CN110746310B

CN110746310B - Preparation method of low-permeability oil reservoir water lock release agent

Info

Publication number: CN110746310B
Application number: CN201910986644.5A
Authority: CN
Inventors: 麻金海; 孔淑玲; 方龙
Original assignee: Qingdao University
Current assignee: Qingdao University
Priority date: 2019-10-12
Filing date: 2019-10-12
Publication date: 2023-05-26
Anticipated expiration: 2039-10-12
Also published as: CN110746310A

Abstract

The invention relates to a method for preparing a novel low-permeability oil reservoir water lock remover by taking 2, 4-difluorobenzyl chloride and amantadine as main raw materials. The invention takes ethanol as solvent and reaction medium, takes potassium hydroxide as catalyst, and reacts 2, 4-difluorobenzyl chloride with amantadine according to the proportion of 3:1 to quaternize the amino group of the amantadine, thus preparing the water-soluble molecule with certain monodispersity. The molecular water solution has lower viscosity and stronger permeability, has excellent water locking unlocking capability on a low-permeability water locking core, has reliable preparation process, and provides a novel preparation method of the ultralow-permeability oil reservoir water locking release agent.

Description

Preparation method of low-permeability oil reservoir water lock release agent

Technical Field

The invention belongs to the field of oil extraction aids in oil fields, and particularly relates to a method for preparing a low-permeability oil reservoir water lock remover from 2, 4-difluorobenzyl chloride and amantadine serving as main raw materials.

Background

The hypotonic ultra-hypotonic oil reservoir accounts for about 17.5% of the petroleum geological reserves in China, but is up to 60.8% of the detected unused geological reserves, and the proportion of the hypotonic oil reservoir to the detected geological reserves is higher along with the progress of exploration technology. In addition, in the processes of drilling, well completion, well repair and oil and gas development, the permeability of the reservoir is reduced due to unreasonable operation measures; in the porous medium, a layer of thin liquid system with different physical and chemical properties from liquid phase is adsorbed on the rock surface, so that the permeability of the reservoir is further reduced. The low permeability reservoir has the characteristics of high content of the clay cementing agent, high water saturation, high capillary pressure, tiny pore throat, serious heterogeneity and the like, is extremely easy to generate water locking damage due to invasion of external fluid in the drilling and production process, and is difficult to recover once damaged. Studies have shown that water-lock damage is the most predominant, most severe type of damage in hypotonic ultra-hypotonic reservoirs, with rates of up to 70% and even up to 90% in some fields. The method for removing the water lock mainly comprises chemical removal, physical removal and physical-chemical coupling removal, but the three methods have the defects that the physical method has high energy consumption, the depth of removal is insufficient, and the chemical method has low removal efficiency. Therefore, improving the efficiency of chemical stripping is a major approach to unlock reservoir water lock. At present, a large number of chemical water unlocking agents are studied at home and abroad, mainly comprise a biosurfactant and a nonionic fluorine-containing polymer surfactant, wherein the biosurfactant can form a hydrophobic environment in an oil layer, so that the oil-water starting pressure is reduced, and the water locking benefit is reduced; the latter can change reservoir wettability and has strong temperature resistance and salt resistance. Although the above chemical agents can solve the problem of water lock of a part of oil reservoirs, for ultra-low permeability oil reservoirs, adsorption on the inner surfaces of pores can lead to the reduction of the oil reservoir permeability due to the large molecular weight. Therefore, developing a small molecular water lock remover is a practical need for the production of oil field ultra-low permeability reservoirs.

The invention takes 2, 4-difluorobenzyl chloride and amantadine as main raw materials to prepare the low-permeability oil reservoir water lock remover, which can remove the water lock of the core with ultra-low permeability and remarkably improve the permeability of the water lock core. Wherein quaternary ammonium cations generated by the amino groups of amantadine and 2, 4-difluorobenzyl chloride can be strongly combined with the inner surface of the negatively charged core pores through electrostatic interaction; whereas 2, 4-difluorobenzyl and adamantane fragments are able to form a strong hydrophobic environment. The molecules are generally made to exhibit excellent low permeability core water lock release capability.

Disclosure of Invention

The invention takes ethanol as solvent and reaction medium, takes potassium hydroxide as catalyst, and reacts 2, 4-difluorobenzyl chloride with amantadine according to the mol ratio of 3:1, so as to quaternize the amino group of the amantadine, thus preparing the water-soluble molecule with certain monodispersity. The molecular water solution has extremely low viscosity, strong permeability, excellent water lock unlocking capability on a low-permeability water lock core, and reliable preparation process, and provides a preparation method of the ultralow-permeability oil reservoir water lock release agent.

Detailed Description

Example 1

4.50 g of amantadine and 100mL of absolute ethyl alcohol are added into a 250mL three-port reaction bottle, stirred and dissolved, then 0.5 g of powdery potassium hydroxide is added, stirred and heated to 65 ℃, then 14.65 g of 2, 4-difluorobenzyl chloride solid powder is slowly added in batches, 2 hours are needed, after the addition is finished, the reaction is carried out for 3 hours at 65 ℃, and the mixture is cooled to room temperature, so that light yellow transparent uniform liquid is obtained.

Example 2

The samples prepared in example 1 were weighed accurately, and dissolved in clear water with stirring to prepare drug solutions having drug concentrations of 0.3%, 0.5%, 1.0%, 3.0%, 5.0% and 10.0%, respectively. Measuring the viscosity of various concentration reagent solutions at 30 ℃, 50 ℃ and 70 ℃ by using a BROOKFILD DV-III+ type rheometer; the results are shown in Table 1.

TABLE 1 viscosity (mPa.s) of solutions of different concentrations of a pharmaceutical agent at different temperatures

Example 3

And selecting oil well cores of different low-permeability oil reservoir blocks of the victory oil field, and preparing the standard core with the length multiplied by the radius of 2.5cm multiplied by 2.5 cm. Washing oil, drying, numbering, vacuumizing and measuring air permeability; simulated formation water having a saturation mineralization of 30000mg/L (wherein ca2+ content is 150 mg/L); accurately weighing the sample prepared in the example 1, and preparing medicament solutions with medicament concentrations of 0.3%, 0.5%, 1.0% and 3.0% by using the same simulated formation water; the displacement of the injection pump is selected to be 1mL/min, the liquid medicine with different concentrations and the simulated formation water are respectively injected at the same displacement at 25 ℃, the permeability of the core to the different fluids is measured, and the results are shown in tables 2, 3, 4 and 5.

Table 2 permeability of oil well core to solutions of different agent concentrations (mDc)

Table 3 permeability of No. two oil well cores to solutions of different agent concentrations (mDc)

Table 4 permeability of No. three oil well cores to solutions of different agent concentrations (mDc)

Table 5 permeability of No. four oil well cores to solutions of different agent concentrations (mDc)

/>

Claims

1. A method for preparing a low-permeability oil reservoir water lock remover by using 2, 4-difluorobenzyl chloride and amantadine as main raw materials comprises the following steps: