Preparation method of micro-branched micro-crosslinked polyacrylamide

Abstract

The invention discloses a preparation method of micro-branched micro-crosslinked polyacrylamide. The preparation method comprises the following steps: adding an acrylamide monomer of which the mass percent is 20-30% into water; then adding dimethylaminoethyl methacrylate, persulfate, a chain transfer agent, EDTA and manganese acetylacetonate, regulating the pH value to 5-8, and initiating a polymerization reaction at 20-40 DEG C; after 5-10 hours of reaction, taking out a colloid, and performing granulation; and the adding NaOH accounting for 1.5-3% of the mass of the colloid, and performing hydrolysis at 80-100 DEG C for 1-3 hours to obtain the finished product. The micro-branched micro-crosslinked polyacrylamide prepared by the method disclosed by the invention has high viscosity, and has excellent thermal stability and mechanical shearing resistance; and experiments indicate that the viscosity retention rate of the micro-branched micro-crosslinked polyacrylamide disclosed by the invention after mechanical shearing is more than 81%, and the viscosity retention rate after 90 days of aging is 79% or above. The method disclosed by the invention has the advantages of mild reaction conditions, simple operation process, low cost and the like.

Description

technical field [0001] The invention relates to a preparation method of micro-branched and micro-crosslinked polyacrylamide, which belongs to the technical field of preparation of oilfield chemicals. Background technique [0002] Polymer flooding, as a kind of chemical flooding, is an important part of enhanced oil recovery technology. Its oil displacement mechanism is clear, the process is relatively simple, and the technology has become increasingly mature. As early as the early 1960s, Daqing and Shengli Oilfields began to Research work on polymer flooding. Since the 1990s, on the basis of laboratory research, oilfields such as Daqing, Dagang, and Shengli have carried out polymer flooding field experiments. At present, a relatively large scale of polymer production and application has been formed in China, and partially hydrolyzed polyacrylamide is generally used. As the main oil displacing agent. [0003] However, some problems are also exposed during the implementation...

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Problems solved by technology

[0003] However, some problems are also exposed during the implementation of polymer flooding. For example, when the polymer solution deforms or flows during the preparation of the polymer and the entire seepage process of the oil layer, the shear stress it bears increases enough to cause When the polymer molecules are broken, the polymer will be mechanically degraded; in the process of polymer injection in the oil field, the highest flow rate will appear when it is close to the injection well, which will also cause the mechanical degradation of the polymer chain, causing a significant decrease in the viscosity of the polymer, thereby affecting ultimate recovery factor

At present, reserves of the type of oil reservoirs with better conditions are less and less, and high-temperature oil reservoirs are the main replacement resources for increasing reserves and production in the future. Problems such as low viscosity retention rate of the solution cannot meet the requirements of high temperature reservoirs

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