Reservoir protection temporary plugging agent and preparation method and application thereof

Abstract

The invention provides a reservoir protection temporary plugging agent and a preparation method and application thereof, and belongs to the technical field of oil field drilling and completion drilling fluid treatment agents, the reservoir protection temporary plugging agent is prepared from the following raw materials by mass: 30-50 parts of an oil soluble material; 1-3 parts of a cationic surface active agent; 0.3 to 0.5 part of a viscosity modifier; 20 to 30 parts of water; wherein the cationic surface active agent is prepared by the following method: heating fatty acid and polyethylene polyamine for reaction to obtain an intermediate product, cooling the intermediate product, and adding a methylation reagent for quaternization reaction to obtain the cationic surface active agent. The oil-soluble material is emulsified and modified by adopting the specific novel cationic surface active agent, and the obtained temporary plugging agent has the characteristics of being positively charged, deformable, oil-soluble, free of fluorescence, environment-friendly and the like, and can be suitable for reservoirs with different porosity and permeability conditions under various wells.

Description

Technical Field

[0001] The invention relates to the technical field of oilfield drilling and completion drilling fluid treating agents, and in particular to a reservoir protection temporary plugging agent and a preparation method and application thereof. Background Art

[0002] Reservoir protection temporary plugging agent is a treatment agent used for temporary plugging during drilling and completion. It can form a temporary plugging zone near the well wall to block the formation channel to prevent leakage. After the operation, the temporary plugging zone is restored through unblocking measures to restore the formation channel, thereby resuming production of the oil well.

[0003] The most widely used temporary plugging agent on site is ultrafine calcium carbonate of different mesh sizes. This material is inexpensive and has good compatibility with drilling fluids. However, the particle size needs to be strictly matched with the reservoir pore throat size to achieve a good plugging effect. In addition, after completion of the well, perforation is required to remove the temporary plugging agent and acidizing operation is carried out at the same time to re-establish a good oil and gas flow channel; oil-soluble resin has a high oil solubility and is easy to unblock and drain, but the commonly used oil-soluble temporary plugging materials have a low softening point and a small application range due to temperature restrictions. The softening point of petroleum resin is generally around 120°C, and the initial softening deformation temperature is even lower, between 100°C and 110°C. The effective application temperature of the temporary plugging agent is generally below 115°C; although asphalt has good deformation ability and does not need to be strictly matched with the reservoir pore throat size, it has a high fluorescence level and cannot be used in exploration wells and evaluation wells. At the same time, the oil film strength after deformation is low, which cannot meet the needs of temporary plugging in deep reservoirs. Summary of the invention

[0004] The present invention selects deformable oil-soluble materials as basic raw materials, and adopts specific cationic surfactants to emulsify and modify the oil-soluble materials. The obtained temporary plugging agent has the characteristics of being positively charged, deformable, oil-soluble, non-fluorescent and environmentally friendly, and can be applied to reservoirs with different porosity and permeability conditions in various well types.

[0005] One of the purposes of the present invention is to provide a reservoir protection temporary plugging agent.

[0006] The second purpose of the present invention is to provide a method for preparing the reservoir protection temporary plugging agent.

[0007] The third object of the present invention is to provide an application of the reservoir protection temporary plugging agent in oil well reservoir protection.

[0008] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0009] In a first aspect, the present invention provides a reservoir protection temporary plugging agent, which is prepared from raw materials including the following parts by weight:

[0010]

[0011] Wherein, the cationic surfactant is prepared by the following method:

[0012] The fatty acid and polyethylene polyamine are heated to react to obtain an intermediate product, and the intermediate product is cooled and then added with a methylating agent to carry out a quaternization reaction to obtain a cationic surfactant.

[0013] The following is a detailed description:

[0014] There is no particular limitation on the oil-soluble material, and it may be any oil-soluble temporary plugging agent material known in the art, including but not limited to rosin resin, terpene resin, C5 petroleum resin or phenolic resin.

[0015] The amount of the oil-soluble material added is 30-50 parts, for example, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, but not limited thereto.

[0016] The cationic surfactant of the present invention is obtained by heating fatty acid and polyethylene polyamine and then quaternizing them.

