A foam-generating dispersion, its preparation and use

Abstract

The present application provides a foamable dispersion, a preparation method and application thereof. The raw materials of the foamable dispersion include polyacrylamide, weathered coal, a betaine surfactant and water.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of oil and gas field development engineering, and particularly relates to a foam-producing dispersion liquid, a preparation method and application thereof. BACKGROUND

[0002] In recent years, the development of profile control and displacement systems for low-temperature (<80℃), low-to-moderate-salinity (<2.0×10 4 mg / L) oil reservoirs has been rapid, and the field application effect is good, but the development of profile control and displacement systems for high-salinity, especially 2.0×10 4 mg / L or higher salinity oil reservoir conditions is slow. On the one hand, a single salt-tolerant surfactant is used, and the upper limit of the single system exists, and there is no potential for deep exploration. On the other hand, for fracture-cave oil reservoirs, the large reservoir space leads to weak foam shearing regeneration ability, and the poor foam stability leads to early gravity differentiation and serious channeling. Therefore, the exploitation of fracture-cave oil reservoirs faces many challenges. SUMMARY

[0003] One of the present application provides a foam-producing dispersion liquid, raw materials of which include polyacrylamide, weathered coal, betaine surfactant and water.

[0004] In one specific embodiment, the polyacrylamide is non-ionic polyacrylamide.

[0005] In one specific embodiment, the relative molecular weight of the non-ionic polyacrylamide is 4 million to 6 million.

[0006] In one specific embodiment, the carbon content of the weathered coal is 60wt% to 65wt%, and the ash content is 15wt% to 22wt%. For example, the weathering time of the weathered coal is 3 months to 4 months. Wherein, the weathering can be atmospheric and sunlight erosion.

[0007] In one specific embodiment, the particle size of the weathered coal is 25μm to 75μm.

[0008] In one specific embodiment, the betaine surfactant is at least one of hydroxylsulfobetaine, cocamide propyl betaine and lauryl propyl betaine.

[0009] In one specific embodiment, taking the mass of water as 100%, the amount of polyacrylamide is 0.5% to 0.8%, the amount of weathered coal is 5% to 15%, and the amount of betaine surfactant is 0.3% to 0.7%.

[0010] The second of the present application provides a method for preparing the foam-producing dispersion liquid as described in any one of the first of the present application, which comprises the following steps:

[0011] 1-1) mixing polyacrylamide with water to obtain a polyacrylamide aqueous solution;

[0012] 2-1) mixing weathered coal with the polyacrylamide aqueous solution to obtain a dispersion liquid;

[0013] 3-1) mixing the dispersion liquid with a betaine surfactant to obtain the foam-generating dispersion liquid.

[0014] Alternatively, the present application II provides a method for preparing the foam-generating dispersion liquid according to any one of the present application I, comprising the following steps:

[0015] 1-2) mixing polyacrylamide with water to obtain a polyacrylamide aqueous solution;

[0016] 2-2) mixing a betaine surfactant with the polyacrylamide aqueous solution to obtain a polyacrylamide-betaine aqueous solution;

[0017] 3-2) mixing the polyacrylamide-betaine aqueous solution with weathered coal to obtain the foam-generating dispersion liquid.

[0018] In one specific embodiment, in step 1-1) or step 1-2), the mixing is uniform at 600 to 800 rpm for 30 to 45 min.

[0019] In one specific embodiment, in step 2-1) or step 3-2), the mixing is uniform at 800 to 1000 rpm for 20 to 30 min, and then dispersed mixing is performed by ultrasonic for 5 to 10 min.

[0020] In one specific embodiment, in step 3-1) or step 2-2), the mixing is performed at 400 to 600 rpm for 5 to 10 min.

[0021] The present application III provides the use of the foam-generating dispersion liquid according to any one of the present application I or prepared by the method according to any one of the present application II in the storage of oil in cracks and / or fractures and pores of high salinity fractured-porous reservoirs.

[0022] In one specific embodiment, the use is in the storage of oil in cracks and / or fractures and pores of high salinity salt rock strata and / or high salinity fractured-porous reservoirs caused by deposition.

[0023] In one specific embodiment, the use is in the storage of oil in cracks and / or fractures and pores of high salinity marine sediments and / or high salinity fractured-porous reservoirs caused by high temperature and high salinity marine deposition.

[0024] In one specific embodiment, the upper limit of the salinity is 21x10 4 mg / L.

[0025] In one specific embodiment, the upper limit of the high temperature is 150℃.

[0026] Advantages of the present application:

[0027] The foam-generating dispersion liquid of the present application has good foaming and foam stabilizing effects, and greatly provides the stability of the foam and prolongs the half-life of the foam through the use of weathered coal and the synergistic effect among the components.

[0028] The foam-generating dispersion liquid of the present application can be applied to high-salt fracture-cave oil reservoirs, can tolerate high salinity of 21x10 4 mg / L, and can tolerate calcium ions of 1.4x10 4 mg / L and magnesium ions of 0.2x10 4 mg / L.

[0029] The foam-generating dispersion liquid of the present application can be applied to normal temperature and high temperature, and has a wide application temperature range.

