Thermal-resistance and salt-tolerance dispersed gel nitrogen foam composite profile control system and preparation method therefor

Abstract

The invention belongs to the field of oilfield chemistry, and particularly relates to a thermal-resistance and salt-tolerance dispersed gel nitrogen foam composite profile control system. The thermal-resistance and salt-tolerance dispersed gel nitrogen foam composite profile control system comprises a gas phase and a liquid phase, wherein the gas phase is nitrogen, and the liquid phase comprises a foaming agent, a foam stabilizer and a liquid dosing water and the balance of water; the mass fraction of the foaming agent in the total mass of the liquid phase is 0.1% to 0.4%, the mass fraction of the foam stabilizer in the total mass of the liquid phase is 0.05% to 0.15%, and the sum of the mass fractions of the components is 100%; and the gas-liquid ratio of the gas phase to the liquid phase is controlled to be 3-5: 1. An adopted nanoscale or micron-sized dispersed gel has good foaming and foam stabilizing synergistic effect with a betaine ampholytic surfactant, the swept volume and displacement efficiency of the foam composite profile control system are improved to the maximum extent, the system can be resistant to the temperature of 130 DEG C, the total salinity of 17*104 mg / L, the calcium ions of 1.0*104 mg / L and the magnesium ions of 1.0*104 mg / L, and the profile control effect of a high temperature and high salt oil deposit can be improved to the maximum extent.

Description

Technical field [0001] The invention belongs to the field of oilfield chemistry, and specifically relates to a phenolic resin gel dispersion nitrogen foam composite control and flooding system for deep control and flooding of high-temperature and high-salt oil reservoirs and a preparation method thereof. Background technique [0002] With the further exploration and development of conventional oil reservoirs, the oil layers are getting deeper and deeper, and the reservoir temperature and salinity are getting higher and higher, and the high temperature (> 80℃), high salt (> 2.0×10 4 mg / L) oil reservoirs have large reserves in the North China Oilfield, Dagang Oilfield, Zhongyuan Oilfield, Tarim Oilfield and other oilfields, but these oilfields have entered the "double high" stage of high water cut and high recovery. Water flooding is inefficient or Ineffective circulation, resulting in a large amount of remaining oil remaining in the formation unusable. Therefore, how to incr...

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Problems solved by technology

However, polymers are greatly affected by temperature and salinity, and there are problems of thermal degradation and salt-sensitive effects, as well as chemical degradation and shear degradation, poor stability, and low viscosity retention; foam systems with gel as the external phase, The gel-forming liquid is greatly affected by the injection equipment and formation pore shear and the physical and chemical properties of the formation during the injection into the formation, which affects the gel-forming performance and the stability of the gel-foam system

CN102746841A discloses a composite foam system with nanoparticles added for oil fields. The system is composed of anionic surfactants, modified silica nanoparticles, counter ion salts and the rest of water, and is suitable for oil with a temperature not exceeding 80°C. Because the foam stabilization system is modified silica inorganic particles, the system has no viscosity, and the foam is only stabilized by adsorption on the surface of the foam liquid film, and the foam stabilization ability is limited; in addition, affected by high temperature, high salt and reservoir fluid, the modified The surface properties of silica inorganic particles are easy to change, which affects the foam stabilization effect

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