Temporary plugging agent composition and temporary plugging agent, and preparation method and application thereof

Abstract

The present application relates to the field of oil field chemistry, in particular to a kind of temporary plugging agent composition and temporary plugging agent and its preparation method and application.The composition includes main monomer, self-degradation material, crosslinking agent, initiator, thickening agent, dispersant and solvent, wherein the main monomer has the general structure shown as formula I:In formula I, R is selected from H and / or alkyl propyl sulfonate group.The temporary plugging agent prepared by the temporary plugging agent composition provided by the present application can realize the temporary plugging operation of 120 DEG C-150 DEG C high temperature fracture reservoir, and has no damage to reservoir.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of oil field chemistry, in particular to a temporary plugging agent composition and a temporary plugging agent and a preparation method and application thereof. BACKGROUND

[0002] The reservoir fracture is not only a seepage channel for oil and gas, but also a main channel for drilling fluid leakage, which is easy to cause drilling fluid leakage and further cause reservoir damage problems, and seriously restricts the efficient drilling and development of fractured oil and gas reservoirs. In order to solve the problem of reservoir fracture in oil and gas development, in recent years, temporary plugging agents have been developed and gradually used in oil and gas well operations. In the process of drilling in fractured reservoirs, not only the reservoir fracture needs to be densely pressure-sealed, but also the temporary plugging agent needs to be considered for plugging after well completion, and preferably self-plugging, so as to protect the reservoir and reduce the cost of well completion operation.

[0003] The temporary plugging agent for reservoir plugging mainly includes the following types: fiber type temporary plugging agent, particle type temporary plugging agent, fiber and particle composite type temporary plugging agent, polymer type temporary plugging agent, and water-absorbing expansion type temporary plugging agent. The existing reported temporary plugging agents have advantages and disadvantages, and most of them are concentrated in the research of medium and low temperature temporary plugging agents, and there are few reports on high temperature resistant temporary plugging agents. The main shortcomings are mainly concentrated in the poor high temperature resistance or the non-degradability of high temperature resistance, which cannot meet the plugging operation demand of high temperature fracture reservoir. SUMMARY

[0004] The purpose of the present application is to overcome the poor high temperature resistance of the existing temporary plugging agent, and to provide a temporary plugging agent composition and a temporary plugging agent and a preparation method and application thereof. The temporary plugging agent obtained from the temporary plugging agent composition has excellent high temperature resistance.

[0005] In order to achieve the above-mentioned purpose, the first aspect of the present application provides a temporary plugging agent composition, which comprises a main monomer, a self-degradable material, a crosslinking agent, an initiator, a thickening agent, a dispersing agent, and a solvent, wherein the main monomer has a general structure as shown in formula I:

[0006]

[0007] In formula I, R is selected from H and / or alkyl propyl sulfonic acid group.

[0008] The second aspect of the present application provides a temporary plugging agent, which is prepared by processing the raw materials of the composition of the first aspect, and has a core-shell structure formed by a polymer gel coating of the self-degradable material. Preferably, the particle size median of the temporary plugging agent is 0.5-2mm.

[0009] The third aspect of the present application provides an application of the temporary plugging agent of the second aspect in temporary plugging of fractured reservoirs.

[0010] The fourth aspect of the present application provides a preparation method of the bridging agent of the second aspect, wherein the method comprises:

[0011] Preparation of the aqueous phase: the main monomer, the self-degradation material, the crosslinking agent, the initiator and the thickening agent are dissolved in water to obtain the aqueous phase;

[0012] Preparation of the oil phase: the dispersing agent is dissolved in the organic solvent to obtain the oil phase;

[0013] Mixing reaction: the aqueous phase is added dropwise into the oil phase, and the initiator is added to initiate the polymerization reaction to obtain the bridging agent initial product;

[0014] Post-treatment: the bridging agent initial product is washed and dried to obtain the bridging agent.

[0015] Through the technical solution, the present application has the following advantages:

[0016] The bridging agent prepared by the bridging agent composition provided by the present application can realize temporary plugging operation for high-temperature fracture reservoirs of 120-150℃, and has no damage to the reservoirs. DETAILED DESCRIPTION

[0017] The endpoints of the ranges and any values disclosed herein are not to be construed as limiting the exact endpoints or values, but rather to be understood as encompassing values close thereto. For values comprising ranges, the endpoints of each range, the endpoints of each range and the individual point values, and the individual point values can be combined to form one or more new ranges, which are to be understood as being specifically disclosed herein.