[0030] The raw material weathered coal particles used in the present application belong to mine resource waste, and the polyacrylamide is low in price and widely used in the field of petroleum and chemical industry. The system greatly reduces the production cost while improving the stability of the foam. DETAILED DESCRIPTION

[0031] The present application will be further described below in conjunction with examples, but the examples of the present application are only exemplary descriptions, and the embodiments do not constitute a limitation on the present application in any case.

[0032] Example 1

[0033] The salt-tolerant foam-generating dispersion liquid includes raw materials: 0.6 parts by mass of non-ionic polyacrylamide with a relative molecular weight of 5 million, 10 parts by mass of 35 μm weathered coal (carbon content of 65 wt%, ash content of 15%, formed by atmospheric and sunlight erosion for 3 months), 0.5 parts by mass of hydroxyl sulfobetaine, and 100 parts by mass of mineralized water.

[0034] The preparation method of the salt-tolerant foam-generating dispersion liquid includes the following specific steps:

[0035] (1) 0.6 parts by mass of polyacrylamide is added to 100 parts by mass of simulated formation water with a salinity of 21x10 4 mg / L (wherein, calcium ions are 1.4x10 4 mg / L, and magnesium ions are 0.2x10 4mg / L) at 600 rpm for 45 min to obtain a polyacrylamide aqueous solution.

[0036] (2) 15 parts by mass of weathered coal particles were added to the polyacrylamide aqueous solution, and stirred at 800 rpm for 30 min to mix uniformly, and then dispersed under ultrasonic waves at 20 kHz for 5 min to obtain a dispersion liquid.

[0037] (3) 0.7 parts by mass of hydroxylsulfobetaine was added to the dispersion liquid, and mixed uniformly at a low speed of 400 rpm for 5 min to prevent foaming during stirring to obtain a foam-producing dispersion liquid.

[0038] The foam-producing dispersion liquid was added to a foam stirrer, and stirred at a high speed of 8000 rpm for 3 min, and after the stirring was completed, a foam system was obtained. The foam system was poured into a graduated cylinder, and a stopwatch was started to record the foaming volume and the half-life of liquid separation. The results are shown in Table 1.

[0039] Example 2

[0040] A salt-resistant foam-producing dispersion liquid included the following raw materials: 0.8 parts by mass of non-ionic polyacrylamide with a relative molecular weight of 5 million, 15 parts by mass of 35 μm weathered coal (carbon content of 65 wt%, ash content of 15 wt%, formed by weathering for 3 months under the action of the atmosphere and sunlight), 0.7 parts by mass of hydroxylsulfobetaine, and 100 parts by mass of mineralized water.

[0041] A method for preparing a salt-resistant foam-producing dispersion liquid included the following steps:

[0042] (1) 0.8 parts by mass of polyacrylamide was added to 100 parts by mass of 21 x 10 4 mg / L simulated formation water with a degree of mineralization (wherein the calcium ion was 1.4 x 10 4 mg / L, and the magnesium ion was 0.2 x 10 4 mg / L) at 600 rpm for 45 min to obtain a polyacrylamide aqueous solution.

[0043] (2) 15 parts by mass of weathered coal particles were added to the polyacrylamide aqueous solution, and stirred at 800 rpm for 30 min to mix uniformly, and then dispersed under ultrasonic waves at 20 kHz for 5 min to obtain a dispersion liquid.

[0044] (3) 0.7 parts by mass of hydroxylsulfobetaine was added to the dispersion liquid, and mixed uniformly at a low speed of 400 rpm for 5 min to prevent foaming during stirring to obtain a foam-producing dispersion liquid.

[0045] The foam-generating dispersion liquid was added to the foam stirrer and stirred at 8000 rpm for 3 min, and after the stirring was completed, a foam system was obtained. The foam system was poured into a measuring cylinder, and a stopwatch was started to record the foaming volume and the half-life of liquid separation. The results are shown in Table 1.

[0046] Example 3

[0047] A salt-tolerant foam-generating dispersion liquid was prepared by adding 0.5 parts by mass of non-ionic polyacrylamide having a relative molecular weight of 5 million, 5 parts by mass of weathered coal (carbon content of 65 wt%, ash content of 15 wt%, formed by weathering for 3 months under the atmosphere and sunlight), 0.3 parts by mass of hydroxylsulfo betaine, and 100 parts by mass of mineral water.

[0048] A method for preparing a salt-tolerant foam-generating dispersion liquid, the specific steps of which are as follows:

[0049] (1) 0.5 parts by mass of polyacrylamide was added to 100 parts by mass of 21 x 10 4 mg / L simulated formation water (wherein the calcium ion is 1.4 x 10 4 mg / L, and the magnesium ion is 0.2 x 10 4 mg / L) to uniformly stir at 600 rpm for 45 min to obtain a polyacrylamide aqueous solution.

[0050] (2) 5 parts by mass of weathered coal particles were added to the polyacrylamide aqueous solution and stirred at 800 rpm for 30 min to uniformly mix, and then dispersed under ultrasonic waves at 20 kHz for 5 min to obtain a dispersion liquid.

[0051] (3) 0.3 parts by mass of hydroxylsulfo betaine was added to the dispersion liquid, and to prevent foaming during stirring, it was mixed uniformly at a low speed of 400 rpm for 5 min to obtain a foam-generating dispersion liquid.

