Hydroxyl hydrocarbon acid salt inhibitor, preparation method thereof and application of hydroxyl hydrocarbon acid salt inhibitor in drilling fluid
By using hydroxyhydrocarbonate inhibitors composed of water, potassium acetate, potassium citrate and potassium tartrate, the environmental pollution and equipment corrosion problems caused by potassium chloride in the drilling fluid are solved, and better inhibition of mud shale hydration and improvement of drilling fluid performance are achieved.
Patent Information
- Application Number
- CN202510431318.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-08
- Publication Date
- 2025-06-27
AI Technical Summary
Potassium chloride inhibitors in existing drilling fluids have the problems of chloride ion aggregation to environmental pollution and corrosion of drilling equipment, and it is necessary to develop alternative inhibitors that do not contain chloride ions.
The hydroxyl hydrocarbonate inhibitor consisting of water, potassium glycolate, potassium citrate and potassium tartrate were prepared by mixing uniformly, heating and stirring, and concentration and vacuum drying. It was used to replace the application of potassium chloride in drilling fluids.
This hydroxyhydrocarbonate inhibitor is not biotoxic, has no environmental pollution, has better inhibition of hydration expansion and dispersion of mud shale, and performs well in drilling fluid systems of different densities, and is suitable for drilling needs of wells of different depths.
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Figure CN120209801A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of oilfield drilling fluid materials, and particularly relates to a hydroxyhydrocarbonate WSALT inhibitor, a preparation method thereof, and an application thereof in drilling fluid. Background Art
[0002] The main rocks encountered in oil and gas field drilling are mudstones, which mainly consist of clay minerals, with an average clay mineral content of 45%. The clay minerals are mainly kaolinite, montmorillonite, illite, and illite-smectite mixed layer (a mixed structure of two layered silicate minerals, illite and montmorillonite), among which the average content of the illite-smectite mixed layer is 42%, and the average content of montmorillonite in the illite-smectite mixed layer is 38%. Therefore, this type of mudstone has strong water sensitivity and is prone to wellbore collapse due to hydration swelling under long-term immersion in drilling fluid. There are also bedding planes and microfractures in the mudstone in some well sections. The invasion of drilling fluid filtrate into the formation causes the mudstone to hydrate and swell, exacerbating the development of bedding planes and microfractures. Once the filter cake is damaged during tripping, the broken rock mass loses its barrier and will cause wellbore collapse. Therefore, enhancing the inhibition of the drilling fluid, that is, the ability to inhibit the hydration of mudstone, is crucial.
[0003] The commonly used inhibitor in water-based drilling fluid is potassium chloride, which has a strong ability to inhibit the dispersion and swelling of drill cuttings. The reason is that K + in the system can be well embedded into the montmorillonite clay lattice, making the clay layers tightly combined together, thereby effectively inhibiting the hydration swelling of shale and playing a role in stabilizing the wellbore. This property has made potassium chloride widely used, especially when used in deep wells, high-temperature, and high-pressure areas, it can effectively prevent wellbore instability and collapse.
[0004] However, the aggregation of chloride ions will cause certain pollution to the environment, and chloride ions also have corrosiveness, posing a potential threat to drilling equipment and pipes. In an environment with a high chloride ion concentration, metal equipment and pipes are prone to electrochemical corrosion, reducing their service life and even causing safety accidents. Therefore, in drilling operations, it is necessary to strictly control the chloride ion content and take necessary anti-corrosion measures to protect equipment and pipes. For this reason, it is of great significance to develop an inhibitor that does not contain chloride ions and can replace potassium chloride. Summary of the Invention
[0005] The purpose of the present invention is to provide a new inhibitor that does not contain chloride ions and can replace potassium chloride, whose inhibition performance is superior to that of potassium chloride, and has no biological toxicity and no pollution to the environment.
[0006] The technical solution of the present invention is described in detail as follows: In the first aspect, the present invention provides a hydroxyhydrocarbonate inhibitor, the raw materials of which consist of water, potassium hydroxyacetate, potassium citrate, and potassium tartrate.
[0007] Optionally or preferably, for the above-mentioned hydroxycarboxylate inhibitor, calculated by weight, the dosage of each raw material component is as follows: 100 parts of water, 15 - 25 parts of potassium hydroxyacetate, 20 - 30 parts of potassium citrate, 5 - 10 parts of potassium tartrate.
[0008] In the second aspect, the present invention provides a preparation method of the above-mentioned hydroxycarboxylate inhibitor, which is to mix water, potassium hydroxyacetate, potassium citrate and potassium tartrate evenly, then heat and stir for concentration, and finally obtain the finished product by vacuum drying.