[0017] The fatty acid may be one or more selected from palmitic acid, arachidonic acid and lauric acid.

[0018] The polyethylene polyamine may be one or more selected from tetraethylene pentamine, pentaethylene hexamine and branched polyethylene imine.

[0019] In some embodiments, the molar ratio of fatty acid to polyethylene polyamine is 1:2.

[0020] In some embodiments, the heating reaction temperature is 130-150°C, preferably 150°C; and / or

[0021] The heating reaction time is 2-4h.

[0022] The methylating agent may be one or more selected from dimethyl carbonate, dimethyl sulfate and methyl iodide.

[0023] In some embodiments, the ratio of the total mass of fatty acid and polyethylene polyamine to the mass of methylating agent is 1:1-5:1, preferably 2:1.

[0024] In some embodiments, the temperature is reduced to 90-110°C; and / or

[0025] The quaternization reaction time is 3-5h.

[0026] In a specific embodiment, the cationic surfactant is prepared by the following method:

[0027] Weigh fatty acids and polyethylene polyamines according to a molar ratio of 1:2 and put them into a reactor, heat to 150°C, stir for 2-4 hours to mix evenly, stop heating and naturally cool the intermediate product to about 100°C for constant temperature, add methylating agent dropwise for quaternization, m(fatty acid+polyethylene polyamine):m(methylating agent)=2:1, react for 3-5 hours to obtain a cationic surfactant.

[0028] The amount of the cationic surfactant added is 1-3 parts, for example, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, but not limited thereto.

[0029] The viscosity modifier is not particularly limited and may be any viscosity modifier known in the art, including but not limited to xanthan gum, hydroxyethyl cellulose or carboxymethyl cellulose.

[0030] The viscosity modifier is added in an amount of 0.3-0.5 parts, for example, 0.3 parts, 0.35 parts, 0.4 parts, 0.45 parts, 0.5 parts, but is not limited thereto.

[0031] The water may be conventional water, deionized water or ultrapure water, etc., and deionized water is preferred.

[0032] The amount of water added is 20-30 parts, for example, 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, 30 parts, but not limited thereto.

[0033] The invention can actively adsorb formation clay minerals to form an electrostatic adsorption layer by adding a specific cationic surfactant, and can significantly improve the performance of the temporary plugging agent.

[0034] In a second aspect, the present invention provides a method for preparing the reservoir protection temporary plugging agent, comprising the following steps:

[0035] The oil-soluble material, water and cationic surfactant are added to the colloid mill in proportion, heated to 130-150° C., a viscosity regulator is added, stirred for 2-4 hours, cooled and dried to obtain a reservoir protection temporary plugging agent.

[0036] The descriptions about the oil-soluble material, water, cationic surfactant and viscosity modifier are the same as those in the first aspect and will not be repeated here.

[0037] In a third aspect, the present invention provides a use of the reservoir protection temporary plugging agent in oil well reservoir protection.

[0038] Beneficial Effects

[0039] The reservoir protection temporary plugging agent of the present invention has a small dependence on the formation pore size and its distribution data. Even when the pore size distribution of the oil and gas layer is not clearly predicted or the reservoir pore size distribution range is relatively wide, it is not necessary to consider strict matching with the pore throats to achieve a good temporary plugging effect and realize self-matching. The temporary plugging particles have positive charges on their surfaces, and due to the attraction between the positive and negative charges and the negatively charged formation clay minerals, an electrostatic adsorption retention layer is formed on the pore throat end face, which can greatly improve the plugging efficiency of the pores. The temporary plugging material is oil-soluble, and the formed temporary plugging ring can be removed by perforating or crude oil production without the need for post-processing. It is simpler and more convenient to use while achieving a better effect of protecting the oil and gas layers.

[0040] The present invention has been described in detail above, but the above embodiments are only illustrative in nature and are not intended to limit the present invention. In addition, this article is not limited by any theory described in the above prior art or invention content or the following examples. DETAILED DESCRIPTION

[0041] The present invention is further described below in conjunction with examples. It should be noted that the following examples are provided for illustrative purposes only and do not constitute a limitation on the scope of protection claimed for the present invention.