[0052] The foam-generating dispersion liquid was added to the foam stirrer and stirred at 8000 rpm for 3 min, and after the stirring was completed, a foam system was obtained. The foam system was poured into a measuring cylinder, and a stopwatch was started to record the foaming volume and the half-life of liquid separation. The results are shown in Table 1.

[0053] Example 4

[0054] The difference from Example 1 is only that the relative molecular weight of the non-ionic polyacrylamide is 4 million.

[0055] A salt-tolerant foam-generating dispersion liquid comprising raw materials: 0.6 parts by mass of non-ionic polyacrylamide having a relative molecular weight of 4 million, 10 parts by mass of 35-μm weathered coal (carbon content of 65% by weight, ash content of 15% by weight, formed by weathering for 3 months under atmospheric and solar radiation), 0.5 parts by mass of hydroxylsulfobetaine, and 100 parts by mass of mineralized water.

[0056] A method for producing a salt-tolerant foam-generating dispersion liquid, comprising the following steps:

[0057] (1) 0.6 parts by mass of polyacrylamide was added to 100 parts by mass of 21 x 10 4 mg / L simulated formation water (wherein calcium ions were 1.4 x 10 4 mg / L, and magnesium ions were 0.2 x 10 4 mg / L) and stirred uniformly at 600 rpm for 45 min to obtain a polyacrylamide aqueous solution.

[0058] (2) 10 parts by mass of weathered coal particles were added to the polyacrylamide aqueous solution and stirred uniformly at 800 rpm for 30 min, and then dispersed under ultrasonic waves at 20 kHz for 5 min to obtain a dispersion liquid.

[0059] (3) 0.5 parts by mass of hydroxylsulfobetaine was added to the dispersion liquid, and low-speed stirring was performed at 400 rpm for 5 min to mix uniformly, thereby obtaining a foam-generating dispersion liquid.

[0060] The foam-generating dispersion liquid was added to a foam stirrer and stirred at a high speed of 8000 rpm for 3 min, and after the stirring was completed, a foam system was obtained. The foam system was poured into a graduated cylinder, and a stopwatch was started to record the foaming volume and the half-life of liquid drainage. The results are shown in Table 1.

[0061] Example 5

[0062] The difference from Example 1 is that the relative molecular weight of the non-ionic polyacrylamide is 6 million.

[0063] A salt-tolerant foam-generating dispersion liquid comprising raw materials: 0.6 parts by mass of non-ionic polyacrylamide having a relative molecular weight of 6 million, 10 parts by mass of 35-μm weathered coal (carbon content of 65% by weight, ash content of 15% by weight, formed by weathering for 3 months under atmospheric and solar radiation), 0.5 parts by mass of hydroxylsulfobetaine, and 100 parts by mass of mineralized water.

[0064] A method for producing a salt-tolerant foam-generating dispersion liquid, comprising the following steps:

[0065] (1) 0.6 parts by mass of polyacrylamide was added to 100 parts by mass of 21 x 10 4mg / L of simulated formation water (wherein calcium ion is 1.4 x 10 4 mg / L, magnesium ion is 0.2 x 10 4 mg / L) at 600 rpm for 45 min to obtain a polyacrylamide aqueous solution.

[0066] (2) 10 parts by mass of weathered coal particles were added to the polyacrylamide aqueous solution, and stirred at 800 rpm for 30 min to mix uniformly, and then dispersed under ultrasonic waves at 20 kHz for 5 min to obtain a dispersion liquid.

[0067] (3) 0.5 parts by mass of hydroxylsulfobetaine was added to the dispersion liquid, and mixed uniformly at a low speed of 400 rpm for 5 min to prevent foaming during stirring, to obtain a foam-producing dispersion liquid.

[0068] The foam-producing dispersion liquid was added to a foam stirrer, and stirred at a high speed of 8000 rpm for 3 min, and after the stirring was completed, a foam system was obtained. The foam system was poured into a graduated cylinder, and a stopwatch was started to record the foaming volume and the half-life of liquid separation. The results are shown in Table 1.

[0069] Example 6

[0070] The only difference from Example 1 is that the particle size of the weathered coal is 25 μm.

[0071] A salt-resistant foam-producing dispersion liquid includes the following raw materials: 0.6 parts by mass of non-ionic polyacrylamide having a relative molecular weight of 5 million, 10 parts by mass of weathered coal (65 wt% of carbon content, 15 wt% of ash content, formed by atmospheric and sunlight erosion for 3 months) having a particle size of 25 μm, 0.5 parts by mass of hydroxylsulfobetaine, and 100 parts by mass of mineralized water.

[0072] A method for preparing a salt-resistant foam-producing dispersion liquid includes the following specific steps:

[0073] (1) 0.6 parts by mass of polyacrylamide was added to 100 parts by mass of 21 x 10 4 mg / L of simulated formation water (wherein calcium ion is 1.4 x 10 4 mg / L, magnesium ion is 0.2 x 10 4 mg / L) at 600 rpm for 45 min to obtain a polyacrylamide aqueous solution.