[0009] In the third aspect, the present invention provides an application of the above-mentioned hydroxycarboxylate inhibitor in the preparation of oilfield drilling fluid.
[0010] In the fourth aspect, the present invention provides a drilling fluid containing the above-mentioned hydroxycarboxylate inhibitor.
[0011] Optionally or preferably, the above-mentioned drilling fluid includes water. Based on 100 parts by weight of water, the addition amount of the hydroxycarboxylate inhibitor is 3 - 10 parts by weight.
[0012] Optionally or preferably, the above-mentioned drilling fluid is an oilfield drilling fluid.
[0013] Compared with the prior art, the present invention has the following beneficial effects: The hydroxycarboxylate inhibitor of the present invention does not contain chloride ions, has a simple composition, and has a better inhibition effect compared with potassium chloride. It is speculated that the hydroxycarboxylate may enhance the adsorption between the drilling fluid and clay by combining with Si - O bonds and Al - O bonds in the clay, thereby effectively inhibiting the hydration swelling and dispersion of shale. The density of the 30% solution of this hydroxycarboxylate inhibitor is greater than 1.10 g / cm 3 , the highest solubility can reach 95%, the chloride ion content is extremely low, being 0.1%, and the cuttings recovery rate in the 5% solution is greater than 60%. This hydroxycarboxylate inhibitor has good performance in drilling fluid systems with different densities and can meet the drilling requirements of wells with different depths. Description of the Drawings
[0014] Figure 1 It is a photo of the recovered particles of Anjihai cuttings in fresh water, 5% WSALT solution (Example 1) and 5% KCl solution. Detailed Embodiments
[0015] To enable those skilled in the art to better understand the solution of this application, the following will clearly and completely describe this application in conjunction with the embodiments and the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts shall fall within the scope of protection of this application.
[0016] Example 1 Take 100 parts of water, 20 parts of potassium hydroxyacetate, 25 parts of potassium citrate, and 8 parts of potassium tartrate by weight in a mixing container, stir well for 2 hours to dissolve and mix evenly, then heat and concentrate while stirring to make the mixture heat evenly and improve the concentration progress, and finally dry under vacuum to obtain the hydroxyhydrocarbonate inhibitor WSALT.
[0017] Example 2 Take 100 parts of water, 22 parts of potassium hydroxyacetate, 28 parts of potassium citrate, and 6 parts of potassium tartrate by weight in a mixing container, stir well for 1 hour to dissolve and mix evenly, then heat and stir to concentrate, and finally dry under vacuum to obtain the hydroxyhydrocarbonate inhibitor WSALT.
[0018] Example 3 Take 100 parts of water, 15 parts of potassium hydroxyacetate, 30 parts of potassium citrate, and 10 parts of potassium tartrate by weight in a mixing container, stir well for 2 hours to dissolve and mix evenly, then heat and stir to concentrate, and finally dry under vacuum to obtain the hydroxyhydrocarbonate inhibitor WSALT.
[0019] Example 4 Take 100 parts of water, 15 parts of potassium hydroxyacetate, 20 parts of potassium citrate, and 5 parts of potassium tartrate by weight in a mixing container, stir well for 1.5 hours to dissolve and mix evenly, then heat and stir to concentrate, and finally dry under vacuum to obtain the hydroxyhydrocarbonate inhibitor WSALT.
[0020] Example 5 Take 100 parts of water, 25 parts of potassium hydroxyacetate, 30 parts of potassium citrate, and 10 parts of potassium tartrate by weight in a mixing container, stir well for 1 hour to dissolve and mix evenly, then heat and stir to concentrate, and finally dry under vacuum to obtain the hydroxyhydrocarbonate inhibitor WSALT.
[0021] Performance Test 1. Density Test Take 90 g of the WSALT product and dissolve it in 300 mL of distilled water, stir at high speed for 20 minutes, and test the density of the 30% solution at room temperature. The test results are shown in Table 1.
[0022] Table 1 Density of Products of Different Examples The density of the 30% solution of the inhibitor product hydroxylate salt is greater than 1.10 g / cm 3 , and the maximum solubility can reach 95%. While having strong inhibition, this product can increase the density of the drilling fluid, reduce the solid content of the drilling fluid, and make the rheology of the drilling fluid easier to control.
[0023] 2. Inhibition evaluation The experimental steps are as follows: Preparation of sample solution: Take 350 mL of clear water, add 5% of the sample (WSALT or KCl in Examples 1 - 5), and stir at high speed for 20 min to dissolve it.
