Plugging composition, plugging agent for water-based drilling fluid as well as preparation method and application of plugging agent

Abstract

The invention discloses a plugging composition, a plugging agent for water-based drilling fluid as well as a preparation method and application of the plugging agent. The plugging composition is prepared from the following raw materials in parts by mass: 100 parts of epoxy resin emulsion, 4-35 parts of a curing agent, 0-2 parts of a curing time regulator, 0-15 parts of a flow pattern regulator and 0-50 parts of a propping agent. The plugging composition or the plugging agent for the water-based drilling fluid, which is provided by the invention, is used as an organic thermal initiation consolidation material, has the characteristics of adjustable thickening time in a range of 0.5-10 hours, high cementing strength, high compressive strength and the like, and is suitable for the formation temperature of 60-150 DEG C; the drilling fluid has good compatibility with various fluids such as drilling fluids and saline water, and is particularly suitable for reinforcing well sections prone to leakage and collapse, the pressure bearing capacity of strata is improved, and well wall reconstruction is achieved.

Description

Technical Field

[0001] The invention relates to a plugging composition, a plugging agent for water-based drilling fluid, and a preparation method and application thereof. Background Art

[0002] During the drilling process of oil and gas fields, problems such as well wall collapse and leakage are often encountered, which bring huge obstacles to drilling construction and greatly increase the cost of drilling construction. Faults, large sections of sandstone layers, mudstone, etc. in the formation are prone to leakage and unstable formations, which are the main causes of formation leakage. Using plugging agents to plug leaking formations or loose formations is a common method.

[0003] At present, the plugging agents used at drilling sites specifically include two categories: physical filling and chemical bonding and sealing. Among them, the use of chemical bonding and sealing can implement more stable and effective sealing of the formation. The traditional chemical bonding and sealing method uses plugging materials mainly composed of inorganic materials such as cement, but it often has problems with poor bonding performance, and is prone to problems such as bonding failure and re-leakage in the later construction, making the plugging and stabilizing the well wall ineffective. In addition, although the use of gel plugging agents for plugging is also a bonding and plugging method, the strength and bonding strength of gel plugging agents themselves are low, and the pressure bearing requirements are often difficult to meet. Summary of the invention

[0004] In order to at least partially solve the above technical problems, the present invention provides a plugging composition with high bonding strength and high pressure resistance and a plugging agent for water-based drilling fluid, which are suitable for drilling plugging and drilling well wall reinforcement.

[0005] As one aspect of the present invention, it relates to a plugging composition, which includes the following raw materials, measured by mass: 100 parts of epoxy resin emulsion, 4 to 35 parts of curing agent, 0 to 2 parts of curing time regulator, 0 to 15 parts of flow pattern regulator, and 0 to 50 parts of proppant.

[0006] In a specific embodiment, the epoxy resin emulsion includes the following raw materials by weight: 50-66 wt % of epoxy resin, 3-15 wt % of emulsifier, and the balance is water.

[0007] In a specific embodiment, the epoxy resin is selected from one or more of bisphenol A epoxy resin, alicyclic epoxy resin, bisphenol F epoxy resin or novolac epoxy resin.

[0008] In a specific embodiment, the emulsifier comprises an anionic surfactant and / or a nonionic surfactant.

[0009] Furthermore, the structural formula of the anionic surfactant is (RX)(Y)n; wherein R is a saturated or unsaturated straight or branched alkyl group of C8 to C20; X is C6 H 4 SO 3- ,-O-SO 3- , SO 3- or CO 2- ; Y is H + , NH 4+ or a protonated trialkylamine, a quaternary ammonium ion or an alkali metal cation.

[0010] Furthermore, the nonionic surfactant is selected from C8-C20 saturated or unsaturated alkyl alcohol polyoxyethylene ether, C8-C20 saturated or unsaturated alkylphenol polyoxyethylene ether, Span series nonionic surfactant or Tween series nonionic surfactant.

[0011] In a specific embodiment, the emulsifier further comprises a reaction product; the reaction product is prepared by a ring-opening reaction between an epoxy resin and a polyethylene glycol derivative via an amino group and an epoxy group.

[0012] In a specific embodiment, the polyethylene glycol derivative is as shown in formula (I):

[0013]

[0014] Or, as shown in formula (II):

[0015]

[0016] In the formula, 15≤n≤100, and n is an integer.

[0017] In a specific embodiment, the molar ratio of the epoxy resin to the polyethylene glycol derivative is (1.5-3):1.

[0018] In a specific embodiment, the curing time regulator is selected from one or more of triethanolamine, N,N-dimethylaniline, benzyldimethylamine, o-hydroxybenzyldimethylamine, tris(dimethylaminomethyl)phenol, triethylamine, 2,4,6-tris(dimethylaminomethyl)phenol or 3,3-(4-methyl-1,3-phenylene)bis(1,1-dimethylurea).