[0018] The first aspect of the present application provides a bridging agent composition, which comprises a main monomer, a self-degradation material, a crosslinking agent, an initiator, a thickening agent, a dispersing agent and a solvent, wherein the main monomer has a general structure as shown in formula I:

[0019]

[0020] In formula I, R is selected from H and / or alkyl propyl sulfonic acid group.

[0021] The bridging agent prepared by the bridging agent composition provided by the present application can realize temporary plugging operation for high-temperature fracture reservoirs of 120-150℃, and has no damage to the reservoirs.

[0022] According to a preferred embodiment of the present application, R is selected from H and / or C1-C3 alkyl propyl sulfonic acid group, preferably H and / or methyl propyl sulfonic acid group. By adopting the foregoing preferred scheme, the high-temperature resistance of the bridging agent prepared by the composition can be further improved.

[0023] In the present application, the main monomer can be a conventional selection in the art, according to a preferred embodiment of the present application, the main monomer is selected from acrylamide and / or 2-acrylamide-2-methylpropane sulfonic acid. By adopting the foregoing preferred scheme, the high temperature resistance of the bridging agent prepared from the composition can be further improved.

[0024] According to a preferred embodiment of the present application, the mass ratio of acrylamide to 2-acrylamide-2-methylpropane sulfonic acid in the main monomer is 2-1. By adopting the foregoing preferred scheme, the high temperature resistance of the bridging agent prepared from the composition can be further improved.

[0025] In the present application, as long as the purpose of the present application can be achieved, the type of the self-degradable material is not particularly limited, according to a preferred embodiment of the present application, the self-degradable material is a polyester polymer, preferably polylactic acid and / or polycaprolactone. By adopting the foregoing preferred scheme, the high temperature resistance of the bridging agent prepared from the composition can be further improved.

[0026] According to a preferred embodiment of the present application, the self-degradable material is a mixture of polylactic acid and polycaprolactone, preferably the mass ratio of polylactic acid to polycaprolactone in the mixture is 2-1. By adopting the foregoing preferred scheme, the high temperature resistance of the bridging agent prepared from the composition can be further improved.

[0027] In the present application, the crosslinking agent can be a conventional selection in the art, according to a preferred embodiment of the present application, the crosslinking agent is selected from at least one of N,N methylene bisacrylamide, 1,6-hexanediol diacrylate, and divinylbenzene. By adopting the foregoing preferred scheme, the synthesized bridging agent can have better high temperature resistance.

[0028] In the present application, the initiator can be a conventional selection in the art, according to a preferred embodiment of the present application, the initiator is selected from ammonium persulfate and / or sodium bisulfite. By adopting the foregoing preferred scheme, the reaction can be initiated at a lower temperature.

[0029] In the present application, the thickening agent can be a conventional selection in the art, according to a preferred embodiment of the present application, the thickening agent is selected from xanthan gum and / or polyacrylamide potassium salt. By adopting the foregoing preferred scheme, the degradable material can be better suspended.

[0030] In the present application, the dispersant can be a conventional selection in the art, according to a preferred embodiment of the present application, the dispersant is selected from at least one of ethyl cellulose, nano-SiO2, SP-80, and SP-60. By adopting the foregoing preferred scheme, the polymerization reaction can be more stable.

[0031] In the present application, the solvent can be a conventional selection in the art, and according to a preferred embodiment of the present application, the solvent comprises water and an organic solvent, preferably the organic solvent is white oil and / or cyclohexane. By adopting the foregoing preferred scheme, the polymerization reaction can be more stable.

[0032] According to a preferred embodiment of the present application, the organic solvent is a mixture of white oil and cyclohexane in a mass ratio of 10:8.

[0033] The second aspect of the present application provides a bridging agent comprising a core-shell structure formed by a polymer gel coating of a self-degradable material, which is prepared from the composition of the first aspect.

[0034] The bridging agent with the foregoing features utilizes the polymer gel shell as a sacrificial agent and a formation water shielding agent to delay the contact degradation of the self-degradable material, such as polylactic acid, with the formation water, thereby achieving excellent high-temperature resistance and realizing temporary plugging operations in high-temperature fractured reservoirs.

