Environment-friendly bactericide for drilling fluid, preparation method and application thereof

Abstract

The present application belongs to the technical field of drilling fluid preparation, and particularly relates to an environmentally-friendly bactericide for drilling fluid, a preparation method and application thereof. The bactericide comprises the following components in parts by weight: water 100 parts, strong alkali 5-10 parts, Malan extract 5-10 parts, Coptis extract 1-10 parts, and buffer 5-20 parts. When the bactericide is used in drilling fluid, the bactericide is first diluted to a mass concentration of 5-10%, and then the diluted bactericide is added to the prepared environmentally-friendly drilling fluid according to 0.1-0.5% of the mass concentration of the drilling fluid, and stirred until uniform. The bactericide is added once every 5-10 days. In the present application, the Malan extract and the Coptis extract are both plant extracts, which are natural and environmentally-friendly without secondary pollution. The Malan extract and the Coptis extract have certain bacteriostatic and bactericidal effects when used alone, and the stability time of the environmentally-friendly drilling fluid is increased by more than 30% when they are used together under alkaline conditions. The bactericide has good compatibility with other components of the drilling fluid, ensuring that the stability and performance of the drilling fluid are not affected.

Description

Technical Field

[0001] This invention belongs to the field of drilling fluid preparation technology, specifically relating to an environmentally friendly bactericide for drilling fluid, its preparation method, and its application. Background Technology

[0002] Oilfield water often contains sulfate-reducing bacteria (SRB), saprophytic bacteria (TGB), and iron bacteria, which can easily cause metal corrosion, formation blockage, and chemical deterioration, among other problems that are detrimental to water quality stability. Drilling fluids play a crucial role in oil exploration and development. However, drilling fluids are prone to the growth of various harmful microorganisms during use. These microorganisms can severely affect the performance of drilling fluids, leading to reduced drilling efficiency and increased costs. Therefore, an effective bactericide is needed to control the growth of these microorganisms and maintain the stability and performance of drilling fluids.

[0003] Oilfield bactericides are mainly divided into aerobic and non-aerobic bactericides. Commonly used ones include dodecyl dimethyl benzyl ammonium chloride (1227), quaternary ammonium salts, organic bromine compounds, glutaraldehyde, THPS, and non-oxidizing bactericides of the organic guanidine type. With increasing environmental awareness, traditional drilling fluid bactericides often contain environmentally harmful chemicals, potentially polluting groundwater and soil after use. Therefore, developing environmentally friendly drilling fluid bactericides has become an urgent need to achieve environmentally friendly drilling operations.

[0004] With the continuous development of oil exploration technology, the performance requirements for drilling fluids are becoming increasingly stringent. Environmentally friendly drilling fluid bactericides not only need to possess highly efficient bactericidal properties, but also need to have good compatibility with other components of the drilling fluid to ensure that the stability and performance of the drilling fluid are not affected.

[0005] CN202110198749.1 discloses a highly efficient and environmentally friendly bactericide for oilfield produced water and its preparation method. The bactericide comprises the following components by weight: 23-25 ​​parts of coupling pyridinone, 8 parts of dodecyl dimethyl betaine, 4 parts of sodium benzoate, 2 parts of m-diazacyclopentene, 4-8 parts of imidazoline biguanide sulfate, 2-4 parts of 77% copper hydroxide wettable powder, 3-5 parts of 57.6% copper hydroxide dry granules, and 30-35 parts of water. It exhibits good bactericidal properties against sulfate-reducing bacteria, saprophytic bacteria, and iron bacteria in wastewater from oilfield injection blocks. However, this bactericide is suitable for oilfield produced water; adding it to drilling fluid will cause incompatibility issues. Summary of the Invention

[0006] The purpose of this invention is to provide an environmentally friendly bactericide for drilling fluids, overcoming the aforementioned technical problems in the prior art.

[0007] Another objective of this invention is to provide a method for preparing an environmentally friendly bactericide for drilling fluids.