[0019] In a specific embodiment, the flow pattern regulator is selected from one or more of a bentonite slurry containing 8wt% to 18wt% bentonite, a sodium cellulose solution containing 0.5wt% to 2wt% sodium carboxymethyl cellulose, or a water-soluble polymer polymerized from a carbon-carbon double bond-containing monomer containing 0.5wt% to 3wt%.

[0020] Furthermore, the monomer containing a carbon-carbon double bond is selected from one or more of acrylic acid, acrylonitrile, acrylamide, methacrylic acid, methacrylamide or 2-acrylamido-2-methylpropanesulfonic acid.

[0021] In a specific embodiment, the proppant is selected from one or more of calcium carbonate, barite, sand, iron ore powder, calcium sulfate, nut shell, sand, tree fiber or galena.

[0022] As another aspect of the present invention, it relates to a method for preparing the above-mentioned plugging composition, which comprises mixing the constituent raw materials.

[0023] In a specific embodiment, the preparation method of the epoxy resin emulsion comprises the following steps:

[0024] S1. Weigh epoxy resin and emulsifier according to mass percentage, heat and mix to obtain a homogeneous mixture;

[0025] S2. Under stirring conditions, water is added to the homogeneous mixture prepared in S1 to obtain an epoxy resin emulsion.

[0026] In a specific embodiment, in S1, the heating temperature is 50-90°C.

[0027] In a specific embodiment, in S2, the stirring rate is 3000-20000 r / min, and the stirring time is 10-60 min.

[0028] As another aspect of the present invention, it relates to a plugging agent for water-based drilling fluid, which includes the plugging composition mentioned above or the plugging composition prepared according to the method mentioned above.

[0029] As another aspect of the present invention, it relates to a drilling process, wherein the process uses the above-mentioned plugging composition or the above-mentioned plugging agent for water-based drilling fluid.

[0030] The plugging composition or plugging agent for water-based drilling fluid provided by the present invention is an organic heat-induced consolidation material, has the characteristics of adjustable thickening time within the range of 0.5 to 10 hours, high cementing strength and compressive strength, and is suitable for formation temperatures of 60 to 150° C.; has good compatibility with a variety of drilling fluids and brine and other fluids, and is particularly suitable for reinforcing leaky and easily collapsed well sections, improving the pressure bearing capacity of the formation, and realizing well wall reconstruction.

[0031] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a picture of the water-based drilling fluid plugging agent before solidification according to an embodiment of the present invention, and the state before solidification is shown as an emulsion;

[0033] Figure 2 This is a picture of the water-based drilling fluid plugging agent after solidification according to an embodiment of the present invention, and the state after solidification is shown as a solidified state;

[0034] Figure 3 This is a graph showing the variation trend of the bonding strength of the water-based drilling fluid plugging agent according to Example 3 of the present invention with shear distance. DETAILED DESCRIPTION

[0035] The present invention is further described below in conjunction with specific embodiments, and the protection scope of the present invention is not limited by the following embodiments. The sources of the materials mainly involved in the embodiments are shown in Table 1 below, and other materials not shown are conventional commercial products.

[0036] Table 1 Material source description

[0037] Serial number materials Model / Specification Manufacturer 1 Epoxy resin NPEF-170, epoxy equivalent 160~180 (g / eq) Henan Water Ring Industrial Co., Ltd. 2 Calcium carbonate 80 mesh Hezhou Qifeng Powder Co., Ltd. 3 Nutshell 20 mesh For the crushed walnut shells, homemade

[0038] The inventors have made a technical solution of the present invention through a large number of experimental studies. The following are specific embodiments of the present invention. The evaluation methods adopted in the embodiments are described as follows: (1) Thickening time and compressive strength test

[0039] The prepared plugging composition / water-based drilling fluid plugging agent was placed in a cement slurry thickener, a predetermined temperature (i.e., the heating temperature in the embodiment) was set, the pressure was increased to 10 MPa, the heating rate was 5°C / min, and the timing was started when the temperature reached the predetermined temperature. When the viscosity increased to 4 times the initial consistency, the thickening time was recorded, and then the sample was transferred to a 50 mL glass bottle, the excess part was discarded, and the glass bottle was placed in a 400 mL stainless steel mud aging tank, and nitrogen was introduced at 1 MPa, and the sample was placed upright in an oven for heating for 24 hours, and the sample was taken out, and the compressive strength of the sample was tested using a 10000-test tester;

[0040] (3) Bond strength test

[0041] The plugging composition / water-based drilling fluid plugging agent is applied to the contact surface of two cubic cement blocks (50×50×50mm) of the same size, with a contact surface area of ​​25cm 2 , heated for 24 hours at the corresponding temperature (consistent with the heating temperature during the thickening time determination), and then measured the minimum shear force F when two cement blocks crack and slide along the contact surface at room temperature using a rock direct shear tester. min , and the bond strength is calculated based on the contact area S, which is: P 胶 =F min / S;

[0042] It should be noted that the thickening time refers to the time required for the viscosity of the mixed liquid to increase 4 times after heating; the compressive strength refers to the strength required to compress the material height by 50%; and the bonding strength refers to the strength required to be applied after shear peeling between the rock surfaces bonded by the plugging composition / water-based drilling fluid plugging agent.

