CN115977580A - Method for sealing outside of pipe of U-shaped communication well - Google Patents
Method for sealing outside of pipe of U-shaped communication well Download PDFInfo
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- CN115977580A CN115977580A CN202211607997.8A CN202211607997A CN115977580A CN 115977580 A CN115977580 A CN 115977580A CN 202211607997 A CN202211607997 A CN 202211607997A CN 115977580 A CN115977580 A CN 115977580A
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- 238000007789 sealing Methods 0.000 title claims abstract description 52
- 238000004891 communication Methods 0.000 title claims abstract description 45
- 238000000034 method Methods 0.000 title claims abstract description 35
- 238000012360 testing method Methods 0.000 claims abstract description 32
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 27
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 24
- 239000004568 cement Substances 0.000 claims abstract description 14
- 239000012530 fluid Substances 0.000 claims abstract description 13
- 239000007788 liquid Substances 0.000 claims abstract description 13
- 239000002002 slurry Substances 0.000 claims abstract description 11
- 238000006243 chemical reaction Methods 0.000 claims description 42
- 239000002245 particle Substances 0.000 claims description 33
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 claims description 24
- 238000006460 hydrolysis reaction Methods 0.000 claims description 14
- 150000003839 salts Chemical class 0.000 claims description 14
- 238000005553 drilling Methods 0.000 claims description 13
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 12
- 230000003111 delayed effect Effects 0.000 claims description 12
- 239000002657 fibrous material Substances 0.000 claims description 12
- 238000010438 heat treatment Methods 0.000 claims description 12
- 229920002401 polyacrylamide Polymers 0.000 claims description 12
- 238000006116 polymerization reaction Methods 0.000 claims description 12
- 229910000029 sodium carbonate Inorganic materials 0.000 claims description 12
- 238000003756 stirring Methods 0.000 claims description 12
- 239000000835 fiber Substances 0.000 claims description 9
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 claims description 8
- 238000010276 construction Methods 0.000 claims description 7
- 238000010408 sweeping Methods 0.000 claims description 7
- HRPVXLWXLXDGHG-UHFFFAOYSA-N Acrylamide Chemical compound NC(=O)C=C HRPVXLWXLXDGHG-UHFFFAOYSA-N 0.000 claims description 6
- 239000006087 Silane Coupling Agent Substances 0.000 claims description 6
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 6
- 230000015271 coagulation Effects 0.000 claims description 6
- 238000005345 coagulation Methods 0.000 claims description 6
- 239000000084 colloidal system Substances 0.000 claims description 6
- 229920006037 cross link polymer Polymers 0.000 claims description 6
- 238000006392 deoxygenation reaction Methods 0.000 claims description 6
- 239000003999 initiator Substances 0.000 claims description 6
- 238000002156 mixing Methods 0.000 claims description 6
- 229910052757 nitrogen Inorganic materials 0.000 claims description 6
- 239000001301 oxygen Substances 0.000 claims description 6
- 229910052760 oxygen Inorganic materials 0.000 claims description 6
- 239000000843 powder Substances 0.000 claims description 6
- 238000002360 preparation method Methods 0.000 claims description 6
- 239000004743 Polypropylene Substances 0.000 claims description 5
- -1 polypropylene Polymers 0.000 claims description 5
- 229920001155 polypropylene Polymers 0.000 claims description 5
- 229910021532 Calcite Inorganic materials 0.000 claims description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 4
- 235000019738 Limestone Nutrition 0.000 claims description 4
- 229910000019 calcium carbonate Inorganic materials 0.000 claims description 4
- 239000010439 graphite Substances 0.000 claims description 4
- 229910002804 graphite Inorganic materials 0.000 claims description 4
- 239000006028 limestone Substances 0.000 claims description 4
- 229920000728 polyester Polymers 0.000 claims description 4
- 229920000642 polymer Polymers 0.000 claims description 4
- 238000010521 absorption reaction Methods 0.000 claims description 3
- 239000008187 granular material Substances 0.000 claims description 3
- 238000003801 milling Methods 0.000 claims description 3
- 238000011161 development Methods 0.000 abstract description 2