[0008] Another objective of this invention is to provide an application of an environmentally friendly drilling fluid bactericide that, when used in combination under alkaline conditions, increases the stability time of the environmentally friendly drilling fluid by more than 30%.

[0009] Therefore, the technical solution provided by the present invention is as follows: An environmentally friendly bactericide for drilling fluids comprises the following components in parts by weight: 100 parts water, 5-10 parts strong alkali, 5-10 parts Malan extract, 1-10 parts Coptis chinensis extract, and 5-20 parts buffer. The strong alkali is sodium hydroxide or potassium hydroxide of industrial grade or higher purity.

[0010] The Malan extract is a water-soluble powder extract made from the dried whole herb or root of the Asteraceae plant Malan through heating and reflux extraction, vacuum concentration, and spray drying.

[0011] The Coptis chinensis extract is a water-soluble powder extract made from the roots of Coptis chinensis, a Ranunculaceae plant harvested in autumn, through heating and reflux extraction, vacuum concentration, and spray drying.

[0012] The buffer is hexamethylenetetramine of industrial grade or higher purity.

[0013] A method for preparing an environmentally friendly bactericide for drilling fluid involves adding a prescribed amount of strong alkali to a prescribed amount of water, stirring until homogeneous, and then sequentially adding prescribed amounts of Malan extract, Coptis chinensis extract, and buffer while stirring until homogeneous solution is formed.

[0014] The water in question is clean water used for oil and gas field production.

[0015] Application of an environmentally friendly bactericide for drilling fluids in the preparation of drilling fluids.

[0016] First, dilute the bactericide to a mass concentration of 5-10%. Then, add the diluted bactericide to the prepared environmentally friendly drilling fluid at a mass concentration of 0.1-0.5%, stirring constantly until homogeneous.

[0017] The dosing cycle is 5-10 days.

[0018] The beneficial effects of this invention are: The environmentally friendly drilling fluid bactericide provided by this invention uses plant extracts, namely, Malan extract and Coptis extract, which are natural, environmentally friendly, and do not cause secondary pollution. Malan extract and Coptis extract have certain antibacterial / bactericidal effects when used alone. When used in combination under alkaline conditions, they can increase the stability time of the environmentally friendly drilling fluid by more than 30%.

[0019] The bactericide of this invention has good compatibility with other components of the drilling fluid, ensuring that the stability and performance of the drilling fluid are not affected. Organic matter can be naturally degraded after use, leaving no residue. Detailed Implementation

[0020] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0021] Exemplary embodiments of the present invention are now described; however, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to fully and completely disclose the invention and to fully convey its scope to those skilled in the art. The terminology used in the exemplary embodiments is not intended to limit the invention.

[0022] Unless otherwise stated, the terms used herein (including technical terms) have their common meaning as understood by one of ordinary skill in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have a meaning consistent with the context of their relevant field, and not to be interpreted as having an idealized or overly formal meaning.

[0023] Example 1 This invention provides an environmentally friendly bactericide for drilling fluids, comprising the following components in parts by weight: 100 parts water, 5-10 parts strong alkali, 5-10 parts Malan extract, 1-10 parts Coptis chinensis extract, and 5-20 parts buffer. The strong alkali is sodium hydroxide or potassium hydroxide of industrial grade or higher purity.

[0024] The Malan extract is a water-soluble powder extract made from the dried whole herb or root of the Asteraceae plant Malan through heating and reflux extraction, vacuum concentration, and spray drying.

[0025] The Coptis chinensis extract is a water-soluble powder extract made from the roots of Coptis chinensis, a Ranunculaceae plant harvested in autumn, through heating and reflux extraction, vacuum concentration, and spray drying.

[0026] The buffer is hexamethylenetetramine of industrial grade or higher purity.