[0043] Among them, in the above test experiments, the model of the multi-touch testing machine used is CTM2100, purchased from Xieqiang Instrument Manufacturing (Shanghai) Co., Ltd.; the model of the rock direct shear testing machine is YSZJ, purchased from Chengdu Donghua Excellence Technology Co., Ltd.

[0044] The inventors prepared Examples 1 to 8 of the present invention by setting reasonable raw material compositions and operating conditions.

[0045] Example 1

[0046] The epoxy resin emulsion of this embodiment is prepared by the following method:

[0047] 100 g of epoxy resin E-44, 1 g of emulsifier OP-4 (nonionic surfactant) and 6 g of emulsifier OP-10 (nonionic surfactant) were added in sequence and mixed evenly; the mixture was heated to 90° C., 93 g of water was added under stirring, the stirring rate was controlled to 10,000 rpm, and the stirring time was 10 min to obtain an epoxy resin emulsion.

[0048] The plugging composition / plugging agent for water-based drilling fluid of this embodiment is prepared by the following method:

[0049] 100 g of epoxy resin emulsion, 25 g of diaminodiphenyl sulfone (curing agent), and a certain mass of o-hydroxybenzyl dimethylamine (curing time regulator) were added in sequence and mixed evenly to obtain a solidified plugging agent.

[0050] Under room temperature conditions, the apparent viscosity of the plugging composition / water-based drilling fluid plugging agent prepared in this example was measured by a rheometer to be 92-95 mPa·s.

[0051] In this scheme, o-hydroxybenzyl dimethylamine is a curing time regulator, and the dosage is variable. Based on the safety needs during plugging construction, different working conditions are simulated, and the curing time is adjusted by changing the dosage. The performance of the obtained solidified plugging composition / water-based drilling fluid plugging agent is shown in Table 2 below:

[0052] Table 2 Performance test results

[0053]

[0054] Example 2

[0055] The epoxy resin emulsion of this embodiment is prepared by the following method:

[0056] 100 g of epoxy resin E-51, 1 g of Span-60 (nonionic surfactant) and 15 g of Tween-80 (nonionic surfactant) were added in sequence and mixed evenly; the mixture was heated to 70° C., 60 g of water was added under stirring, the stirring rate was controlled to 8000 rpm, and the stirring time was 30 min to obtain an epoxy resin emulsion.

[0057] The plugging composition / plugging agent for water-based drilling fluid of this embodiment is prepared by the following method:

[0058] 100g epoxy resin emulsion, 30g diaminodiphenylmethane (curing agent), a certain mass of 2,4,6-tris(dimethylaminomethyl)phenol (curing time regulator), 5g 14% bentonite slurry (flow pattern regulator) and 50g calcium carbonate (80 mesh, proppant) were added in sequence and mixed evenly to prepare a consolidation plugging agent.

[0059] Under room temperature, the apparent viscosity of the plugging composition / water-based drilling fluid plugging agent prepared in this example was measured by a rheometer to be 155-160 mPa·s.

[0060] In this scheme, 2,4,6-tris(dimethylaminomethyl)phenol is a curing time regulator, and the dosage is variable. Based on the safety needs during plugging construction, different working conditions are simulated, and the curing time is adjusted by changing the dosage. The performance of the obtained solidified plugging composition / water-based drilling fluid plugging agent is shown in Table 3 below:

[0061] Table 3 Performance test results

[0062]

[0063] Example 3

[0064] The epoxy resin emulsion of this embodiment is prepared by the following method:

[0065] 100 g of epoxy resin NPEF-170, 2 g of sodium dodecylbenzene sulfonate (anionic surfactant) and 18 g of emulsifier TO-10 (nonionic surfactant) were added in sequence and mixed evenly; the mixture was heated to 50° C., 80 g of water was added under stirring, the stirring rate was controlled to 8000 rpm, and the stirring time was 60 min to obtain an epoxy resin emulsion.

[0066] The plugging composition / plugging agent for water-based drilling fluid of this embodiment is prepared by the following method:

[0067] 100g of epoxy resin emulsion, 5g of melamine (curing agent), a certain mass of o-hydroxybenzyldimethylamine (curing time regulator), 5g of 12% bentonite slurry (flow pattern regulator) and 50g of sand (60 mesh, proppant) were added in sequence and mixed evenly to prepare a consolidation plugging agent.

