Seawater-based polyacrylamide high-temperature gel profile control system

Abstract

The invention provides a seawater-based polyacrylamide high-temperature gel profile control system. The system comprises a main agent, a cross-linking agent, a high-temperature stabilizer and simulated seawater; the main agent is a polyacrylamide polymer; the cross-linking agent is an organic phenolic aldehyde cross-linking agent; and the high-temperature stabilizer is one or a combination of thiourea, amino acid, oxalate, citrate and salicylate. The seawater-based polyacrylamide high-temperature gel profile control system provided by the invention can meet the use requirements of seawater sample preparation and 90-130 DEG C high-temperature environment in profile control and water plugging operation of an offshore high-temperature oil field; when being used in a stratum, the gel plugging agent preferentially enters a high-permeability layer, a high-strength and non-flowing gel system is formed under the oil reservoir condition, and the purposes of plugging the high-permeability layer, improving the injection efficiency and increasing the crude oil recovery rate can be achieved; and the system has the advantages of long gelling time and high gel strength, can be stable for a long time in a high-temperature environment without being damaged for 60 days, and has better plugging capacity.

Description

technical field [0001] The invention belongs to the technical field of oilfield chemical profile control and water plugging, and in particular relates to a seawater-based polyacrylamide high-temperature gel profile control system. Background technique [0002] Jelly is a colloid with a three-dimensional network structure formed by cross-linking of polymers and cross-linking agents. Because of its controllable gelation strength and gelation time, and low cost, it is widely used in onshore oilfield profile control and water shutoff , and achieved a better effect of water control and oil increase. With the vigorous development of offshore oil fields, a large amount of water / gas is produced from oil wells, and channeling has become an increasingly prominent problem. It is urgent to carry out profile control and water shutoff operations to block high-permeability channeling channels. However, the characteristics of seawater sample preparation (high salinity, high calcium and mag...

AI Technical Summary

Problems solved by technology

Disadvantages of this method: 1) The experimental temperature is only 55-90°C, which cannot meet the requirements of high-temperature (>120°C) environments; 2) The jelly is severely damaged after aging for 30 days, and cannot meet the requirements of long-term use in high-temperature, high-salt environments. Require

Disadvantages of this method: 1) The concentration is high, and there is a problem of high cost; 2) The use of clean water for sample preparation is not clear about the adaptability to high salinity, especially high calcium and magnesium ion concentration, and cannot meet the requirements of offshore oilfield seawater sample preparation. 3) The main agent and high-temperature stabilizer used in the invention patent of this application are significantly different from the aforementioned patents, which can overcome the above-mentioned problems

The disadvantages of this method: 1) the concentration of the main components of the jelly is large and difficult to obtain, and there is a problem of high cost; 2) the use of chlorine-containing substances as catalysts is more dangerous in actual use; 3) the main agent used in the invention patent of this application And high temperature stabilizers are significantly different from the aforementioned patents and can overcome the above problems

Disadvantages of this method: 1) the foregoing patents select particles with complex manufacturing processes as high-temperature plugging agents, while the invention of the patent application is a significantly different high-temperature jelly system, which has the advantages of low cost and simple process; 2) the foregoing patents use The preparation of tap water has unclear adaptability to high salinity, especially high calcium and magnesium ion concentration, and cannot meet the requirements for seawater sample preparation.

The shortcoming of this method: 1) nano-graphite stabilizes and strengthens jelly stability, makes complex, and use cost is high, and what apply for patent invention is a kind of significantly different high-temperature jelly system, has low cost, the advantage of simple process, and freezing The glue main agent, cross-linking agent and stabilizer are different from the aforementioned patents; 2) The aforementioned patents are not clear about the environmental adaptability of high calcium and magnesium ion concentrations in seawater, and cannot meet the requirements for seawater sample preparation

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