[0035] According to a preferred embodiment of the present application, the bridging agent has a median particle size of 0.5-2 mm, preferably 0.5-1 mm.

[0036] The third aspect of the present application provides an application of the bridging agent of the second aspect in temporary plugging of fractured reservoirs.

[0037] The fourth aspect of the present application provides a preparation method of the bridging agent of the second aspect, wherein the method comprises:

[0038] Preparation of the aqueous phase: dissolving the main monomer, the self-degradable material, the crosslinking agent, the initiator, and the thickening agent in water to obtain the aqueous phase;

[0039] Preparation of the oil phase: dissolving the dispersant in the organic solvent to obtain the oil phase;

[0040] Mixing reaction: adding the aqueous phase into the oil phase dropwise, and then adding the initiator to initiate the polymerization reaction to obtain a preliminary product of the bridging agent;

[0041] Post-treatment: washing and drying the preliminary product of the bridging agent to obtain the bridging agent.

[0042] The method of the present application can prepare a bridging agent with good high-temperature resistance, and is simple and reliable in technology, has a high yield, and is suitable for large-scale industrial production.

[0043] According to a preferred embodiment of the present application, by mass, the aqueous phase contains 5-40 wt% of the main monomer, preferably 5-20 wt%, 3-25 wt% of the self-degradable material, 0.2-1 wt% of the crosslinking agent, and 0.01-1 wt% of the thickening agent, and the remainder is water.

[0044] According to a preferred embodiment of the present application, the oil phase contains 0.3-3wt% of the dispersant, and the rest is the organic solvent.

[0045] According to a preferred embodiment of the present application, the ratio of the mass of the initiator to the total mass of the water phase is 0.1-1:100.

[0046] According to a preferred embodiment of the present application, the oil phase is prepared at 20-40℃.

[0047] In the present application, the mixing reaction conditions can be conventional choices in the art, and according to a preferred embodiment of the present application, the mixing reaction conditions include: 1 part by weight of the water phase is added dropwise into 1-6 parts by weight of the oil phase, the initiator is added after oxygen removal by inert gas, and the reaction is carried out at 30-60℃ and 200-600r / min for 2-5h to obtain the temporary plugging agent initial product.

[0048] According to a preferred embodiment of the present application, the inert gas is nitrogen.

[0049] The present application will be described in detail below through examples. In the following examples, the complete degradation time is measured in a high-temperature and high-pressure reaction kettle; the raw materials are acrylamide, nano-SiO2, and ethyl cellulose, all of which are of analytical purity and from Shanghai Maikelin Biochemical Technology Co., Ltd.; polylactic acid powder (PLA) is from Nature Works, USA; N,N-methylene bisacrylamide is of analytical purity and from Tianjin Guangfu Fine Chemical Research Institute; ammonium persulfate and sodium bisulfite are of analytical purity and from National Pharmaceutical Group Chemical Reagent Co., Ltd.; white oil is from Jingmen Petrochemical; and deionized water is self-made. Other reagents not specifically mentioned can be commercially available.

[0050] Example 1

[0051] 15g of acrylamide, 4.3g of polylactic acid, 0.08g of N,N-methylene bisacrylamide, and 0.01g of xanthan gum are sequentially weighed into 20g of deionized water, and stirred uniformly to obtain a water phase; 80g of white oil is placed in a three-necked flask, and then 0.24g of ethyl cellulose and 0.32g of nano-SiO2 are sequentially added thereto, and stirred uniformly at 30℃ to obtain an oil phase; under the condition that the stirring speed is 400r / min, the water phase is added dropwise into the oil phase, and then 0.07g of ammonium persulfate and 0.05g of sodium bisulfite are added after oxygen removal by nitrogen, and the reaction is carried out at 45℃ for 3h to obtain a temporary plugging agent initial product, which is washed and dried to obtain a temporary plugging agent A with a core-shell structure formed by the polylactic acid polymer gel coating, and the particle size median is 2mm.