[0027] Principle of this invention: Certain active ingredients in *Kalimeris indica* extract have inhibitory effects on the growth of bacteria, actinomycetes, yeasts, and molds. These active ingredients may achieve their bactericidal effect by disrupting the cell structure of microorganisms or interfering with their metabolic processes. Berberine and other components in *Coptis chinensis* extract have significant antibacterial activity. Their mechanisms of action include disrupting bacterial structure (such as causing deformation of bacterial septa and loss of staining granules), inhibiting bacterial sugar metabolism (such as inhibiting the oxidative decarboxylation of pyruvate), and inhibiting the synthesis of nucleic acids and proteins.

[0028] When *Kalimeris indica* extract, *Coptis chinensis* extract, and hexamethylenetetramine are used together, they synergistically enhance the bactericidal effect through different mechanisms of action. *Kalimeris indica* extract and *Coptis chinensis* extract can directly inhibit the growth of microorganisms, while hexamethylenetetramine enhances this inhibitory effect by promoting chemical reactions and indirectly promotes bactericidal action by altering the growth environment of microorganisms.

[0029] The environmentally friendly drilling fluid bactericide provided by this invention uses plant extracts, namely, Malan extract and Coptis extract, which are natural, environmentally friendly, and do not cause secondary pollution. Malan extract and Coptis extract have certain antibacterial / bactericidal effects when used alone. When used in combination under alkaline conditions, they can increase the stability time of the environmentally friendly drilling fluid by more than 30%.

[0030] Example 2 Based on Example 1, this example provides an environmentally friendly bactericide for drilling fluid, comprising the following components in parts by weight: 100 parts water, 5 parts strong alkali, 5 parts Malan extract, 10 parts Coptis chinensis extract, and 20 parts buffer. Preparation process: Add the prescribed amount of strong alkali to the prescribed amount of water, stir well, and then add the prescribed amounts of Malan extract, Coptis chinensis extract and buffer while stirring, stirring until a uniform medicinal solution is formed.

[0031] In this embodiment, the strong base is potassium hydroxide, the buffer is hexamethylenetetramine, and the extracts of Malan and Coptis chinensis are commercially available products.

[0032] Example 3 Based on Example 1, this example provides an environmentally friendly bactericide for drilling fluid, comprising the following components in parts by weight: 100 parts water, 6 parts strong alkali, 6 parts Malan extract, 9 parts Coptis chinensis extract, and 15 parts buffer. The preparation process is the same as in Example 2.

[0033] In this embodiment, the strong base is sodium hydroxide, the buffer is hexamethylenetetramine, and the extracts of Malan and Coptis chinensis are commercially available products.

[0034] Example 4 Based on Example 1, this example provides an environmentally friendly bactericide for drilling fluid, comprising the following components in parts by weight: 100 parts water, 8 parts strong alkali, 8 parts Malan extract, 7 parts Coptis chinensis extract, and 15 parts buffer. The preparation process is the same as in Example 2.

[0035] In this embodiment, the strong base is sodium hydroxide, the buffer is hexamethylenetetramine, and the extracts of Malan and Coptis chinensis are commercially available products.

[0036] Example 5 Based on Example 1, this example provides an environmentally friendly bactericide for drilling fluid, comprising the following components in parts by weight: 100 parts water, 10 parts strong alkali, 10 parts Malan extract, 2 parts Coptis chinensis extract, and 20 parts buffer. The preparation process is the same as in Example 2.

[0037] In this embodiment, the strong base is potassium hydroxide, the buffer is hexamethylenetetramine, and the extracts of Malan and Coptis chinensis are commercially available products.

[0038] Example 6 Based on Example 1, this example provides an environmentally friendly bactericide for drilling fluid, comprising the following components in parts by weight: 100 parts water, 6 parts strong alkali, 7 parts Malan extract, 6 parts Coptis chinensis extract, and 5 parts buffer. The preparation process is the same as in Example 2.