- 230000035484 reaction time Effects 0.000 description 3
- 239000008398 formation water Substances 0.000 description 2
- 210000001503 joint Anatomy 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000012412 chemical coupling Methods 0.000 description 1
- 239000007822 coupling agent Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000000284 extract Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 238000003809 water extraction Methods 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/10—Geothermal energy
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- Sealing Material Composition (AREA)
Abstract
The invention belongs to the technical field of geothermal energy development, and particularly relates to an external sealing method for a U-shaped communication well, which comprises the following steps: a casing is put into the directional well to enter a communication point, cementing is carried out to fix the well, and a drill bit is put into the vertical well to circularly sweep the plug at the communication point; closing the vertical well, testing the pressure according to the maximum working pressure after the U-shaped well is put into operation, if leakage or pressure reduction is found, injecting delay expansion plugging liquid into a drill rod of the vertical well, and circulating the replacement slurry until the plugging agent reaches the bottom of the drill rod; extruding the time-delay expansion leakage-stopping fluid into the cracks of the stratum and the cement plug; after waiting for setting, the test is carried out again. When the cement sheath outside the pipe at the communication point is cracked or broken, the time-delay expansion plugging agent is injected and squeezed into cracks and strata, so that a sealing ring with good sealing property, high bearing strength and good toughness is formed outside the pipe, the stratum water is prevented from directly entering a shaft, and the purpose of 'no water is obtained when the ground heat is extracted' is ensured.
Description
Technical Field
The invention belongs to the technical field of geothermal energy development, and particularly relates to an external sealing method for a U-shaped communication well.
Background
Four ways are provided for developing about 3000m middle-deep layer hydrothermal geothermal resources in China, namely, a vertical well directly extracts underground hot water without reinjection; extracting a vertical well, and reinjecting peripheral vertical wells; a concentric pipe is arranged under the vertical shaft for cold and hot water circulating heat exchange; the four modes of forming a group of U-shaped communicating wells by using one straight well and one directional well (horizontal well). The first three methods have the problems that a shaft is not isolated from a heat reservoir, underground water is directly or indirectly extracted, the underground water is polluted by reinjection, the flow of circulating water is small, the heat exchange capacity is small and the like, and the fourth method can achieve the purpose of 'no water extraction for exploiting geothermal heat', and is a method which is popularized and applied at present.
Three technical problems need to be solved in the U-shaped communication well, namely, the two well bores are in butt joint and communicated, the communication point is prevented from effectively sealing formation water entering a shaft, and the sleeve at the communication point needs to be milled and communicated. After two boreholes are in butt joint and communicated, a casing needs to be put into the directional well (horizontal well) from the directional well to enter a communication point, then cementing is carried out to fix the well, and the cement sheath outside the pipe is used for realizing the outside sealing of the communication point, so that formation water is prevented from directly entering the pipe. However, the cement plug outside the pipe has certain brittleness, and in the processes of drilling plug sweeping and communicating milling construction, due to vibration and other reasons, the cement ring outside the pipe can crack or even break, so that the sealing outside the pipe at the communicating point fails.
Disclosure of Invention
The present invention has been made to overcome the above-mentioned problems occurring in the conventional art, and an object of the present invention is to provide a method for sealing the outside of a pipe for a U-shaped communication well.
