling fluid. The performance and basic conditions of the drilling fluid were tested with reference to the test standards and methods of Example 1. The performance and basic conditions of the low conductivity strong inhibition and anti-slump drilling fluid are shown in Table 5.

[0063] Table 5 Performance and basic information of low conductivity strong inhibition drilling fluid

[0064] The prepared low-conductivity, strong-inhibition, anti-collapse drilling fluid was then heated at 90°C for 16 hours, cooled to room temperature, and tested for its performance and basic characteristics. Specific performance and basic characteristics are shown in Table 6.

[0065] Table 6 Performance and basic conditions of low conductivity strong inhibition drilling fluid after hot rolling

[0066] Example 3:

[0067] This embodiment provides a low conductivity inhibitor and a drilling fluid containing the low conductivity inhibitor, as follows:

[0068] (1) The preparation of low conductivity inhibitor is carried out according to the following steps and dosage:

[0069] Add 200g of raw tertiary amine (100g of octadecyldimethylbenzyl ammonium chloride and 100g of triethylamine) to a reactor at room temperature, then add 50g of raw epoxy coupling agent (25g of trichloroethylene oxide and 25g of epichlorohydrin), stir at a constant speed for 10min, set the temperature to 30℃, then increase the temperature until the temperature stabilizes, then set the temperature to 95℃, and start the 3h timer when it reaches 95℃ (i.e., start the 3h timer when the temperature in the reactor reaches 95℃). After 3h of reaction, turn off the heating system and continue stirring until it cools to room temperature. Take 50g of terminator (50g of sodium lauryl sulfate) and mix thoroughly. Lower the water bath temperature to 70℃ and stir for 20min. Finally, add 200g of conditioning agent (100g of potassium silicate, 50g of sodium oleate, and 50g of oleic acid) and stir thoroughly again for 20-30min. After mixing evenly, a low conductivity strong inhibitor is obtained. After the product cools to room temperature, seal and store. The conductivity of the low conductivity strong inhibitor (1%, 2%, 3% low conductivity inhibitor, i.e., 1g, 2g, 3g low conductivity inhibitor added to 100ml aqueous solution) at different aqueous solution concentrations was measured using a DDS drilling fluid conductivity meter produced by Qingdao Shande Petroleum Instruments. The conductivity data of the inhibitors at different concentrations are shown in Table 7.

[0070] Table 7 Conductivity of low conductivity inhibitors

[0071] (2) The low conductivity inhibitor drilling fluid is prepared according to the following weight percentage components (based on the mass of water as 100%), specifically: 400 ml of water, 0.05% soda ash, 0.20% caustic soda, 5.0% bentonite, 3.0% low conductivity inhibitor, 0.3% viscosity enhancer hydroxyethyl cellulose, 0.5% film-forming agent fucoidan, 0.3% shear enhancer xanthan gum, 2.0% fluid loss reducer temperature-resistant modified starch, 2.0% anti-collapse agent organic amine inhibitor, 2.0% plugging agent emulsified paraffin (particle size less than 300 microns), 40% weighting agent barite, and 0.05%-0.1% fungicide to obtain the low conductivity inhibitor drilling fluid. The performance and basic conditions of the drilling fluid were tested with reference to the test standards and methods of Example 1. The performance and basic conditions of the low conductivity strong inhibition and anti-collapse drilling fluid are shown in Table 8.

[0072] Table 8 Performance and basic information of low conductivity strong inhibition drilling fluid

[0073] The prepared low conductivity strong inhibition anti-collapse drilling fluid (2) was further heated at 90°C for 16 hours, cooled to room temperature and tested for its performance and basic conditions. Specific performance and basic conditions are shown in Table 9.

[0074] Table 9 Performance and basic conditions of low conductivity strong inhibition drilling fluid after hot rolling

[0075] Example 4:

[0076] This embodiment provides a low conductivity inhibitor and a drilling fluid containing the low conductivity inhibitor, as follows:

[0077] (1) The preparation of low conductivity inhibitor is carried out according to the following steps and dosage:

[0078] Add 200g of raw material tertiary amine (100g of trimethylammonium chloride, 50g of octadecyldimethylbenzyl ammonium chloride, 50g of triethylamine) to the reactor at room temperature, then add 50g of raw material epoxy coupling agent (25g of trichloroethylene oxide, 25g of epichlorohydrin), stir at a certain speed for 10min, set the temperature to 30℃, then heat until the temperature is stable, then set the temperature to 95℃, start timing 3h when it reaches 95℃ (that is, when the temperature in the reactor reaches 95℃, start timing 3h), react for 3h, turn off the heating system and continue stirring until it cools to room temperature, take 50g of terminator (50g of hexadecyltrimethylammonium bromide) and mix thoroughly, reduce the water bath temperature to 70℃, stir for 20min, finally add 200g of tonic agent (100g of potassium silicate, 100g of sodium oleate), and stir thoroughly again for 20-30min. After mixing evenly, a low conductivity strong inhibitor is obtained, and the product is cooled to room temperature and sealed for storage. The conductivity of the low conductivity strong inhibitor (1%, 2%, 3% low conductivity inhibitor, i.e., 1g, 2g, 3g low conductivity inhibitor added to 100ml aqueous solution) at different aqueous solution concentrations was measured using a DDS drilling fluid conductivity meter produced by Qingdao Shande Petroleum Instruments. The conductivity data of the inhibitors at different concentrations are shown in Table 10.

[0079] Table 10 Conductivity of low conductivity inhibitors

[0080] (2) The low conductivity inhibitor drilling fluid is prepared according to the following weight percentage components (based on the mass of water as 100%), specifically: 400 ml of clean water, 0.05% soda ash, 0.20% caustic soda, 4.0% bentonite, 2.0% low conductivity inhibitor, 0.25% viscosity enhancer hydroxyethyl cellulose, 0.25% viscosity enhancer high viscosity polyanionic cellulose, 0.5% film-forming agent polyol (cloud point adjustable between 60-110°C), 0.3% shear enhancer xanthan gum, 2.0% fluid loss reducer sulfonated phenolic resin, 2.0% anti-collapse agent ethylene glycol-propylene glycol copolymer, 2.0% plugging agent emulsified paraffin (particle size less than 300 μm), 40% weighting agent barite, and the required amount of 0.05%-0.1% fungicide are added under high-speed stirring to obtain a low conductivity inhibitor drilling fluid. The performance and basic conditions of the drilling fluid were tested with reference to the test standards and methods of Example 1. The performance and basic conditions of the low conductivity, strong inhibition and anti-collapse drilling fluid are shown in Table 11.

[0081] Table 11 Performance and basic information of low conductivity strong inhibition drilling fluid

[0082] The prepared low-conductivity, strong-inhibition, anti-collapse drilling fluid was then heated at 90°C for 16 hours, cooled to room temperature, and tested for its performance and basic characteristics. Specific performance and basic characteristics are shown in Table 12.

[0083] Table 12 Performance and basic conditions of low conductivity strong inhibition drilling fluid after hot rolling

[0084] Example 5:

[0085] This embodiment provides a low conductivity inhibitor and a drilling fluid containing the low conductivity inhibitor, as follows:

[0086] (1) The preparation of low conductivity inhibitor is carried out according to the following steps and dosage:

[0087] 200g of raw material tertiary amine (100g of trimethylammonium chloride, 50g of octadecyldimethylbenzyl ammonium chloride, 50g of N,N-dipropyl-1-propylamine) was added to the reactor at room temperature, and then 50g of raw material epoxy coupling agent (25g of trichloroethylene oxide, 25g of epichlorohydrin) was added. The mixture was stirred at a certain speed for 10min, the temperature was set to 30°C, and then the temperature was raised until the temperature was stable. Then the temperature was set to 95°C, and the timing was started when it reached 95°C for 3h (that is, when the temperature in the reactor reached 95°C, the timing was started for 3h). After reacting for 3h, the heating system was turned off and stirring was continued until it cooled to room temperature. 50g of terminator (50g of hexadecyltrimethylammonium bromide) was taken and fully mixed. The water bath temperature was lowered to 70°C and stirred for 20min. Finally, 200g of tonic agent (100g of potassium silicate, 50g of sodium oleate, 50g of oleic acid) was added and stirred again for 20-30min. After mixing evenly to obtain a strong low-conductivity inhibitor, the product was cooled to room temperature and then sealed for storage. The conductivity of the strong low-conductivity inhibitor at different aqueous solution concentrations (1%, 2%, and 3% low-conductivity inhibitor, i.e., 1g, 2g, and 3g of low-conductivity inhibitor added to 100ml of aqueous solution) was measured using a DDS drilling fluid conductivity meter produced by Qingdao Shande Petroleum Instruments. The conductivity data for different inhibitor concentrations are shown in Table 13.

