A Particle Size Matching Method of Polymer Microspheres in Low Permeability Reservoirs

Abstract

The invention discloses a method for matching particle sizes of polymer microspheres in a low-permeability oil reservoir. The method comprises the steps that a reverse phase suspension polymerizationmethod is selected to synthesize the polymer microspheres; polymer microspheres with different particle sizes are blocked off by adopting a sand-filled pipe for test, simulative formation water is injected until inlet and outlet displacement pressure difference is stable; a polymer microsphere solution and simulative formation water are injected until the inlet and outlet displacement pressure difference is stable, the inlet and outlet displacement pressure difference is collected, and sand-filled pipe permeability and stemming rate are calculated; the polymer microsphere particle size required for a field test is determined according to a YPS particle size matching formula; on-line injection of polymer microspheres is performed, injection quantity per day of an injection well is not changed, and a regulating and driving effect of the polymer microspheres is evaluated through average oil production per day per well of a plot and a water content rate change curve. The method utilizes agood effect of deep regulating and driving of the polymer microspheres to verify the scientificity and practicability of the particle size matching method guided by a theoretical calculation method ofincreasing specific surface and reducing permeability.

Description

Technical field [0001] The invention relates to the technical field of water injection development for low-permeability oilfields, in particular to a method for matching the particle size of polymer microspheres based on the theory of increasing specific surface area and reducing permeability. Background technique [0002] Changqing Oilfield is a typical "low pressure, low permeability, and low yield" reservoir. Due to the strong heterogeneity of the reservoir, as the oil field develops, the injected water often bursts along the high permeability layer, and the degree of artificial water flooding is relatively controlled. Low, serious interference in the interlayer, high dispersion of remaining oil, greatly reducing the recovery rate of water flooding, therefore, increasing the swept volume of injected water is an important method to improve the recovery rate of crude oil. [0003] However, as the oilfield enters a period of high water cut, the problems of water injection developme...

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Problems solved by technology

[0007] In order to solve the technical situation that the existing polymer microsphere particle size matching method is not suitable for low-permeability reservoirs in Changqing Oilfield, the purpose of the present invention is to provide a polymer microsphere particle size based on increasing the specific surface and reducing the permeability. matching method

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