CN114774091B - A kind of high temperature resistant polymer drilling fluid - Google Patents

Abstract

The invention discloses a high-temperature resistant polymer drilling fluid, which includes the following components by weight: 100 parts of water, 2-10 parts of bentonite, 0.2-1.0 parts of sodium carbonate, 0.01-0.3 parts of sodium hydroxide, and coating agent FA -3670.2-4 parts, 1-5 parts of fluid loss agent, 0.5-5 parts of viscosity reducing agent, 0.5-2.2 parts of blocking agent, 10-60 parts of barite. The fluid loss reducer is polymerized by 2-acrylamide-2-methylpropanesulfonic acid, acrylamide and sodium 4-styrenesulfonate at 55-65°C. The preparation method of polymer drilling fluid provided by the invention includes base slurry preparation, polymer preparation and drilling fluid preparation. The drilling fluid of the present invention has good rheology and appropriate filtration loss under high temperature and high pressure environments, and can solve the problems of reduced drilling fluid filtration and poor flocculation and lubrication effects of polymers under high temperature and high pressure conditions.

Description

A kind of high temperature resistant polymer drilling fluid

Technical field

The present invention relates to the technical field of drilling fluids, in particular to a high-temperature resistant polymer drilling fluid.

Background technique

Drilling fluid is an important part of drilling engineering in the oil and gas drilling process. The performance of drilling fluid greatly affects the drilling speed, quality and cost. Therefore, drilling fluid is of great significance to fast, safe and low-cost drilling engineering.

During the drilling process, due to the existence of geothermal gradient, the bottom hole temperature will gradually increase as the drilling depth increases, and the formation pressure will also increase with the increase of the well depth. Under normal circumstances, when the well depth exceeds 6000m, the bottom hole temperature can reach 200°C. Above ℃, the formation pressure reaches 63MPa, and the properties of treatment agents, viscosity reducers and other ingredients in drilling fluids will change greatly under high temperatures and pressures. Although oil-based drilling fluids are less affected by temperature and pressure, they are highly polluting. High temperature and high pressure water-based drilling fluid is the main research direction of deep well drilling. Water-based drilling fluid is mainly composed of water, treatment agents, viscosity reducers, etc. Its performance is closely related to the composition and ratio of various substances such as treatment agents, viscosity reducers, etc. With the continuous advancement of water-based drilling fluid technology, polymer treatment agents represented by acrylamide and acrylic acid multi-copolymers have been formed, and corresponding polymer drilling fluid systems have been formed, thus promoting the development of drilling fluid technology. progress. Since their application in the 1980s, the temperature resistance of polymer treatment agents has not been ideal. Especially in the case of high-temperature composite salts, the ability to reduce drilling fluid filtration loss is poor, which makes polymers show its unique limitations. Therefore, there is an urgent need for a high-temperature resistant polymer treatment agent that can reduce drilling fluid filtration loss, flocculation, and poor lubrication effects under high-temperature conditions.

Contents of the invention

The purpose of the present invention is to provide a high-temperature-resistant polymer drilling fluid in view of the problems that existing drilling fluids have poor temperature resistance and that polymers reduce drilling fluid filter loss and have poor lubrication effects under high-temperature and high-pressure conditions.

The high-temperature resistant polymer drilling fluid provided by the invention includes the following components by weight:

100 parts of water, 2-10 parts of bentonite, 0.2-1.0 parts of sodium carbonate, 0.01-0.3 parts of sodium hydroxide, 2-4 parts of coating agent FA-3670, 1-5 parts of fluid loss agent, 0.5-5 parts of viscosity reducer parts, 0.5-2.2 parts of sealing agent, 10-60 parts of barite;

The fluid loss reducer is prepared by the following method:

(1) Add 2-acrylamide-2-methylpropanesulfonic acid to the sodium hydroxide aqueous solution and stir to obtain a solution;

(2) At -8-2°C, add acrylamide and sodium 4-styrenesulfonate to the solution in step (1) and stir. After the water bath is heated to 55-65°C, add the initiator and continue to circulate nitrogen. And stir for 2-4h to obtain the complex. Add the complex to the acetone solution to extract and leave it for 2-4h. Filter to obtain a solid. Add the solid to a 1:1 mixture of formamide and acetic acid for purification and leave it for 2-4h. After filtering, Obtain the polymer and dry it in a vacuum at 45-55°C for 12 hours to obtain the polymer solid fluid loss agent.

