Cation polypropylene amides gel micro-ball and preparation method thereof

Abstract

The invention discloses a cation polyacrylamide gel microsphere and preparation method thereof. Molecular weight of the polyacrylamide gel is 10-30 millions, and diameter of the microsphere is 2-80 micron. The preparation method includes steps: mixing acrylamide monomer, methacryloyloxyethyl trimethyl ammonium chloride, N,N-methylene diacrylamide and ammonium persulphate to confect water solution, atomizing the water solution by compressed air, spraying the solution by atomization nozzle with aperture of 2-80 micron to oil phase of 80-120 DEG C for carrying suspension polymerization reaction and forming cation gel microsphere which size can be controlled by adjusting nozzle aperture according to oil layer rock pore scale. The cation gel microsphere is injected to oil layer with water in succeeding water drive after polymer drive, cross links with anion polymer remained in oil layer by positive and negative charge, and forms space meshy three-dimensional structure, thereby increasing flow resistance greatly, enhancing oil layer wave and coefficient again, and improving crude oil recovery ratio.

Description

Technical field: [0001] The invention relates to a new material for improving oil recovery by using residual polymer in oil layer after polymer flooding in oil field and a preparation method thereof. The material is a cationic polymer gel, which can pass through the anionic polymer remaining in the oil layer Positive and negative charges are cross-linked to form a three-dimensional space network structure, thereby greatly increasing the flow resistance, increasing the oil layer sweep coefficient again, and enhancing oil recovery. Background technique: [0002] Polymer flooding is currently the world's most mature and largest chemical flooding EOR method, especially in my country's Daqing, Shengli and other oil fields, polymer flooding has seen obvious effects of increasing oil production, reducing water loss and enhancing oil recovery. It has made a great contribution to the stable production of the oil field. However, about 50% of the remaining oil remains in the formation ...

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Problems solved by technology

Gel is a semi-solid substance with a strength between fluid and solid. It is a colloidal dispersion gel formed underground with trivalent aluminum ions, trivalent chromium ions, etc. and polyacrylamide solution (US patent US 4974477, etc.) It has been proved that there is a good diversion ability of deep liquid flow, which can increase the swept volume of the oil layer, but the gel formed by cross-linking in the underground is affected by the formation temperature, salinity and the adsorption of various components by the rock, so it is difficult to form a gel

Liu Yuzhang et al. (Chinese Patent No. 98120664.6) used a pre-crosslinking method to synthesize gels on the ground, and then dried them into solids and crushed them into pre-crosslinked particles with a particle size of 0.1 to 3000 microns for profile control in water wells. It is a neutral particle, uncharged, does not cross-link with the anionic polymer remaining in the oil layer, and cannot reuse the anionic polymer remaining in the oil layer, and the solid particle size is large and made by crushing, the particle size is extremely large Irregular, poor migration ability in the reservoir

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