High temperature resistant foaming agent for foam drilling

Abstract

The application discloses a high-temperature-resistant foaming agent for foam drilling, and solves the problems of insufficient temperature resistance and salt resistance of foaming agents in current foam drilling fluid systems, and can well meet the requirements of drilling construction in complex formations. The foaming agent is composed of the following components in percentage by mass: 30-70wt% main foaming agent, 20-50wt% auxiliary foaming agent, and the balance of water. The main foaming agent is a quaternary ammonium salt cationic surfactant containing silicon, and the auxiliary foaming agent is a zwitterionic surfactant containing a betaine structure. The foaming agent system prepared by the application has the temperature resistance of 160 DEG C, the salt resistance of 100000mg / L (Ca 2+ 5000mg / L), excellent foaming effect, good temperature resistance and salt resistance, and good inhibition effect on hydration of shale and mudstone.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of high-temperature foaming agent for foam drilling, specifically to upper bottom layer sand shale interbedding frequently, low pressure, low permeability high-temperature formation, belong to oilfield drilling fluid processing agent field. BACKGROUND

[0002] Foam drilling is the use of air or nitrogen and foaming agent base fluid mixed to form a honeycomb foam fluid as drilling fluid drilling method, foam fluid is lower than conventional mud drilling fluid density, bottom hole clamping effect is small, not only can effectively control drilling fluid circulation loss, improve the rate of penetration, but also can reduce reservoir damage, protect low pressure oil and gas reservoir.

[0003] At present, domestic foam is applied to a variety of basic theory of oil field has carried on a lot of research, especially in oil drilling, the research and application of foam are more, but the efficient temperature-resistant foam is less, now with the oil production into later period, water content in oil well gradually increases, which brings more and more high-temperature harsh formation makes the originally unstable foam application has received great limitation, the existing foam and cannot meet the requirements of the scene.

[0004] Silicon-containing cationic surfactant has strong surface activity and corrosion resistance, high temperature resistance, non-toxic and other characteristics, because it has positive charge, it also plays a certain inhibitory effect on clay hydration, can effectively inhibit clay hydration and enhance wellbore stability. SUMMARY

[0005] In order to solve the above problems in the prior art, the present application uses silicon-containing cationic surfactant with strong surface activity and good high temperature resistance, corrosion resistance and other characteristics, and the strong surface activity of betaine zwitterionic surfactant to develop a high-temperature-resistant foaming agent with strong surface activity. At the same time, the cationic groups in the molecular structure of silicon-containing cationic surfactant and betaine zwitterionic surfactant react with the negative surface of mud shale, shorten the distance between clay layers, and squeeze out interlayer adsorbed water, thereby achieving the effect of inhibiting clay hydration, which can well meet the requirements of drilling operation in complex formation.

[0006] In the first aspect, the present application provides a high-temperature-resistant foaming agent for foam drilling, and the weight percentage of the foaming agent system is as follows: 30-70wt% of main foaming agent, 20-50wt% of auxiliary foaming agent, and the balance of water.

[0007] The main foaming agent is a silicon-containing quaternary ammonium salt cationic surfactant.

[0008] The auxiliary foaming agent is a betaine structure-containing zwitterionic surfactant.

[0009] The high-temperature resistant foaming agent has a temperature resistance of 160 DEG C.

[0010] The structure of the silicon-containing quaternary ammonium salt cationic surfactant is:

[0011]

[0012] wherein R is selected from any one of -C 12 H 25 , -C 14 H 29 , -C 16 H 33 , -C 18 H 37 .

[0013] As a specific embodiment of the present application, the betaine-structure-containing zwitterionic surfactant is any one of cocamidopropyl betaine, myristyl sulfobetaine and lauryl amidopropyl betaine.

[0014] As a specific embodiment of the present application, the silicon-containing quaternary ammonium salt cationic surfactant preferably accounts for 40-65 wt%, and the betaine-structure-containing zwitterionic surfactant preferably accounts for 30-45 wt%.

[0015] As a specific embodiment of the present application, the silicon-containing quaternary ammonium salt cationic surfactant has R preferably being -C 18 H 37 .

[0016] In the second aspect, the present application provides a preparation method of the foaming agent, and the preparation steps are as follows: firstly, the main foaming agent is added into a proper amount of water, and slowly stirred until completely dissolved; and then, the auxiliary foaming agent is added, and slowly stirred until uniform.

