Search

CN-121991659-A - Oil-gas well cement sheath microcrack repairing gel and preparation method thereof

CN121991659ACN 121991659 ACN121991659 ACN 121991659ACN-121991659-A

Abstract

The invention provides a repair gel for a cementing ring micro-crack of an oil and gas well and a preparation method thereof, wherein the repair gel comprises 65-85 parts by weight of glycidol amine epoxy resin, 10-25 parts by weight of toluene glycidyl ether, 0.1-1.5 parts by weight of vinyl triisopropenyloxy silane and 5-10 parts by weight of curing agent. The preparation method comprises the following steps of 1, mixing and stirring glycidol amine epoxy resin and toluene glycidyl ether, 2, mixing and stirring the mixture obtained in the step1 and vinyl triisopropenoxysilane to obtain a resin mixture, and 3, carrying out a curing reaction on the resin mixture and a curing agent to obtain the oil-gas well water ring microcrack repairing gel. The repairing gel system has lower viscosity, is suitable for the temperature of a shaft to reach 150-200 ℃, effectively repairs micro cracks in a cement sheath of an oil-gas well after curing, has high cementing strength, can not cause the problem of softening a cured body, and can resist long-term corrosion of acid gas.

Inventors

  • ZU YU
  • LI YINGHUI
  • GUO HONGYU
  • Zhao Chenkang
  • Dai man
  • GAO SHAN
  • FENG SIHAN
  • JIANG WEI
  • LIU YANFENG
  • WANG DONGJUN

Assignees

  • 中国石油天然气股份有限公司

Dates

Publication Date
20260508
Application Date
20241105

Claims (10)

  1. 1. An oil and gas well cement sheath microcrack repair gel, comprising: 65-85 parts by weight of glycidol amine epoxy resin; 10-25 parts by weight of toluene glycidyl ether; 0.1-1.5 parts by weight of vinyl triisopropenoxysilane; 5-10 parts of a curing agent.
  2. 2. The oil and gas well cement sheath microcrack repair gel of claim 1 wherein the glycidylamine type epoxy resin is N, N-di (glycidyl) aniline and the toluene glycidyl ether is 2-toluene glycidyl ether.
  3. 3. The oil and gas well cement sheath microcrack repair gel of claim 1 wherein the curing agent is one or more of tetrahydrophthalic anhydride, diethylformamide, dicyandiamide, diethyltoluenediamine.
  4. 4. The oil and gas well cement sheath microcrack repair gel of claim 1 further comprising 0.5-2.0 parts by weight of an antifoaming agent.
  5. 5. The oil and gas well cement sheath microcrack repair gel of claim 4 wherein said defoamer is a polyether modified silicone oil defoamer, GPE type polyoxyethylene ether.
  6. 6. The oil and gas well cement sheath microcrack repair gel of claim 1 comprising: 75-85 parts of glycidol amine epoxy resin; 10-18 parts by weight of toluene glycidyl ether; 0.1-1 parts by weight of vinyl triisopropenoxysilane; 6-10 parts of curing agent.
  7. 7. The method for preparing the oil and gas well cement sheath microcrack repair gel as claimed in any one of claims 1 to 6, which is characterized by comprising the following steps: Step 1, mixing glycidol amine epoxy resin and toluene glycidyl ether, and stirring; step2, mixing the mixture obtained in the step1 with vinyl triisopropenoxysilane, and stirring to obtain a resin mixture; And step 3, carrying out a curing reaction on the resin mixture and a curing agent to obtain the oil and gas well cement sheath microcrack repairing gel.
  8. 8. The method for preparing a micro-crack repairing gel for a cement sheath of an oil and gas well according to claim 7, wherein a defoaming agent is further added in the curing reaction in the step 3.
  9. 9. The method for preparing the oil and gas well cement sheath microcrack repair gel according to claim 7, wherein the stirring speed in the step 1 is 1400-1600 r/min, and the stirring speed in the step 2 is 800-1200 r/min.
  10. 10. The method for preparing the oil-gas well cement sheath microcrack repair gel according to claim 7, wherein the curing reaction temperature in the step 3 is 10-20 ℃, the curing reaction time is 8-12min, and stirring is carried out at 400-600 r/min in the curing reaction.