[0088] Table 13 Conductivity of low conductivity inhibitors

[0089] (2) The low conductivity inhibitor drilling fluid is prepared by configuring the components in the following weight percentages (based on the mass of water as 100%), specifically: 400 ml of clean water, with high-speed stirring, adding 0.05% soda ash, 0.25% caustic soda, 4.0% bentonite, 3.0% low conductivity inhibitor, 0.5% viscosity enhancer hydroxyethyl cellulose, 0.5% film-forming agent polyol (cloud point adjustable between 60-110° C.), 0.3% shear enhancer hydroxypropyl guar gum, 2.0% fluid loss reducer sulfonated phenolic resin, 2.0% anti-collapse agent ethylene glycol-propylene glycol copolymer, 2.0% plugging agent emulsified paraffin (particle size less than 300 μm), 40% weighting agent barite, and 0.05-0.1% fungicide to obtain a low conductivity inhibitor drilling fluid. The performance and basic conditions of the drilling fluid were tested with reference to the test standards and methods of Example 1. The performance and basic conditions of the low conductivity, strong inhibition and anti-collapse drilling fluid are shown in Table 14.

[0090] Table 14 Performance and basic information of low conductivity strong inhibition drilling fluid

[0091] The prepared low-conductivity, strong-inhibition, anti-collapse drilling fluid was then heated at 90°C for 16 hours, cooled to room temperature, and tested for its performance and basic characteristics. Specific performance and basic characteristics are shown in Table 15.

[0092] Table 15 Performance and basic conditions of low conductivity strong inhibition drilling fluid after hot rolling

[0093] Example 6:

[0094] This embodiment provides a low conductivity inhibitor and a drilling fluid containing the low conductivity inhibitor, as follows:

[0095] (1) The preparation of low conductivity inhibitor is carried out according to the following steps and dosage:

[0096] 200g of raw material tertiary amine (100g of trimethylammonium chloride, 50g of octadecyldimethylbenzyl ammonium chloride, 50g of N,N-dipropyl-1-propylamine) was added to the reactor at room temperature, and then 50g of raw material epoxy coupling agent (25g of trichloroethylene oxide, 25g of epichlorohydrin) was added. The mixture was stirred at a certain speed for 10min, the temperature was set to 30°C, and then the temperature was raised until the temperature was stable. Then the temperature was set to 95°C, and the timing was started when it reached 90°C for 2h (that is, when the temperature in the reactor reached 90°C, the timing was started for 2h). After reacting for 2h, the heating system was turned off and stirring was continued until it cooled to room temperature. 50g of terminator (50g of hexadecyltrimethylammonium bromide) was taken and fully mixed. The water bath temperature was lowered to 70°C and stirred for 20min. Finally, 200g of tonic agent (100g of potassium silicate, 50g of sodium oleate, 50g of oleic acid) was added and fully stirred again for 20-30min. After mixing evenly to obtain a strong low-conductivity inhibitor, the product was cooled to room temperature and then sealed for storage. The conductivity of the strong low-conductivity inhibitor at different aqueous solution concentrations (1%, 2%, and 3% low-conductivity inhibitor, i.e., 1g, 2g, and 3g of low-conductivity inhibitor added to 100ml of aqueous solution) was measured using a DDS drilling fluid conductivity meter produced by Qingdao Shande Petroleum Instruments. The conductivity data for different inhibitor concentrations are shown in Table 16.

[0097] Table 16 Conductivity of low conductivity inhibitors

[0098] (2) The low conductivity inhibitor drilling fluid is prepared by configuring the components in the following weight percentages (based on the mass of water as 100%), specifically: 400 ml of clean water, with high-speed stirring, adding 0.05% soda ash, 0.25% caustic soda, 4.0% bentonite, 3.0% low conductivity inhibitor, 0.5% viscosity enhancer hydroxyethyl cellulose, 0.5% film-forming agent polyol (cloud point adjustable between 60-110° C.), 0.3% shear enhancer hydroxypropyl guar gum, 2.0% fluid loss reducer sulfonated phenolic resin, 2.0% anti-collapse agent ethylene glycol-propylene glycol copolymer, 2.0% plugging agent emulsified paraffin (particle size less than 300 μm), 40% weighting agent barite, and 0.05-0.1% fungicide to obtain a low conductivity inhibitor drilling fluid. The performance and basic conditions of the drilling fluid were tested with reference to the test standards and methods of Example 1. The performance and basic conditions of the low conductivity, strong inhibition and anti-collapse drilling fluid are shown in Table 17.

[0099] Table 17 Performance and basic information of low conductivity strong inhibition drilling fluid

[0100] The prepared low-conductivity, strong-inhibition, anti-collapse drilling fluid was then heated at 90°C for 16 hours, cooled to room temperature, and tested for its performance and basic conditions. Specific performance and basic conditions are shown in Table 18.

