Demulsifier for eliminating aged oil mixture in oil-water interlayer in settling tank

Abstract

The invention discloses a demulsifier for eliminating an aged oil mixture in an oil-water interlayer in a settling tank. The demulsifier comprises the following components in parts by mass: 3-4 partsof fatty alcohol-polyoxyethylene ether, 6-7 parts of methanol, 75-80 parts of a functional main agent F, 2-3 parts of erucylamide propyl hydroxysulfobetaine and the balance of water. The demulsifier is applied to the treatment of eliminating the middle-layer aged oil mixture in a settling tank, and has good demulsification and dehydration treatment effects on combined treatment stations of different oil reservoirs and the middle-layer aged oil mixture at different depths in the settling tank. For treating an interlayer aged oil mixture, from the position 3.5 m in a settling tank of a certain combined treatment station, of which raw oil density is 0.8765 g / cm <3>, the viscosity is 54.7 mPa*S at the temperature of 50 DEG C, the content of colloid asphaltene is 54.3%, the wax content is 10.2%and the water content of the middle-layer aging oil mixture is 38.7%, 0.7% of the demulsifier is added at 60 DEG C according to the Petroleum and Natural Gas Industry Standard SY / T 5281-2000 of the People's Republic of China, and test results show that the average dehydration rate of the demulsifier in 30 min is 96.6%, and the average dehydration rate of the demulsifier after settlement for 6 h is 99.6%.

Description

technical field [0001] The invention relates to the technical field of oil recovery in oilfields, in particular to a demulsifier for eliminating the aged oil mixture in the oil-water intermediate layer in a settling tank. Background technique [0002] With the continuous deepening of oil field development, on the one hand, in the case of water displacement medium for oil displacement, part of the relatively heavy crude oil that cannot be driven by conventional water and adsorbed on the pore surface of underground reservoirs relies on technology. Innovative technical means have been produced; on the other hand, along with the further improvement of the technical level of reservoir understanding, some low-quality and difficult-to-recover reserves with relatively poor physical properties of crude oil have been discovered and put into production. The composition of the produced fluid of these oil wells is complex and the content of heavy components is high. Due to the increase o...

AI Technical Summary

Problems solved by technology

The composition of the produced fluid of these oil wells is complex and the content of heavy components is high. Due to the increase of the density and viscosity of crude oil or the high content of heavy paraffin components or oil sludge with a small amount of oil, the produced oil-water mixture emulsification phenomenon Seriously, the natural sedimentation and separation speed of the oil-water mixture is slowed down, which is more difficult to handle than the conventional water flooding oil well production fluid

The effect of demulsification and dehydration is poor when treated with commonly used demulsifiers, the water content in the separated crude oil is high, and the oil content in the sewage exceeds the standard, which does not meet the specified requirements, and is even so serious that it is difficult to handle and affect normal production.

[0003] In short, in terms of the treatment of the aged oil-water mixture in the middle layer of the settling tank, the dehydration speed is slowed down, the dehydration rate is reduced, the quality of the sewage is reduced, the oil-water interface is not clear, and the middle layer of the aged oil is getting bigger, which causes the electric dehydration system to fail to operate normally.

The performance of sewage treatment after dehydration: the separation speed of oil and water slows down, the sewage treatment capacity decreases, the oil content of sewage exceeds the standard, and it is difficult to meet the requirements of the petroleum industry standard

[0004] In order to solve the problem of dehydration treatment of this kind of oil well produced fluid mixture, technicians in the oilfield development industry have also carried out some exploratory research, and most of the research results are based on the properties of crude oil in various reservoirs, using different types of demulsifier compounding and adding It is solved by using a large concentration, and has not formed a demulsifier with strong pertinence, wide application range and strong adaptability for the dehydration of the middle layer of the aging oil mixture in the settling tank of the joint treatment station