High-compression-resistance epoxy formula system as well as preparation method and application thereof

Abstract

The invention discloses a high-compression-resistance epoxy formula system. The high-compression-resistance epoxy formula system is prepared by mixing epoxy resin, a curing agent, a nano reinforced filler g-C3N4-NS, a foaming agent, a diluent and a solvent according to a mass ratio. The invention further discloses a preparation method of the high-compression-resistance epoxy formula system. The preparation method comprises the following steps: preparing the nano reinforced filler g-C3N4-NS; respectively weighing the epoxy resin, the curing agent, the nano reinforced filler g-C3N4-NS, the foaming agent, the diluent and the solvent according to the mass ratio; and dissolving and uniformly stirring to obtain the product. The high-compression-resistance epoxy resin system is high in consolidation strength, good in permeability and good in compatibility with saline water and 0 # diesel oil, the problem of sand production of oil and gas fields can be effectively solved, and safe development of oil and gas resources is guaranteed.

Description

Technical Field

[0001] The present invention belongs to the technical field of oilfield exploitation, relates to a high-compressive epoxy formulation system, also relates to a preparation method of the above high-compressive epoxy formulation system, and also relates to an application of the above high-compressive epoxy formulation system. Background Art

[0002] In the exploitation mode of loose formations, sand grains migrate into the wellbore along with production fluids such as oil, gas, and water, and this phenomenon is called sand production. Sand production in oil and gas wells will bury the oil reservoir sand and block the tubing with sand, accelerate the abrasion of downhole equipment, tools, etc. When it is serious, it will cause the bottom hole to collapse, damage the casing, stop the production of the oil well, affect the production, and greatly increase the downhole operation volume and oil production cost. Sand production has become a common problem in sandstone reservoirs and is also a major challenge in the petroleum industry.

[0003] In order to reduce the risk of sand production in oil wells, sand control technologies need to be adopted to ensure the normal production of oil wells. Currently, the commonly used sand control methods in oilfields can be divided into two categories: mechanical methods and chemical methods. In mechanical methods, devices such as slotted liners, gravel packs, or wire-wrapped screens are used to prevent sand grains from being transported from the formation to the wellbore. Since the special devices used in this method will be damaged over time, need to be repaired and are not durable, as the water cut in the oil well continuously increases, the formation sand production becomes more and more serious, and the migration of fine silt and clay in the oil reservoir makes the near-wellbore area and the sand control layer gradually blocked, and simple mechanical sand control cannot meet the requirements.

[0004] In chemical methods, fluids are injected into the formation to bond the loose sand grains together, and finally a stable matrix is formed in the nearby wellbore. The main purpose of this method is to increase the compressive strength of sand grains through the adhesion force of the fluid and prevent the absolute permeability from decreasing due to the injection of chemical fluids. A major challenge in current chemical sand consolidation technologies is usually an inverse relationship between strength and permeability. When using polymer resins, the permeability usually decreases by 30 - 50%. Achieving an appropriate balance between compressive strength and permeability through optimizing materials and additives has always been the focus of researchers.

[0005] In existing chemical sand consolidation, epoxy resins are widely used due to advantages such as low cost, high adhesion, and low curing rate. However, the epoxy resin system for sand consolidation has disadvantages such as high viscosity and reduced initial permeability. Solvents need to be used or the resin concentration needs to be reduced to maintain low viscosity. However, using solvents or reducing the resin concentration often leads to a significant reduction in compressive strength. To ensure strength, nanoparticles such as silica, alumina, or quartz sand are often used in epoxy resins to increase the compressive strength. However, the surface of this type of nanoparticle does not have any active functional groups to form covalent bonds with the polymer resin matrix, resulting in low strength and durability. If the dispersion is uneven, it will even reduce the permeability, and it is difficult to simultaneously meet the strength and permeability of the sand consolidant. Summary of the Invention

[0006] The object of the present invention is to provide a high compressive strength epoxy formulation system, which solves the problems of low compressive strength and poor permeability existing in the existing sand control technology.

[0007] Another object of the present invention is to provide a preparation method of the above high compressive strength epoxy formulation system.

[0008] Another object of the present invention is to provide the application of the high compressive strength epoxy formulation system.

[0009] The technical solution adopted by the present invention is a high compressive strength epoxy formulation system, which is prepared by mixing epoxy resin, curing agent, nano-enhanced filler g-C3N4-NS, foaming agent, diluent and solvent according to a mass ratio.