[0039] In this embodiment, the strong base is sodium hydroxide, the buffer is hexamethylenetetramine, and the extracts of Malan and Coptis chinensis are commercially available products.

[0040] Example 7 Based on Example 1, this example provides an environmentally friendly bactericide for drilling fluid, comprising the following components in parts by weight: 100 parts water, 8 parts strong alkali, 10 parts Malan extract, 1 part Coptis chinensis extract, and 10 parts buffer. The preparation process is the same as in Example 2.

[0041] In this embodiment, the strong base is potassium hydroxide, the buffer is hexamethylenetetramine, and the extracts of Malan and Coptis chinensis are commercially available products.

[0042] Example 8 Based on Example 1, this example provides an environmentally friendly bactericide for drilling fluid, comprising the following components in parts by weight: 100 parts water, 10 parts strong alkali, 5 parts Malan extract, 10 parts Coptis chinensis extract, and 15 parts buffer. The preparation process is the same as in Example 2.

[0043] In this embodiment, the strong base is potassium hydroxide, the buffer is hexamethylenetetramine, and the extracts of Malan and Coptis chinensis are commercially available products.

[0044] Example 9 Based on Example 1, this example provides an environmentally friendly bactericide for drilling fluid, comprising the following components in parts by weight: 100 parts water, 5 parts strong alkali, 10 parts Malan extract, 2 parts Coptis chinensis extract, and 6 parts buffer. The preparation process is the same as in Example 2.

[0045] In this embodiment, the strong base is sodium hydroxide, the buffer is hexamethylenetetramine, and the extracts of Malan and Coptis chinensis are commercially available products.

[0046] To further illustrate the effects of the present invention, the bactericides prepared in Examples 2-9 were added to the modified starch-based environmentally friendly drilling fluid, and their viscosity was measured.

[0047] According to the petroleum and natural gas industry standard GB / T 16783.1-2006, the ZNN-D6S six-speed rotational viscometer was used to evaluate the performance of the prepared drilling fluid and test its apparent viscosity (AV).

[0048] The modified starch-based environmentally friendly drilling fluid is formulated by adding easily fermentable modified starch to a 4% bentonite-based slurry. The modified starch includes corn starch, potato starch, and cassava starch. The viscosity measurement results are shown in Table 1.

[0049] The bactericide prepared in Example 2 was diluted with water to a mass concentration of 5%, and then added to the diluted bactericide at a mass concentration of 0.1% of the modified starch-based environmentally friendly drilling fluid (the modified starch is corn starch with a mass concentration of 1%), which is denoted as System A.

[0050] The bactericide prepared in Example 3 was diluted with water to a mass concentration of 5%, and then added to the diluted bactericide at a mass concentration of 0.2% of the modified starch-based environmentally friendly drilling fluid (the modified starch was potato starch with a mass concentration of 1%), which was denoted as System B.

[0051] The bactericide prepared in Example 4 was diluted with water to a mass concentration of 5%, and then added to the diluted bactericide at a mass concentration of 0.4% of the modified starch-based environmentally friendly drilling fluid (the modified starch was cassava starch with a mass concentration of 1%), which was denoted as system C.

[0052] The bactericide prepared in Example 5 was diluted with water to a mass concentration of 5%, and then added to the diluted bactericide at a mass concentration of 0.3% of the modified starch-based environmentally friendly drilling fluid (the modified starch is cassava starch with a mass concentration of 1%), which is denoted as system D.

[0053] The bactericide prepared in Example 6 was diluted with water to a mass concentration of 5%, and then added to the diluted bactericide at a mass concentration of 0.3% of the modified starch-based environmentally friendly drilling fluid (the modified starch is cassava starch with a mass concentration of 1%), which is denoted as system E.

[0054] The bactericide prepared in Example 7 was diluted with water to a mass concentration of 5%, and then added to the diluted bactericide at a mass concentration of 0.2% of the modified starch-based environmentally friendly drilling fluid (the modified starch is cassava starch with a mass concentration of 1%), which is denoted as system F.

