An underground cross-linked resin plugging agent prepared by seawater and its application

Abstract

The invention provides an underground cross-linking type resin plugging agent prepared from seawater and application thereof. The underground cross-linking type resin plugging agent includes 3 wt% to7 wt% of sulfonated resol phenolic prepolymer, 2wt% to 4wt% of curing agent, 0.1wt% to 0.3wt% of coagulant, and the balance water. The sulfonated resol phenolic prepolymer sulfonate functional groupsimpart good water solubility of an anionic polymer in brine, and a phenoxy ether bond structure ensures the crosslinked body coating and water retaining capability. The cross-linking type resin plugging agent can be prepared from the seawater or saline with a higher degree of mineralization, can selectively enter a deep part of a high-permeability formation by general injection to delay the polycondensation and curing to form a thermosetting and thermal inertia resin gel which retains water highly. Under high temperature and high humidity formation conditions, the underground cross-linking type resin plugging agent can withstand formation differential pressure, water flow thrust and suction force of near-well zone negative pressure operation on the plugging agent for a long term.

Description

technical field [0001] This specification relates to an underground cross-linked resin plugging regulator that can be prepared from seawater and its application. Background technique [0002] my country's offshore reserves are rich in oil and gas resources, and the efficient development of offshore oilfields is becoming more and more important to national economic development and national energy security. However, offshore oilfields have thick reservoirs, good permeability, and serious horizontal and vertical heterogeneity, and the service life of offshore oil production platforms is generally limited to only 15-20 years. Strong production or early polymer injection and other development methods to improve short-term return on investment, resulting in a crude oil recovery rate of less than 15%, and an oil recovery rate of only 1-2%. The recovery degree of onshore oilfields is generally higher than 50%. The water cut of oil wells in offshore oilfields rises rapidly, and the...

AI Technical Summary

Problems solved by technology

However, the existing problem is that the resole phenolic prepolymer is an anionic low-molecular polymer, and the anions and cations undergo electrical neutralization reactions in salt water, lack of intermolecular electrostatic repulsion, and the irregular thermal movement of the molecules leads to the instability of the prepolymer, flocculation and precipitation.

In the prior art, the salt-resistant modification of phenolic resin is mainly concentrated in the field of concrete water reducer; however, the sulfonation reaction in this method mainly occurs at the ortho-para position of phenol, and the cross-linked body formed by addition and polycondensation of formaldehyde is in the There are a large number of leakage points on the spatial network structure, and the binding and water-locking capabilities are poor, and it is still impossible to solidify and seal in seawater

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