[0101] Table 18 Performance and basic conditions of low conductivity strong inhibition drilling fluid after hot rolling

[0102] Example 7:

[0103] This embodiment provides a low conductivity inhibitor and a drilling fluid containing the low conductivity inhibitor, as follows:

[0104] (1) The preparation of low conductivity inhibitor is carried out according to the following steps and dosage:

[0105] 200g of raw material tertiary amine (100g of trimethylammonium chloride, 50g of octadecyldimethylbenzyl ammonium chloride, 50g of N,N-dipropyl-1-propylamine) was added to the reactor at room temperature, and then 50g of raw material epoxy coupling agent (25g of trichloroethylene oxide, 25g of epichlorohydrin) was added. The mixture was stirred at a certain speed for 10min, the temperature was set to 30°C, and then the temperature was increased until the temperature was stable. Then the temperature was set to 95°C, and the timing was started when it reached 95°C for 5h (that is, when the temperature in the reactor reached 95°C, the timing was started for 5h). After reacting for 5h, the heating system was turned off and stirring was continued until it cooled to room temperature. 50g of terminator (50g of hexadecyltrimethylammonium bromide) was taken and fully mixed. The water bath temperature was lowered to 70°C and stirred for 20min. Finally, 200g of tonic agent (100g of potassium silicate, 50g of sodium oleate, 50g of oleic acid) was added and stirred again for 20-30min. After mixing evenly to obtain a strong low-conductivity inhibitor, the product was cooled to room temperature and then sealed for storage. The conductivity of the strong low-conductivity inhibitor at different aqueous solution concentrations (1%, 2%, and 3% low-conductivity inhibitor, i.e., 1g, 2g, and 3g of low-conductivity inhibitor added to 100ml of aqueous solution) was measured using a DDS drilling fluid conductivity meter produced by Qingdao Shande Petroleum Instruments. The conductivity data for different inhibitor concentrations are shown in Table 19.

[0106] Table 19 Conductivity of low conductivity inhibitors

[0107] (2) The low conductivity inhibitor drilling fluid is prepared by configuring the components in the following weight percentages (based on the mass of water as 100%), specifically: 400 ml of clean water, with high-speed stirring, adding 0.05% soda ash, 0.25% caustic soda, 4.0% bentonite, 3.0% low conductivity inhibitor, 0.5% viscosity enhancer hydroxyethyl cellulose, 0.5% film-forming agent polyol (cloud point adjustable between 60-110° C.), 0.3% shear enhancer hydroxypropyl guar gum, 2.0% fluid loss reducer sulfonated phenolic resin, 2.0% anti-collapse agent ethylene glycol-propylene glycol copolymer, 2.0% plugging agent emulsified paraffin (particle size less than 300 μm), 40% weighting agent barite, and 0.05-0.1% fungicide to obtain a low conductivity inhibitor drilling fluid. The performance and basic conditions of the drilling fluid were tested with reference to the test standards and methods of Example 1. The performance and basic conditions of the low conductivity, strong inhibition and anti-collapse drilling fluid are shown in Table 20.

[0108] Table 20 Performance and basic information of low conductivity strong inhibition drilling fluid

[0109] The prepared low-conductivity, strong-inhibition, anti-collapse drilling fluid was then heated at 90°C for 16 hours, cooled to room temperature, and tested for its performance and basic characteristics. Specific performance and basic characteristics are shown in Table 21.

[0110] Table 21 Performance and basic conditions of low conductivity strong inhibition drilling fluid after hot rolling

[0111] Tables 3, 6, 9, 12, 15, 18, and 21 show that the density, water loss, and rheological properties of the low-conductivity, highly inhibited drilling fluid remain stable after hot rolling. Key technical indicators, such as conductivity, inhibition, and environmental performance, outperform comparable systems. The low-conductivity, highly inhibited drilling fluid of this invention will further meet specialized logging requirements, such as array sensing, and provide technical support for the discovery and identification of low-resistivity oil reservoirs. It has a significant future market size and broad application prospects.

Claims

1. A method for preparing a low conductivity inhibitor, wherein: The preparation method comprises: The tertiary amine and the epoxy coupling agent are mixed, and a first heating reaction is performed, and a terminator is added after cooling, and a conditioning agent is added after a second heating to prepare an inhibitor for drilling fluid; Wherein, the mass ratio of the tertiary amine, the epoxy coupling agent, the terminator and the regulator is (1-20): (1-10): (1-9): (1-10).

