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Prepad fluid and preparation method thereof

A technology of pre-fluid and plugging materials, which is applied in the direction of chemical instruments and methods, drilling compositions, etc., can solve problems such as unfavorable coal seam interface cementation, decreased modification effect, and limited adsorption efficiency, and achieve excellent water quality. The effect of wettability, uniform modification, and improvement of bonding strength

Active Publication Date: 2021-03-19
CHINA UNITED COALBED METHANE +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005]However, since the adsorption of lipophilic groups of surfactants to the coal seam surface is mainly based on hydrophobic interaction, its adsorption strength is low and the adsorption efficiency is limited
Moreover, in order to ensure sufficient wetting modification effect and compatibility with cement slurry, anionic surfactants are often used. On the one hand, this leads to a low adsorption density of surfactants on the surface of coal rocks under electrostatic action. On the other hand, , the anionic groups of the surfactant may combine with the cationic minerals on the surface of the coal rock, causing the hydrophobic groups to go outward, resulting in a decrease in the modification effect
Furthermore, the Si-OH groups produced by the hydrolysis of the silane coupling agent will be adsorbed on the surface of the cement particles to form a coating layer, which prevents further contact between the cement and water, has a strong retarding side effect on the cement, and is not conducive to the cementation of the coal seam interface.

Method used

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preparation example Construction

[0034] The present invention also provides a preparation method of the above-mentioned pre-fluid, comprising: mixing water and neoprene latex, then adding a plugging agent, a performance modifier and an antifoaming agent and mixing uniformly to obtain a pre-flux.

[0035] In the present invention, after mixing water and chloroprene latex, it is preferred to add the performance modifier first, then add the plugging agent, and finally add the defoamer; Calcium particles and wood fibers.

[0036] All raw materials of the present invention, their grades and abbreviations belong to the conventional grades and abbreviations in this field, and each grade and abbreviation are all clear and definite in the field of its related use. Those skilled in the art can according to the grades, abbreviations and corresponding uses, It can be purchased from commercial sources or prepared by conventional methods.

[0037] The present invention has no special limitation on the preparation method o...

Embodiment 1

[0045] 100 parts by mass of clear water, and then dissolve 7 parts by mass of neoprene latex into clear water; add polyvinyl alcohol fluid loss reducer and sulfonated aldehyde and ketone dispersant at a ratio of 5:3, a total of 0.7 parts by mass; then press 22: Add expanded vermiculite, ultrafine calcium carbonate particles, lignin fiber, and expanded vermiculite in a ratio of 12:1, the particle size is mainly 4.0mm, and the bulk density is 0.65g / cm 3 , the particle size of ultrafine calcium carbonate particles is mainly 20μm, and the bulk density is 1.1g / cm 3 , the length of the wood fiber is mainly 5mm, the diameter is mainly 0.6μm, a total of 1 part by mass, so that it is fully and evenly dispersed in the slurry system; finally add 0.3 parts by mass of defoamer; stir the slurry evenly to form a strengthened cement Preflux, labeled S1.

Embodiment 2

[0047] 100 parts by mass of clear water, and then dissolve 9 parts by mass of neoprene latex into clear water; add polyvinyl alcohol fluid loss reducer and sulfonated aldehyde and ketone dispersant in a ratio of 5:3, a total of 3.0 parts by mass; then press 50: Add expanded vermiculite, ultra-fine calcium carbonate particles, lignin fiber and expanded vermiculite in the ratio of 20:3 in sequence, the particle size is mainly 2.0mm, and the bulk density is mainly 0.69g / cm 3 , the ultrafine calcium carbonate particle size is mainly 10μm, and the bulk density is 1.2g / cm 3 , the length of the wood fiber is 4mm, the diameter is mainly 0.53μm, a total of 1 part by mass, so that it is fully and evenly dispersed in the slurry system; finally, 0.6 parts by mass of defoamer is added; the slurry is evenly stirred to form a strengthened cement Prefluid, labeled S2.

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Abstract

The invention provides a prepad fluid. The prepad fluid comprises the following components in parts by weight: 100 parts of water; 7-9 parts by weight of neoprene latex; 1-3.2 parts by weight of a plugging agent; 0.7-3.0 parts by weight of a performance conditioning agent; and 0.3-0.6 part by weight of a defoaming agent. According to the prepad fluid, the neoprene latex is added into the prepad fluid to serve as a surface modification material; a high-molecular polymer in the system and the surfactant can play a compounding synergistic effect, can tightly adsorb a coal core and densely lay onthe surface of the coal core, so that the surface of the coal core is modified uniformly, and the cementing quality of well cementation is effectively improved; and therefore, the coal-bed gas well cementation prepad fluid provided by the invention not only has good compatibility with drilling fluid and cement paste, but also has good improvement on the surface wettability of coal, enables the coal core to have excellent water wettability and improves the cementation strength of a second interface of well cementation; and various performance indexes of the prepad fluid meet on-site well cementation requirements.

Description

technical field [0001] The invention belongs to the technical field of coalbed gas exploitation, and in particular relates to a pre-flush and a preparation method thereof. Background technique [0002] The total and average annual growth of natural gas consumption in developing countries represented by China is at a relatively high level. Coalbed methane (Coalbed Methane) is mainly composed of methane. The total reserves of coalbed methane in the range of 300-2000m buried depth in my country reach 31.46 trillion cubic meters, which is only less than Russia and the United States. The resource volume ranks third in the world. The amount of conventional natural gas resources is equivalent, and there are abundant reserves. Coalbed methane not only has a high calorific value, but also has no pollution to the environment. It is a new energy source with very broad application prospects. [0003] The composition of the coal seam is mainly composed of layered sedimentary rock mass c...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K8/467C09K8/03
CPCC09K8/426C09K8/467C09K8/03C09K2208/08
Inventor 马腾飞孙晗森杨刚高计县张坤马洪涛王海侨侯岩波王成文
Owner CHINA UNITED COALBED METHANE