[0010] The characteristics of the present invention also lie in that

[0011] The mass ratio of epoxy resin, curing agent, nano-enhanced filler g-C3N4-NS, foaming agent, diluent and solvent is 100:5-15:0.1-3:0.5-5:5-15:30-150.

[0012] Another technical solution adopted by the present invention is a preparation method of the high compressive strength epoxy formulation system, which is specifically implemented according to the following steps:

[0013] Step 1, prepare the nano-enhanced filler g-C3N4-NS;

[0014] Step 2, weigh epoxy resin, curing agent, nano-enhanced filler g-C3N4-NS, foaming agent, diluent and solvent respectively according to the mass ratio;

[0015] Step 3, dissolve the epoxy resin with the solvent to obtain an epoxy resin solution; add the nano-enhanced filler g-C3N4-NS to the prepared epoxy resin solution and stir evenly to obtain a mixed solution;

[0016] Step 4, sequentially add the foaming agent and diluent to the mixed solution prepared in Step 3, and then dropwise add the curing agent into the reaction solution and continue to stir for 15-20 min to obtain the product.

[0017] The specific process of Step 1 is as follows:

[0018] Step 1.1, weigh 10 g of white melamine powder and heat it, heat it to 550 °C within 75 min, keep it for 4 h, and cool it at a rate of 4 °C / min to obtain g-C3N4-B;

[0019] Step 1.2, weigh 0.5 g of g-C3N4-B prepared in Step 1 and heat it, heat it to 500 °C within 100 min, and keep it for 4 h to obtain g-C3N4-NS.

[0020] The molecular structural formula of the nano-enhanced filler g-C3N4-NS is as follows:

[0021]

[0022] The epoxy value of the epoxy resin is 0.20 - 0.55 eq / mg. A polyamine curing agent is used as the curing agent, a magnesium-containing compound is used as the foaming agent, and tetrahydrofurfuryl alcohol is used as the diluent, and xylene is used as the solvent.

[0023] The epoxy resin used is a bisphenol A epoxy resin with an epoxy value of 0.44 eq / mg and a grade of E-44.

[0024] The polyamine curing agent is any one of triethylenetetramine, cyclohexylamine, and diethylenetriamine.

[0025] The magnesium-containing compound is any one of magnesium carbonate, magnesium sulfate, and magnesium oxysulfate.

[0026] Another technical solution adopted by the present invention is that the prepared high-compressive epoxy system is applied to the formation condition where the sand production particle size is 90 - 900 μm.

[0027] The beneficial effects of the present invention are as follows: The consolidated cores prepared with the respective proportioning amounts of the high-compressive epoxy formulation system of the present invention have the characteristics of high compressive strength, good permeability, good compatibility with brine and 0# diesel, etc. It is applicable to both oil wells and gas wells, and has excellent resistance to media. The high-compressive epoxy system product prepared by the present invention meets the processing technology requirements and is environmentally friendly and pollution-free. Specific Embodiments

[0028] The present invention will be described in detail below in conjunction with specific embodiments.

[0029] The high-compressive epoxy formulation system of the present invention is prepared by mixing epoxy resin, curing agent, nano-enhanced filler g-C3N4-NS, foaming agent, diluent, and solvent according to a mass ratio; the mass ratio of epoxy resin, curing agent, nano-enhanced filler g-C3N4-NS, foaming agent, diluent, and solvent is 100:5 - 15:0.1 - 3:0.5 - 5:5 - 15:30 - 150.

[0030] The epoxy value of the epoxy resin is 0.20 - 0.55 eq / mg. A polyamine curing agent is used as the curing agent, a magnesium-containing compound is used as the foaming agent, and the foaming agent and the nano-enhanced filler cooperate to increase the permeability; tetrahydrofurfuryl alcohol is used as the diluent, and xylene is used as the solvent.

[0031] The nano-enhanced filler g-C3N4-NS is a carbon nitride nanosheet (g-C3N4-NS) with a planar two-dimensional sheet structure similar to graphene, which is prepared from melamine powder by a thermal polymerization method and plays a role in increasing the compressive strength.

[0032] Bisphenol A epoxy resin of grade E-44 with an epoxy value of 0.44 eq / mg.

[0033] The polyamine curing agent is any one of triethylenetetramine, cyclohexylamine, and diethylenetriamine.