[0017] In the third aspect, the present application provides an application of the foaming agent in the field of foam drilling, and the foaming agent is especially suitable for high-temperature strata with frequent interbedding of sandstone and mudstone in the upper strata, low pressure and low permeability.

[0018] As a specific embodiment of the present application, the mass fraction of the foaming agent in the drilling fluid is 0.5-2.0 wt%.

[0019] Compared with the prior art, the present application has the following beneficial effects:

[0020] (1) The foaming agent of the present application has a temperature resistance of 160 DEG C, and has good foaming effect and good foam stability. Compared with the prior art, the present application provides a foaming agent for foam drilling, which has high temperature resistance and excellent comprehensive performance, and can maintain good foam performance under complex strata conditions.

[0021] (2) The invention has significantly improved rolling recovery rate of clean water and good effect of inhibiting hydration of cuttings;

[0022] (3) The invention uses a silicon-containing cationic surfactant as a main foaming agent, which has excellent surface activity and is non-toxic and harmless to the environment.

[0023] The present application is a treatment agent in the field of oil field drilling, and is suitable for high-temperature formations with frequent upper bottom sand-shale interbedding, low pressure and low permeability.

[0024] The foaming agent system prepared by the present application has a temperature resistance of 160 DEG C, good foaming effect, and strong inhibition effect on hydration of shale. Compared with the prior art, the present application provides a foaming agent for foam drilling with high temperature resistance and excellent comprehensive performance, which can maintain good foam performance under complex formation conditions. DETAILED DESCRIPTION

[0025] The present application will be described in detail below with reference to examples.

[0026] Example 1:

[0027] Take 50g of silicon-containing cationic surfactant (R is -C 18 H 37 ) and add it to 20g of water, slowly stir until completely dissolved, then add 30g of lauryl amido propyl betaine, slowly stir until uniform, which is foaming agent 1.

[0028] Example 2:

[0029] Take 40g of silicon-containing cationic surfactant (R is -C 18 H 37 ) and add it to 20g of water, slowly stir until completely dissolved, then add 40g of cocamide propyl betaine, slowly stir until uniform, which is foaming agent 2.

[0030] Example 3:

[0031] Take 60g of silicon-containing cationic surfactant (R is -C 18 H 37 ) and add it to 10g of water, slowly stir until completely dissolved, then add 30g of tetradecyl sulfobetaine, slowly stir until uniform, which is foaming agent 3.

[0032] Example 4:

[0033] Take 40g of silicon-containing cationic surfactant (R is -C 14 H 29 ) and add it to 15g of water, slowly stir until completely dissolved, then add 45g of lauryl amido propyl betaine, slowly stir until uniform, which is foaming agent 4.

[0034] Example 5

[0035] Take 65 g of the silicon-containing cationic surfactant (R is -C 16 H 33 ) into 5 g of water, slowly stir until completely dissolved, then add 30 g of lauryl amido propyl betaine into it, slowly stir until uniform, which is foaming agent 5.

[0036] Example 6

[0037] Take 45 g of the silicon-containing cationic surfactant (R is -C 12 H 25 ) into 25 g of water, slowly stir until completely dissolved, then add 30 g of cocamide propyl betaine into it, slowly stir until uniform, which is foaming agent 6.

[0038] Example 7

[0039] Take 45 g of the silicon-containing cationic surfactant (R is -C 16 H 33 ) into 25 g of water, slowly stir until completely dissolved, then add 30 g of tetradecyl sulfobetaine into it, slowly stir until uniform, which is foaming agent 7.

[0040] Test Example 1

[0041] Take 0.5 g of the above foaming agent, add it into simulated water with a salinity of 100000 mg / L (Ca 2+ 5000 mg / L), and measure the foam performance by using the high-speed stirring method.

[0042] Test Example 2

[0043] Take 1.5 g of the above foaming agent, add it into 300 g of clean water, heat it at 160℃ for 16 h, then cool it to room temperature, and measure the foam performance by using the high-speed stirring method.

[0044] Test Example 3

[0045] Take 1.5 g of the above foaming agent, add it into 300 g of clean water, then add 20 g of rock debris, heat it at 160℃ for 16 h, filter the rock debris, dry it and weigh it, and measure the performance of inhibiting hydration of the rock debris.

[0046] Comparative Example 1

[0047] Take foaming agent FP-1 commonly used by a certain drilling company, and measure its foam performance before and after high temperature, and the performance of inhibiting hydration of rock debris by referring to the methods of Test Examples 1, 2 and 3, and comparing them with the present application.