[0068] Under room temperature conditions, the apparent viscosity of the plugging composition / water-based drilling fluid plugging agent prepared in this example was measured by a rheometer to be 178-186 mPa·s.

[0069] In this scheme, o-hydroxybenzyl dimethylamine is a curing time regulator, and the dosage is variable. Based on the safety needs during plugging construction, different working conditions are simulated, and the curing time is adjusted by changing the dosage. The performance of the obtained solidified plugging composition / water-based drilling fluid plugging agent is shown in Table 4 below:

[0070] Table 4 Performance test results

[0071]

[0072] When the addition amount of o-hydroxybenzyl dimethylamine is 0.08 g, the change trend of the bonding strength of the plugging composition / water-based drilling fluid plugging agent prepared in Example 3 with the shear distance is as follows: Figure 3 shown.

[0073] Example 4

[0074] The epoxy resin emulsion of this embodiment is prepared by the following method:

[0075] 100 g of epoxy resin E-44 and 5 g of sodium dodecylbenzene sulfonate (anionic surfactant) were added in sequence and mixed evenly; the mixture was heated to 70° C., 80 g of water was added under stirring, the stirring rate was controlled to 10,000 rpm, and the stirring time was 30 min to obtain an epoxy resin emulsion.

[0076] The plugging composition / plugging agent for water-based drilling fluid of this embodiment is prepared by the following method:

[0077] 100 g of epoxy resin emulsion, 12 g of 4-trifluoromethyl o-phenylenediamine (curing agent), a certain mass of o-hydroxybenzyl dimethylamine (curing time regulator) and 30 g of fruit shell (20 mesh, proppant) were added in sequence and mixed evenly to prepare a consolidation plugging agent.

[0078] Under room temperature conditions, the apparent viscosity of the plugging composition / water-based drilling fluid plugging agent prepared in this example was measured by a rheometer to be 149-157 mPa·s.

[0079] In this scheme, o-hydroxybenzyl dimethylamine is a curing time regulator, and the dosage is variable. Based on the safety needs during plugging construction, different working conditions are simulated, and the curing time is adjusted by changing the dosage. The performance of the obtained solidified plugging composition / water-based drilling fluid plugging agent is shown in Table 5 below:

[0080] Table 5 Performance test results

[0081]

[0082] Example 5

[0083] The epoxy resin emulsion of this embodiment is prepared by the following method:

[0084] 100 g of epoxy resin E-44 and 15 g of Tween 80 (non-ionic surfactant) were added in sequence and mixed evenly; the mixture was heated to 80° C., 50 g of water was added under stirring, the stirring rate was controlled to 10,000 rpm, and the stirring time was 20 min to obtain an epoxy resin emulsion.

[0085] The plugging composition / plugging agent for water-based drilling fluid of this embodiment is prepared by the following method:

[0086] 100 g of epoxy resin emulsion, 30 g of 4,4'-methylenebis(2-chloroaniline) (curing agent), a certain mass of o-hydroxybenzyldimethylamine (curing time regulator), 20 g of barite (300 mesh, proppant) and 10 g of fruit shell (20 mesh, proppant) were added in sequence and mixed evenly to prepare a consolidation plugging agent.

[0087] Under room temperature, the apparent viscosity of the plugging composition / water-based drilling fluid plugging agent prepared in this example was measured by a rheometer to be 137-145 mPa·s.

[0088] In this scheme, o-hydroxybenzyl dimethylamine is a curing time regulator, and the dosage is variable. Based on the safety needs during plugging construction, different working conditions are simulated, and the curing time is adjusted by changing the dosage. The performance of the obtained solidified plugging composition / water-based drilling fluid plugging agent is shown in Table 6 below:

[0089] Table 6 Performance test results

[0090]

[0091] Example 6

[0092] The emulsifier of this embodiment is prepared by the following method:

[0093] 5 g of epoxy resin E-51 and 14 g of methoxypolyethylene glycol amine (molecular weight 1000, polyethylene glycol derivative) were added in sequence and mixed evenly; the mixture was stirred at room temperature for 30 minutes to obtain an emulsifier.

[0094] The epoxy resin emulsion of this embodiment is prepared by the following method:

[0095] 150 g of epoxy resin E-51 and 19 g of the above emulsifier were added in sequence and mixed evenly; the mixture was heated to 80°C, and 50 g of water was added under stirring. The stirring rate was controlled to 10,000 rpm and the stirring time was 15 min to obtain an epoxy resin emulsion.

[0096] The plugging composition / plugging agent for water-based drilling fluid of this embodiment is prepared by the following method:

[0097] 100 g of epoxy resin emulsion, 30 g of 4,4'-methylenebis(2-chloroaniline) (curing agent), a certain mass of 2,4,6-tris(dimethylaminomethyl)phenol (curing time regulator), 20 g of barite (300 mesh, proppant) and 10 g of fruit shell (20 mesh, proppant) were added in sequence and mixed evenly to prepare a consolidation plugging agent.

