Micro-foam foaming system for drilling fluid
1. A micro-foam foaming system for drilling fluid is characterized in that the foaming agent system comprises a main polymer foaming agent, an auxiliary foaming agent and water, and is prepared by the following components in proportion:
10 to 34 percent of main polymer foaming agent
5 to 20 percent of auxiliary foaming agent
The balance of water;
the main polymer foaming agent is a non-ionic polymer surfactant containing a rigid benzene ring structure,
the secondary foaming agent is selected from amino acid type zwitterionic surfactants containing sulfonic acid groups or sulfate groups.
2. The micro-foam foaming system for drilling fluid as claimed in claim 1, wherein the molecular structural formula of the main polymer foaming agent is:
wherein x: y =2 (1 ~ 8), R = CH3(CH2)nN =7, 8, 11, 13 or 15.
3. A micro-foam blowing system for drilling fluids according to claim 1 wherein the micro-foam has an average size of 50 to 84 μm.
4. A micro-foam foaming system for drilling fluids according to claim 3 wherein the micro-foam has an average size of 61 to 84 μm.
5. The micro-foam foaming system for drilling fluids of claim 2, wherein x: y =2: (2-4).
6. The micro-foam foaming system for drilling fluids of claim 2, wherein n is 11.
7. The micro-foam foaming system for drilling fluid as claimed in claim 1 or 2, wherein the main polymer foaming agent is prepared by condensing alkylphenol containing rigid benzene ring structure with formaldehyde, reacting with ethylene oxide and propylene oxide to obtain a non-ionic polymer surfactant, and sulfating the surfactant to obtain the main polymer foaming agent.
8. The micro-foam foaming system for drilling fluid according to claim 1, wherein the amino acid type zwitterionic surfactant containing a sulfonic acid group or a sulfate group is sulfoethyl amino acid: R-NHCH2CH2SO3Na; sulfopropyl amino acid: R-NHCH2CH2CH2SO3Na; hydroxypropyl sulfate amino acid: R-NHCH2(OH)CH2CH2OSO3Na, wherein above R = C9H19、C12H25、C14H29、C16H33Or C18H37。
Background
At present, the great trend of low-cost development pushes the structure of a well drilling shaft to be continuously optimized (simplified), the drilling construction of a large-size ultra-long open hole section becomes common, a plurality of sets of pressure systems and complex stratum lithology coexist in the large-size ultra-long open hole section, the stability risk of the shaft is increased, a safety construction window is narrowed, higher requirements are put on the functions of the drilling fluid, and the strengthening (leakage prevention and collapse prevention) task of the shaft while drilling is important. And the horizontal well continuously extends along with the section length, the problem of the detritus bed is obvious, safe drilling is greatly challenged, and higher requirements are provided for the rock carrying capacity of the drilling fluid.
The micro-bubbles exist in a uniform, non-aggregated and non-continuous state, the size of the micro-bubbles is between 0 and 100 mu m, the gas content is less than that of common foams, the bubbles are wrapped by a plurality of layers of liquid films, adjacent bubbles can be effectively prevented from being combined, the stability of the foams is improved, and the micro-bubbles have certain leakage-proof and plugging effects due to the characteristics of small size, high strength and good stability.
ZL200910157353.1 discloses a microbubble drilling fluid, the surfactant of which is a mixture of sodium dodecyl sulfate and sodium dodecyl benzene sulfonate.
ZL200710113558.0 discloses a circulating microfoam drilling or completion fluid whose surfactant employs fatty alcohol glyceryl ether sulfonate, polymeric alcohol, coconut oil amide sulfosuccinic acid monoester sodium salt.
However, the surfactants used in the micro-foam drilling fluid are all linear surfactants, have single structure and poor rock carrying capacity, and meanwhile, due to the fact that the anionic surfactants are poor in salt resistance and calcium resistance, the requirements of complex stratum drilling construction are difficult to meet.
Disclosure of Invention
One object of the present invention is to provide a microfoam foaming system for drilling fluids. The micro-foam prepared by the foaming agent has lower density, stronger capability of carrying rocks and suspending drilling cuttings and stronger salt and calcium resistance, and can well meet the drilling construction requirements of complex stratums.