The preparation method of the high temperature resistant polymer drilling fluid is as follows:

(1) Add bentonite and sodium carbonate to water in sequence, stir for 1 hour, and let stand for 24 hours to obtain a base slurry;

(2) Under high-speed stirring conditions, add coating agent FA-367, viscosity reducing agent, blocking agent, and weighting agent to the base slurry in sequence. After mixing evenly, add fluid loss agent and stir until completely mixed; use hydrogen Sodium oxide adjusts the pH of the solution to 9-11 to obtain a high-temperature resistant polymer drilling fluid.

The viscosity reducing agent is one or more of amphoteric polymer viscosity reducing agent JN-1, oligomer viscosity reducing agent XB-40, and composite ionic polymer viscosity reducing agent PSC90-6.

The sealing agent is one or more of single pressure sealing agent DF-1 and sulfonated asphalt FT-1.

Preferably, it includes the following components by weight: 100 parts of water, 2-6 parts of bentonite, 0.4-1.0 parts of sodium carbonate, 0.05-0.2 parts of sodium hydroxide, 0.5-3 parts of coating agent FA-367, and 0.5-3 parts of filter loss reduction agent. 2-4 parts of agent, 3 parts of zwitterionic polymer viscosity reducer JN-11-3 parts, 10.7-2.0 parts of sulfonated asphalt FT-15-55 parts of barite. The density of the drilling fluid is 1.45-1.65g/cm ³ .

Sulfonated asphalt contains sulfonic acid groups and has a strong hydration effect. When adsorbed on the shale interface, it can prevent the hydration and dispersion of shale particles and prevent collapse. At the same time, the water-insoluble part can fill pore throats and fractures to seal them, and can cover the shale interface to improve the quality of the mud cake. Sulfonated asphalt also plays a role in lubrication and reducing high-temperature and high-pressure filtration loss in drilling fluids.

As a weighting agent, barite can not only increase the hydrostatic column pressure of drilling fluid, balance the collapse stress of the formation, stabilize the well wall, but also balance the fluid pressure of the formation in high-pressure wells to prevent accidents such as well kicks and blowouts. occur.

The bentonite can be purchased from Lingshou County Yinchao Mineral Products Co., Ltd., model number is 003; the main components are silica, aluminum oxide and water, and also contain iron, magnesium, calcium, sodium, potassium and other elements, and have strong It has excellent hygroscopicity and swelling properties. It can absorb 8-15 times the amount of water of its own volume. Its volume can expand several times to 30 times. It can be dispersed into gelatinous and suspended forms in water media.

The sodium carbonate can be purchased from Suzhou Qichuang Chemical Co., Ltd., model is QC-1; sodium carbonate is commonly known as soda, and lotion alkali belongs to the salt class, which is a strong alkali and weak acid salt, has the properties and stability of salt, and is easy to use. Soluble in water, its aqueous solution is alkaline.

The coating agent FA-367 is a linear macropolymer that introduces cationic, anionic, and nonionic groups into the molecule. Its appearance is gray-yellow powder, soluble in water, and the aqueous solution is a viscous liquid. The main function of drilling fluid is to inhibit the dispersion of rock cuttings and increase the viscosity of drilling fluid. Its coating inhibition ability is quite strong, so it has a strong load-bearing capacity against rock powder contamination. It is easy to purify and treat rock powder contamination, and can Reducing the content of submicron particles in the system is beneficial to increasing the ROP and protecting the production layer. In terms of temperature resistance, its performance has also been improved.

Compared with the prior art, the benefits of the present invention are:

The drilling fluid of the present invention uses a self-made polymer fluid loss agent. Compared with the existing technology, the fluid loss agent not only has excellent fluid loss performance, but also has excellent lubrication performance. At the same time, it has good rheology and appropriate filtration loss under high temperature and high pressure environments, and can solve the problems of polymers reducing drilling fluid filtration loss, poor flocculation and lubrication effects under high temperature and high pressure conditions.

