Intramolecular Al cross-linked polymer gel and its prepn

Abstract

The present invention relates to one kind of intramolecular Al3+ cross-linked polymer gel and its preparation process. The gel cross-linking reaction happens mainly between the branch chains inside the identical polymer molecule to form í‹localíŒ netted molecular configuration. The polymer gel has basically unchanged viscosity before and after the gel is formed, and can flow in porous medium with flow resistance obviously greater than that of polymer solution in the same viscosity and residual resistance coefficient greater than the resistance coefficient. The polymer gel features consists of partially hydrolyzed polyacrylamide 0.04-0.08 wt%, aluminum citrate 0.01-0.04 wt%, and NaCl or KCl mineralization degree regulator 0.05-1.0 wt% except oil field sewage. The polymer gel has excellent profile modifying characteristic.

Description

Technical field: [0001] The invention relates to an auxiliary agent for adjusting the liquid absorption profile of an oil field water injection well or for oil displacement, especially a kind of intramolecular Al 3+ Cross-linked polymer gel and method for its preparation. Background technique: [0002] With the continuous increase of comprehensive water cut in domestic waterflood development oilfields, how to reduce the inefficient and ineffective circulation of injected water in high permeability layers or large pores, and expand the swept volume of medium and low permeability layers has become a major technical problem in the process of oilfield development . At present, the plugging agent (referred to as profile control agent) commonly used in oilfields to adjust the liquid absorption profile of water injection wells mainly includes Al 3+ 、Cr 3+ Polymer gels and solid particles such as clay, oil well production sludge, fly ash and zeolite as cross-linking agents with c...

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Problems solved by technology

[0004] Compared with the indoor conditions, the preparation and gelation process of the mine is restricted by factors such as the "complex chemical environment" of the reservoir, "small and poorly continuous pore space environment" and "flow and shear action", resulting in the accumulation of oil in the reservoir. The large-scale "intermolecular" cross-linking reaction cannot be achieved by the material molecules, and the "intra-molecular" cross-linking reaction has become extremely difficult, which is the root cause of the poor application effect of cross-linked polymer mines

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