[0098] Under room temperature conditions, the apparent viscosity of the plugging composition / water-based drilling fluid plugging agent prepared in this example was measured by a rheometer to be 143-152 mPa·s.

[0099] In this scheme, 2,4,6-tris(dimethylaminomethyl)phenol is a curing time regulator, and the dosage is variable. Based on the safety needs during plugging construction, different working conditions are simulated, and the curing time is adjusted by changing the dosage. The performance of the obtained solidified plugging composition / water-based drilling fluid plugging agent is shown in Table 7 below:

[0100] Table 7 Performance test results

[0101]

[0102]

[0103] Example 7

[0104] The emulsifier of this embodiment is prepared by the following method:

[0105] 5 g of epoxy resin E-51 and 17.5 g of polyethylene glycol diamine (molecular weight 2000, a polyethylene glycol derivative) were added in sequence and mixed evenly; the mixture was stirred at room temperature for 30 minutes to obtain an emulsifier.

[0106] The epoxy resin emulsion of this embodiment is prepared by the following method:

[0107] 150 g of epoxy resin E-51 and 19 g of the above emulsifier were added in sequence and mixed evenly; the mixture was heated to 80°C, and 50 g of water was added under stirring. The stirring rate was controlled to 10,000 rpm and the stirring time was 15 min to obtain an epoxy resin emulsion.

[0108] The plugging composition / plugging agent for water-based drilling fluid of this embodiment is prepared by the following method:

[0109] 100 g of epoxy resin emulsion, 5 g of dicyandiamide (curing agent), a certain mass of 3,3-(4-methyl-1,3-phenylene)bis(1,1-dimethylurea) (curing time regulator), 5 g of 12% bentonite slurry (flow pattern regulator) and 50 g of sand (60 mesh, proppant) were added in sequence and mixed evenly to prepare a consolidation plugging agent.

[0110] Under room temperature conditions, the apparent viscosity of the plugging composition / water-based drilling fluid plugging agent prepared in this example was measured by a rheometer to be 168-174 mPa·s.

[0111] In this scheme, 3,3-(4-methyl-1,3-phenylene)bis(1,1-dimethylurea)phenol is a curing time regulator, and the dosage is variable. Based on the safety needs during plugging construction, the curing time is adjusted by changing the dosage under simulated different working conditions. The performance of the obtained solidified plugging composition / water-based drilling fluid plugging agent is shown in Table 8 below:

[0112] Table 8 Performance test results

[0113]

[0114] Example 8

[0115] The emulsifier of this embodiment is prepared by the following method:

[0116] 10 g of epoxy resin E-51 and 42 g of methoxypolyethylene glycol amine (molecular weight 4000, a polyethylene glycol derivative) were added in sequence and mixed evenly; the mixture was stirred at room temperature for 30 minutes to obtain an emulsifier.

[0117] The epoxy resin emulsion of this embodiment is prepared by the following method:

[0118] 150 g of epoxy resin E-51 and 19 g of the above emulsifier were added in sequence and mixed evenly; the mixture was heated to 80°C, and 60 g of water was added under stirring. The stirring rate was controlled to 10,000 rpm and the stirring time was 15 min to obtain an epoxy resin emulsion.

[0119] The plugging composition / plugging agent for water-based drilling fluid of this embodiment is prepared by the following method:

[0120] 100 g of epoxy resin emulsion, 30 g of 4,4'-methylenebis(2-chloroaniline) (curing agent), a certain mass of o-hydroxybenzyldimethylamine (curing time regulator), 20 g of barite (300 mesh, proppant) and 20 g of sand (30 mesh, proppant) were added in sequence and mixed evenly to prepare a consolidation plugging agent.

[0121] Under room temperature, the apparent viscosity of the plugging composition / water-based drilling fluid plugging agent prepared in this example was measured by a rheometer to be 144-152 mPa·s.

[0122] In this scheme, o-hydroxybenzyl dimethylamine is a curing time regulator, and the amount added is variable. Based on the safety needs during plugging construction, the curing time is adjusted by changing the amount added under simulated different working conditions. The performance of the obtained solidified plugging composition / water-based drilling fluid plugging agent is shown in Table 9 below:

[0123] Table 9 Performance test results

[0124]

[0125] Example 9

[0126] The emulsifier of this embodiment is prepared by the following method:

[0127] 10 g of epoxy resin E-51 and 2 g of polyethylene glycol diamine (molecular weight 2000, a polyethylene glycol derivative) were added in sequence and mixed evenly; the mixture was stirred at room temperature for 30 minutes to obtain an emulsifier.

[0128] The epoxy resin emulsion of this embodiment is prepared by the following method:

[0129] 150 g of epoxy resin E-51 and 15 g of the above emulsifier were added in sequence and mixed evenly; the mixture was heated to 80°C, and 65 g of water was added under stirring. The stirring rate was controlled to 10,000 rpm and the stirring time was 15 min to obtain an epoxy resin emulsion.