[0052] Example 2

[0053] Take 10 g of acrylamide, 5 g of 2-acrylamide-2-methylpropanesulfonic acid, 4.3 g of polylactic acid, 0.08 g of N, N-methylenebisacrylamide, and 0.01 g of xanthan gum in 20 g of deionized water, stir to obtain the water phase; take 80 g of white oil into a three-necked flask, then add 0.24 g of ethyl cellulose and 0.24 g of SP-80, heat to 30°C and stir to obtain the oil phase; under the condition of stirring speed of 400 r / min, drop the water phase into the oil phase, after oxygen removal by nitrogen, add 0.07 g of ammonium persulfate and 0.05 g of sodium bisulfite, and react at 45°C for 3 h to obtain the temporary plugging agent initial product, wash and dry to obtain the temporary plugging agent B with core-shell structure formed by polylactic acid polymer gel coating, and the particle size median is 1 mm.

[0054] Example 3

[0055] Take 7.5 g of acrylamide, 7.5 g of 2-acrylamide-2-methylpropanesulfonic acid, 4.3 g of polylactic acid, 0.08 g of N, N-methylenebisacrylamide, and 0.01 g of polyacrylamide potassium salt in 20 g of deionized water, stir to obtain the water phase; take 80 g of white oil into a three-necked flask, then add 0.24 g of ethyl cellulose and 0.24 g of SP-60, heat to 30°C and stir to obtain the oil phase; under the condition of stirring speed of 450 r / min, drop the water phase into the oil phase, after oxygen removal by nitrogen, add 0.07 g of ammonium persulfate and 0.05 g of sodium bisulfite, and react at 45°C for 3 h to obtain the temporary plugging agent initial product, wash and dry to obtain the temporary plugging agent C with core-shell structure formed by polylactic acid polymer gel coating, and the particle size median is 0.5 mm.

[0056] Example 4

[0057] The same as example 2, except that the main monomer is 12 g of acrylamide and 3 g of 2-acrylamide-2-methylpropanesulfonic acid, to obtain the temporary plugging agent D with core-shell structure formed by polylactic acid polymer gel coating, and the particle size median is 1.5 mm.

[0058] Example 5

[0059] The same as example 2, except that the self-degradable material uses 2.8 g of polylactic acid and 1.5 g of polycaprolactone, to obtain the temporary plugging agent E with core-shell structure formed by polylactic acid polymer gel coating, and the particle size median is 1 mm.

[0060] Example 6

[0061] The same as example 2, except that the water phase is directly mixed with the oil phase to add the dispersant, to prepare the temporary plugging agent F without core-shell structure.

[0062] Example 7

[0063] The same as example 2, except that the raw materials are mixed at one time to prepare the temporary plugging agent G without core-shell structure.

[0064] Example 8

[0065] The same as example 2, except that 80 g of white oil is replaced by 72 g of white oil and 8 g of cyclohexane to obtain the temporary plugging agent H with core-shell structure coated by the polymeric gel for polylactic acid, and the particle size median is 0.8 mm.

[0066] Example 9

[0067] The same as example 2, except that 80 g of white oil is replaced by 40 g of white oil and 40 g of cyclohexane to obtain the temporary plugging agent I with core-shell structure coated by the polymeric gel for polylactic acid, and the particle size median is 1.2 mm.

[0068] Comparative example 1

[0069] The same as example 2, except that the main monomer is acrylic acid to obtain the temporary plugging agent J with core-shell structure.

[0070] Comparative example 2

[0071] The same as example 2, except that the main monomer is N-isopropyl acrylamide to obtain the temporary plugging agent K with core-shell structure.

[0072] Example 8

[0073] The degradation time of the temporary plugging agent B at different temperatures is prepared by using distilled water to prepare a temporary plugging agent dispersion system with a mass fraction of 2%, and is aged at different temperatures (60℃, 90℃, 120℃, 150℃, 180℃, 200℃) respectively, and the complete degradation time of the temporary plugging agent at each aging temperature is determined. The results are shown in Table 1.

[0074] Table 1

[0075] Temperature / °C 60 90 120 150 180 200 Degradation time / h Not degraded Not degraded 98 83 20 11

[0076] As can be seen from Table 1, the temporary plugging agent obtained by the composition of the present application has better temporary plugging effect under the condition of higher temperature 120-150℃.