In order to achieve the technical purpose and achieve the technical effect, the invention is realized by the following technical scheme:
a method for sealing the outside of a pipe for a U-shaped communication well comprises the following steps:
1) A casing is put into the directional well to enter a communication point, cement is injected to fix the well, and a drill bit is put into the vertical well to circularly sweep plugs at the communication point;
2) Closing the vertical well, testing the pressure according to the maximum working pressure after the U-shaped well is put into operation, and if the pressure is not reduced and is not lost, indicating that the external seal of the pipe is normal; if leakage or pressure drop is found, which indicates that the sealing outside the pipe is not good, the prepared time-delay expansion leakage plugging liquid needs to be injected from the drill rod of the vertical well, and the slurry is circulated to the leakage plugging agent to reach the bottom of the drill rod;
3) Closing the vertical well, continuously circulating slurry to replace, and squeezing the time-delay expansion plugging fluid into the stratum and the cracks of the cement plug;
4) Opening the vertical well mouth for at least two cycles, and lifting the drilling tool to the casing pipe for waiting for setting;
5) After waiting for coagulation, testing the pressure again; if the pressure test is unqualified, repeating the steps 2) to 4); and if the pressure test is qualified, finishing the pressure test sealing leak stoppage construction.
Further, according to the method for sealing the outside of the pipe of the U-shaped communication well, in the step 1), the directional well is a horizontal well.
Further, according to the method for sealing the outside of the U-shaped communication well, in the step 1), milling of the casing is avoided in the process of circulating plug sweeping.
Further, according to the method for sealing the outside of the pipe of the U-shaped communication well, in the step 2), the time-delay expansion leakage plugging liquid comprises the following components in parts by weight: 70-90 parts of water-based drilling fluid, 4-6 parts of delayed expansion plugging agent, 2-4 parts of rigid particles, 2-4 parts of elastic particles and 0.5-1 part of fiber material.
Further, according to the method for sealing the outside of the pipe of the U-shaped communication well, the delayed expansion plugging agent is a cross-linked polymer plugging agent, is a gel polymer with strong water absorption expansibility, has the characteristic of delayed expansion, and can ensure that the granular material has enough time to enter a downhole leakage layer and then continues to expand.
Further, the method for sealing the outside of the pipe of the U-shaped communication well is characterized in that the crosslinked polymer plugging agent is temperature-resistant salt-resistant polyacrylamide, and the preparation method comprises the following steps:
1) Adding softened water, acrylamide powder and a silane coupling agent into a reactor, keeping the temperature of a reaction system at 20 ℃, fully stirring and uniformly mixing, adding a sodium carbonate solution into the reaction system after the sodium carbonate solution is completely dissolved, adjusting the pH value of the reaction system, continuously stirring until the solution is fully mixed, and then introducing nitrogen into the reaction system until oxygen in the reaction system is completely removed;
2) After deoxygenation is finished, adding an initiator into the reactor to initiate polymerization reaction, and simultaneously sealing the reactor for 3-4 h, wherein the final reaction temperature is 60-65 ℃;
3) And after the polymerization reaction is finished, heating the reaction system to 70-80 ℃ for hydrolysis reaction for 4-5 h, stopping heating when colloid appears, and finishing the hydrolysis reaction to obtain the temperature-resistant and salt-resistant polyacrylamide.
Further, according to the method for sealing the outside of the pipe for the U-shaped communication well, the rigid particles are at least one of calcite, limestone and calcium carbonate, and the elastic particles are at least one of elastic graphite particles and elastic rubber particles.
Further, according to the method for sealing the outside of the pipe for the U-shaped communication well, the fiber material is at least one of polypropylene fiber and polyester fiber.
The invention has the beneficial effects that:
when the cement sheath outside the pipe at the communicating point is cracked or broken, the time-delay expansion plugging agent is injected and extruded into cracks and stratums, and a sealing ring with good sealing performance, high bearing strength and good toughness is formed outside the pipe, so that stratum water is prevented from directly entering a shaft, and the purpose of 'collecting geothermal energy without getting water' is ensured to be implemented.
Of course, it is not necessary for any one product that embodies the invention to achieve all of the above advantages simultaneously.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention provides a method for sealing the outside of a pipe of a U-shaped communication well, which comprises the following steps:
1) A casing is put into the directional well to enter a communication point, cementing is carried out to fix the well, and a drill bit is put into the vertical well to circularly sweep the plug at the communication point; the directional well is a horizontal well, and the casing pipe is prevented from being milled in the circulating plug sweeping process.