Other advantages, objects, and features of the present invention will be apparent in part from the description below, and in part will be understood by those skilled in the art through study and practice of the present invention.

Detailed ways

Preferred embodiments of the present invention are described below. It should be understood that the preferred embodiments described here are only used to illustrate and explain the present invention and are not intended to limit the present invention.

Example 1

Preparation method of polymer fluid loss agent:

(1) Add 30 parts by weight of 2-acrylamide-2-methylpropanesulfonic acid to 100 ml, 0.5 mol/L sodium hydroxide aqueous solution, and stir for 25 minutes at a low speed stirrer of 2000 rpm to obtain a solution.

(2) At -3°C, add 5 parts by weight of acrylamide and 3 parts by weight of sodium 4-styrenesulfonate to 25 parts by weight of the solution prepared in step 1, stir evenly with a glass rod, and heat in a water bath to 60°C. Afterwards, 1 part by weight of the initiator ammonium persulfate was added, nitrogen gas was continuously supplied and the mixture was stirred for 3 hours to obtain a composite.

(3) Add the complex obtained in (2) to the acetone solution for extraction and leave it for 3 hours, filter to obtain a solid; add the solid to a mixture of formamide and acetic acid with a volume ratio of 1:1 for purification and leave it for 3 hours, and filter to obtain polymer. The polymer is dried in a vacuum at 50°C for 12 hours to obtain a polymer solid fluid loss agent.

Example 2

Preparation method of polymer fluid loss agent:

(1) Add 20 parts by weight of 2-acrylamide-2-methylpropanesulfonic acid to 100 ml, 0.4 mol/L sodium hydroxide aqueous solution, and stir for 20 minutes at a low-speed stirrer of 1500 rpm to obtain a solution.

(2) At -8°C, add 5 parts by weight of acrylamide and 3 parts by weight of sodium 4-styrenesulfonate to 25 parts by weight of the solution prepared in step 1, stir evenly with a glass rod, and heat in a water bath to 55°C Afterwards, 0.5 parts by weight of the initiator ammonium persulfate was added, and nitrogen gas was continuously supplied and stirred for 2 hours to obtain a composite.

(3) Add the complex obtained in (2) to the acetone solution for extraction and leave it for 3 hours, filter to obtain a solid; add the solid to a mixture of formamide and acetic acid with a volume ratio of 1:1 for purification and leave it for 2 hours, and filter to obtain polymer. The polymer is dried in a vacuum at 45°C for 12 hours to obtain a polymer solid fluid loss agent.

Example 3

Preparation method of polymer fluid loss agent:

(1) Add 40 parts by weight of 2-acrylamide-2-methylpropanesulfonic acid to 100 ml, 0.6 mol/L sodium hydroxide aqueous solution, and stir for 30 minutes at a low speed stirrer of 2000 rpm to obtain a solution.

(2) At 2°C, add 5 parts by weight of acrylamide and 3 parts by weight of sodium 4-styrenesulfonate to 25 parts by weight of the solution prepared in step 1 and stir evenly with a glass rod. Heat the water bath to 65°C. , add 2 parts by weight of initiator ammonium persulfate, continuously vent nitrogen and stir for 4 hours to obtain a complex.

(3) Add the complex obtained in (2) to the acetone solution for extraction and leave it for 4 hours, filter to obtain a solid; add the solid to a mixture of formamide and acetic acid with a volume ratio of 1:1 for purification and leave it for 4 hours, and filter to obtain polymer. The polymer was dried in a vacuum at 55°C for 12 hours to obtain a polymer solid fluid loss agent.

Comparative example 1

A kind of fluid loss reducer, the preparation method steps are the same as Example 2, the difference lies in step (2): at -10°C, add 5 parts by weight of acrylamide and 3 parts by weight of sodium 4-styrenesulfonate. 1. Add 25 parts by weight of the solution prepared in 1 and stir evenly with a glass rod. After heating the water bath to 55°C, add 0.5 parts by weight of the initiator ammonium persulfate, continue to circulate nitrogen and stir for 2 hours to obtain a composite.