[0130] The plugging composition / plugging agent for water-based drilling fluid of this embodiment is prepared by the following method:

[0131] 100 g of epoxy resin emulsion, 5 g of dicyandiamide (curing agent), a certain mass of 3,3-(4-methyl-1,3-phenylene)bis(1,1-dimethylurea) (curing time regulator), 2 g of 1% sodium carboxymethyl cellulose aqueous solution (flow pattern regulator), 30 g of sand (60 mesh, proppant) and 5 g of fruit shell (proppant) were added in sequence and mixed evenly to prepare a consolidation plugging agent.

[0132] Under room temperature conditions, the apparent viscosity of the plugging composition / water-based drilling fluid plugging agent prepared in this example was measured by a rheometer to be 162-172 mPa·s.

[0133] In this scheme, o-hydroxybenzyl dimethylamine is a curing time regulator, and the dosage is variable. Based on the safety needs during plugging construction, different working conditions are simulated, and the curing time is adjusted by changing the dosage. The performance of the obtained solidified plugging composition / water-based drilling fluid plugging agent is shown in Table 10 below:

[0134] Table 10 Performance test results

[0135]

[0136] The inventor selected two plugging agents with cement and hydrogel added in the raw materials as comparative examples 1 to 2 of the present invention. The compressive performance and bonding strength of the materials were tested by the evaluation method adopted by the present invention. The results showed that the bonding strength of the cement used for drilling plugging to the formation was less than 1MPa, the bonding strength of the polyacrylamide hydrogel used for drilling plugging to the formation was also less than 1MPa, and the compressive strength of the polyacrylamide hydrogel used for plugging was less than 2MPa.

[0137] Through the performance test results of Tables 2 to 10, combined with Examples 1 to 9 and Comparative Examples 1 to 2, we can see that the consolidation plugging composition / water-based drilling fluid plugging agent prepared by the present invention is significantly stronger in bonding strength than cement inorganic consolidation materials or polyacrylamide hydrogel materials for drilling plugging, and far exceeds polyacrylamide hydrogel plugging agents in terms of compressive strength. And the plugging composition or water-based drilling fluid plugging agent provided by the present invention, as an organic heat-induced consolidation material, has the characteristics of adjustable thickening time within the range of 0.5 to 10 hours, high bonding strength and compressive strength, and can be applied to formation temperatures of 60 to 150°C.

[0138] In addition, by comparing Examples 1 to 5 with Examples 6 to 9, we can also find that the compressive strength and bonding strength of Examples 6 to 9 are better than those of Examples 1 to 5. Therefore, the inventors speculate that when the polyethylene glycol derivative and the epoxy resin are used as reactants of the emulsifier, the curing effect and emulsification effect will be better. This may be because the reaction of the polyethylene glycol derivative and the epoxy resin has a self-emulsifying characteristic, which can reduce the effect of the additionally added emulsifier on the curing performance, thereby achieving a better curing and emulsification effect.

[0139] The inventors took Example 3 and Example 8 as examples, conducted compatibility evaluation in a simulated application experiment, and made Application Examples 1 to 12. Among them, the sources of the fillers used in the following application examples are as follows:

[0140] Salt water slurry: It is the on-site slurry of a well in Dagang Oilfield;

[0141] Polysulfone drilling fluid: It is the on-site slurry of a well in Dagang Oilfield;

[0142] Bentonite slurry: 16 g sodium bentonite was mixed with 400 mL water, stirred at 10000 r / min for 10 min, and then allowed to stand for 24 h for later use;

[0143] Simulated formation water: Add 10g sodium chloride, 0.28g anhydrous calcium chloride, 0.08g barium chloride, 0.08g magnesium chloride, 0.4g sodium carbonate and 0.2g sodium sulfate to 1L water.

[0144] In addition, the GGS71-B high temperature and high pressure filter loss instrument used in the evaluation test experiment was from Qingdao Hengtaida Electromechanical Equipment Co., Ltd.

[0145] Application Examples 1 to 6

[0146] 100 g of the drilling consolidation plugging composition / water-based drilling fluid plugging agent prepared in Example 3 was mixed with a certain amount of filler to test the thickening time and the changes in the bonding strength and compressive strength. The test data results are shown in Table 11 below.

[0147] The drilling consolidation plugging composition / water-based drilling fluid plugging agent prepared in Example 3 is prepared by uniformly mixing 100g of the epoxy resin emulsion prepared in Example 3, 5g of melamine, 0.12g of o-hydroxybenzyldimethylamine, 5g of 12% bentonite slurry and 50g of sand (60 mesh).

[0148] Table 11 Evaluation test results

[0149]

[0150] The compatibility experimental study of application examples 1 to 6 shows that the plugging composition / plugging agent for water-based drilling fluid prepared by Example 3 has good compatibility with brine slurry, polysulfone drilling fluid, bentonite slurry, brine, formation water, etc.