[0042] Unless otherwise specified, the raw materials, reagents, methods, etc. used in the examples are conventional raw materials, reagents, methods in the art.

[0043] Palmitic acid, arachidonic acid, and lauric acid were purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0044] Tetraethylenepentamine and pentaethylenehexamine were purchased from Nanjing Mangyuanzhixu Chemical Co., Ltd.;

[0045] Branched polyethyleneimine (molecular weight 25000) was purchased from Gongbik New Materials Technology (Shanghai);

[0046] Dimethyl carbonate, dimethyl sulfate, and methyl iodide were purchased from Guangdong Wengjiang Chemical Reagent Co., Ltd.;

[0047] The reactor adopts the NS series magnetic stirring reactor produced by Anhui Kemi Instrument Co., Ltd.

[0048] The colloid mill used was the JM-L vertical colloid mill produced by Shanghai Aisijie Pump Manufacturing Co., Ltd.

[0049] Example 1

[0050] Weigh palmitic acid and tetraethylenepentamine in a molar ratio of 1:2 into a reactor, heat to 150°C, stir for 2 hours to mix evenly, stop heating and naturally cool the intermediate product to about 100°C for constant temperature, add dimethyl carbonate dropwise for quaternization, m(palmitic acid+tetraethylenepentamine):m(dimethyl carbonate)=2:1, react for 3 hours to obtain a cationic surfactant;

[0051] Rosin resin, distilled water and cationic surfactant are added into the colloid mill in a mass ratio of 3:2:0.1. After heating to 130°C, xanthan gum is added. The mass ratio of xanthan gum to cationic surfactant is 0.03:0.1. After stirring for 2 hours, the temporary plugging agent for reservoir protection is obtained by cooling and drying.

[0052] Example 2

[0053] Arachidonic acid and pentaethylenehexamine were weighed in a molar ratio of 1:2 and put into a reaction kettle, heated to 150°C, stirred for 3 hours to mix evenly, and the heating was stopped to allow the intermediate product to naturally cool to about 100°C for constant temperature, and dimethyl sulfate was added dropwise in batches for quaternization, m(arachidonic acid+pentaethylenehexamine):m(dimethyl sulfate)=2:1, and the cationic surfactant was obtained after reacting for 4 hours;

[0054] Terpene resin, distilled water and cationic surfactant are added into the colloid mill in a mass ratio of 3:2:0.1. After heating to 140°C, hydroxyethyl cellulose is added. The mass ratio of hydroxyethyl cellulose to cationic surfactant is 0.03:0.1. After stirring for 3 hours, the temporary plugging agent for reservoir protection is obtained by cooling and drying.

[0055] Example 3

[0056] Lauric acid and branched polyethyleneimine were weighed in a molar ratio of 1:2 and put into a reaction kettle, heated to 150°C, stirred for 4 hours to mix evenly, and the heating was stopped to allow the intermediate product to naturally cool to about 100°C for constant temperature, and iodomethane was added dropwise in batches for quaternization, m(lauric acid+polyethyleneimine):m(iodomethane)=2:1, and the cationic surfactant was obtained after reacting for 4 hours;

[0057] C5 petroleum resin, distilled water and cationic surfactant are added into the colloid mill in a mass ratio of 3:2:0.1. After heating to 150°C, carboxymethyl cellulose is added in a mass ratio of carboxymethyl cellulose to cationic surfactant of 0.03:0.1. After stirring for 4 hours, the mixture is cooled and dried to obtain a reservoir protection temporary plugging agent.

[0058] Example 4

[0059] Weigh palmitic acid and branched polyethyleneimine in a molar ratio of 1:2 and put them into a reactor, heat to 150°C, stir for 4 hours to mix evenly, stop heating and naturally cool the intermediate product to about 100°C for constant temperature, add iodomethane dropwise for quaternization, m(palmitic acid+polyethyleneimine):m(iodomethane)=2:1, react for 4 hours to obtain a cationic surfactant;

[0060] Phenolic resin, distilled water and cationic surfactant are added into the colloid mill in a mass ratio of 3:2:0.1. After heating to 140°C, hydroxyethyl cellulose is added. The mass ratio of hydroxyethyl cellulose to cationic surfactant is 0.03:0.1. After stirring for 3 hours, the temporary plugging agent for reservoir protection is obtained by cooling and drying.