Comparative example 2

A kind of fluid loss reducer, the preparation method steps are the same as Example 2, the difference lies in step (2): at 4°C, add 5 parts by weight of acrylamide and 3 parts by weight of sodium 4-styrenesulfonate into step 1 Add 25 parts by weight of the prepared solution and stir evenly with a glass rod. After heating the water bath to 55°C, add 0.5 parts by weight of the initiator ammonium persulfate, continue to circulate nitrogen and stir for 2 hours to obtain a composite.

Comparative example 3

A kind of fluid loss reducer, the preparation method steps are the same as Example 2, the difference lies in step (2): at -8°C, add 5 parts by weight of acrylamide and 3 parts by weight of sodium 4-styrenesulfonate. 1. Add 25 parts by weight of the solution prepared in 1 and stir evenly with a glass rod. After heating the water bath to 70°C, add 0.5 parts by weight of the initiator ammonium persulfate, continue to circulate nitrogen and stir for 2 hours to obtain a composite.

Comparative example 4

A kind of fluid loss reducer, the preparation method steps are the same as Example 2, the difference lies in step (2): at -8°C, add 5 parts by weight of acrylamide and 3 parts by weight of sodium 4-styrenesulfonate. 1. Add 25 parts by weight of the solution prepared in 1 and stir evenly with a glass rod. After heating the water bath to 50°C, add 0.5 parts by weight of the initiator ammonium persulfate, continue to circulate nitrogen and stir for 2 hours to obtain a composite.

The fluid loss agents prepared in Examples 1-3 and Comparative Examples 1-4 were used to prepare drilling fluid respectively. The preparation method of drilling fluid is as follows:

(1) Add 6 parts by weight of bentonite (bentonite can be purchased from Lingshou County Yinchao Mineral Products Co., Ltd., model number is 003) and 0.6 parts by weight of sodium carbonate into 100 parts by weight of water in sequence, stir for 1 hour, and let stand for 24 hours to obtain base pulp.

(2) Under high-speed stirring conditions, 1 part by weight of coating agent FA-367 (purchased from Minquan Dongxing Mud Materials Co., Ltd.) and 2 parts by weight of zwitterionic polymer viscosity reducer JN-1 (purchased from Minquan Dongxing Mud Materials Co., Ltd.) Mud Materials Co., Ltd.), 1.5 parts by weight of the sealing agent sulfonated asphalt FT-1, and 20 parts by weight of barite were added to the prehydrated base slurry, stirred and mixed evenly, and then added 4 parts by weight of filter reduction Lose the agent and stir to mix completely; use sodium hydroxide to adjust the pH of the drilling fluid to 10 to obtain the drilling fluid.

The drilling fluids prepared using the fluid loss additives of Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4 are named Drilling Fluid 1, Drilling Fluid 2, and Drilling Fluid respectively. 3. Drilling fluid 4, drilling fluid 5, drilling fluid 6, drilling fluid 7. Drilling fluid 8 uses the commercially available fluid loss agent KJ-1 (produced by Minquan Dongxing Mud Materials Co., Ltd.)

The performance and effect test results of various drilling fluids are shown in the table below:

It can be seen from the test data in the above table:

(1) In the preparation process of the high-temperature resistant polymer fluid loss agent in Examples 1-3, the amount of each component material and the preparation conditions are optimal. The drilling fluid added to the polymer fluid loss agent will lose fluid under high temperature and high pressure. In the experiment, the water loss was relatively low, the mud cake was thin, the filter loss reduction effect was good, and it also had good lubrication performance.

(2) The temperature control for preparing the fluid loss agent in Comparative Examples 1-4 is different from that of the present invention, and the final products failed to achieve a good fluid loss reduction effect in the drilling fluid. This is because the temperature control in step 2 of preparing the fluid loss agent is inappropriate, and the high temperature resistant polymer fluid loss agent cannot be produced or only a small amount of the high temperature resistant polymer fluid loss agent is produced. This shows that during the preparation process of the fluid loss reducer, the temperature control in step 2 is very important. Acrylamide and sodium 4-styrenesulfonate must be added to the solution prepared in step 1 at -8-2°C and a glass rod is used. Stir evenly, heat the water bath to 55-65°C, add the initiator, continue to circulate nitrogen and stir for 2-4 hours to obtain the composite. In this step, the two temperature stages (-8-2°C, 55-65°C) must be accurately controlled at the same time to prepare the best high-temperature resistant fluid loss reducer.