[0034] The magnesium-containing compound is any one of magnesium carbonate, magnesium sulfate, and magnesium oxysulfate.

[0035] The preparation method of the high-compressive epoxy system of the present invention is specifically implemented according to the following steps:

[0036] Step 1, prepare the nano-enhanced filler g-C3N4-NS;

[0037] Step 1.1, weigh 10 g of white melamine powder and heat it. Heat it to 550 °C within 75 min, keep it for 4 h, and cool it at a rate of 4 °C / min to obtain g-C3N4-B;

[0038] Step 1.2, weigh 0.5 g of g-C3N4-B prepared in Step 1 and heat it. Heat it to 500 °C within 100 min and keep it for 4 h to obtain g-C3N4-NS. The molecular structural formula is:

[0039]

[0040] Step 2, weigh epoxy resin, curing agent, nano-enhanced filler g-C3N4-NS, foaming agent, diluent, and solvent respectively according to the mass ratio;

[0041] The mass ratio of epoxy resin, curing agent, nano-enhanced filler g-C3N4-NS, foaming agent, diluent, and solvent is 100:5-15:0.1-3:0.5-5:5-15:30-150.

[0042] Step 3, dissolve the epoxy resin with a solvent to obtain an epoxy resin solution; add the nano-enhanced filler g-C3N4-NS to the prepared epoxy resin solution and stir it evenly with a homogenizer to obtain a mixed solution;

[0043] Step 4, add the foaming agent and diluent to the mixed solution prepared in Step 3 in sequence and disperse them evenly by ultrasonic wave; then add the curing agent dropwise to the reaction solution under normal temperature stirring and continue stirring for 15-20 min to obtain the product.

[0044] The high-compressive epoxy system of the present invention is applied to the formation condition where the sand production particle size is 90 - 900 μm.

[0045] Example 1

[0046] The preparation method of the high-compressive epoxy system of the present invention is specifically implemented according to the following steps:

[0047] Step 1, prepare the nano-enhanced filler g-C3N4-NS;

[0048] Step 1.1, weigh 10 g of white melamine powder and heat it. Heat it to 550 °C within 75 min, hold for 4 h, and cool it at a rate of 4 °C / min to obtain g-C3N4-B;

[0049] Step 1.2, weigh 0.5 g of g-C3N4-B prepared in Step 1 and heat it. Heat it to 500 °C within 100 min and hold for 4 h to obtain it;

[0050] Step 2, respectively weigh epoxy resin, curing agent, nano-enhanced filler g-C3N4-NS, foaming agent, diluent, and solvent according to the mass ratio of 100:5:0.1:0.5:5:30; the epoxy value of the epoxy resin is 0.20 eq / mg, the curing agent uses triethylenetetramine, the foaming agent uses magnesium carbonate, the diluent uses tetrahydrofurfuryl alcohol, and the solvent uses xylene.

[0051] Step 3, dissolve the epoxy resin with xylene to obtain an epoxy resin solution; add the nano-enhanced filler g-C3N4-NS to the prepared epoxy resin solution and stir it evenly with a homogenizer to obtain a mixed solution;

[0052] Step 4, sequentially add magnesium carbonate and tetrahydrofurfuryl alcohol to the mixed solution prepared in Step 3, and disperse it evenly by ultrasonic wave; then dropwise add triethylenetetramine to the reaction solution under normal temperature stirring, and continue to stir for 15 min to obtain it.

[0053] Example 2

[0054] The preparation method of the high-compressive epoxy system of the present invention is specifically implemented according to the following steps:

[0055] Step 1, prepare the nano-enhanced filler g-C3N4-NS;

[0056] Step 1.1, weigh 10 g of white melamine powder and heat it. Heat it to 550 °C within 75 min, hold for 4 h, and cool it at a rate of 4 °C / min to obtain g-C3N4-B;

[0057] Step 1.2, weigh 0.5 g of g-C3N4-B prepared in Step 1 and heat it. Heat it to 500 °C within 100 min and hold for 4 h to obtain it;

[0058] Step 2: Weigh epoxy resin, curing agent, nano-enhanced filler g-C3N4-NS, foaming agent, diluent, and solvent according to a mass ratio of 100:10:1:1:10:60 respectively. The epoxy resin used is bisphenol A epoxy resin of grade E-44 with an epoxy value of 0.44 eq / mg. The curing agent used is cyclohexylamine, the foaming agent used is magnesium sulfate, the diluent used is tetrahydrofurfuryl alcohol, and the solvent used is xylene.