The main technical scheme of the invention is as follows: a micro-foam foaming system for drilling fluid is characterized in that the foaming system comprises a polymer main foaming agent, an auxiliary foaming agent and water, and is prepared by the following components in proportion: 10-34% of main foaming agent, 5-20% of auxiliary foaming agent and the balance of water.
The main polymer foaming agent is a non-ionic polymer surfactant containing a rigid benzene ring structure.
The secondary foaming agent is selected from amino acid type zwitterionic surfactants containing sulfonic acid groups or sulfate groups.
The average size of the micro-foam is 50-84 μm, preferably 61-84 μm.
The molecular structural formula of the main foaming agent is as follows:
wherein x: y =2 (1 ~ 8), R = CH3(CH2)nN =7, 8, 11, 13 or 15.
In the molecular structure of the main foaming agent, x is as follows: the most appropriate ratio of y is 2: (2-4).
Most preferably, n in the molecular structure of the primary blowing agent is 11.
The preparation method of the main foaming agent comprises the steps of condensing alkylphenol containing a rigid benzene ring structure with formaldehyde, then reacting with ethylene oxide and propylene oxide to obtain a nonionic polymer surfactant, and sulfating the surfactant to obtain the main foaming agent.
The amino acid type zwitterionic surfactant containing sulfonic acid groups or sulfate groups is sulfoethyl amino acid: R-NHCH2CH2SO3Na; sulfopropyl amino acid: R-NHCH2CH2CH2SO3Na; hydroxypropyl sulfate amino acid: R-NHCH2(OH)CH2CH2OSO3Na, wherein above R = C9H19、C12H25、C14H29、C16H33Or C18H37。
The micro-bubble foaming agent system prepared by the invention has low density (0.71-0.84 g/cm)3) 50000ppm of salt resistance, 2000ppm of calcium resistance and good foaming effect. Compared with the prior art, the method has the following outstanding effects: provides a micro-bubble foaming agent system with excellent comprehensive performance, and can keep better foaming performance under the condition of complex stratum.
Detailed Description
The present invention will be described in detail with reference to examples.
Example 1
A micro-foam foaming system for drilling fluid is prepared by the following specific steps: 85g of water was put into a beaker, and 10g (x: y =2: 1; n = 11), C, of a main blowing agent was slowly added with stirring9H19NHCH2CH2SO3And (5) Na 5g, slowly heating to 40 ℃, and uniformly stirring to obtain the micro-bubble foaming agent system 1. Using the Waring Blender method at 50000ppm (Ca)2+2000 ppm), and the density change before and after hot rolling for 16h at 120 ℃ is measured, and the particle size of the foam of the prepared micro-foam foaming agent is measured by a microscope.
Example 2
A micro-foam foaming system for drilling fluid is prepared by the following specific steps: 82g of water were placed in a beaker, and 10g of the main blowing agent (x: y =2: 1; n = 9), C, were slowly added with stirring14H29NH CH2CH2CH2SO3And (3) slowly heating Na 8g to 40 ℃, and uniformly stirring to obtain the microbubble foaming system 2. Using the Waring Blender method at 50000ppm (Ca)2+2000 ppm), and the density change before and after hot rolling for 16h at 120 ℃ is measured, and the particle size of the foam of the prepared micro-foam foaming agent is measured by a microscope.
Example 3
A micro-foam foaming system for drilling fluid is prepared by the following specific steps: 59g of water was put into a beaker, and 34g (x: y =1: 1; n = 11), C, of a main foaming agent was slowly added with stirring12H25NHCH2CH2SO3And (3) Na 7g, slowly heating to 40 ℃, and uniformly stirring to obtain the microbubble foaming system 3. Using the Waring Blender method at 50000ppm (Ca)2+2000 ppm) conditionsAnd (3) measuring the foam performance, measuring the density change of the foam before and after hot rolling for 16h at 120 ℃, and measuring the particle size of the foam of the prepared micro-foam foaming agent by using a microscope.
