Preparation method of high temperature-resistant and high salt-resistant type polymer gelatinizing agent for profile control and water shutoff

Abstract

The invention discloses a preparation method of a high temperature-resistant and high salt-resistant type polymer gelatinizing agent for profile control and water shutoff. The preparation method is characterized in that a plurality of temperature-resistant, salt-resistant and hydrolysis-resistant functional monomers are introduced into the synthesizing process of the polymer, a proper amount of modifying additive is added, and a molecular main chain is designed to properly adjust the molar percentage of functional monomer and amide group, so that the synthesized polymer has higher gelatinizing strength and better heat stability through crosslinking under the extreme oil reservoir conditions of temperature higher than or equal to 110 DEG C and mineralizing degree more than or equal to 100000ppm; the enough crosslinking time is guaranteed, and the effective shutoff effect is realized under the strict oil reservoir condition; in the granulating process, a small amount of stabilizer is introduced, and the dissolvability and heat stability of the polymer are further improved; the viscosity average molecular weigh of the polymer is low and is less than 10000000ppm, the dissolvability is better, and the gelatinizing type profile control and water shutoff agent crosslinked with the organic crosslinking agent has strong high temperature-resistant and high salt-resistant ability, free and controllable gelatinizing time, high gelatinizing strength and better heat stability.

Description

technical field [0001] The invention belongs to the field of oil well water shutoff, and in particular relates to a preparation method of a polymer gelling agent for high temperature and high salt profile control and water shutoff. Background technique [0002] At present, most domestic onshore oil fields are in the middle and late stages of development, and water production from oil wells has become a serious problem affecting crude oil recovery. A large amount of water from oil wells will greatly increase development costs, and aggravate pipeline corrosion and scaling, so it is very necessary to shut off oil wells. [0003] The mechanical water plugging method is often used in the early stage of oilfield development, but in the middle and late stages of development, due to water flooding, water channeling, water cones and other phenomena, mechanical methods alone cannot meet the water plugging requirements, and chemical water plugging methods are required at this time . ...

AI Technical Summary

Problems solved by technology

[0004] Polyacrylamide gel water blocking agent is a kind of chemical water blocking agent widely studied and applied. It is generally obtained by directly preparing acrylamide polymer and crosslinking agent, but this kind of gel water blocking agent has shown The following problems: one is that the viscosity-average molecular weight of the polymer used is higher, which can cause the macromolecule retention damage of the reservoir channel; the second is that the injection ability of the gel in the low-permeability formation is poor, which brings difficulties to the field construction; the third is Gel is used in high-temperature and high-salt deep wells. In order to ensure that it can be injected into the destination layer before gelation, it is difficult to well control the delayed gelation time of gelation and the thermal stability of gelation is poor; the fourth is currently the most widely used in my country. The most widely used are polymer chromium gels, which have good shear resistance and can effectively regulate plugging. However, chromium gels have poor thermal stability, dehydration and degradation rates are fast above 100°C, and heavy metal ions seriously pollute groundwater.