[0059] Step 3: Dissolve the epoxy resin in the solvent to obtain an epoxy resin solution. Add the nano-enhanced filler g-C3N4-NS to the prepared epoxy resin solution and stir evenly with a homogenizer to obtain a mixed solution.

[0060] Step 4: Add the foaming agent and diluent to the mixed solution prepared in Step 3 in sequence, and disperse evenly by ultrasonic treatment. Then, dropwise add cyclohexylamine to the reaction solution under normal temperature stirring, and continue stirring for 15 min to obtain the product.

[0061] Example 3

[0062] The preparation method of the high-compressive epoxy system of the present invention is specifically implemented according to the following steps:

[0063] Step 1: Prepare the nano-enhanced filler g-C3N4-NS.

[0064] Step 1.1: Weigh 10 g of white melamine powder and heat it. Heat it to 550 °C within 75 min, keep it for 4 h, and cool it at a rate of 4 °C / min to obtain g-C3N4-B.

[0065] Step 1.2: Weigh 0.5 g of g-C3N4-B prepared in Step 1 and heat it. Heat it to 500 °C within 100 min and keep it for 4 h to obtain the product.

[0066] Step 2: Weigh epoxy resin, curing agent, nano-enhanced filler g-C3N4-NS, foaming agent, diluent, and solvent according to a mass ratio of 100:10:0.6:3:10:100 respectively.

[0067] Step 3: Dissolve the epoxy resin in the solvent to obtain an epoxy resin solution. Add the nano-enhanced filler g-C3N4-NS to the prepared epoxy resin solution and stir evenly with a homogenizer to obtain a mixed solution. The epoxy value of the epoxy resin is 0.55 eq / mg, the curing agent used is diethylenetriamine, the foaming agent used is magnesium thiosulfate, the diluent used is tetrahydrofurfuryl alcohol, and the solvent used is xylene.

[0068] Step 4: Add magnesium thiosulfate and tetrahydrofurfuryl alcohol to the mixed solution prepared in Step 3 in sequence, and disperse evenly by ultrasonic treatment. Then, dropwise add diethylenetriamine to the reaction solution under normal temperature stirring, and continue stirring for 20 min to obtain the product.

[0069] Example 4

[0070] The preparation method of the high-compressive epoxy system of the present invention is specifically implemented according to the following steps:

[0071] Step 1, prepare the nano-enhanced filler g-C3N4-NS;

[0072] Step 1.1, weigh 10 g of white melamine powder and heat it. Heat it to 550 °C within 75 min, hold for 4 h, and cool at a rate of 4 °C / min to obtain g-C3N4-B;

[0073] Step 1.2, weigh 0.5 g of g-C3N4-B prepared in Step 1 and heat it. Heat it to 500 °C within 100 min and hold for 4 h to obtain it;

[0074] Step 2, weigh epoxy resin, curing agent, nano-enhanced filler g-C3N4-NS, foaming agent, diluent, and solvent according to a mass ratio of 100:15:3:5:15:150 respectively; the epoxy value of the epoxy resin is 0.55 eq / mg, the curing agent uses triethylenetetramine, the foaming agent uses magnesium carbonate, the diluent uses tetrahydrofurfuryl alcohol, and the solvent uses xylene.

[0075] Step 3, dissolve the epoxy resin with the solvent to obtain an epoxy resin solution; add the nano-enhanced filler g-C3N4-NS to the prepared epoxy resin solution and stir evenly with a homogenizer to obtain a mixed solution;

[0076] Step 4, sequentially add magnesium carbonate and tetrahydrofurfuryl alcohol to the mixed solution prepared in Step 3, and disperse evenly by ultrasonic wave; then dropwise add triethylenetetramine to the reaction solution under normal temperature stirring, and continue to stir for 15-20 min to obtain it.

[0077] Use the high-compressive epoxy systems prepared in the above 4 examples as epoxy resin sand consolidants. Mix the prepared epoxy resin sand consolidants with the cleaned quartz sand evenly with a stirrer, pour them into a mold, and cure at 100 °C for 12 hours to obtain consolidated core samples.