Example 4
A micro-foam foaming system for drilling fluid is prepared by the following specific steps: 82g of water were placed in a beaker, and 10g (x: y =2: 4; n = 11), C, of the main blowing agent were slowly added with stirring9H19NHCH2(OH)CH2CH2OSO3And (4) slowly heating Na 8g to 40 ℃, and uniformly stirring to obtain the microbubble foaming system 4. Using the Waring Blender method at 50000ppm (Ca)2+2000 ppm), and the density change before and after hot rolling for 16h at 120 ℃ is measured, and the particle size of the foam of the prepared micro-foam foaming agent is measured by a microscope.
Example 5
A micro-foam foaming system for drilling fluid is prepared by the following specific steps: 70g of water was put into a beaker, and 10g (x: y =2: 7; n = 13), C, of a main blowing agent was slowly added with stirring14H29NHCH2CH2CH2SO3And (3) slowly heating the mixture to 40 ℃ by using 20g of Na, and uniformly stirring the mixture to obtain the micro-bubble foaming system 5. Using the Waring Blender method at 50000ppm (Ca)2+2000 ppm), and the density change before and after hot rolling for 16h at 120 ℃ is measured, and the particle size of the foam of the prepared micro-foam foaming agent is measured by a microscope.
Example 6
A micro-foam foaming system for drilling fluid is prepared by the following specific steps: 65g of water were placed in a beaker, and 30g (x: y =1: 4; n = 8), C of a main blowing agent were slowly added with stirring9H19NHCH2CH2CH2SO3And (5) Na 5g, slowly heating to 40 ℃, and uniformly stirring to obtain the microbubble foaming system 6. Using the Waring Blender method at 50000ppm (Ca)2+2000 ppm), and the density change before and after hot rolling for 16h at 120 ℃ is measured, and the particle size of the foam of the prepared micro-foam foaming agent is measured by a microscope.
Example 7
A micro-foam foaming system for drilling fluid is prepared by the following specific steps: 66g of water were taken in a beaker and 24g of the main blowing agent (x: y =1: 4; n = 15), C were added slowly with stirring9H19NHCH2(OH)CH2CH2OSO3Na10g, slowly heating to 40 ℃, and uniformly stirring to obtain the micro-bubble foaming system 7. Using the Waring Blender method at 50000ppm (Ca)2+2000 ppm), and the density change before and after hot rolling for 16h at 120 ℃ is measured, and the particle size of the foam of the prepared micro-foam foaming agent is measured by a microscope.
TABLE 1 evaluation of microcellular foaming agent Properties
Sample (I)
Foam volume/mL
Half life of liquid separation/min
Foam half life/min
Commercially available microcellular foaming agent
380
29
143
C9H19NHCH2CH2SO3Na
395
9
69
C14H29NH CH2CH2CH2SO3Na
420
11
74
C12H25NHCH2CH2SO3Na
405
9.5
63
C9H19NHCH2(OH)CH2CH2OSO3Na
400
13
81
C9H19NHCH2CH2CH2SO3Na
425
10
76
Microcellular foaming System 1
520
43
491
Micro-bubble foaming system 2
535
39
583
Micro-bubble foaming system 3
510
51
467
Micro-bubble foaming system 4
545
67
398
Micro-bubble foaming system 5
505
62
492
Micro-bubble foaming system 6
520
53
671
Micro-bubble foaming system 7
515
49
580
TABLE 2 microfoam particle size
Sample (I)
Average particle diameter/. mu.m
C9H19NHCH2CH2SO3Na
792
C14H29NH CH2CH2CH2SO3Na
718
C12H25NHCH2CH2SO3Na
734
C9H19NHCH2(OH)CH2CH2OSO3Na
824
C9H19NHCH2CH2CH2SO3Na
867
Commercially available microcellular foaming agent
89
Microcellular foaming System 1
64
Micro-bubble foaming system 2
72
Micro-bubble foaming system 3
84
Micro-bubble foaming system 4
61
Micro-bubble foaming system 5
82
Micro-bubble foaming system 6
79
Micro-bubble foaming system 7
71
TABLE 3 drilling fluid Properties
From the test data of the above embodiment, it can be seen that the micro-foam foaming system of the present invention has good foam stability, good drilling fluid performance, and strong salt and temperature resistance.
