Slow-crosslinked high-strength jelly profile control water-plugging agent

Abstract

The invention discloses a slow-crosslinked high-strength jelly profile control water-plugging agent. The slow-crosslinked high-strength jelly profile control water-plugging agent comprises, by mass, 0.3% to 0.6% of a hydrophobic associating polymer, 0. 3% to 0.6% of a melamine resin crosslinking agent, 0.03% to 0.05% of a phenol crosslinking agent, 0.2% to 0.4% of an oxygen scavenger, 0.1% to 0.3% of a delayed crosslinking agent, 0.1% to 0.2% of a water loss inhibitor and the balance water. The phenol crosslinking agent comprises one or two of resorcinol and hydroquinone. The oxygen scavenger comprises one or more of thiourea, sodium sulfite and sodium bisulfate. The delayed crosslinking agent comprises one or two of ammonium chloride and sodium trimetaphosphate. The water loss inhibitor comprises one or two of sodium malonate and sodium salicylate. The gelatinization time of the jelly provided by the invention is adjustable and is 6 days or more. After gelatinization, the jelly strength at least reach to level H based on visual inspection. The water-plugging agent has excellent thermal stability, does not lose water after hot treatment at a temperature of 60-90 DEG C for 270 days and can satisfy the requirements on most of deep oil reservoir displacement.

Description

[0001] Technical field: [0002] The invention relates to a hydrophobic associative polymer plugging agent, in particular to a slow-crosslinking high-strength jelly, which belongs to the technical field of oilfield chemistry. [0003] Background technique: [0004] In the process of oilfield development, when the original energy of the oil layer begins to decrease, it is necessary to manually supplement the energy to the formation, that is, inject water into the oil reservoir to improve the oil recovery rate. However, due to the heterogeneity of the formation and the difference in oil-water mobility ratio or improper exploitation methods, the injected water is unevenly advanced along the high-permeability layer or high-permeability zone, resulting in premature water production from the oil well until flooding. At present, most of the oilfields developed by water injection in my country have entered the stage of high water cut. According to statistics, the average water content...

AI Technical Summary

Problems solved by technology

However, although phenolic jelly has high gelling strength, in view of the high toxicity and irritation of phenol and aldehydes, it is rarely used on site. Currently, hydroquinone and resorcinol can replace phenol, and urotropine can replace formaldehyde. Cross-linking agent, but the high price of polyhydric phenol greatly increases the production cost

The inorganic chromium jelly system can be converted from Cr by controlling the redox reaction 6+ produce Cr 3+ Prolong the gelation time, but the gelation strength is weak, the long-term thermal stability is poor, and it is not suitable for high salinity reservoirs

As a cross-linking agent, organic chromium can form a gel with a relatively long gelation time, but it is generally only suitable for systems with a temperature below 60°C, which is expensive, complicated to prepare, and poor in operability

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