Nanometer drag reducer for sandstone surface pretreatment and preparation method of nanometer drag reducer

Abstract

The invention relates to a nanometer drag reducer for the sandstone surface pretreatment and a preparation method of the nanometer drag reducer. The nanometer drag reducer comprises following components: 5-15% of nano-silica material modified by a silane coupling agent, 25-50% of surfactant and 40-70% of cosurfactant, wherein the surfactant is one or two kinds of an anion active agent, a cation surface active agent, a non-ionic surface active agent and an amphoteric surfactant. The nanometer drag reducer has the advantages that the nanometer drag reducer can be mixed with water in a certain proportion to form an uniform and transparent micro-emulsion, and diesel is replaced by water in the work progress, so that the construction cost is greatly lowered; the nanometer drag reducer can be firmly adsorbed on the surface of rocks so as to form a layer of strong nano hydrophobic membrane, so that the flow resistance of the formation water is effectively reduced and the water flooding effect is enhanced.

Description

technical field [0001] The invention belongs to the technical field of oilfield chemicals, in particular to a nano drag reducer for sandstone surface pretreatment and a preparation method thereof, which is a chemical additive capable of reducing water flow resistance in the near wellbore zone of a water injection well, and is especially suitable for low permeability oilfields Water injection development. Background technique [0002] As an irreplaceable basic energy, petroleum occupies a very important strategic position in the national economy. According to relevant statistics, as of the end of 2002, among the proven oil reserves in my country, the geological reserves of low-permeability oil reservoirs accounted for about 30.9%. The proportion of low-permeability reservoirs will be gradually increased, and low-permeability reservoirs will be an important reserve resource for the stable and increased production of oil and gas in my country for a considerable period of time i...

AI Technical Summary

Problems solved by technology

Only two cases of patents related to nano-drag reducing and injection-increasing agents have been found. Patent 201010138382.6 involves a nano-polysilicon particle and its preparation method and application. The nano-polysilicon particle has a small particle size, uniform distribution, and good hydrophobicity. It has good dispersibility in organic medium, and it has a good application effect on water injection wells in low-permeability oilfields or ultra-low-permeability oilfields as a drag-reducing and injection-increasing agent; the disadvantage is that diesel oil is required to carry it into the well, and the cost is high, and there are transportation, Safety issues in storage and use, etc.

Patent 200910200548.X relates to a water-based oilfield injection booster based on nanomaterials and its preparation method. After the injection booster is mixed with water in a certain proportion and injected into the oilfield by a specific process, the water injection pressure can be significantly reduced. The contact angle of the core surface treated with nano-water-based injection agent solution is greater than 90°, but the disadvantage is that the hydrophobicity is insufficient, which limits the application in oilfield water injection

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