[0151] Pressure bearing capacity evaluation object: the plugging composition / plugging agent for water-based drilling fluid prepared in Example 3;

[0152] Pressure bearing capacity evaluation method: The pressure bearing capacity of the drilling consolidation plugging agent is evaluated using a high-temperature and high-pressure filter loss meter for mud. Fill the high-temperature and high-pressure filter loss meter with 40 mesh sand to simulate the leaking layer, the filling height is 50% of the filter loss meter height, add clean water to the sand surface, and then add the plugging composition / water-based drilling fluid plugging agent in Example 3 with a remaining cavity height of 50%, and then press in a 3 cm thick plugging composition / water-based drilling fluid plugging agent at a pressure of 1 MPa, and remove the plugging composition / water-based drilling fluid plugging agent on the upper surface of the sand, replace it with bentonite slurry, heat it at 95°C for 24h, then open the upper air inlet valve and the bottom liquid outlet valve of the high-temperature and high-pressure filter loss meter, pressurize it from the top with nitrogen, maintain it at 7 MPa for 30 minutes, test whether there is liquid flowing out from the bottom, and then test its pressure bearing capacity.

[0153] The test results show that when the upper and lower pressure difference of the high temperature and high pressure filter loss tester is maintained at 7MPa for 30 minutes, no liquid flows out, which proves that the consolidation plugging agent of Example 3 can withstand a pressure of at least 7MPa.

[0154] Application Examples 7 to 12

[0155] 100 g of the drilling consolidation plugging composition / water-based drilling fluid plugging agent prepared in Example 8 was mixed with a certain amount of filler to test the thickening time and the changes in the bonding strength and compressive strength. The test data results are shown in Table 12 below.

[0156] Among them, the drilling consolidation plugging composition / water-based drilling fluid plugging agent prepared in Example 8 is prepared by uniformly mixing 100g of the epoxy resin emulsion prepared in Example 8, 30g of 4,4'-methylenebis(2-chloroaniline), 0.03g of o-hydroxybenzyldimethylamine, 20g of barite (300 mesh) and 20g of sand (30 mesh).

[0157] Table 12 Evaluation test results

[0158]

[0159] The compatibility experimental study of application examples 7 to 12 shows that the plugging composition / plugging agent for water-based drilling fluid prepared by Example 8 has good compatibility with brine slurry, polysulfone drilling fluid, bentonite slurry, brine, formation water, etc.

[0160] Pressure bearing capacity evaluation object: the plugging composition / plugging agent for water-based drilling fluid prepared in Example 8;

[0161] Pressure bearing capacity evaluation method: The pressure bearing capacity of the drilling consolidation plugging agent is evaluated using a high-temperature and high-pressure filter loss meter for mud. Fill the high-temperature and high-pressure filter loss meter with 40 mesh sand to simulate the leaking layer, the filling height is 50% of the filter loss meter height, add clean water to the sand surface, and then add the plugging composition / water-based drilling fluid plugging agent in Example 8 with a remaining cavity height of 50%, and then pressurize it at a pressure of 1MPa. The plugging composition / water-based drilling fluid plugging agent is pressed in at a thickness of 3 cm, and the plugging composition / water-based drilling fluid plugging agent on the upper surface of the sand is removed and replaced with bentonite slurry, heated at 95°C for 24h, and then the upper air inlet valve and the bottom liquid outlet valve of the high-temperature and high-pressure filter loss meter are opened, and nitrogen is used to pressurize from the top, and maintained at 7MPa for 30min to test whether there is liquid flowing out from the bottom, and then test its pressure bearing capacity.

[0162] The test results show that when the upper and lower pressure difference of the high temperature and high pressure filter loss tester is maintained at 7MPa for 30 minutes, no liquid flows out, which proves that the consolidation plugging agent of Example 8 can withstand a pressure of at least 7MPa.

[0163] In summary, through the evaluation test results and compatibility experiments of Application Examples 1 to 12, as well as the pressure-bearing capacity evaluation of the materials of Example 3 and Example 8, we believe that the plugging composition or plugging agent provided by the present invention has good compatibility with a variety of drilling fluids and brine, simulated formation water and other fluids, and exhibits good plugging pressure-bearing capacity.

[0164] The above are only preferred feasible embodiments of the present invention, and the protection scope of the present invention is not limited thereto. Various modifications or applications made according to the above embodiments are within the protection scope of this technical solution.

[0165] Although the specific embodiments of the present invention have been described in detail, it will be understood by those skilled in the art. According to all the teachings disclosed, various modifications and replacements can be made to those details, and these changes are all within the protection scope of the present invention. The full scope of the present invention is given by the attached claims and any equivalents thereof.

