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Low-temperature and high-salinity organic water shutoff gel for oil reservoirs

A high-salinity, organic technology, applied in the direction of chemical instruments and methods, drilling compositions, etc., can solve the problems of long gelation time and low salinity, and achieve improved sweep coefficient, good salt resistance, Improving the effect of formation heterogeneity

Inactive Publication Date: 2021-07-20
CHINA NAT OFFSHORE OIL CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The invention overcomes the deficiencies in the prior art. The existing polymer jelly system for water plugging has the problems of long gelation time and low salinity under low temperature conditions, and provides a low-temperature high-salinity oil reservoir. Organic water blocking gel, the gelling time of the water blocking gel can be adjusted, the formed gel has high strength, good salt resistance, good stability, and the plugging rate of the core can reach more than 93%, which can meet the requirements of the oil reservoir

Method used

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  • Low-temperature and high-salinity organic water shutoff gel for oil reservoirs

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Add 0.2g of polyacrylamide to 99.55g of clear water while stirring, stir for 2h and then let the polymer solution stand for 12h. Then add 0.3 g of phenolic cross-linking agent, 0.05 g of resorcinol, 0.05 g of oxalic acid and 0.05 g of thiourea to the polymer solution successively while stirring, and wait to stir evenly to obtain jelly to form a gel. Its composition is 0.2% of polyacrylamide, 0.3% of phenolic crosslinking agent, 0.05% of resorcinol, 0.05% of oxalic acid, 0.05% of thiourea and 99.55% of water in terms of mass fraction. The time is 114.3h, and the strength of the gel is 62412mPa·s.

Embodiment 2

[0032] Add 0.5g of polyacrylamide to 99.06g of clear water while stirring, stir for 2h and then let the polymer solution stand for 12h. Then add 0.2 g of phenolic cross-linking agent, 0.1 g of resorcinol, 0.07 g of oxalic acid and 0.07 g of thiourea to the polymer solution successively while stirring, and wait to stir evenly to obtain jelly to form a gel. Its composition is 0.5% of polyacrylamide, 0.2% of phenolic crosslinking agent, 0.1% of resorcinol, 0.07% of oxalic acid, 0.07% of thiourea and 99.06% of water in terms of mass fraction. The time is 26.7h, and the strength of the gel is 152372mPa·s.

Embodiment 3

[0034] Add 0.3g of polyacrylamide to 98.9g of clear water while stirring, stir for 2h and then let the polymer solution stand for 12h. Then add 0.4g of phenolic crosslinking agent, 0.2g of accelerator (a mixture of resorcinol and hydroquinone, the mass ratio is 3:1), 0.1g of oxalic acid and 0.1g of thiourea to the polymer solution successively while stirring. , to be stirred evenly to get jelly into glue. Its composition is 0.3% of polyacrylamide, 0.4% of phenolic crosslinking agent, 0.2% of resorcinol, 0.1% of oxalic acid, 0.1% of thiourea and 98.9% of water in terms of mass fraction. The gelation time is 19.5h, and the strength of the gel is 116471mPa·s.

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Abstract

The invention provides a low-temperature and high-salinity organic water shutoff gel for oil reservoirs, which is composed of the following substances in percentage by mass: 0.2-0.5% of main agent, wherein anionic polyacrylamide is selected, the weight-average molecular mass is 18*10<6>-24*10<6>, and the hydrolysis degree is 18-23%; 0.2-0.4% of a cross-linking agent, which a phenolic resin cross-linking agent is selected, and the content of hydroxymethyl is 28.49%-45.28%; 0.05-0.2% of an accelerant which is selected from hydroquinone or resorcinol; 0.03-0.1% of a conditioning agent, wherein hydrochloric acid or oxalic acid is selected; 0.05-0.15% of a stabilizing agent, wherein thiourea is selected; and the balance water. The gel forming time of the water plugging gel is adjustable, the formed gel is high in strength, good in salt tolerance and good in stability, the plugging rate of a rock core reaches 93% or above, and the requirements of oil reservoirs can be met.

Description

technical field [0001] The invention relates to the technical field of oilfield chemistry, in particular to an organic water-plugging jelly for low-temperature high-salinity oil reservoirs. Background technique [0002] With the continuous development of water injection in oilfields, the heterogeneity of oilfields is getting stronger and stronger, and the situation of injected water rushing and ineffective circulation is serious. Profile control and water shutoff technology is the most effective technology to solve the problem of high water cut in conventional oilfields. Profile control water shutoff technology is mainly divided into mechanical and chemical controlled water shutoff technologies. Compared with mechanical controlled water shutoff, chemical controlled water shutoff is more widely used in oilfields due to its simple operation, controllable formation depth, and partial oil-water selectivity. . In the chemical plugging and water control technology, the polymer je...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K8/512C09K8/88
CPCC09K8/512C09K8/887
Inventor 陈维余魏子扬黄波杨万有朱立国吴清辉彭齐国张艳辉
Owner CHINA NAT OFFSHORE OIL CORP
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