[0024] Measure 350 mL of the sample solution into a high - temperature aging tank, put 50 g of Anjihai cuttings (6 - 10 mesh) into it, heat - roll at 120 °C for 16 hours, then use a 40 - mesh standard sieve to obtain the remaining cuttings, dry them at 105 ± 2 °C for 4 hours, weigh them, and calculate the cutting recovery rate.
[0025] The cutting recovery rates of Anjihai cuttings in clear water, 5% WSALT solution, and 5% KCl solution are shown in Table 1.
[0026] Table 2 Cutting recovery rates of Anjihai cuttings in different solutions The recovered cuttings are as Figure 1 shown. It can be seen from the data in Table 1 that the cutting recovery rate of the hydroxylate salt WSALT solution is much higher than that of the KCl solution. And it can be seen from Figure 1 that the recovered cutting particles remain intact and undispersed, indicating that the hydroxylate salt WSALT has stronger inhibition performance.
[0027] 3. Determination of chloride ion content Preparation of sample solution: Weigh 50 g of the hydroxylate salt WSALT sample and dissolve it in distilled water, dilute it to a 500 - mL volumetric flask with distilled water, and shake well to obtain the sample solution.
[0028] Take 25.00 mL of the sample solution and put it into a conical flask, add 3 drops of phenolphthalein solution, and the test solution turns pink. Adjust it to the disappearance of the pink color with 1% (coarse adjustment) and 0.1% (fine adjustment) nitric acid solutions respectively. Then, add 10 drops of potassium chromate indicator to the test solution and titrate it with a silver nitrate standard solution until the color changes from yellow to orange - red (this color should be maintained for 30 seconds), which is the titration end - point, and record the burette reading as V. The chloride ion content in the sample is calculated by the following formula.
[0029] In the formula: C——Concentration of the silver nitrate standard solution; V —— Volume of silver nitrate standard solution.
[0030] The chloride ion content of the hydroxycarboxylate salt determined by this method is extremely low, being 0.1%, which has less impact on the drilling fluid itself and the environment.
[0031] 4. Performance comparison in drilling fluid The hydroxycarboxylate salt WSALT and potassium chloride were respectively applied to the same drilling fluid system, and the performance of the drilling fluid was tested to compare the application effects of the two products, as shown in Table 3.
[0032] Table 3 Performance comparison of two inhibitors in drilling fluid Remarks: ① Rolling temperature: 120 °C, rolling time: 16 h ② Redu1 is a commercially available fluid loss reducer for drilling fluid; 10 s Gel represents the gel strength (initial shear force) formed after the drilling fluid stands still for 10 seconds; 10 min Gel represents the gel strength (final shear force) formed after the drilling fluid stands still for 10 minutes; AV: Apparent viscosity; PV: Plastic viscosity; YP: Yield point; HTHP: High temperature and high pressure fluid loss volume, the test temperature is the corresponding rolling temperature, and the pressure is 3.5 MPa.
[0033] It can be seen from the data in Table 3 that: a) The viscosity of the drilling fluid using the hydroxycarboxylate salt WSALT is better maintained after hot rolling than that using KCl, and it has better temperature resistance. The apparent viscosity (AV) of the WSALT system before hot rolling is 9.5 mPa•s, and after hot rolling it is 8.5 mPa•s, with little change. The apparent viscosity (AV) of the KCl system before hot rolling is 13.5 mPa•s, and after hot rolling it is 4 mPa•s, with a relatively large decrease in viscosity, indicating that its temperature resistance is not very good.
[0034] b) Under the condition of the same viscosity and fluid loss volume, the dosage of the fluid loss reducer used in the hydroxycarboxylate salt WSALT system is reduced by more than 30% compared with the KCl system. It can be seen from the dosage of the fluid loss reducer Redu1 in the above table that the dosage of Redu1 in the KCl system is 5.25 g, and the dosage of Redu1 in the WSALT system is 3.5 g.