[0074] (2) 10 parts by mass of weathered coal particles were added to the polyacrylamide aqueous solution, and stirred at 800 rpm for 30 min to mix uniformly, and then dispersed under ultrasonic waves at 20 kHz for 5 min to obtain a dispersion liquid.

[0075] (3) 0.5 parts by mass of hydroxysulfobetaine was added to the dispersion liquid, and low-speed stirring was performed at 400 rpm for 5 min to uniformly mix the same, to obtain a foam-generating dispersion liquid.

[0076] The foam-generating dispersion liquid was added to a foam stirrer, and high-speed stirring was performed at 8000 rpm for 3 min, to obtain a foam system. The foam system was poured into a graduated cylinder, and a stopwatch was started at the same time, and the foaming volume and the half-life of liquid separation were measured. The results are shown in Table 1.

[0077] Example 7

[0078] The only difference from Example 1 was that the particle diameter of the weathered coal was 75 μm.

[0079] A salt-resistant foam-generating dispersion liquid was prepared by using the following raw materials: 0.6 parts by mass of nonionic polyacrylamide having a relative molecular mass of 5 million, 10 parts by mass of 75-μm weathered coal (carbon content: 65% by weight, ash content: 15% by weight, formed by weathering for 3 months under the influence of air and sunlight), 0.5 parts by mass of hydroxysulfobetaine, and 100 parts by mass of mineralized water.

[0080] A method for preparing a salt-resistant foam-generating dispersion liquid was performed by the following steps.

[0081] (1) 0.6 parts by mass of polyacrylamide was added to 100 parts by mass of 21 x 10 4 mg / L simulated formation water (calcium ion: 1.4 x 10 4 mg / L, magnesium ion: 0.2 x 10 4 mg / L) to uniformly stir the same at 600 rpm for 45 min, to obtain a polyacrylamide aqueous solution.

[0082] (2) 10 parts by mass of weathered coal particles were added to the polyacrylamide aqueous solution, and the same was uniformly mixed by stirring at 800 rpm for 30 min, and then dispersed under ultrasonic waves at 20 kHz for 5 min, to obtain a dispersion liquid.

[0083] (3) 0.5 parts by mass of hydroxysulfobetaine was added to the dispersion liquid, and low-speed stirring was performed at 400 rpm for 5 min to uniformly mix the same, to obtain a foam-generating dispersion liquid.

[0084] The foam-generating dispersion liquid was added to a foam stirrer, and high-speed stirring was performed at 8000 rpm for 3 min, to obtain a foam system. The foam system was poured into a graduated cylinder, and a stopwatch was started at the same time, and the foaming volume and the half-life of liquid separation were measured. The results are shown in Table 1.

[0085] Example 8

[0086] The difference from Example 1 is that the hydroxysultaine is replaced by cocamidopropyl betaine.

[0087] A salt-tolerant foam-generating dispersion liquid comprising raw materials: 0.6 parts by mass of nonionic polyacrylamide having a relative molecular weight of 5 million, 10 parts by mass of 35-μm weathered coal (carbon content of 65 wt%, ash content of 15 wt%, formed by weathering for 3 months under atmospheric and solar radiation), 0.5 parts by mass of cocamidopropyl betaine, and 100 parts by mass of mineralized water.

[0088] A method for preparing a salt-tolerant foam-generating dispersion liquid, the specific steps being as follows:

[0089] (1) 0.6 parts by mass of polyacrylamide was added to 100 parts by mass of 21 x 10 4 mg / L simulated formation water (wherein calcium ions were 1.4 x 10 4 mg / L, and magnesium ions were 0.2 x 10 4 mg / L) to perform uniform stirring at 600 rpm, and the stirring time was 45 min to obtain a polyacrylamide aqueous solution.

[0090] (2) 10 parts by mass of weathered coal particles were added to the polyacrylamide aqueous solution to perform stirring at 800 rpm for 30 min to make them uniformly mixed, and then dispersion was performed under ultrasonic waves at 20 kHz for 5 min to obtain a dispersion liquid.

[0091] (3) 0.5 parts by mass of cocamidopropyl betaine was added to the dispersion liquid, low-speed stirring was performed at 400 rpm for 5 min to make them uniformly mixed to prevent foaming during stirring, and a foam-generating dispersion liquid was obtained.

[0092] The foam-generating dispersion liquid was added to a foam stirrer to perform high-speed stirring at 8000 rpm for 3 min, and after completion of the stirring, a foam system was obtained. The foam system was poured into a graduated cylinder, and a stopwatch was opened to record the foaming volume and the half-life of liquid separation, and the results are shown in Table 1.

[0093] Example 9

[0094] The difference from Example 1 is that the hydroxysultaine is replaced by cocamidopropyl betaine.

[0095] A salt-tolerant foam-generating dispersion liquid comprising raw materials: 0.6 parts by mass of nonionic polyacrylamide having a relative molecular weight of 5 million, 10 parts by mass of 35-μm weathered coal (carbon content of 65 wt%, ash content of 15 wt%, formed by weathering for 3 months under atmospheric and solar radiation), 0.5 parts by mass of cocamidopropyl betaine, and 100 parts by mass of mineralized water.