2) Closing the vertical well, testing the pressure according to the maximum working pressure after the U-shaped well is put into operation, and if the pressure is not reduced or lost, indicating that the external sealing of the pipe is normal; if leakage or pressure drop is found, which indicates that the sealing outside the pipe is not good, the prepared time-delay expansion leakage plugging liquid needs to be injected from the drill rod of the vertical well, and the slurry is circulated to the leakage plugging agent to reach the bottom of the drill rod;
3) Closing the vertical well, continuously circulating to replace mud, and squeezing the time-delay expansion leakage-stopping fluid into the stratum and the cracks of the cement plug;
4) Opening the vertical well mouth for at least two cycles, and lifting the drilling tool to the casing pipe for waiting for setting;
5) After waiting for coagulation, testing the pressure again; if the pressure test is unqualified, repeating the steps 2) to 4); and if the pressure test is qualified, finishing the pressure test sealing leak stoppage construction.
In the invention, the time-delay expansion leakage-stopping liquid comprises the following components in parts by weight: 70-90 parts of water-based drilling fluid, 4-6 parts of delayed expansion plugging agent, 2-4 parts of rigid particles, 2-4 parts of elastic particles and 0.5-1 part of fiber material. The delayed expansion plugging agent is a cross-linked polymer plugging agent, is a gel polymer with strong water absorption expansibility, has the characteristic of delayed expansion, and can ensure that the granular material has enough time to enter an underground leakage layer and then continuously expands. Because the temperature-resistant salt-resistant group and the chemical coupling agent are introduced into the molecular chain, the polymer and the temperature-resistant material are connected into a whole, so that the high-temperature-resistant material has good strength, toughness and thermal stability under the conditions of high temperature and high salt.
In the invention, the cross-linked polymer plugging agent is temperature-resistant salt-resistant polyacrylamide, and the preparation method comprises the following steps:
1) Adding softened water, acrylamide powder and a silane coupling agent into a reactor, keeping the temperature of a reaction system at 20 ℃, fully stirring and uniformly mixing, adding a sodium carbonate solution into the reaction system after the sodium carbonate solution is completely dissolved, adjusting the pH value of the reaction system, continuously stirring until the solution is fully mixed, and then introducing nitrogen into the reaction system until oxygen in the reaction system is completely removed;
2) After deoxygenation is finished, adding an initiator into the reactor to initiate polymerization reaction, and simultaneously sealing the reactor for 3-4 h, wherein the final reaction temperature is 60-65 ℃;
3) And after the polymerization reaction is finished, heating the reaction system to 70-80 ℃ for hydrolysis reaction for 4-5 h, stopping heating when colloid appears, and finishing the hydrolysis reaction to obtain the temperature-resistant and salt-resistant polyacrylamide.
In the invention, the rigid particles are at least one of calcite, limestone and calcium carbonate, and the elastic particles are at least one of elastic graphite particles and elastic rubber particles.
In the present invention, the fiber material is at least one of polypropylene fiber and polyester fiber.
The following embodiments are relevant to the present invention:
example 1
The embodiment provides a method for sealing the outside of a pipe of a U-shaped communication well, which comprises the following steps:
1) A casing is put into the directional well to enter a communication point, cementing is carried out to fix the well, and a drill bit is put into the vertical well to circularly sweep the plug at the communication point; the directional well is a horizontal well, and the casing pipe is prevented from being milled in the circulating plug sweeping process.
2) Closing the vertical well, testing the pressure according to the maximum working pressure after the U-shaped well is put into operation, and if the pressure is not reduced and is not lost, indicating that the external seal of the pipe is normal; if leakage or pressure drop is found, which indicates that the sealing outside the pipe is not good, the prepared time-delay expansion leakage plugging liquid needs to be injected from the drill rod of the vertical well, and the slurry is circulated to the leakage plugging agent to reach the bottom of the drill rod;
3) Closing the vertical well, continuously circulating slurry to replace, and squeezing the time-delay expansion plugging fluid into the stratum and the cracks of the cement plug;
4) Opening the vertical well mouth for at least two weeks, and lifting the drilling tool to the casing for waiting for setting;
5) After waiting for coagulation, testing pressure again; if the pressure test is unqualified, repeating the steps 2) to 4); and if the pressure test is qualified, finishing the pressure test sealing leak stoppage construction.