2. The preparation method according to claim 1, wherein The mass ratio of the tertiary amine, the epoxy coupling agent, the terminator and the regulator is (2-8): (1-2)(1-2): (2-8).

3. The preparation method according to claim 1, wherein The tertiary amine is selected from one or a combination of two or more of N,N-dimethylaniline, N,N-dipropyl-1-propylamine, triethylamine, trimethylammonium chloride, and octadecyldimethylbenzylammonium chloride.

4. The preparation method according to claim 1, wherein The tertiary amine is selected from one or a combination of two or more of 1-3 parts by mass of N,N-dimethylaniline, 1-5 parts by mass of N,N-dipropyl-1-propylamine, 1-3 parts by mass of triethylamine, 1-4 parts by mass of trimethylammonium chloride, and 1-5 parts by mass of octadecyldimethylbenzylammonium chloride.

5. The preparation method according to claim 1, wherein The epoxy coupling agent is selected from one or a combination of two or more of trichloroethylene oxide, tetrachloroethylene oxide and epichlorohydrin.

6. The preparation method according to claim 1, wherein The epoxy coupling agent is selected from one or a combination of two or more of 1-3 parts by mass of trichloroethylene oxide, 1-3 parts by mass of tetrachloroethylene oxide, and 1-4 parts by mass of epichlorohydrin.

7. The preparation method according to claim 1, wherein The terminator is selected from one or a combination of sodium dodecyl sulfate and hexadecyltrimethylammonium bromide.

8. The preparation method according to claim 1, wherein The terminator is selected from 2-3 parts by mass of sodium dodecyl sulfate and 2-6 parts by mass of hexadecyltrimethylammonium bromide, or a combination of the two.

9. The preparation method according to claim 1, wherein The conditioning agent is selected from potassium silicate, oleic acid, sodium oleate, or a combination of two or more thereof.

10. The preparation method according to claim 1, wherein: The conditioning agent is selected from one or a combination of two or more of 1-2 parts by mass of potassium silicate, 1-3 parts by mass of oleic acid, and 1-5 parts by mass of sodium oleate.

11. The preparation method according to claim 1, wherein: The reaction temperature of the first heating reaction is 85-95° C., and the reaction time is 2-5 h.

12. The preparation method according to claim 1, wherein: The second heating temperature is 70-85°C and the time is 10-60 minutes.

13. The preparation method according to claim 1, wherein The reaction temperature of the first heating reaction is 90-95° C., and the reaction time is 2-5 h.

14. The preparation method according to claim 1, wherein: The second heating temperature is 70-85°C and the time is 10-20 minutes.

15. A low conductivity inhibitor prepared according to the preparation method according to any one of claims 1 to 14.

16. A drilling fluid comprising the low conductivity inhibitor according to claim 15.

17. The drilling fluid according to claim 16, wherein: Taking the mass of water as 100%, the raw material composition of the drilling fluid includes: 0.01%-0.05% soda ash, 0.01%-0.25% caustic soda, 3.0%-5.0% bentonite, 1.0%-3.0% low conductivity inhibitor, 0.2%-0.5% viscosity enhancer, 0.2%-1.0% film-forming agent, 0.3%-0.5% shear enhancer, 1.0%-4.0% fluid loss reducer, 1.0%-3.0% anti-collapse agent, 1.0%-3.0% plugging agent.

18. The drilling fluid according to claim 17, wherein: The viscosity enhancing agent includes one or a combination of two or more of the following: drilling fluid preparation soil, high viscosity polyanionic cellulose, carboxymethyl cellulose, and hydroxyethyl cellulose; The film-forming agent includes one or a combination of two or more of brown algae oligosaccharide, fucoidan, soybean gum, and polyol; The cutting agent includes one or a combination of xanthan gum and hydroxypropyl guar gum; The fluid loss reducer comprises one or a combination of two or more of low-viscosity polyanionic cellulose, temperature-resistant modified starch, and sulfonated phenolic resin; The anti-collapse agent includes one or a combination of two or more of ethylene glycol-propylene glycol copolymer, organic amine inhibitor, and polyethylene glycol; The plugging agent includes one or a combination of two or more of ultrafine calcium carbonate, barite, emulsified asphalt and emulsified paraffin.

19. The drilling fluid according to any one of claims 16 to 18, having an electrical conductivity of ≤ 0.65 μs / m.

20. The drilling fluid according to any one of claims 16 to 18, wherein the EC 50 Value ≥30000mg / L.

Images