[0096] A method for preparing a salt-tolerant foam-generating dispersion liquid, the specific steps being as follows:

[0097] (1) 0.6 parts by mass of polyacrylamide was added to 100 parts by mass of simulated formation water with a salinity of 21 x 10 4 mg / L (wherein calcium ions were 1.4 x 10 4 mg / L, and magnesium ions were 0.2 x 10 4 mg / L) and stirred uniformly at 600 rpm for 45 min to obtain a polyacrylamide aqueous solution.

[0098] (2) 10 parts by mass of weathered coal particles were added to the polyacrylamide aqueous solution and stirred at 800 rpm for 30 min to mix uniformly, and then dispersed under ultrasonic waves at 20 kHz for 5 min to obtain a dispersion liquid.

[0099] (3) 0.5 parts by mass of lauryl propyl betaine was added to the dispersion liquid, and low-speed stirring was performed at 400 rpm for 5 min to mix uniformly to obtain a foam-producing dispersion liquid.

[0100] The foam-producing dispersion liquid was added to a foam stirrer and stirred at a high speed of 8000 rpm for 3 min, and after stirring was completed, a foam system was obtained. The foam system was poured into a graduated cylinder, and a stopwatch was started to record the foaming volume and the half-life of liquid separation. The results are shown in Table 1.

[0101] Example 10

[0102] The difference from Example 1 is that the weathering time is different, and the carbon content and ash content are different.

[0103] A salt-resistant foam-producing dispersion liquid includes the following raw materials: 0.6 parts by mass of non-ionic polyacrylamide with a relative molecular mass of 5 million, 10 parts by mass of 35 μm weathered coal (carbon content of 60 wt%, ash content of 22 wt%, formed by atmospheric and sunlight erosion for 4 months), 0.5 parts by mass of hydroxyl sulfobetaine, and 100 parts by mass of mineralized water.

[0104] A method for preparing a salt-resistant foam-producing dispersion liquid includes the following specific steps:

[0105] (1) 0.6 parts by mass of polyacrylamide was added to 100 parts by mass of simulated formation water with a salinity of 21 x 10 4 mg / L (wherein calcium ions were 1.4 x 10 4 mg / L, and magnesium ions were 0.2 x 10 4 mg / L) and stirred uniformly at 600 rpm for 45 min to obtain a polyacrylamide aqueous solution.

[0106] (2) 10 parts by mass of weathered coal particles were added to the polyacrylamide aqueous solution, and stirred at 800 rpm for 30 min to mix uniformly, and then dispersed under ultrasonic waves at 20 kHz for 5 min to obtain a dispersion liquid.

[0107] (3) 0.5 parts by mass of hydroxylsulfobetaine was added to the dispersion liquid, and mixed uniformly at a low speed of 400 rpm for 5 min to prevent foaming during stirring, to obtain a foam-generating dispersion liquid.

[0108] The foam-generating dispersion liquid was added to a foam stirrer, and stirred at a high speed of 8000 rpm for 3 min, and after completion of the stirring, a foam system was obtained. The foam system was poured into a graduated cylinder, and a stopwatch was started to measure the foaming volume and the half-life of the liquid separation. The results are shown in Table 1.

[0109] Example 11

[0110] The difference from Example 1 is that the mixing conditions in steps (2) to (5) are different.

[0111] A salt-resistant foam-generating dispersion liquid including the following raw materials: 0.6 parts by mass of non-ionic polyacrylamide having a relative molecular weight of 5 million, 10 parts by mass of weathered coal (carbon content of 65 wt%, ash content of 15%, formed by weathering for 3 months under the atmosphere and sunlight), 0.5 parts by mass of hydroxylsulfobetaine, and 100 parts by mass of mineralized water.

[0112] A method for preparing a salt-resistant foam-generating dispersion liquid, and the specific steps are as follows:

[0113] (1) 0.6 parts by mass of polyacrylamide was added to 100 parts by mass of 21 x 10 4 mg / L simulated formation water (wherein, calcium ion 1.4 x 10 4 mg / L, magnesium ion 0.2 x 10 4 mg / L) to uniformly stir at 1000 rpm, and the stirring time was 30 min to obtain a polyacrylamide aqueous solution.

[0114] (2) 10 parts by mass of weathered coal particles were added to the polyacrylamide aqueous solution, and stirred at 1000 rpm for 20 min to mix uniformly, and then dispersed under ultrasonic waves at 20 kHz for 10 min to obtain a dispersion liquid.

[0115] (3) 0.5 parts by mass of hydroxylsulfobetaine was added to the dispersion liquid, and mixed uniformly at a low speed of 600 rpm for 10 min to prevent foaming during stirring, to obtain a foam-generating dispersion liquid.

[0116] The foam-generating dispersion liquid was added to the foam stirring instrument and stirred at a speed of 8000 rpm for 3 min. After stirring, the foam system was obtained. The foam system was poured into a measuring cylinder, and a stopwatch was opened at the same time. The foaming volume and liquid drainage half-life were recorded. The results are shown in Table 1.

[0117] Comparative Example 1

[0118] The difference from Example 1 is that the non-ionic polyacrylamide is replaced by polyethylene oxide.