In the embodiment, the time-delay expansion leakage-stopping liquid comprises the following components in parts by weight: 80 parts of water-based drilling fluid, 5 parts of expansion-delaying plugging agent, 3 parts of rigid particles, 3 parts of elastic particles and 0.7 part of fiber material. The rigid particles are calcite, the elastic particles are elastic graphite particles, and the fiber material is polypropylene fiber.
In the embodiment, the delayed expansion plugging agent is temperature-resistant salt-resistant polyacrylamide, and the preparation method comprises the following steps:
1) Adding softened water, acrylamide powder and a silane coupling agent into a reactor, keeping the temperature of a reaction system at 20 ℃, fully stirring and uniformly mixing, adding a sodium carbonate solution into the reaction system after the sodium carbonate solution is completely dissolved, adjusting the pH value of the reaction system, continuously stirring until the solution is fully mixed, and then introducing nitrogen into the reaction system until oxygen in the reaction system is completely removed;
2) After deoxygenation is finished, adding an initiator into the reactor to initiate polymerization reaction, and simultaneously sealing the reactor for treatment, wherein the reaction time is 3.5h, and the final reaction temperature is 63 ℃;
3) And after the polymerization reaction is finished, heating the reaction system to 75 ℃ for hydrolysis reaction, wherein the hydrolysis reaction is carried out for 4.5h, when colloid appears, heating is stopped, and the hydrolysis reaction is finished to obtain the temperature-resistant and salt-resistant polyacrylamide.
Example 2
The embodiment provides a method for sealing the outside of a pipe of a U-shaped communication well, which comprises the following steps:
1) A casing is put into the directional well to enter a communication point, cement is injected to fix the well, and a drill bit is put into the vertical well to circularly sweep plugs at the communication point; the directional well is a horizontal well, and the casing pipe is prevented from being milled in the circulating plug sweeping process.
2) Closing the vertical well, testing the pressure according to the maximum working pressure after the U-shaped well is put into operation, and if the pressure is not reduced and is not lost, indicating that the external seal of the pipe is normal; if leakage or pressure drop is found, which indicates that the sealing outside the pipe is not good, the prepared time-delay expansion leakage plugging liquid needs to be injected from the drill rod of the vertical well, and the slurry is circulated to the leakage plugging agent to reach the bottom of the drill rod;
3) Closing the vertical well, continuously circulating slurry to replace, and squeezing the time-delay expansion plugging fluid into the stratum and the cracks of the cement plug;
4) Opening the vertical well mouth for at least two weeks, and lifting the drilling tool to the casing for waiting for setting;
5) After waiting for coagulation, testing the pressure again; if the pressure test is unqualified, repeating the steps 2) to 4); and if the pressure test is qualified, finishing the pressure test sealing leak stoppage construction.
In the embodiment, the time-delay expansion leakage-stopping liquid comprises the following components in parts by weight: 70 parts of water-based drilling fluid, 6 parts of expansion-delaying plugging agent, 2 parts of rigid particles, 4 parts of elastic particles and 0.5 part of fiber material. The rigid particles are calcium carbonate, the elastic particles are elastic rubber particles, and the fiber material is polypropylene fiber.