[0077] Example 9

[0078] The self-degradation performance of the temporary plugging agents A-H at 150℃ is tested, and the experimental method is: using distilled water to prepare a temporary plugging agent dispersion system with a mass fraction of 2%, and aging at 150℃, and observing the complete degradation time. The effect is shown in Table 2.

[0079] Table 2

[0080] Temporary plugging agent A B C D E Degradation time / h 72 83 82 75 90

[0081] Table 2 (continued)

[0082] F G H I J K 68 65 89 85 41 38

[0083] It can be seen from the results in Table 2 that the temporary plugging agent prepared by using the temporary plugging agent composition of the present application can be used under high temperature conditions and has obviously better high temperature resistance.

[0084] The preferred embodiments of the present application are described in detail above, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including that each technical feature is combined in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the present application and belong to the protection scope of the present application.

Claims

1. A temporary plugging agent, characterized in that, The temporary plugging agent is prepared from a composition raw material, has a core-shell structure formed by a polymer gel coating of a self-degradation material, and the composition comprises a main monomer, a self-degradation material, a crosslinking agent, an initiator, a thickening agent, a dispersing agent, and a solvent, wherein the main monomer has a general structure as shown in Formula I: Formula I; In Formula I, R is selected from H and / or C1-C3 alkyl propyl sulfonic acid group; The self-degradation material is polylactic acid and / or polycaprolactone, and the solvent comprises water and an organic solvent; The preparation method of the temporary plugging agent comprises: water phase configuration: dissolving the main monomer, the self-degradation material, the crosslinking agent, and the thickening agent in water to obtain a water phase; oil phase configuration: dissolving the dispersing agent in an organic solvent to obtain an oil phase; mixing reaction: adding the water phase into the oil phase drop by drop, and then adding an initiator to initiate a polymerization reaction to obtain a temporary plugging agent primary product; post-treatment: washing and drying the temporary plugging agent primary product to obtain the temporary plugging agent. The water phase contains 5-40 wt% of the main monomer, 3-25 wt% of the self-degradation material, 0.2-1 wt% of the crosslinking agent, and 0.01-1 wt% of the thickening agent, and the rest is water; the oil phase contains 0.3-3 wt% of the dispersing agent, and the rest is an organic solvent.

2. The bridge plug of claim 1, wherein, The R is H and / or methyl propyl sulfonic acid group.

3. The bridge plug of claim 2, wherein, The main monomer is selected from acrylamide and / or 2-acrylamide-2-methyl propyl sulfonic acid.

4. The bridge plug of claim 1, wherein, The main monomer is a mixture of acrylamide and 2-acrylamide-2-methyl propyl sulfonic acid with a mass ratio of 2:

1.

5. The bridge plug of claim 1, wherein, The self-degradation material is a mixture of polylactic acid and polycaprolactone, and the mass ratio of polylactic acid to polycaprolactone in the mixture is 2:

1.

6. The temporary plugging agent according to claim 1, wherein, The crosslinking agent is selected from at least one of N,N methylene bisacrylamide, 1,6-hexanediol diacrylate, and divinylbenzene; and / or The initiator is selected from ammonium persulfate and / or sodium bisulfite; and / or The thickening agent is selected from xanthan gum and / or polyacrylamide potassium salt; and / or The dispersing agent is selected from at least one of ethyl cellulose, nano-SiO2, SP-80, and SP-60; and / or The organic solvent is white oil and / or cyclohexane.

7. The bridge plug of claim 6, wherein, The organic solvent is a mixture of white oil and cyclohexane with a mass ratio of 10:

8.

8. The bridge plug of claim 1, wherein, The temporary plugging agent has a median particle size of 0.5-2 mm.

9. The bridge plug of claim 1, wherein, The mass ratio of the mass of the initiator to the total mass of the water phase is 0.1-1:

100.

10. The bridge plug of claim 1, wherein, The mixing reaction conditions include: adding 1 part by weight of the water phase into 2-6 parts by weight of the oil phase drop by drop, adding an initiator after oxygen removal by inert gas, and reacting at 30-60°C and 200-600 r / min for 2-5 h to obtain the temporary plugging agent primary product.

11. The bridge plug of claim 10, wherein, The inert gas is nitrogen.

12. Use of the temporary plugging agent according to any one of claims 1-11 in temporary plugging of a fracture type reservoir.

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