[0119] The foam-generating dispersion liquid includes raw materials: 0.6 parts by mass of polyethylene oxide with a relative molecular weight of 5 million, 10 parts by mass of 35 μm weathered coal (carbon content of 65 wt%, ash content of 15 wt%, formed by atmospheric and sunlight erosion for 3 months), 0.5 parts by mass of hydroxyl sulfobetaine, and 100 parts by mass of mineralized water.

[0120] The preparation method of the foam-generating dispersion liquid includes the following specific steps:

[0121] (1) 0.6 parts by mass of polyethylene oxide was added to 100 parts by mass of 21 x 10 4 mg / L simulated formation water (wherein, calcium ion 1.4 x 10 4 mg / L, magnesium ion 0.2 x 10 4 mg / L) to uniformly stir at 600 rpm for 45 min to obtain a polyethylene oxide aqueous solution.

[0122] (2) 10 parts by mass of weathered coal particles were added to the polyethylene oxide aqueous solution to uniformly stir at 800 rpm for 30 min, and then dispersed under ultrasonic waves at 20 kHz for 5 min to obtain a dispersion liquid.

[0123] (3) 0.5 parts by mass of hydroxyl sulfobetaine was added to the dispersion liquid. To prevent stirring foaming, low-speed stirring was performed at 400 rpm for 5 min to uniformly mix to obtain a foam-generating dispersion liquid.

[0124] The foam-generating dispersion liquid was added to the foam stirring instrument and stirred at a speed of 8000 rpm for 3 min. After stirring, the foam system was obtained. The foam system was poured into a measuring cylinder, and a stopwatch was opened at the same time. The foaming volume and liquid drainage half-life were recorded. The results are shown in Table 1.

[0125] Comparative Example 2

[0126] The difference from Example 1 is that the weathered coal particles are replaced by fly ash particles.

[0127] A foam-generating dispersion liquid includes raw materials: 0.6 parts by mass of non-ionic polyacrylamide having a relative molecular weight of 5 million, 10 parts by mass of 35-μm fly ash particles, 0.5 parts by mass of hydroxysulfobetaine, and 100 parts by mass of mineralized water.

[0128] A method for preparing a foam-generating dispersion liquid includes the following specific steps:

[0129] (1) 0.6 parts by mass of polyacrylamide is added to 100 parts by mass of 21 x 10 4 mg / L mineralized simulated formation water (wherein calcium ions are 1.4 x 10 4 mg / L, and magnesium ions are 0.2 x 10 4 mg / L) to perform uniform stirring at 600 rpm, and the stirring time is 45 min to obtain a polyacrylamide aqueous solution.

[0130] (2) 10 parts by mass of fly ash particles are added to the polyacrylamide aqueous solution to perform stirring at 800 rpm for 30 min to uniformly mix the fly ash particles, and then the fly ash particles are dispersed under ultrasonic waves at 20 kHz for 5 min to obtain a dispersion liquid.

[0131] (3) 0.5 parts by mass of hydroxysulfobetaine is added to the dispersion liquid, low-speed stirring is performed at 400 rpm for 5 min to uniformly mix the hydroxysulfobetaine, and a foam-generating dispersion liquid is obtained.

[0132] The foam-generating dispersion liquid is added to a foam stirrer to perform high-speed stirring at 8000 rpm for 3 min, nitrogen is introduced during the stirring process to prevent the viscosity from being too large to cause a decrease in foaming effect, and after the stirring is completed, a foam system is obtained. The foam system is poured into a graduated cylinder, a stopwatch is opened, and the foaming volume and the liquid drainage half-life are recorded. The results are shown in Table 1.

[0133] Comparative Example 3

[0134] The difference from Example 1 is that weathered coal is replaced by rubber particles.

[0135] A foam-generating dispersion liquid includes raw materials: 0.6 parts by mass of non-ionic polyacrylamide having a relative molecular weight of 5 million, 10 parts by mass of 35-μm fly ash particles, 0.5 parts by mass of hydroxysulfobetaine, and 100 parts by mass of mineralized water.

[0136] A method for preparing a foam-generating dispersion liquid includes the following specific steps:

[0137] (1) 0.6 parts by mass of polyacrylamide is added to 100 parts by mass of 21 x 10 4 mg / L mineralized simulated formation water (wherein calcium ions are 1.4 x 10 4 mg / L, and magnesium ions are 0.2 x 10 4mg / L) at 600 rpm for 45 min to obtain a polyacrylamide aqueous solution.

[0138] (2) 10 parts by mass of rubber particles were added to the polyacrylamide aqueous solution, and stirred at 800 rpm for 30 min to mix uniformly, and then dispersed under ultrasonic waves at 20 kHz for 5 min to obtain a dispersion liquid.

[0139] (3) 0.5 parts by mass of hydroxylsulfobetaine were added to the dispersion liquid, and mixed uniformly at a low speed of 400 rpm for 5 min to prevent bubbling during stirring to obtain a bubble-producing dispersion liquid.

[0140] The bubble-producing dispersion liquid was added to a foam stirrer and stirred at a high speed of 8000 rpm for 3 min, and after the stirring was completed, a foam system was obtained. The foam system was poured into a graduated cylinder, and a stopwatch was started to record the foaming volume and the half-life of liquid separation. The results are shown in Table 1.