[0061] Example 5

[0062] Arachidonic acid and tetraethylenepentamine were weighed in a molar ratio of 1:2 and put into a reaction kettle, heated to 150°C, stirred for 2 hours to mix evenly, and the heating was stopped to naturally cool the intermediate product to about 100°C for constant temperature, and dimethyl carbonate was added dropwise in batches for quaternization, m(arachidonic acid+tetraethylenepentamine):m(dimethyl carbonate)=2:1, and the cationic surfactant was obtained after reacting for 3 hours;

[0063] Rosin resin, distilled water and cationic surfactant are added into the colloid mill in a mass ratio of 3:2:0.1. After heating to 150°C, carboxymethyl cellulose is added in a mass ratio of 0.03:0.1 to the cationic surfactant. After stirring for 4 hours, the mixture is cooled and dried to obtain a reservoir protection temporary plugging agent.

[0064] Example 6

[0065] Lauric acid and pentaethylenehexamine were weighed in a molar ratio of 1:2 and put into a reaction kettle, heated to 150°C, stirred for 3 hours to mix evenly, and the heating was stopped to naturally cool the intermediate product to about 100°C for constant temperature, and dimethyl sulfate was added dropwise for quaternization, m(lauric acid+pentaethylenehexamine):m(dimethyl sulfate)=2:1, and the cationic surfactant was obtained after reacting for 5 hours;

[0066] C5 petroleum resin, distilled water and cationic surfactant are added into the colloid mill in a mass ratio of 3:2:0.1. After heating to 130°C, xanthan gum is added. The mass ratio of xanthan gum to cationic surfactant is 0.03:0.1. After stirring for 2 hours, the temporary plugging agent for reservoir protection is obtained by cooling and drying.

[0067] Comparative Example 1

[0068] The difference from Example 1 is that the cationic surfactant is replaced by hexadecyltrimethylammonium chloride.

[0069] Comparative Example 2

[0070] The difference from Example 1 is that the cationic surfactant is replaced by dioctadecyl dimethyl ammonium chloride (D1821).

[0071] Test Example 1

[0072] The performance of temporary plugging agent is evaluated as follows:

[0073] 1. Dispersibility in water:

[0074] (1) Preparation of base slurry: prepare a slurry by mixing the temporary plugging agent for reservoir protection to be tested according to the following weight ratio: 20-30 parts of water, 50-80 parts of temporary plugging agent for reservoir protection to be tested, and 0.2-1 part of dispersant (sodium hexametaphosphate);

[0075] (2) Measurement: Weigh m1 g of the reservoir protection temporary plugging agent to be tested, filter it through a 325-mesh filter, and use the water flow pressure to flush it during the process. Then, dry the residue in an oven at 105°C for 60 min, and weigh m2 g of the residue;

[0076] (3) Calculation: The dispersibility code in water is γ. The smaller the γ value, the better the dispersibility of the substance in water. γ = m2 / m1×100%.

[0077] 2. Colloid stability:

[0078] Use a zeta potential meter to measure the zeta potential reading of the sample. The larger the reading, the more stable it is.

[0079] 3. Electromotive potential:

[0080] Using a micro-electrophoresis instrument to measure the electrophoresis velocity:

[0081] (1) Prepare the sample into a very dilute suspension (0.02%);

[0082] (2) Clean the electrophoresis tube with washing solution, and then fix the electrophoresis tube on the microscope stage. Connect the electrophoresis outlet to the negative pressure bottle with a rubber tube. Inject distilled water into the inlet funnel of the electrophoresis tube, turn the piston of the electrophoresis tube outlet, and use the suction of the negative pressure bottle to suck the distilled water into the negative pressure bottle. Repeat this cleaning process until the electrophoresis tube is completely clean.

[0083] (3) Positioning: Perform the planar positioning of the electrophoresis tube according to the above method. After the planar positioning, carefully fix it with the stage clamp. Then perform vertical positioning so that the objective lens focuses on the non-electroosmotic area;

[0084] (4) Sample loading: Shake the colloidal suspension to be tested (generally at a concentration of 0.2 ppm) and inject it into the inlet funnel of the electrophoresis tube. Turn the outlet piston to suck the colloidal suspension into the electrophoresis tube. After washing the electrophoresis tube with a small amount of colloidal suspension, close the piston.

