Large-pore-path plugging compound water shutoff agent for sandstone reservoir and preparation method of large-pore-path plugging compound water shutoff agent

Abstract

The invention provides a large-pore-path plugging compound water shutoff agent for a sandstone reservoir. The large-pore-path plugging compound water shutoff agent comprises the following components by mass percent: 10-20% of superfine cement, 5-10% of clay, 4-8% of silica powder, 0-0.5% of an early strength agent, 1-2% of a fluid loss agent, 5-10% of an oil-soluble polymer, 3-5% of oil-soluble fibers, 2-5% of a water-soluble polymer, 1-2% of an active agent and 35-70% of water, wherein the total mass percent of the components is 100%. The invention further provides a preparation method of thelarge-pore-path plugging compound water shutoff agent. The large-pore-path plugging compound water shutoff agent for the sandstone reservoir has the following beneficial effects: the strength is high, the erosion resisting effect is excellent, and the construction effect is guaranteed; the components can be appropriately adjusted to adapt to different well conditions; safe injection is ensured, and the water plugging radius is increased; and the preparation is easy, the pump injection performance is favorable, the construction process is simple and the construction efficiency is high.

Description

technical field [0001] The invention relates to a large pore channel sealing agent for water wells, in particular to a composite water shutoff agent for large pore channel sealing in sandstone oil reservoirs and a preparation method thereof. Background technique [0002] In the process of water flooding development, due to the difference in physical properties between reservoirs, the injected water will be fingered along the high-permeability channel, and the water flooding effect will be poor, which will lead to intensified production contradictions of the well group and a large bottom water body. During the production process, once the bottom water breaks through and enters the reservoir, the water cut of the oil well rises rapidly, resulting in a sharp drop in production. At present, most of the water shutoff agents used in oilfields are polymer jelly, conventional cement or precipitation water shutoff agent; polymer jelly will degrade under high temperature and high sali...

AI Technical Summary

Problems solved by technology

[0002] During the water injection development process, due to the difference in physical properties between the reservoirs, the injected water will point along the high-permeability channel, and the water flooding effect will be poor, which will lead to the intensification of the production contradiction of the well group, and at the same time, there will be a large bottom water body

During the production process, once the bottom water breaks through and enters the reservoir, the water cut of the oil well rises rapidly, resulting in a sharp drop in production

At present, most of the water shutoff agents used in oilfields are polymer jelly, conventional cement or precipitation water shutoff agent; polymer jelly will degrade under high temperature and high salinity formation conditions, and the solution viscosity is high, the pump The injection resistance is large, and it is easy to block pipelines and other equipment; conventional cement is easy to leak and pollute the production layer, and the water blocking radius is small, and the effective water blocking range is small; the precipitation type water blocking agent has low strength, short validity period, and increased overall cost. Meet oilfield production needs

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