In the embodiment, the delayed expansion plugging agent is temperature-resistant salt-resistant polyacrylamide, and the preparation method comprises the following steps:
1) Adding softened water, acrylamide powder and a silane coupling agent into a reactor, keeping the temperature of a reaction system at 20 ℃, fully stirring and uniformly mixing, adding a sodium carbonate solution into the reaction system after the sodium carbonate solution is completely dissolved, adjusting the pH value of the reaction system, continuously stirring until the solution is fully mixed, and then introducing nitrogen into the reaction system until oxygen in the reaction system is completely removed;
2) After deoxygenation is finished, adding an initiator into the reactor to initiate polymerization, and simultaneously sealing the reactor, wherein the reaction time is 3h, and the final reaction temperature is 65 ℃;
3) And after the polymerization reaction is finished, heating the reaction system to 70 ℃ for hydrolysis reaction for 5 hours, stopping heating when colloid appears, and finishing the hydrolysis reaction to obtain the temperature-resistant and salt-resistant polyacrylamide.
Example 3
The embodiment provides a method for sealing the outside of a pipe for a U-shaped communication well, which comprises the following steps:
1) A casing is put into the directional well to enter a communication point, cementing is carried out to fix the well, and a drill bit is put into the vertical well to circularly sweep the plug at the communication point; the directional well is a horizontal well, and the casing pipe is prevented from being milled in the circulating plug sweeping process.
2) Closing the vertical well, testing the pressure according to the maximum working pressure after the U-shaped well is put into operation, and if the pressure is not reduced and is not lost, indicating that the external seal of the pipe is normal; if leakage or pressure drop is found, which indicates that the sealing outside the pipe is not good, the prepared time-delay expansion leakage plugging liquid needs to be injected from the drill rod of the vertical well, and the slurry is circulated to the leakage plugging agent to reach the bottom of the drill rod;
3) Closing the vertical well, continuously circulating slurry to replace, and squeezing the time-delay expansion plugging fluid into the stratum and the cracks of the cement plug;
4) Opening the vertical well mouth for at least two weeks, and lifting the drilling tool to the casing for waiting for setting;
5) After waiting for coagulation, testing pressure again; if the pressure test is unqualified, repeating the steps 2) to 4); and if the pressure test is qualified, finishing the pressure test sealing leak stoppage construction.
In the embodiment, the time-delay expansion leakage-stopping liquid comprises the following components in parts by weight: 90 parts of water-based drilling fluid, 4 parts of expansion-delaying plugging agent, 4 parts of rigid particles, 2 parts of elastic particles and 1 part of fiber material. The rigid particles are limestone, the elastic particles are elastic rubber particles, and the fiber material is polyester fiber.
In the embodiment, the delayed expansion plugging agent is temperature-resistant salt-resistant polyacrylamide, and the preparation method comprises the following steps:
1) Adding softened water, acrylamide powder and a silane coupling agent into a reactor, keeping the temperature of a reaction system at 20 ℃, fully stirring and uniformly mixing, adding a sodium carbonate solution into the reaction system after the sodium carbonate solution is completely dissolved, adjusting the pH value of the reaction system, continuously stirring until the solution is fully mixed, and then introducing nitrogen into the reaction system until oxygen in the reaction system is completely removed;
2) After deoxygenation is finished, adding an initiator into the reactor to initiate polymerization, and simultaneously sealing the reactor, wherein the reaction time is 4h and the final reaction temperature is 60 ℃;
3) And after the polymerization reaction is finished, heating the reaction system to 80 ℃ for hydrolysis reaction, wherein the hydrolysis reaction is carried out for 4 hours, heating is stopped when colloid appears, and the hydrolysis reaction is finished to obtain the temperature-resistant and salt-resistant polyacrylamide.
The preferred embodiments of the invention disclosed above are intended to be illustrative only. The preferred embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention. The invention is limited only by the claims and their full scope and equivalents.