[0085] (5) Voltage adjustment: Connect the DC power supply and use the potentiometer to adjust the voltage to the required DC voltage (e.g. 80V).

[0086] (6) Measurement: Close the reversing switch and observe the direction of movement of the colloid particles near the center line of the microscope field of view to determine the charge sign of the colloid particles (moving toward the positive electrode is negatively charged, and moving in the opposite direction is positively charged). At the same time, a stopwatch can be used to measure the time (seconds) required for a certain colloid particle to pass a fixed distance (e.g., 180 microns). Turn the reversing switch to measure the time required for the colloid particle to pass the above distance in the opposite direction. Repeat the measurement of the electrophoretic velocity of 10-30 particles.

[0087] (7) Temperature measurement: At the same time, a small thermometer can be used to measure the temperature of each colloidal suspension in the electrophoresis tube funnel;

[0088] (8) Calculation:

[0089]

[0090] Where:

[0091] ζ is the electromotive potential, in V;

[0092] K generally depends on the shape of the particles. The K of spherical particles is 6, and the K of flaky particles is 4.

[0093] ε is the dielectric constant of the medium, which is 80 for water;

[0094] η is the viscosity of the medium, in poise;

[0095] u is the electrophoresis velocity, cm / s;

[0096] 9×10 4 is the factor used to convert electrostatic units into real units.

[0097] 4. Oil solubility:

[0098] (1) The quantitative filter paper was dried in an oven at (105±3)℃ for 2 h, taken out and placed in a desiccator to cool to room temperature, and then weighed;

[0099] (2) Weigh 5 g of the sample (accurate to 0.0001 g; the colloidal sample should be weighed after drying in an oven at 105±3℃ for 8 h), add it to 100 mL of decolorized and decolloided kerosene, heat to 70±5℃, stir to dissolve it, then place the dried quantitative filter paper in an insulating funnel and filter at 70±5℃. After filtration, place the filter paper and the residue in an oven at 105±3℃ for 5 h, take it out and place it in a desiccator to cool to room temperature, and weigh it.

[0100] (3) Calculation:

[0101]

[0102] Where:

[0103] W is oil solubility, %;

[0104] m is the mass of the sample, g;

[0105] m1 is the mass of filter paper and residue after drying, g;

[0106] m2 is the mass of filter paper and residue after drying in the blank test, g.

[0107] The results are shown in Table 1.

[0108] Table 1 Evaluation table of dispersibility, stability, positive charge and oil solubility

[0109]

[0110] As can be seen from Table 1, the reservoir protection temporary plugging agent of the present invention has good dispersibility and alternating stability in water, and can therefore be used in a water-based drilling fluid system; it has a certain positive charge and can be adsorbed with formation rock particles through electrostatic action to enhance the temporary plugging effect; the oil solubility at room temperature is determined by the decolorized and decolloided kerosene dissolution and filtration method, and the experimental results show that the new shielding temporary plugging agent has a high oil solubility.

[0111] Test Example 2

[0112] Different temporary plugging agents were added to 3% bentonite slurry, and the filtration loss test was carried out on a φ2.5cm×4cm core using a QY-C12 high-temperature and high-pressure core displacement device. The test conditions were: temperature 80℃, pressure difference 3.5MPa, filtration time 60min, and temporary plugging agent addition 3%.

[0113] Table 2 Plugging performance test of reservoir protection temporary plugging agent

[0114]

[0115]

[0116] As can be seen from Table 2, when bentonite slurry without temporary plugging agent is used, the water loss on the core is large, indicating that the quality of the filter cake formed is poor. When the temporary plugging agent is added, the filtration loss on the core decreases significantly, indicating that the new temporary plugging agent has a broad-spectrum plugging effect and is suitable for use in oil layers with strong heterogeneity.

