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Research Progress of Cementing Additives and Special Cement Slurry System (Part 3)

1.2.2 polymer retarder

Polymer retarder is a kind of retarder which has been studied most at home and abroad in recent years. Because a variety of different functional monomers can be combined by polymerization technology, and the length of molecular chain, the size and distribution of molecular weight can be controlled, the molecular design idea can be used to guide the synthesis of this kind of retarder, and the retarder with better comprehensive performance can be obtained. Damps copolymer

(1) AMPS / AA Copolymer. Example 1: the molar fraction of AMPs in the copolymer is 40-60%, and the molecular weight is less than 5000. The use temperature of the retarder can reach 121 ℃, the mixing amount of bwoc is 0.3-15%, the thickening experimental rule is good in the range of 66-118 ℃, and the thickening time is easy to adjust. Example 2: when the molar fraction of AMPs in the copolymer reaches 65-85%, it is a good medium and low temperature retarder. Example 3: when ampsiaa copolymer is combined with lignosulfonate, borax, organic acid and other retarders, the temperature application range can be expanded. For example, when ampsiaa copolymer is combined with sodium tartrate, the service temperature can reach 260 ℃.

(2) AMPS / ia copolymer. Example: the molar ratio of amps to IA in the copolymer is 73:27. The retarding effect of the retarder is obviously better than that of AMPS / AA retarder. It does not need to add borax, organic acid and other retarding agents, and the temperature can reach 260 ℃ when used alone.

(3) Other binary or ternary copolymers containing carboxyl groups. Examples: AMPS / MA, AMPS / IA / AA, AMPS / IA / am, etc.

Typical foreign products such as Halliburton's SCR-100,SCR-500, domestic products in this area are not very mature, and are still in the initial stage of promotion and application. Typical products such as ZOC-H50L of ZORANOC company. 2) Other polymers

(1) Polymers containing sulfonic acid and carboxylic acid groups. Example: styrene sulfonic acid maleic anhydride binary copolymer, the polymer in organic acid and other retarding agent synergistic effect, retarding temperature can be as high as 302 ℃.

(2) Polymer containing phosphonic acid and carboxylic acid groups. Example: the polymer composed of repeated structural units of "[chco0hch-po0hch-chcooh1] -" has a molecular weight of about 4000 and a temperature range of 93-232 ℃.

(3) Graft polymer. Example 1: the main chain is sugar (including its hydrolysate hydroxycarboxylic acid), sorbitol, gluconic acid, tartaric acid, etc. are recommended; the side chain is ethylene copolymer, and the comonomers are AA, amps, vinyl phosphonic acid, etc. with molecular weight of 1000-15000, and the service temperature is above 121 ℃. Example 2: the main chain is polycondensate, acetone / formaldehyde / sodium sulfite polycondensate is recommended, the side chain is carboxylic acid / sulfonic acid copolymer, the carboxylic acid monomer is recommended AAIA, Ma, etc., and the sulfonic acid monomer is recommended amps; The temperature can reach 177 ℃.

Research progress of 2 special cement slurry system

With the progress of cementing technology, more and more deep wells, ultra deep wells and special wells are encountered in cementing. There are some special problems in cementing operation of these wells, which are difficult to be solved only by basic cement additives. In order to solve these special problems, people continue to create many special cement slurry systems. Limited to space, the following focuses on the research progress of latex cement, fiber cement, anti-corrosion cement, high performance low (high) density cement and other four special cement slurry systems.