Description

Oil-gas well cement sheath microcrack repairing gel and preparation method thereof Technical Field The invention relates to the field of oil and gas well annulus microcrack repairing, in particular to oil and gas well cement sheath microcrack repairing gel and a preparation method thereof. Background In the development of oil and gas wells, the integrity of the cement sheath is critical to the safety and stability of the wellbore. Especially for thermal recovery wells or high-temperature wells, microcracks often occur in cement rings due to multiple factors such as physical property changes, friction effects, gravity effects, and endothermic and exothermic effects caused by thermal fluid state changes in the recovery process. These microcracks can not only lead to formation fluid invasion into the wellbore, but can also cause serious problems such as oil and gas leakage, wellbore instability, etc., which presents a great challenge to the safe production and economic benefits of oil and gas wells. At present, the repairing technology for the microcracks of the cement rings of the oil and gas wells mainly comprises cement squeezing, cement stone self-repairing (self-repairing materials are added in the well cementation cement paste) and filling the microcracks by adopting chemical materials in the later period. From the actual situation on site, the cement squeezing repairing effect is very little. The cement stone self-repairing method only needs to add self-repairing materials into the well cementation cement paste, and has simple operation, but has low repairing efficiency, and is difficult to completely fill micro cracks. And filling the micro-cracks in the later period, mainly using a method of repairing by using a chemical plugging agent, and realizing plugging by using the mutual bonding effect of the chemical plugging agent and the micro-cracks by injecting the chemical plugging agent, so long as a repairing material can be well injected into the micro-cracks, and the repairing effect is relatively good. Chinese patent CN110229651A provides a resin plugging agent for repairing cement annulus cracks, which is mainly used for cracks and pores in cement annuluses connected with a christmas tree, microcracks in cement stones and microcirculatory gaps in two interfaces of well cementation, but the use temperature of the plugging agent is between 35 ℃ and 60 ℃, the highest compressive strength of a solidified body is 23MPa, and the use temperature range of the plugging agent is lower and is mainly applied to a wellhead. Chinese patent CN116462798A provides a cement sheath microcrack repairing nano composite hydrogel, which is prepared by mainly utilizing a nano material, an anion monomer, a functional monomer generating anions after hydrolysis and a cationic group generated by hydrolysis when encountering acid gas, and then adding the nano composite hydrogel into cement paste to prepare self-repairing cement, wherein the plugging agent is mainly applied to a CCUS well, and can only act when the microcracks are generated in the cement sheath by leaked acid gas. Chinese patent CN103468231A provides a silane coupling agent coated self-repairing agent for cement sheath, which is characterized in that the silane coupling agent is used for coating active minerals, a waterproof protective film is formed on the surface of the active minerals, so that the activity of the active minerals becomes potential activity, the active minerals do not participate in hydration reaction in a well cementation cement slurry system, only when the surface film of the active minerals is damaged due to damage of a well cementation cement sheath, the hydration reaction is started, hydration products are formed to automatically repair the damaged part of the cement sheath, the efficiency of the self-repairing type material to play the effect is extremely low, firstly, the activation condition is required to be met, and secondly, the self-repairing efficiency is lower. The prior chemical plugging technology in the practice shows that the prior plugging gel has the condition of mechanical property reduction under the high-temperature environment, and if the performance is required to be obtained, the consumption of functional materials is required to be increased, the problem is that the initial viscosity is increased and the initial viscosity is not easy to be injected into micro cracks, so that the requirements of on-site construction of the cement sheath micro cracks and long-term effective plugging of the micro cracks in the later period are difficult to be met. CN 113930200A discloses a sealing agent for treating annular space with pressure and a preparation method thereof, wherein the sealing agent comprises composite resin, a curing agent, a toughening agent and a viscosity reducer. The sealant is extruded into the oil-gas well annulus from the ground annulus and solidifies to seal the microcrack of the cement sheath, so that the o