[0048] The specific test data are as follows:

[0049] Table 1 Foam properties

[0050]

[0051] Table 2 Inhibition of shale hydration properties

[0052] Sample Rolling recovery of cuttings / % Tap water comparison 9.8 Foaming system 1 35.1 Foaming system 2 39.4 Foaming system 3 34.1 Foaming system 4 29.4 Foaming system 5 26.8 Foaming system 6 28.3 Foaming system 7 24.3 Comparative example 1 11.5

[0053] From the test data of Examples 1-7 and Comparative Example 1 in Tables 1-2 above, it can be seen that the cationic foaming system of the present application still has excellent foam properties under high temperature and high salt conditions, showing excellent temperature resistance (160°C) and salt resistance (100000 mg / L (Ca 2+ 5000mg / L), and the preferred combination of the present application is 40-65wt% of the main foaming agent, 30-45wt% of the auxiliary foaming agent, and the balance being water. The recovery rate of clean water cut rolling is significantly improved, and the performance in all aspects is better than that of commercially available foaming agents.

[0054] Any numerical values recited herein include all values from the lower value and up to the upper value. Values that are near to or fall within a range provided in the written description are intended to be encompassed by the range. For example, if a range is stated as 50-90, it is intended that values such as 51-89, 52-88, etc., are embraced within the range. For values that are not integers, one unit is intended for every 0.1, 0.01, 0.001, or 0.0001 as appropriate. This same principle applies to ranges recited in the following claims. In the application, all possible combinations between recited ranges are considered to be disclosed.

[0055] It should be noted that the foregoing examples have been provided merely for the purposes of explanation and are in no way to be construed as limiting. The present application is described with reference to exemplary embodiments, but it is understood that the words which have been used herein are words of description, and that they are being used to describe the preferred embodiments of the present application. The application is, however, capable of modifications in various obvious respects, all without departing from the scope and spirit of the present application. Although the application has been described with reference to particular means, materials and embodiments, from the foregoing description, one skilled in the art can effect a variety of changes and modifications. While the application has been described with reference to particular methods, materials and embodiments, from the foregoing description, one skilled in the art can effect a variety of changes and modifications. Although the application has been described with reference to particular methods, materials and embodiments, from the foregoing description, one skilled in the art can effect a variety of changes and modifications. Although the application has been described with reference to particular methods, materials and embodiments, from the foregoing description, one skilled in the art can effect a variety of changes and modifications. Although the application has been described with reference to particular methods, materials and embodiments, from the foregoing description, one skilled in the art can effect a variety of changes and modifications.

Claims

1. A high temperature resistant foaming agent for foamed drilling, characterized by, The foaming agent system weight percentage components are: Main foaming agent 30-70wt% Auxiliary foaming agent 20-50wt% Water balance; The main foaming agent is a silicon-containing quaternary ammonium salt cationic surfactant; The auxiliary foaming agent is a zwitterionic surfactant containing a betaine structure; The high-temperature-resistant foaming agent has a temperature resistance of 160℃; The structure of the silicon-containing quaternary ammonium salt cationic surfactant is: wherein R is selected from any one of -C 12 H 25 , -C 14 H 29 , -C 16 H 33 , -C 18 H 37 ​ 2. The high temperature resistant foaming agent for foamed drilling fluid according to claim 1, wherein, The zwitterionic surfactant containing a betaine structure is any one of cocamide propyl betaine, tetradecyl sulfobetaine, and lauryl amide propyl betaine.

3. The high temperature resistant blowing agent for foamed drilling fluid of claim 1, wherein, The main foaming agent component is 40-65wt%, and the auxiliary foaming agent component is 30-45wt%.

4. The high temperature resistant foaming agent for foamed drilling fluid of claim 1, wherein, Silicon-containing quaternary ammonium salt cationic surfactant: R is selected from -C 18 H 37 .

5. The high temperature resistant foaming agent for foamed drilling fluid according to claim 1, wherein The preparation steps are: first, add the main foaming agent to an appropriate amount of water, slowly stir until completely dissolved, then add the auxiliary foaming agent, slowly stir until uniform, and obtain the high-temperature-resistant foaming agent for foam drilling.

6. Use of a high temperature resistant blowing agent for foamed drilling according to any one of claims 1 to 5, characterized in that It is used in the field of foam drilling and is suitable for high-temperature formations with frequent sand-shale interbedding, low pressure, and low permeability in the upper formation.

7. Use according to claim 6, characterized in that, The mass fraction of the foaming agent in the drilling fluid is 0.5-2.0wt%.

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