(3) A commercially available fluid loss agent is added to the drilling fluid 8, which has a certain fluid loss effect. However, compared with the high temperature resistant polymer fluid loss agent of the present invention, the fluid loss effect is far behind. .

In summary, by adding a self-made fluid loss agent to the high-temperature resistant polymer drilling fluid of the present invention, the drilling fluid can form a dense filter cake, effectively reduce fluid loss, reduce the invasion of filtrate, and thereby improve the wellbore efficiency. stability.

The above are only preferred embodiments of the present invention and are not intended to limit the present invention in any form. Although the present invention has been disclosed above in preferred embodiments, they are not intended to limit the present invention. Anyone familiar with this field will Skilled persons can make some changes or modifications to equivalent embodiments using the technical content disclosed above without departing from the scope of the technical solution of the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the invention still fall within the scope of the technical solution of the present invention.

Claims (6)

1. The high temperature resistant polymer drilling fluid is characterized by comprising the following components in parts by weight:

100 parts of water, 2-10 parts of bentonite, 0.2-1.0 part of sodium carbonate, 0.01-0.3 part of sodium hydroxide, 0.2-4 parts of coating agent FA-367, 1-5 parts of filtrate reducer, 0.5-5 parts of viscosity reducer, 0.5-2.2 parts of plugging agent and 10-60 parts of heavy crystal stone;

the filtrate reducer is prepared by the following method:

(1) Adding 2-acrylamide-2-methylpropanesulfonic acid into sodium hydroxide aqueous solution, and stirring to obtain solution;

(2) Adding acrylamide and 4-sodium styrene sulfonate into the solution in the step (1) at the temperature of-8-2 ℃ and stirring, heating in a water bath to 55-65 ℃, adding an initiator, continuously introducing nitrogen and stirring for 2-4 hours to obtain a compound, adding the compound into an acetone solution, extracting and standing for 2-4 hours, and filtering to obtain a solid; addition of solids to 1 of formamide and acetic acid: and (1) purifying the mixture, standing for 2-4h, filtering to obtain a polymer, and drying in vacuum at 45-55 ℃ for 12h to obtain the polymer solid filtrate reducer.

2. The high temperature resistant polymer drilling fluid of claim 1, wherein the method of preparation comprises:

(1) Sequentially adding bentonite and sodium carbonate into water, stirring for 1h, and standing for 24h to obtain base slurry;

(2) Sequentially adding a coating agent FA-367, a viscosity reducer, a plugging agent and a weighting agent into the base slurry under the condition of high-speed stirring, adding a filtrate reducer after uniformly mixing, and stirring to completely mix; and regulating the pH value of the solution to 9-11 by using sodium hydroxide to obtain the high-temperature-resistant polymer drilling fluid.

3. The high temperature resistant polymer drilling fluid of claim 1, wherein the viscosity reducer is one or more of a zwitterionic polymer viscosity reducer JN-1, an oligomer viscosity reducer XB-40, and a composite ionic polymer viscosity reducer PSC 90-6.

4. The high temperature resistant polymer drilling fluid according to claim 3, wherein the plugging agent is one or more of single pressure plugging agent DF-1 and sulfonated asphalt FT-1.

5. The high temperature resistant polymer drilling fluid of claim 4, wherein the drilling fluid has a density of 1.45 to 1.65g/cm ³ 。

6. The high temperature resistant polymer drilling fluid of claim 5, comprising the following components in parts by weight: 100 parts of water, 2-6 parts of bentonite, 0.4-1.0 part of sodium carbonate, 0.05-0.2 part of sodium hydroxide, 0.5-3 parts of coating agent FA-367, 2-4 parts of filtrate reducer, 1-3 parts of viscosity reducer, 0.7-2.0 parts of plugging agent and 15-55 parts of barite.