Slow cross-linking gel for profile control of medium-high temperature oil reservoir and preparation method of slow cross-linking gel

Abstract

The invention relates to slow cross-linking jelly for profile control of medium-high temperature oil reservoirs and a preparation method of the slow cross-linking gel. The gel comprises the following components in percentage by mass: 0.4%-1.0% of a main agent, 0.2%-1.0% of a cross-linking agent, 0.05%-0.2% of a catalyst, 0.3%-1.0% of a stabilizer, 0.025%-0.1% of an accelerant and the balance of water, and the sum of the components is 100%. The main agent is an acrylamide / 2-acrylamide-2-methylpropanesulfonic acid (AM-AMPS) copolymer, the cross-linking agent is melamino-formaldehyde resin, the catalyst is ammonium chloride, the stabilizer is acidic silica sol, and the accelerant is hydroquinone. The slow crosslinking gel for profile control of the medium-high temperature oil reservoir is suitable for water shutoff and profile control of an oil layer with the temperature of 90-110 DEG C and the mineralization degree of 1.0*10<5>-4.0*10<5> mg / L, the gel forming time is controllable within 72-168 hours, and the formed gel is high in strength, can reach the G-I level, is good in stability and can meet the requirements of deep profile control field operation.

Description

technical field [0001] The invention relates to the field of oilfield chemistry, in particular to a slowly cross-linked jelly for profile control in medium-high temperature reservoirs, which can be used as a water shutoff agent for large-dose plugging or deep profile control. Background technique [0002] In the late stage of oilfield water injection development, due to the heterogeneity of the reservoir and the difference in oil-water mobility, etc., water channeling often occurs in the oil well, and the water cut increases sharply. Premature water channeling of oil wells will lead to small reservoir swept volume and low recovery rate. At the same time, it will cause problems such as large sewage treatment volume and pipeline corrosion, which will increase the cost of oil production and easily cause environmental pollution. Profile control and water plugging is an important technology for water control and oil stabilization in high water-cut oilfields, and the key is pluggi...

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Problems solved by technology

Although this type of plugging agent has strong temperature resistance, it is difficult to break through heat and gel breaker once the gel is formed, and the formed jelly is brittle, lacks elasticity, and is difficult to form effective plugging due to weak adhesion.

And the plugging measures carried out by precipitation, such as the patent CN102040975A discloses a silicate water blocking agent, although a kind of silicate water plugging agent with convenient preparation and low price is constructed by sodium silicate, aluminum sulfate, calcium chloride, starch and cement. Salt plugging agent, but its gelation time is short at high temperature, which is not conducive to field application

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