CN-117623663-B - Oil well cement preservative, oil and gas well cementing middle-high-temperature cement slurry and preparation method thereof

Abstract

The invention provides an oil well cement preservative, cement slurry for well cementation of an oil and gas well and a preparation method thereof. The preparation method of the oil well cement preservative comprises the steps of carrying out waterborne modification on epoxy resin by using 2-acrylamide-2-methylpropanesulfonic acid, recovering a solvent through reduced pressure distillation to obtain waterborne epoxy resin, dissolving the waterborne epoxy resin in water, and then dropwise adding diisopropoxyl di (ethoxyacetyl) titanium for grafting synthesis to obtain the oil well cement preservative. The well cementation corrosion-resistant medium-temperature cement slurry for the oil and gas well comprises an oil well cement preservative, micro silicon, cement, fly ash, a dispersing agent, a fluid loss agent, a retarder, a defoaming agent and water. The oil-gas well cementing corrosion-resistant high-temperature cement slurry comprises an oil-gas well cement preservative, silica fume, micro-silica, cement, fly ash, a dispersing agent, a fluid loss agent, a retarder, a defoaming agent and water. The oil well cement preservative can be cured into a film in cement without using a curing agent, and solves the problem of compatibility of an epoxy resin curing agent and cement paste.

Inventors

• WANG CHUNQUAN
• YAN HAIBING
• ZHAO QIYANG
• MA BIAO
• YAO YAN
• CHEN MIN
• FENG BIN
• HUANG WEI

Assignees

• 中国石油天然气集团有限公司
• 中国石油集团川庆钻探工程有限公司

Dates

Publication Date

20260508

Application Date

20220809

Claims (9)

1. 1. A method for preparing an oil well cement preservative, which is characterized by comprising the following steps: the epoxy resin is modified by 2-acrylamido-2-methylpropanesulfonic acid in a water-based manner, and the solvent is recovered by reduced pressure distillation to obtain the water-based epoxy resin, wherein the mass ratio of the epoxy resin to the 2-acrylamido-2-methylpropanesulfonic acid is 1 (1-1.5), and And (3) after the water-based epoxy resin is dissolved in water, dropwise adding diisopropoxybis (ethoxyacetyl) titanium for grafting synthesis to obtain the oil well cement preservative, wherein the mass ratio of the water-based epoxy resin to the water is 1 (4-6), the mass ratio of the water-based epoxy resin to the diisopropoxybis (ethoxyacetyl) titanium is 10 (1-3), and the grafting synthesis is carried out by stirring at normal temperature for 2-4 hours at high speed to obtain the oil well cement preservative.
2. 2. The method of preparing an oil well cement preservative according to claim 1, wherein the step of aqueous modification comprises: Dissolving epoxy resin in n-butanol solvent, introducing nitrogen, heating to 80-110 ℃, dropwise adding benzoyl peroxide acetone solution to obtain a reaction solution, and Slowly dripping 2-acrylamide-2-methylpropanesulfonic acid into the reaction liquid, and reacting for 3-4 hours at constant temperature.
3. 3. The method for preparing the oil well cement preservative according to claim 2, characterized in that the temperature of the constant temperature reaction is 80-110 ℃.
4. 4. An oil well cement preservative, characterized in that it is produced by the process for producing an oil well cement preservative according to any one of claims 1 to 3.
5. 5. The oil well cement preservative of claim 4, wherein the oil well cement preservative is a self-crosslinking aqueous epoxy resin.
6. 6. The corrosion-resistant oil and gas well cementation medium-temperature cement slurry is characterized by comprising, by mass, 3-7 parts of the oil well cement preservative, 4-6 parts of micro silicon, 90-110 parts of cement, 4-6 parts of fly ash, 0.5-2 of dispersing agent, 1-3 of fluid loss additive, 0.1-0.5 of retarder and 0.1-0.5 of defoamer, wherein the water-solid ratio of the corrosion-resistant oil and gas well cementation cement slurry is 0.37-0.45.
7. 7. The corrosion-resistant oil and gas well cementation high-temperature cement slurry is characterized by comprising, by mass, 3-7 parts of the oil well cement preservative as set forth in claim 4, 25-35 parts of silica powder, 4-6 parts of microsilica, 90-110 parts of cement, 4-6 parts of fly ash, 0.5-2 of dispersing agent, 1-3 of fluid loss agent, 0.1-0.5 of retarder and 0.1-0.5 of defoamer, wherein the water-solid ratio of the corrosion-resistant oil and gas well cementation cement slurry is 0.37-0.45.
8. 8. A method for preparing corrosion-resistant oil and gas well cementing medium-temperature cement slurry according to claim 6, wherein the preparation method comprises the following steps: fully and uniformly mixing cement, micro-silicon, fly ash and a dispersing agent to obtain a dry mixed material; Mixing oil well cement preservative, fluid loss agent, retarder, defoamer and water to obtain slurry mixing water, and And adding the dry mixed material into slurry mixing water and stirring uniformly at a high speed to obtain corrosion-resistant oil-gas well cementation medium-temperature cement slurry.
9. 9. A method of preparing a corrosion resistant oil and gas well cementing high temperature cement slurry according to claim 7, comprising the steps of: Fully and uniformly mixing cement, silica fume, micro-silica, fly ash and a dispersing agent to obtain a dry mixed material; Mixing oil well cement preservative, fluid loss agent, retarder, defoamer and water to obtain slurry mixing water, and And adding the dry mixed material into slurry mixing water and stirring uniformly at a high speed to obtain corrosion-resistant oil-gas well cementation high-temperature cement slurry.