Claims (8)
1. A method for sealing the outside of a pipe for a U-shaped communication well is characterized by comprising the following steps:
1) A casing is put into the directional well to enter a communication point, cementing is carried out to fix the well, and a drill bit is put into the vertical well to circularly sweep the plug at the communication point;
2) Closing the vertical well, testing the pressure according to the maximum working pressure after the U-shaped well is put into operation, and if the pressure is not reduced or lost, indicating that the external sealing of the pipe is normal; if leakage or pressure drop is found, which indicates that the sealing outside the pipe is not good, the prepared time-delay expansion leakage plugging liquid needs to be injected from the drill rod of the vertical well, and the slurry is circulated to the leakage plugging agent to reach the bottom of the drill rod;
3) Closing the vertical well, continuously circulating to replace mud, and squeezing the time-delay expansion leakage-stopping fluid into the stratum and the cracks of the cement plug;
4) Opening the vertical well mouth for at least two weeks, and lifting the drilling tool to the casing for waiting for setting;
5) After waiting for coagulation, testing the pressure again; if the pressure test is unqualified, repeating the steps 2) to 4); and if the pressure test is qualified, finishing the pressure test sealing leak stoppage construction.
2. The method for sealing the outside of the pipe for the U-shaped communication well according to claim 1, wherein in the step 1), the directional well is a horizontal well.
3. The method for sealing the outside of the pipe for the U-shaped communication well according to claim 1, wherein in the step 1), the milling of the casing pipe is avoided in the process of circulating and sweeping the plug.
4. The method for sealing the outside of the pipe for the U-shaped communication well according to claim 1, wherein in the step 2), the time-delay expansion leakage-blocking liquid consists of the following components in parts by weight: 70-90 parts of water-based drilling fluid, 4-6 parts of delayed expansion plugging agent, 2-4 parts of rigid particles, 2-4 parts of elastic particles and 0.5-1 part of fiber material.
5. The method for sealing the outside of a pipe for the U-shaped communication well as defined in claim 4, wherein the delayed expansion plugging agent is a cross-linked polymer plugging agent, is a gel polymer with strong water absorption expansibility, has a delayed expansion characteristic, and can ensure that the granular material has enough time to enter a downhole leakage layer and then continues to expand.
6. The method for sealing the outside of the pipe of the U-shaped communication well according to claim 5, wherein the cross-linked polymer plugging agent is temperature-resistant and salt-resistant polyacrylamide, and the preparation method comprises the following steps:
1) Adding softened water, acrylamide powder and a silane coupling agent into a reactor, keeping the temperature of a reaction system at 20 ℃, fully stirring and uniformly mixing, adding a sodium carbonate solution into the reaction system after the sodium carbonate solution is completely dissolved, adjusting the pH value of the reaction system, continuously stirring until the solution is fully mixed, and then introducing nitrogen into the reaction system until oxygen in the reaction system is completely removed;
2) After deoxygenation is finished, adding an initiator into the reactor to initiate polymerization reaction, and simultaneously sealing the reactor for 3-4 h, wherein the final reaction temperature is 60-65 ℃;
3) And after the polymerization reaction is finished, heating the reaction system to 70-80 ℃ for hydrolysis reaction for 4-5 h, stopping heating when colloid appears, and finishing the hydrolysis reaction to obtain the temperature-resistant and salt-resistant polyacrylamide.
7. The method for sealing the outside of the pipe for the U-shaped communication well according to claim 5, wherein the rigid particles are at least one of calcite, limestone and calcium carbonate, and the elastic particles are at least one of elastic graphite particles and elastic rubber particles.
8. The method for sealing outside of a pipe for a U-shaped communication well according to claim 5, wherein the fiber material is at least one of polypropylene fiber and polyester fiber.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202211607997.8A CN115977580A (en) | 2022-12-14 | 2022-12-14 | Method for sealing outside of pipe of U-shaped communication well |
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| CN202211607997.8A CN115977580A (en) | 2022-12-14 | 2022-12-14 | Method for sealing outside of pipe of U-shaped communication well |
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| CN115977580A true CN115977580A (en) | 2023-04-18 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116283159A (en) * | 2023-05-11 | 2023-06-23 | 连云港建港实业有限公司 | Process for preparing wear-resistant interlocking block by using iron ore screening material |
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2022
- 2022-12-14 CN CN202211607997.8A patent/CN115977580A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116283159A (en) * | 2023-05-11 | 2023-06-23 | 连云港建港实业有限公司 | Process for preparing wear-resistant interlocking block by using iron ore screening material |
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