Temperature-sensitive and salt-sensitive copolymer gel and preparation method thereof

Abstract

The invention discloses a temperature-sensitive and salt-sensitive copolymer gel. The temperature-sensitive and salt-sensitive copolymer gel is prepared from the following raw materials of acrylamide,functional monomers and starch through crosslinking and polymerizing. The temperature-sensitive and salt-sensitive copolymer gel is prepared by the following steps of (1) adding the starch into water, stirring, and pasting to the complete transparent state in a 75-DEG C constant-temperature water bath pot, so as to obtain a starch water solution; (2) adding the acrylamide and the functional monomers into the starch water solution, so as to obtain a first reaction solution; (3) adding a crosslinking agent and a free radical initiator into the first reaction solution, uniformly stirring, sealing a reaction container, and reacting for 24 to 36h at the temperature of 60 to 70 DEG C, so as to obtain a crude gel; (4) adding the crude gel into pure water, soaking and stirring for 12h, and drying, so as to obtain the temperature-sensitive and salt-sensitive copolymer gel. The synthesized temperature-sensitive and salt-sensitive copolymer gel has the characteristics that the temperature-sensitive and salt-sensitive properties with high expansion rate at high temperature and high salt condition are realized, and the like; by using the starch as a substrate for grafting and copolymerizing, the degradability of the gel is realized; the damage to stratum is little, the environment-friendly effect is realized, and the modern green development value is met.

Description

technical field [0001] The patent belongs to the field of petroleum exploitation, and specifically relates to a temperature-sensitive salt-sensitive copolymer gel water blocking agent and a preparation method thereof. Background technique [0002] Oilfield development generally enters the high water cut stage in the middle and late stages. Due to the original heterogeneity of the reservoir formation and the long-term water flooding, the heterogeneity is further aggravated. The injected water mainly flows into the high permeability zone, forming a water flow dominant channel, thereby reducing Sweep efficiency of injected water. Using cross-linked polymer gel to control the profile control and water shutoff of the dominant water flow channel to improve the sweep efficiency of water flooding and oil recovery is currently the most widely used profile control water shutoff and deep water flow diversion technology at home and abroad. The cross-linked gel involved in this technolo...

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Problems solved by technology

[0007] Another purpose of the present invention is to solve the problem that the existing water blocking agent has poor temperature and salt resistance, is easy to dehydrate and flocculate, is not suitable for use in high salinity oil layers, and cannot form a good plugging technology for high temperature and high salt oil reservoirs question

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