[0078] Use a mechanical testing machine with a maximum load of 50 KN to test the compressive strength of the consolidated core samples. The test shows that the compressive strength of the samples can reach 20.68 MPa. Use a HKY-6 type automatic permeability measuring instrument to measure the permeability of the consolidated core samples. The test shows that the permeability of the samples can reach 4 μm 2 . Place the consolidated cores in different medium environments respectively, and detect the medium resistance performance of the consolidated cores by measuring their compressive strength and permeability.

[0079] The selected medium environments are as follows: brine and 0# diesel oil. The consolidated cores are soaked in them at 25°C for evaluation. The medium resistance performance experiment shows that: the consolidated core samples of this epoxy system have good medium resistance performance. After being soaked in the brine medium, the compressive strength of the samples is about 20.75 MPa, and the permeability is about 4.02 μm 2 ; after being soaked in the 0# diesel oil medium, the compressive strength of the samples is about 20.55 MPa, and the permeability is about 3.92 μm 2 , and the consolidated core has good tolerance to both oil and water.

[0080] In the high compressive strength epoxy system prepared by the present invention, the nano-enhanced filler is carbon nitride nanosheets (g-C3N4-NS) with a planar two-dimensional sheet structure similar to graphene, which is prepared from melamine powder by a thermal polymerization method and plays a role in increasing the compressive strength.

Claims

1. A high compressive strength epoxy formulation system, characterized in that, It is prepared by mixing epoxy resin, curing agent, nano-enhanced filler g-C3N4-NS, foaming agent, diluent and solvent according to a mass ratio.

2. The high compressive strength epoxy formulation system according to claim 1, characterized in that, The mass ratio of the epoxy resin, curing agent, nano-enhanced filler g-C3N4-NS, foaming agent, diluent and solvent is 100:5-15:0.1-3:0.5-5:5-15:30-150.

3. A preparation method of the high compressive strength epoxy formulation system for preparing the high compressive strength epoxy formulation system according to claim 1, characterized in that, Specifically, it is implemented according to the following steps: Step 1, prepare the nano-enhanced filler g-C3N4-NS; Step 2, weigh epoxy resin, curing agent, nano-enhanced filler g-C3N4-NS, foaming agent, diluent and solvent respectively according to the mass ratio; Step 3, dissolve the epoxy resin with the solvent to obtain an epoxy resin solution; add the nano-enhanced filler g-C3N4-NS to the prepared epoxy resin solution and stir evenly to obtain a mixed solution; Step 4, sequentially add the foaming agent and diluent to the mixed solution prepared in Step 3, then add the curing agent dropwise to the reaction solution, and continue to stir for 15-20 min to obtain it.

4. The preparation method of the high compressive strength epoxy formulation system according to claim 3, characterized in that, The specific process of the said Step 1 is: Step 1.1, weigh 10 g of white melamine powder and heat it. Heat it to 550 °C within 75 min, keep it for 4 h, and cool it at a rate of 4 °C / min to obtain g-C3N4-B; Step 1.2, weigh 0.5 g of g-C3N4-B prepared in Step 1 and heat it. Heat it to 500 °C within 100 min and keep it for 4 h to obtain g-C3N4-NS.

5. The preparation method of the high compressive strength epoxy formulation system according to claim 4, characterized in that, The molecular structural formula of the said nano-enhanced filler g-C3N4-NS is:

6. The preparation method of the high compressive strength epoxy formulation system according to claim 3, characterized in that, The epoxy value of the said epoxy resin is 0.20-0.55 eq / mg, the curing agent uses a polyamine curing agent, the foaming agent uses a magnesium-containing compound; the diluent uses tetrahydrofurfuryl alcohol, and the solvent uses xylene.

7. The preparation method of the high compressive strength epoxy formulation system according to claim 6, characterized in that, The said epoxy resin uses bisphenol A epoxy resin with an epoxy value of 0.44 eq / mg and a grade of E-44.

8. The preparation method of the high compressive strength epoxy formulation system according to claim 6, characterized in that, The said polyamine curing agent uses any one of triethylenetetramine, cyclohexylamine, and diethylenetriamine.

9. The preparation method of the high compressive strength epoxy formulation system according to claim 6, characterized in that, The said magnesium-containing compound uses any one of magnesium carbonate, magnesium sulfate, and magnesium oxysulfate.

10. The prepared high compressive strength epoxy system is applied to the formation condition with sand production particle size of 90 - 900 μm.

Images