[0141] Comparative Example 4

[0142] The difference from Example 1 is only that the weathering time of the weathered coal is different, so that the carbon content and the ash content are different. Specifically, the carbon content is 55 wt%, and the ash content is 25 wt%, which is formed by atmospheric and sunlight erosion for 5 months.

[0143] The bubble-producing dispersion liquid includes the following raw materials: 0.6 parts by mass of non-ionic polyacrylamide with a relative molecular weight of 5 million, 10 parts by mass of 35 μm weathered coal, 0.5 parts by mass of hydroxylsulfobetaine, and 100 parts by mass of mineralized water.

[0144] The specific steps of the bubble-producing dispersion liquid preparation method are as follows:

[0145] (1) 0.6 parts by mass of polyacrylamide were added to 100 parts by mass of 21 x 10 4 mg / L of simulated formation water with a mineralization degree (wherein, calcium ion 1.4 x 10 4 mg / L, magnesium ion 0.2 x 10 4 mg / L) at 600 rpm for 45 min to obtain a polyacrylamide aqueous solution;

[0146] (2) 10 parts by mass of rubber particles were added to the polyacrylamide aqueous solution, and stirred at 800 rpm for 30 min to mix uniformly, and then dispersed under ultrasonic waves at 20 kHz for 5 min to obtain a dispersion liquid.

[0147] (3) 0.5 parts by mass of hydroxylsulfobetaine were added to the dispersion liquid, and mixed uniformly at a low speed of 400 rpm for 5 min to prevent bubbling during stirring to obtain a bubble-producing dispersion liquid.

[0148] The foam-generating dispersion liquid was added to the foam stirring instrument and stirred at a speed of 8000 rpm for 3 min. After stirring, the foam system was obtained. The foam system was poured into a measuring cylinder, and a stopwatch was opened at the same time. The foaming volume and liquid drainage half-life were recorded. The results are shown in Table 1.

[0149] Comparative Example 5

[0150] The difference from Example 1 is only that the weathering time of the weathered coal is different, so that the carbon content and the ash content are different. Specifically, the carbon content is 70 wt%, and the ash content is 10 wt%. The weathering is formed by atmospheric and sunlight erosion for 2 months.

[0151] The foam-generating dispersion liquid includes raw materials: 0.6 parts by mass of non-ionic polyacrylamide with a relative molecular mass of 5 million, 10 parts by mass of 35 μm weathered coal, 0.5 parts by mass of hydroxyl sulfobetaine, and 100 parts by mass of mineralized water.

[0152] The specific steps of the preparation method of the foam-generating dispersion liquid are as follows:

[0153] (1) 0.6 parts by mass of polyacrylamide was added to 100 parts by mass of 21 × 10 4 mg / L simulated formation water (wherein the calcium ion is 1.4 × 10 4 mg / L, and the magnesium ion is 0.2 × 10 4 mg / L) and stirred at a high speed of 600 rpm for 45 min to obtain a polyacrylamide aqueous solution;

[0154] (2) 10 parts by mass of weathered coal particles were added to the polyacrylamide aqueous solution and stirred at 800 rpm for 30 min to mix uniformly, and then dispersed under ultrasonic waves at 20 kHz for 5 min to obtain a dispersion liquid;

[0155] (3) 0.5 parts by mass of hydroxyl sulfobetaine was added to the dispersion liquid, and low-speed stirring was performed at 400 rpm for 5 min to mix uniformly to prevent foaming during stirring, thereby obtaining a foam-generating dispersion liquid.

[0156] The foam-generating dispersion liquid was added to the foam stirring instrument and stirred at a speed of 8000 rpm for 3 min. After stirring, the foam system was obtained. The foam system was poured into a measuring cylinder, and a stopwatch was opened at the same time. The foaming volume and liquid drainage half-life were recorded. The results are shown in Table 1.

[0157] Comparative Example 6

[0158] The foam-generating dispersion liquid includes raw materials: 0.6 parts by mass of non-ionic polyacrylamide with a relative molecular mass of 5 million, 10 parts by mass of 35 μm weathered coal, 0.5 parts by mass of hydroxyl sulfobetaine, and 100 parts by mass of mineralized water.

[0159] The specific steps of the preparation method of the foam-generating dispersion liquid are as follows:

[0160] (1) 0.6 parts by mass of polyacrylamide was added to 100 parts by mass of 21 x 10 4 mg / L salinity simulated formation water (wherein calcium ion 1.4 x 10 4 mg / L, magnesium ion 0.2 x 10 4 mg / L) was stirred uniformly at 600 rpm for 45 min to obtain a polyacrylamide aqueous solution.

[0161] (2) 0.5 parts by mass of hydroxylsulfo betaine was added to the polyacrylamide aqueous solution, and was mixed uniformly at 400 rpm for 5 min to prevent foaming during stirring to obtain a foam generating dispersion liquid.

[0162] The foam generating dispersion liquid was added to a foam stirrer and was stirred at 8000 rpm for 3 min, and after stirring was completed, a foam system was obtained. The foam system was poured into a graduated cylinder, and a stopwatch was opened at the same time, and the foaming volume and liquid drainage half-life were recorded. The results are shown in Table 1.

