Highly effective pour depressant for thermodynamic oil extraction process

Abstract

A high-efficiency pour point depressant for thermal recovery process comprises (1) biphenyl, polycyclic aromatic hydrocarbons or polycyclic aromatic hydrocarbon derivatives free of chlorine and sulfur elements; (2) liquid petroleum products containing arene larger than 5%, petroleum resin in liquid state at normal temperature or natural hydrocarbon aggregates in particle state at normal temperature; (3) surfactant; (4) fusel oil; (5) alcohol ethers having a closed cup flash point larger than 20 DEG C; and (6) oil-soluble or water-soluble polymers respectively having a nonpolar section eutectic with paraffin molecule and a polar section for twisting crystal form of wax crystal on a main chain and/or a branch chain. The high-efficiency pour point depressant of the invention performs all functions of both water-base pour point depressant and oil-base pour point depressant, and can efficiently assist the prior various thermal recovery processes in exploring high pour-point oil and heavy oil reservoirs, with the advantages of greatly reduced exploitation cost, prolonged production cycle of the oil well, increased output of the oil well, increased ultimate recovery of the oil reservoir,as well as significant economic benefit.

Description

technical field [0001] The invention relates to a pour point depressant for oil exploitation, in particular to a high-efficiency pour point depressant for thermal exploitation of high pour point oil and heavy oil. Background technique [0002] At present, the thermal oil recovery process is mainly used in the recovery of high pour point oil and heavy oil, and the pour point depressant is generally used as an auxiliary method. The existing pour point depressants are generally divided into two types: water-based pour point depressants and oil-based pour point depressants, and water-based pour point depressants are further divided into water-soluble pour point depressants, oil-in-water emulsion pour point depressants; oil-based pour point depressants; Base pour point depressants are further divided into oil-soluble pour point depressants and organic solvent-based pour point depressants. [0003] Water-soluble pour point depressants are mainly composed of surfactants and water,...

AI Technical Summary

Problems solved by technology

[0003] Water-soluble pour point depressants are mainly composed of surfactants and water, and they have the following defects when used in thermal oil recovery technology: First, they mainly use the principle of emulsification to depress pour point, and cannot directly dissolve asphaltene, colloid, and wax crystals, and their pour point depressant ability is limited The second is that it is difficult to automatically diffuse into the crude oil after being injected into the oil layer from the oil well; the third is that there is no effect or the opposite effect when the crude oil in the oil layer has a low water content

[0004] Oil-in-water emulsion pour point depressants are mainly composed of surfactants, water, and organic solvents. They have the following defects when used in thermal oil recovery processes: First, they mainly use the emulsification principle to directly dissolve and break asphaltenes and colloids. 1. The wax crystal structure ability is limited, and the pour point depressing ability is limited; the second is that it is difficult to automatically diffuse into the crude oil after being injected into the oil layer from the oil well; the third is that there is no effect or the opposite effect when the oil in the oil layer has a low water content; Immediate delamination under fluid heating, unable to achieve synergistic injection

[0005] Oil-soluble pour point depressants are mainly composed of oil-soluble polymers, organic solvents, etc., and have the following defects: First, although oil-soluble pour point depressants can inhibit or disperse wax crystals, colloid sheets, and asphaltene layers, they cannot achieve True sol particle size, limited ability to reduce pour point and viscosity; second, oil-soluble pour point depressant has a low flash point, and there is a safety problem with high-temperature fluid injection; third, oil-soluble pour point depressant is highly targeted, and the screening test workload is heavy; Fourth, it cannot solve the problem of emulsified particle blockage in the oil layer; fifth, there is a timeliness problem, that is, its ability to reduce pour point and viscosity decreases with time; sixth, the cost is high, and it is difficult to apply large doses in thermal oil recovery technology

[0006] Organic solvent-type pour point depressants are mainly composed of hydrocarbons, and have the following defects: First, organic solvent-type pour point depressants have limited ability to dissolve wax crystals and colloids, and have extremely poor solubility to layered asphaltene, so their pour point depressant ability is limited; Second, organic solvent-based pour point depressants have a low flash point, and there are safety problems associated with high-temperature fluid injection; third, organic solvent-based pour point depressants are difficult to suppress the geometry of asphaltene and wax crystal structures, and cannot solve the problem of emulsified particles in oil reservoirs Fourth, there is a problem of timeliness, that is, its pour point depressing ability will continue to decrease with time; fifth, the amount of addition is too large, resulting in a significant increase in production costs, making it difficult to apply it in thermal oil recovery processes

[0007] In short, most of the current pour point depressants have certain defects, and the comprehensive effect is not very good in the thermal oil recovery process.