Efficient compound oil displacement agent and preparation method thereof

Abstract

The invention discloses an efficient compound oil displacement agent. The oil displacement agent is prepared from the following raw materials: lignosulfonate, fatty alcohol polyoxyethylene ether sulfonate, xanthan gum, a dimeric surfactant, an anion surfactant, an organic solvent and water. According to the oil displacement agent disclosed by the invention, alkali is not added, so that damages, caused by alkali, on a stratum are reduced and sustainable exploitation of an oilfield is facilitated; the oil displacement agent disclosed by the invention has good thermal stability and high temperature resistance; when the temperature of the stratum is 130 DEG C, the oil displacement agent is not muddy and has no sediment; the effect of reducing interface tension can be effectively expressed andthe anion surfactant and the dimeric surfactant are compounded so that the oil displacement agent can be used for low-pressure and low-permeability oilfields; the oil displacement agent disclosed by the invention can be tightly combined with a sulfur-containing component in thick oil, and moistening and reversed transformation, and crude oil viscosity reduction effects can be expressed better, sothat the viscosity of the thick oil can be remarkably reduced under a utilization condition of relatively low concentration and the recovery ratio is improved.

Description

technical field [0001] The invention belongs to the technical field of petroleum exploitation, and in particular relates to a high-efficiency composite oil displacement agent and a preparation method thereof. Background technique [0002] According to oil production, there are three stages: primary oil recovery, secondary oil recovery and tertiary oil recovery. Primary oil recovery refers to the exploitation of the natural energy of the reservoir, and its recovery rate is less than 15%; secondary oil recovery refers to the use of external supplementary formation energy (such as water injection, gas injection) to maintain the improvement of formation energy, and its recovery rate Up to 45%, tertiary oil recovery is through the injection of other fluids. Use physics, chemistry, heat, biology, etc. to change the properties of reservoir rocks and fluids, and improve the recovery rate of the oil reservoir after water flooding, and the recovery rate can reach 50-90%. Most of my ...

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Problems solved by technology

[0004] With the continuous exploitation of oil, most oilfields on land in my country have entered the late stage of development, that is, the stage of high water cut and ultra-high water cut. Polymer flooding is not suitable for low pressure and low permeability oil fields. ASP flooding is alkali-polymer-surfactant , because the alkali and polymer contained in it have brought great damage to the formations and oil wells near the oil field, and the existing oil displacement agents are not resistant to high temperature and salt, and are not suitable for high temperature, high salt, low pressure, In the exploitation of low-permeability formation oil, and the oil displacement agents such as petroleum sulfonate, alkylbenzene sulfonate, and petroleum carboxylate at the current stage have problems such as unguaranteed source of raw materials and high production costs

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