[0117] Test Example 3

[0118] Taking Example 1 as an example, a reservoir protection temporary plugging agent is added to 3% bentonite slurry as a temporary plugging system to test the plugging rate of the core and the permeability recovery rate after slicing. The experimental procedure is as follows:

[0119] 1) Prepare 3% bentonite slurry as base slurry;

[0120] 2) Preparation of temporary plugging system: base slurry + 3% of Example 1;

[0121] 3) Evacuation and saturation of the core;

[0122] 4) Core forward water permeability K L Determination of; According to the empirical formula is the porosity, and the average pore throat diameter d of the core is calculated 孔 ;

[0123] 5) Determination of reverse oil phase permeability Ko of core;

[0124] 6) Perform positive temporary plugging of the core at 70°C, 3.5MPa, and 1.5h;

[0125] 7) Take out the core from the temporary plugging device, remove the filter cake, and measure the forward water permeability K of the core after temporary plugging. L ′;

[0126] 8) Calculate the plugging rate D of the core R ;

[0127] 9) Cut off a certain length of the temporary plugging end;

[0128] 10) Determine the reverse oil phase permeability Ko′ after core slicing;

[0129] 11) Calculate the core permeability recovery value R′ after slicing.

[0130] Table 3 Core plugging rate and permeability recovery value test

[0131]

[0132] It can be seen from Table 3 that within the pore size range of 2.56 to 34.65 μm, the plugging rates of the oil-soluble shielding temporary plugging agent for cores with different pore throat diameters are all greater than 93.5%, and the permeability recovery values ​​are all above 94.4%, further indicating that the oil-soluble shielding temporary plugging agent has good broad-spectrum and temporary plugging performance.

[0133] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments may be modified, or some or all of the technical features thereof may be replaced by equivalents, without departing from the spirit and essence of the claims of the present invention; and these modifications or replacements are still within the scope defined by the claims of the present invention.

Claims

1. A reservoir protection temporary plugging agent, characterized in that: It is prepared from the following raw materials in parts by weight: Wherein, the cationic surfactant is prepared by the following method: The fatty acid and polyethylene polyamine are heated to react to obtain an intermediate product, and the intermediate product is cooled and then added with a methylating agent to carry out a quaternization reaction to obtain a cationic surfactant.

2. The reservoir protection temporary plugging agent according to claim 1, characterized in that: It is prepared from the following raw materials in parts by weight:

3. The reservoir protection temporary plugging agent according to claim 1 or 2, characterized in that: The oil-soluble material is one or more selected from rosin resin, terpene resin, C5 petroleum resin and phenolic resin.

4. The reservoir protection temporary plugging agent according to claim 1 or 2, characterized in that: The fatty acid is one or more selected from palmitic acid, arachidonic acid and lauric acid; and / or The polyethylene polyamine is one or more selected from tetraethylene pentamine, pentaethylene hexamine and branched polyethylene imine; Preferably, the molar ratio of fatty acid to polyethylene polyamine is 1:

2.

5. The reservoir protection temporary plugging agent according to claim 1 or 2, characterized in that: The heating reaction temperature is 130-150°C, preferably 150°C; and / or The heating reaction time is 2-4h.

6. The reservoir protection temporary plugging agent according to claim 1 or 2, characterized in that: The methylating agent is one or more selected from dimethyl carbonate, dimethyl sulfate and methyl iodide; Preferably, the ratio of the total mass of the fatty acid and the polyethylene polyamine to the mass of the methylating agent is 1:1-5:1, preferably 2:

1.

7. The reservoir protection temporary plugging agent according to claim 1 or 2, characterized in that: Cool down to 90-110°C; and / or The quaternization reaction time is 3-5h.

8. The reservoir protection temporary plugging agent according to claim 1 or 2, characterized in that: The viscosity modifier is one or more selected from xanthan gum, hydroxyethyl cellulose and carboxymethyl cellulose.

9. A method for preparing a reservoir protection temporary plugging agent according to any one of claims 1 to 8, characterized in that: The following steps are involved: The oil-soluble material, water and cationic surfactant are added to the colloid mill in proportion, heated to 130-150° C., a viscosity regulator is added, stirred for 2-4 hours, cooled and dried to obtain a reservoir protection temporary plugging agent.

10. Use of the reservoir protection temporary plugging agent according to any one of claims 1 to 8 in oil well reservoir protection.

Images