Description

Oil well cement preservative, oil and gas well cementing middle-high-temperature cement slurry and preparation method thereof Technical Field The invention belongs to the technical field of petroleum well cementation, and particularly relates to an oil well cement preservative and a preparation method thereof, corrosion-resistant oil and gas well cementation middle-temperature cement paste and a preparation method thereof, and corrosion-resistant oil and gas well cementation high-temperature cement paste and a preparation method thereof. Background Along with the continuous deep exploration and development of oil and gas resources, the corrosion of acid gas with high H 2S、CO2 content has become an important difficult problem in the development of oil and gas fields at home and abroad. In a High Temperature and High Pressure (HTHP) downhole environment, H 2S、CO2 may even be in a supercritical state, having a more aggressive nature, severely threatening the integrity of the cement sheath. The cement sheath is used as a first protective barrier for oil and gas exploitation, and plays a vital role in the service life of oil and gas wells and the safe exploitation of oil and gas resources. The cement sheath refers to cement stones formed between the casing and the stratum by cement paste, and the cement sheath is used for supporting and suspending the casing, blocking stratum fluid and preventing interlayer channeling, and the casing and the stratum are cemented together through the cement sheath (namely the cement stones) after cementing operation. If the cement sheath is severely corroded by H 2S、CO2 and loses mechanical properties, the sealing of the cement sheath is invalid, corrosive gas directly acts on the sleeve and the oil pipe, finally, the oil well is scrapped, harmful gas can be overflowed from the ground more seriously, and life and property safety is seriously threatened. The currently used materials for preventing H 2S、CO2 from corroding mainly comprise inorganic materials such as micro-silicon, volcanic ash and the like, and organic materials such as resin, latex and the like. The inorganic anti-corrosion material is added to improve the compactness of the cement stone, effectively reduce the content of calcium hydroxide in the cement stone, and improve the resistance of the cement stone to H 2S、CO2 corrosion. However, the addition of such inorganic anti-corrosive materials is limited, and pozzolans and other inorganic materials contain a large amount of aluminum oxide, in an environment rich in H 2 S, sulfate, aluminum oxide and calcium hydroxide are converted into ettringite, so that cement stones expand to generate microcracks, and the integrity of cement rings is damaged. The organic anti-corrosion materials such as latex and resin not only can reduce the porosity of the cement stone, but also can form a film on the surface of a hydration product to prevent the cement stone from contacting with corrosive gas. However, field practice shows that the latex has the problems of poor stability, easy generation of a large amount of bubbles in cement paste, increased permeability of cement stones, reduced anti-corrosion effect and the like, and the epoxy resin has limited anti-corrosion performance due to poor compatibility in the cement paste and lack of a proper curing agent which can be used in the cement paste. The Chinese patent with the publication number of CN106947446A discloses a low-density well cementation cement slurry system for corrosion prevention and a preparation method thereof, wherein the low-density well cementation cement slurry system comprises, by weight, 65-90 parts of G-grade cement, 10-35 parts of well cementation lightening material, 10-30 parts of non-penetrating agent, 1.8-2.2 parts of oil well cement fluid loss agent, 1-1.5 parts of cement corrosion inhibitor and 55-90 parts of water. But cannot improve the resistance of the cement stone to H 2S、CO2 corrosion. Disclosure of Invention The present invention aims to address at least one of the above-mentioned deficiencies of the prior art. For example, it is an object of the present invention to provide a method for preparing an oil well cement preservative. Another object of the present invention is to provide an oil well cement preservative. It is still another object of the present invention to provide a corrosion resistant medium temperature, high temperature oil and gas well cementing slurry. The invention further aims at providing a preparation method of corrosion-resistant oil and gas well cementation medium-temperature and high-temperature cement slurry. In order to achieve the above object, an aspect of the present invention provides an oil well cement preservative and a method for preparing the same. The preparation method comprises the steps of carrying out waterborne modification on epoxy resin by using 2-acrylamide-2-methylpropanesulfonic acid, and recovering a solvent through reduced pressure distillation to o