Thixotropy high-strength gel diverting agent

Abstract

The invention relates to a thixotropy high-intensity gel diverting agent which is used for high water-cut oil field cracks and the plugging of extra-high permeable zone channeling path. The process for preparation comprise the following steps: adding xanthan gum (XC) 0.1%-1%, chromic acetate 0.001-0.1%, 0.025-0.5% thixotropic control system of mixed solution of ammonium phosphate and monoammonium phosphate in a nomer solution system which is formed by conventional acrylamide monomer, wherein the viscosity is 12.6-32.0MPa.S under the temperature scope which is 30-80 DEG C, and shearing speed which is 100s-1, wherein viscosity can rapidly backs up to 50-100 times in 30 min under low-shearing state in carks and big pore path, the intensity G' is 0.5-1Pa, effectively protecting plugging agent solution system from being diluted by water, guaranteeing the stability of each water soluble component ratio of the plugging agent system, and the final gelling time is 2-10 hours, which can be controlled, and the final intensity G' is 200-500 Pa.

Description

technical field [0001] The invention relates to a thixotropic high-strength gel-steering agent used for plugging channeling passages such as fractures in high water-cut oilfields and ultra-high permeability zones. Background technique [0002] Water injection development is a development method commonly used in my country's oilfields. At present, the annual water injection volume of the eastern oilfield alone is nearly 700 million m 3 , The cost of water injection is more than 4 billion yuan. However, the existence of a large number of fractures, high-permeability strips and other water-flow dominant channels in the reservoir leads to inefficient or ineffective circulation of injected water along the high-permeability dominant channels, causing problems such as high water cut in the oil field and a substantial increase in oil production costs, resulting in a huge waste of resources. [0003] It has become the main body and focus of the development work of old oilfields to i...

AI Technical Summary

Problems solved by technology

[0006] (1) During the migration of the solution in the large pores and hyperpermeable strips and the process of polymerizing and cross-linking to form a gel under formation conditions, it is very easy to be diluted under the action of reservoir formation water, and the dilution will cause the monomer solution system The change of the proportion of each reaction component leads to the failure of the monomer solution system to form a gel, or the performance of the formed gel is reduced, which cannot meet the design requirements, resulting in the failure or poor effect of the operation measures;

[0007] (2) The system tends to enter the low-permeability non-target layer too much, causing unnecessary formation pollution and damaging the production layer

During the migration of the solution in the large pores and hypertonic strips and the process of standing still and polymerizing and cross-linking to form a gel under the formation conditions, the higher the viscosity itself, the more it can prevent the dilution of the formation water, and the more it can reduce It has the ability to enter the low-permeability non-target layer, but the high viscosity will bring difficulties to the pumping of the system at the same time