Claims

1. A plugging composition, characterized in that: The composition comprises the following raw materials by weight: 100 parts of epoxy resin emulsion, 4 to 35 parts of curing agent, 0 to 2 parts of curing time regulator, 0 to 15 parts of flow pattern regulator and 0 to 50 parts of proppant.

2. The plugging composition according to claim 1, characterized in that: The epoxy resin emulsion comprises the following raw materials by weight: 50-66 wt % of epoxy resin, 3-15 wt % of emulsifier, and the balance is water.

3. The plugging composition according to claim 2, characterized in that: The epoxy resin is selected from one or more of bisphenol A epoxy resin, alicyclic epoxy resin, bisphenol F epoxy resin or novolac epoxy resin.

4. The plugging composition according to claim 2, characterized in that: The emulsifier comprises an anionic surfactant and / or a nonionic surfactant.

5. The plugging composition according to claim 4, characterized in that: The structural formula of the anionic surfactant is (RX)(Y)n; In the formula, R is a C8-C20 saturated or unsaturated straight or branched alkyl group; X is C6H4SO 3- ,-O-SO 3- , SO 3- or CO 2- ; Y is H + , NH 4+ or a protonated trialkylamine, a quaternary ammonium ion or an alkali metal cation.

6. The plugging composition according to claim 4, characterized in that: The nonionic surfactant is selected from C8-C20 saturated or unsaturated alkyl alcohol polyoxyethylene ether, C8-C20 saturated or unsaturated alkylphenol polyoxyethylene ether, Span series nonionic surfactant or Tween series nonionic surfactant.

7. The plugging composition according to claim 4, characterized in that: The emulsifier further comprises a reaction product; the reaction product is prepared by a ring-opening reaction between an epoxy resin and a polyethylene glycol derivative through an amino group and an epoxy group.

8. The plugging composition according to claim 7, characterized in that: The polyethylene glycol derivative is shown in formula (I): Or, as shown in formula (II): In the formula, 15≤n≤100, and n is an integer.

9. The plugging composition according to claim 7, characterized in that: The molar ratio of the epoxy resin to the polyethylene glycol derivative is (1.5-3):

1.

10. The plugging composition according to claim 1, characterized in that: The curing agent is selected from one or more of diethylaminopropylamine, diaminodiphenyl sulfone, diaminodiphenylmethane, 4,4'-methylenebis(2-chloroaniline), 4-chloro-o-phenylenediamine, dicyandiamide, melamine, 4-trifluoromethyl-o-phenylenediamine or m-phenylenediamine.

11. The plugging composition according to claim 1, characterized in that: The curing time regulator is selected from one or more of triethanolamine, N,N-dimethylaniline, benzyldimethylamine, o-hydroxybenzyldimethylamine, tris(dimethylaminomethyl)phenol, triethylamine, 2,4,6-tris(dimethylaminomethyl)phenol or 3,3-(4-methyl-1,3-phenylene)bis(1,1-dimethylurea).

12. The plugging composition according to claim 1, characterized in that: The flow pattern regulator is selected from one or more of bentonite slurry containing 8wt% to 18wt% bentonite, sodium carboxymethyl cellulose solution containing 0.5wt% to 2wt% sodium cellulose, or 0.5wt% to 3wt% water-soluble polymers polymerized from monomers containing carbon-carbon double bonds.

13. The plugging composition according to claim 12, characterized in that: The monomer containing a carbon-carbon double bond is selected from one or more of acrylic acid, acrylonitrile, acrylamide, methacrylic acid, methacrylamide or 2-acrylamido-2-methylpropanesulfonic acid.

14. The plugging composition according to claim 1, characterized in that: The proppant is selected from one or more of calcium carbonate, barite, sand, iron ore powder, calcium sulfate, nutshell, sand, tree fiber or galena.

15. A method for preparing the plugging composition according to any one of claims 1 to 14, characterized in that: The method comprises mixing the constituent raw materials.

16. The method for preparing the plugging composition according to claim 15, characterized in that: The preparation method of the epoxy resin emulsion comprises the following steps: S1. Weigh epoxy resin and emulsifier according to mass percentage, heat and mix to obtain a homogeneous mixture; S2. Under stirring conditions, water is added to the homogeneous mixture prepared in S1 to obtain an epoxy resin emulsion.

17. The method for preparing the plugging composition according to claim 16, characterized in that: In S1, the heating temperature is 50-90°C.

18. The method for preparing the plugging composition according to claim 16, characterized in that: In S2, the stirring rate is 3000-20000 r / min, and the stirring time is 10-60 min.

19. A plugging agent for water-based drilling fluid, characterized in that: The plugging agent for water-based drilling fluid comprises the plugging composition according to any one of claims 1 to 14.

20. A drilling process, characterized in that: The process uses the plugging composition as described in any one of claims 1 to 18; or the plugging agent for water-based drilling fluid as described in claim 19.

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