[0035] 5. Application in drilling fluids with different densities The drilling fluid inhibitor hydroxycarboxylate salt WSALT was added to drilling fluid systems with different densities, and hot rolled for 16 h at different temperatures, and its drilling fluid performance was tested. ① Water + 0.3% Na2CO3+ 3% Visco1 + 0.2% XC + 1.2% NAT20 + 0.2% IND30 + 2% NFA-25 + 4% PGCS-1 + 4% NAX50 + 5% WSALT (heated at 120 °C for 16 h, system density is 1.0 g / cm 3 )
[0036] ② Water + 0.3% Na2CO3+ 1% Visco1 + 8% Redu2 + 0.5% NAT20 ++ 2% NFA-25 + 2% PGCS-1 + 2% NAX50 + 5% WSALT + 80% barite (heated at 150 °C for 16 h, system density is 1.5 g / cm 3 )
[0037] ③ Water + 0.3% Na2CO3+ 0.2% NaOH + 3% Visco1 + 4% Redu2 + 4% Redu200 ++ 2% NFA-25 + 2% PGCS-1 + 2% NAX50 + 5% WSALT + 140% barite (heated at 180 °C for 16 h, system density is 1.8 g / cm 3 )
[0038] ④ Water + 0.3% Na2CO3+ 0.2% NaOH + 3% Visco1 + 7% Redu200 ++ 2% NFA-25 + 2% PGCS-1 + 2% NAX50 + 5% WSALT + 140% barite (heated at 200 °C for 16 h, system density is 1.8 g / cm 3 )
[0039] In the above formulas, Visco1 is a modified silicate Visco1, a viscosifier for commercially available drilling fluids; XC is xanthan gum XC, a viscosifier for commercially available drilling fluids; NAT20 is a modified natural polymer NAT20, a filtrate reducer for commercially available drilling fluids; IND30 is a modified natural polymer IND30, an encapsulating inhibitor for commercially available drilling fluids; NFA-25 is non-fluorescent white asphalt NFA-25, an inhibition and anti-collapse agent for commercially available drilling fluids; PGCS-1 is solid polyol PGCS-1, for commercially available drilling fluids; NAX50 is nano-sealing agent NAX50 for commercially available drilling fluids; Redu2 is carboxyhydroxyalkene copolymer Redu2, a filtrate reducer for commercially available drilling fluids; Redu200 is carboxyhydroxyalkene copolymer Redu200, a filtrate reducer for commercially available drilling fluids.
[0040] Table 4 Application and properties of hydroxyhydrocarbonate in drilling fluid systems with different densities In the table, Ф600 / Ф300 refers to the readings of the drilling fluid at two rotational speeds (600 rpm and 300 rpm) of a six-speed rotational viscometer; Gel 10” / 10’ represents the gel strength (initial gel strength) formed after the drilling fluid has been static for 10 seconds and the gel strength (final gel strength) formed after being static for 10 minutes, which is used to reflect the ability of the drilling fluid to maintain suspended cuttings after being static for different times. AV: Apparent viscosity; PV: Plastic viscosity; YP: Yield point; API: Filtrate loss at normal temperature and medium pressure; HTHP: Filtrate loss at high temperature and high pressure, the test temperature is the corresponding hot rolling temperature, and the pressure is 3.5 MPa; From the data in Table 4, it can be seen that the hydroxyhydrocarbonate inhibitor for drilling fluid has good performance in drilling fluid systems with different densities and can meet the drilling requirements of wells with different depths.
[0041] The densities of the above 4 drilling fluid system formulations are 1.0 g / cm 3 , 1.5 g / cm 3 , 1.8 g / cm 3 and 1.8 g / cm 3 respectively, and the hot rolling temperatures are 120 °C, 150 °C, 180 °C and 200 °C respectively, which basically cover the temperatures and densities required for drilling at different well depths. The viscosities and shear forces of the four drilling fluid systems are moderate before and after hot rolling, that is, the rheology is good, the API filtrate loss is about 5 mL, and the HTHP filtrate loss is within 20 mL, meeting the requirements of on-site drilling.
[0042] In this article, specific examples are used to elaborate in detail on the inventive concept. The description of the above embodiments is only used to help understand the core idea of the present invention. It should be pointed out that for those of ordinary skill in the art of this technology, any obvious modifications, equivalent replacements or other improvements made without departing from the inventive concept should be included within the protection scope of the present invention.
Claims
1. A hydroxycarbonate inhibitor, characterized in that The raw materials consist of water, potassium glycolate, potassium citrate and potassium tartrate.
2. The hydroxycarbonate inhibitor according to claim 1, characterized in that Calculated by weight, the amount of each component is: 100 parts water, Potassium glycolate 15-25 parts, Potassium citrate 20-30 parts, 5-10 parts of potassium tartrate.
3. The method for preparing the hydroxycarbonate inhibitor according to claim 1 or 2, characterized in that: The water, potassium glycolate, potassium citrate and potassium tartrate are mixed evenly, then heated, stirred and concentrated, and finally vacuum dried to obtain the finished product.
4. Use of the hydroxycarbonate inhibitor according to claim 1 or 2 in the preparation of oilfield drilling fluid.
5. A drilling fluid, characterized in that: Containing the hydroxycarbonate inhibitor according to claim 1 or 2.
6. The drilling fluid according to claim 5, characterized in that: The drilling fluid includes water. Based on 100 parts by weight of water, the amount of the hydroxycarbonate inhibitor added is 3 to 10 parts by weight.
7. The drilling fluid according to claim 5, characterized in that: Drilling fluid for oil fields.