[0055] The bactericide prepared in Example 8 was diluted with water to a mass concentration of 5%, and then added to the diluted bactericide at a mass concentration of 0.3% of the modified starch-based environmentally friendly drilling fluid (the modified starch is cassava starch with a mass concentration of 1%), which is denoted as system G.

[0056] The bactericide prepared in Example 9 was diluted with water to a mass concentration of 5%, and then added to the diluted bactericide at a mass concentration of 0.5% of the modified starch-based environmentally friendly drilling fluid (the modified starch is cassava starch with a mass concentration of 1.5%), which is denoted as system H.

[0057] Table 1 Viscosities of drilling fluid systems at different modification times

[0058] Table 1 shows that the drilling fluid in system A showed no fermentation odor after 5 days, with a viscosity retention rate of 95%. System B showed no fermentation odor after 6 days, with a viscosity retention rate of 96%. System C showed no fermentation odor after 7 days, with a viscosity retention rate of 91%. System D showed no fermentation odor after 5 days, with a viscosity retention rate of 90%. System E showed no deterioration or viscosity decrease after 5 days. System F showed no fermentation odor after 7 days, with a viscosity retention rate of 94%. System G showed no fermentation odor after 5 days, with a viscosity retention rate of 90%. System H showed no fermentation odor after 6 days, with a viscosity retention rate of 92%. The test results indicate that the bactericide has a good bactericidal effect and does not affect the viscosity of the drilling fluid.

[0059] The above examples are merely illustrative of the present invention and do not constitute a limitation on the scope of protection of the present invention. All designs that are the same as or similar to the present invention are within the scope of protection of the present invention.

Claims

1. An environmentally friendly bactericide for drilling fluids, characterized in that: The product comprises the following components in parts by weight: 100 parts water, 5-10 parts strong alkali, 5-10 parts Malan extract, 1-10 parts Coptis chinensis extract, and 5-20 parts buffer.

2. The environmentally friendly drilling fluid bactericide according to claim 1, characterized in that: The strong alkali is sodium hydroxide or potassium hydroxide of industrial grade or higher purity.

3. The environmentally friendly drilling fluid bactericide according to claim 1, characterized in that: The Malan extract is a water-soluble powder extract made from the dried whole herb or root of the Asteraceae plant Malan through heating and reflux extraction, vacuum concentration, and spray drying.

4. The environmentally friendly drilling fluid bactericide according to claim 1, characterized in that: The Coptis chinensis extract is a water-soluble powder extract made from the roots of Coptis chinensis, a Ranunculaceae plant harvested in autumn, through heating and reflux extraction, vacuum concentration, and spray drying.

5. The environmentally friendly drilling fluid bactericide according to claim 1, characterized in that: The buffer is hexamethylenetetramine of industrial grade or higher purity.

6. The method for preparing an environmentally friendly drilling fluid bactericide according to claim 1, characterized in that: Add the prescribed amount of strong alkali to the prescribed amount of water, stir well, and then add the prescribed amounts of Malan extract, Coptis chinensis extract and buffer while stirring, stirring until a uniform medicinal solution is formed.

7. The method for preparing an environmentally friendly drilling fluid bactericide according to claim 6, characterized in that: The water in question is clean water used for oil and gas field production.

8. The application of the environmentally friendly drilling fluid bactericide according to claim 1 in the preparation of drilling fluid.

9. The application of the environmentally friendly drilling fluid bactericide according to claim 8 in the preparation of drilling fluid, characterized in that: First, dilute the bactericide to a mass concentration of 5-10%. Then, add the diluted bactericide to the prepared environmentally friendly drilling fluid at a mass concentration of 0.1-0.5%, stirring constantly until homogeneous.

10. The application of the environmentally friendly drilling fluid bactericide according to claim 8 in the preparation of drilling fluid, characterized in that: The dosing cycle is 5-10 days.

Images