[0163] Comparative Example 7

[0164] The foam generating dispersion liquid included raw materials: 10 parts by mass of 35 μm weathered coal (carbon content 65 wt%, ash content 15%, formed by atmospheric and sunlight erosion for 3 months), 0.5 parts by mass of hydroxylsulfo betaine, and 100 parts by mass of mineralized water.

[0165] The method for preparing the foam generating dispersion liquid included the following specific steps:

[0166] (1) 10 parts by mass of weathered coal particles were added to 100 parts by mass of 21 x 10 4 mg / L salinity simulated formation water (wherein calcium ion 1.4 x 10 4 mg / L, magnesium ion 0.2 x 10 4 mg / L), and was stirred at 800 rpm for 30 min to mix uniformly, and then was dispersed under ultrasonic waves at 20 kHz for 5 min to obtain a dispersion liquid.

[0167] (2) 0.5 parts by mass of hydroxylsulfo betaine was added to the dispersion liquid, and was mixed uniformly at 400 rpm for 5 min to prevent foaming during stirring to obtain a foam generating dispersion liquid.

[0168] The foam generating dispersion liquid was added to a foam stirrer and was stirred at 8000 rpm for 3 min, and after stirring was completed, a foam system was obtained. The foam system was poured into a graduated cylinder, and a stopwatch was opened at the same time, and the foaming volume and liquid drainage half-life were recorded. The results are shown in Table 1.

[0169] Table 1

[0170] Example Foam volume / ml Lysis half-life / min Example 1 310 92 Example 2 350 136 Example 3 325 72 Example 4 345 112 Example 5 310 110 Example 6 325 125 Example 7 300 61 Example 8 315 81 Example 9 310 60 Example 10 305 80 Example 11 310 93 Comparative Example 1 270 42 Comparative Example 2 325 51 Comparative Example 3 245 48 Comparative Example 4 295 50 Comparative Example 5 265 55 Comparative Example 6 275 45 Comparative Example 7 305 35

[0171] From the above Table 1, it can be seen that the foam-producing dispersion provided by the application has excellent foaming performance and half-life, and can meet the high requirement of foam stability of complex oil and gas fields, especially high salinity.

[0172] Although the application has been described with reference to specific embodiments, it is understood that various changes can be made without departing from the true spirit and scope of the application. In addition, various changes can be made to the subject, spirit and scope of the application to adapt to specific circumstances, materials, material compositions and methods. All these changes are included in the scope of the claims of the application.

Claims

1. A foaming dispersion, the raw materials of which include polyacrylamide, weathered coal, betaine-type surfactant and water; The polyacrylamide is a nonionic polyacrylamide; The nonionic polyacrylamide has a relative molecular weight of 4 million to 6 million. The weathered coal has a carbon content of 60 wt% to 65 wt% and an ash content of 15 wt% to 22 wt%. The particle size of the weathered coal is 25 μm to 75 μm; Using the mass of water as 100%, the amount of polyacrylamide used is 0.5% to 0.8%, the amount of weathered coal used is 5% to 15%, and the amount of betaine-type surfactant used is 0.3% to 0.7%.

2. The foam-generating dispersion according to claim 1, characterized in that, The betaine-type surfactant is at least one of hydroxysulfobetaine, cocamidopropyl betaine, and lauroylpropyl betaine.

3. A method for preparing the foam-generating dispersion as described in claim 1 or 2, comprising the following steps: 1-1) Mix polyacrylamide with water to obtain an aqueous solution of polyacrylamide; 2-1) The weathered coal is mixed with the polyacrylamide aqueous solution to obtain a dispersion; 3-1) The dispersion is mixed with a betaine-type surfactant to obtain the foam-generating dispersion; or 1-2) Mix polyacrylamide with water to obtain an aqueous solution of polyacrylamide; 2-2) Mix the betaine-type surfactant with the polyacrylamide aqueous solution to obtain a polyacrylamide-betaine aqueous solution; 3-2) The polyacrylamide-betaine aqueous solution is mixed with weathered coal to obtain the foam-producing dispersion.

4. The method according to claim 3, characterized in that, In step 1-1) or step 1-2), mix thoroughly at 600 to 1000 rpm for 30 to 45 minutes.

5. The method according to claim 3, characterized in that, In step 2-1) or step 3-2), first stir at 800 to 1000 rpm for 20 to 30 minutes to mix evenly, and then sonicate for 5 to 10 minutes to disperse and mix.

6. The method according to claim 3, characterized in that, In step 3-1) or step 2-2), mix at 400 to 600 rpm for 5 to 10 minutes.

7. The application of the foam-producing dispersion according to claim 1 or 2, or the foam-producing dispersion prepared by the method according to any one of claims 3 to 6, in displacing fractured and / or fractured reservoir oil in high-salinity fractured-vuggy reservoirs; The application is for use in displacing highly saline rock formations and / or storing oil in fractures and / or within fractures and cavities in highly saline fracture-cavity reservoirs due to sedimentation. The application is for displacing oil in shallow and / or high-temperature, high-salinity fracture-vuggy reservoirs caused by marine sedimentary strata with high salinity, in fractures and / or in fracture-vuggy reservoirs. The upper limit of the high temperature is 150℃, and the upper limit of the mineralization is 21×10⁻⁶. 4 mg / L.