CN-121006209-B - Salt-resistant oil displacement system for alkali-free binary compound flooding, and preparation method and application thereof

CN121006209BCN 121006209 BCN121006209 BCN 121006209BCN-121006209-B

Abstract

The application relates to a salt-tolerant oil displacement system for alkali-free binary compound flooding and a preparation method and application thereof, and belongs to the technical field of oil extraction. The oil displacement system comprises 0.1-0.5wt% of amino silane coupling agent modified xanthan gum, 0.1-0.5wt% of surfactant, 0.05-0.2wt% of high-temperature stabilizer, 0.05-0.1wt% of chitosan quaternary ammonium salt, 0.05-0.1wt% of silane coupling agent modified nano silicon dioxide and the balance of water, wherein the high-temperature stabilizer is one or more of polyvinyl alcohol, polyethylene glycol and polypropylene glycol. The oil displacement system provided by the application is prepared by compounding the xanthan gum serving as a core compound and the surfactant, is an alkali-free binary compound oil displacement system for driving, utilizes the advantage of high salt resistance of the xanthan gum, improves the defects of poor water solubility, easiness in high temperature decomposition and easiness in bacterial degradation, obviously improves the profile control performance, and can be used in a high-salt high-temperature environment.

Inventors

SONG XINWANG
ZHANG PENGTU
WANG XUDONG
GUO YANG
YIN SHUMING

Assignees

山东石油化工学院

Dates

Publication Date: 20260512
Application Date: 20251027

Claims (4)

1. The salt-resistant oil displacement system for alkali-free binary composite flooding is characterized by comprising the following components of 0.1-0.5wt% of amino silane coupling agent modified xanthan gum, 0.1-0.5wt% of surfactant, 0.05-0.2wt% of high-temperature stabilizer, 0.05-0.1wt% of chitosan quaternary ammonium salt, 0.05-0.1wt% of silane coupling agent modified nano silicon dioxide and the balance of water; The surfactant is selected from one or more of tetradecyl dipropyl hydroxypropyl sulfobetaine, hexadecyl dipropyl carboxyl betaine or octadecyl dipropyl hydroxypropyl sulfobetaine; The high-temperature stabilizer is one or more of polyvinyl alcohol, polyethylene glycol and polypropylene glycol; The preparation method of the amino silane coupling agent modified xanthan gum comprises the steps of adding water into the xanthan gum, stirring uniformly, and then adding an amino silane coupling agent with the dosage of 2-5wt% of the xanthan gum for stirring reaction, wherein the amino silane coupling agent is one or more of N-beta-aminoethyl-gamma-aminopropyl trimethoxysilane, bis (gamma-trimethoxysilylpropyl) amine and N-phenyl-gamma-aminopropyl trimethoxysilane; The preparation method of the gamma- (methacryloyloxy) propyl trimethoxysilane modified nano silicon dioxide comprises the steps of adding nano silicon dioxide into water to be uniformly dispersed to obtain silicon dioxide suspension, adding acidified gamma- (methacryloyloxy) propyl trimethoxysilane into the silicon dioxide suspension, and then carrying out heating reflux reaction to obtain the gamma- (methacryloyloxy) propyl trimethoxysilane modified nano silicon dioxide.
2. The alkali-free binary compound flooding salt-tolerant oil displacement system according to claim 1, wherein the molecular weight of the chitosan quaternary ammonium salt is 20-50 ten thousand, and/or, The molecular weight of the xanthan gum raw material is 300-500 ten thousand, and/or, The average grain diameter of the nano silicon dioxide raw material is 100-300 nm, and/or, The molecular weight of the high-temperature stabilizer is 10000-30000.
3. The method for preparing the salt-tolerant oil displacement system for alkali-free binary composite flooding according to claim 1 or 2, which is characterized by comprising the step of dissolving an aminosilane coupling agent modified xanthan gum, a surfactant, a high-temperature stabilizer, chitosan quaternary ammonium salt and silane coupling agent modified nano silicon dioxide in water to prepare a mixed solution.
4. The use of the salt-tolerant flooding system for alkali-free binary composite flooding according to claim 1 or 2 in reservoir flooding.

Description

Salt-resistant oil displacement system for alkali-free binary compound flooding, and preparation method and application thereof Technical Field The application relates to a salt-tolerant oil displacement system for alkali-free binary compound flooding and a preparation method and application thereof, and belongs to the technical field of oil extraction. Background Polymer flooding is realized by adding polymer into water phase, increasing the viscosity of water, reducing the water-oil fluidity ratio, and simultaneously reducing the relative permeability of water, thereby realizing the adjustment of water absorption profile and improving the swept volume of water phase. The polymer solution is a viscoelastic fluid, and the residual oil which is generated by the tensile deformation and the viscoelastic effect and is not easy to be affected in the pore cracks is changed into a silk wadding state in the pore canal or pushed by a piston type, so that the residual oil is displaced by the polymer solution, thereby improving the oil washing efficiency. However, in high temperature, hypersalinity reservoirs, polymer molecules are prone to curling resulting in reduced mobility control. The partially Hydrolyzed Polyacrylamide (HPAM) is the most widely used synthetic polymer, the synthetic raw materials of the partially hydrolyzed polyacrylamide are easy to obtain, the synthetic mode is simple, the cost is low, the industrial production is easy, the viscosity increasing performance is good, and the polymer has the greatest application of polymer flooding. However, HPAM is affected by high temperature and high mineralization and microbial activity in porous medium, and is extremely easy to degrade to cause viscosity loss, and has poor high-salt and high-temperature resistance. The natural polymer xanthan gum shown in fig. 1 is a high molecular biological polysaccharide, has a double helix structure at low temperature, but the double helix structure gradually changes into disordered helix along with the rise of temperature, and has the problem of no high temperature resistance, however, xanthan gum has better high salt resistance than HPAM, and is more stable than HPAM under higher mineralization degree, so that the xanthan gum is more suitable for high salt conditions, and the problem of easy degradation of both the xanthan gum and the HPAM under high temperature conditions exists. Xanthan gum has less application in polymer flooding relative to HPAM. The prior art patent CN111849447B discloses a method for modifying xanthan gum and a modified xanthan gum oil displacement agent, which utilize phenylboronic acid polymer to modify the xanthan gum, so that the viscosity, the ageing resistance and the anti-interference performance on ethylene glycol and 1, 3-propylene glycol of the xanthan gum are improved. However, the performance requirements of the oil displacement agent in the environment of high salt resistance and high temperature resistance are not paid much attention, and in addition, the problem that the xanthan gum is easily influenced by the degradation of stratum bacteria when in use still exists. Therefore, the oil displacement system for binary compound flooding with xanthan gum as a polymer and no alkali is provided under the condition of high salt and high temperature, and the oil displacement effect is improved. Disclosure of Invention In order to solve the problems, the salt-resistant oil displacement system for alkali-free binary composite flooding and the preparation method and application thereof are provided, and the oil displacement system is compounded by taking xanthan gum as a core compound and a surfactant, utilizes the high salt resistance advantage of the xanthan gum, and improves the defects of poor water solubility, easy decomposition at high temperature and easy influence of microorganisms, so that the oil displacement system is suitable for high-temperature and high-salt environments, has better oil displacement performance, and particularly has obvious improvement effect on profile control performance. The application provides a salt-resistant oil displacement system for alkali-free binary compound flooding, which is characterized by comprising the following components of 0.1-0.5wt% of amino silane coupling agent modified xanthan gum, 0.1-0.5wt% of surfactant, 0.05-0.2wt% of high-temperature stabilizer, 0.05-0.1wt% of chitosan quaternary ammonium salt, 0.05-0.1wt% of silane coupling agent modified nano silicon dioxide and the balance of water; The high-temperature stabilizer is one or more of polyvinyl alcohol, polyethylene glycol and polypropylene glycol. Optionally, the aminosilane coupling agent in the aminosilane coupling agent modified xanthan gum is a bisaminosilane coupling agent; The double amino silane coupling agent is selected from one or more of N-beta-aminoethyl-gamma-aminopropyl trimethoxy silane, bis (gamma-trimethoxy silylpropyl) amine and N-phenyl-gamma-aminopropyl trimetho