Method for improving steam assisted gravity drainage (SAGD) development effect by using ammonia

Abstract

The invention provides a method for improving a steam assisted gravity drainage (SAGD) development effect by using ammonia. The method comprises the steps of adding ammonia or ammonia water in the producing well continuous production stage in the SAGD steam injection production process; after the ammonia or ammonia water is mixed with steam, injecting the ammonia or the ammonia water and the steam into an oil reservoir; when the instant oil-steam ratio is reduced to 0.2, stopping injecting the ammonia or the ammonia water; and in the process from beginning to add the ammonia or the ammonia water to stopping injecting the ammonia or the ammonia water, by mass of the ammonia, the use amount ratio of the ammonia / ammonia water and the steam is 3-20%. An appropriate amount of ammonia or ammonia water (the ammonia is released after the ammonia or the ammonia water is injected into a gas-injection well) in the steam injection process; through mechanisms such as alkaline water displacement and gas pressurization, the steam utilization rate in a steam cavity is improved, oil displacement efficiency of the steam cavity is improved, thermal efficiency and the oil-steam ratio in the steam injection development process are effectively improved, and the goals of improving the development effect and economically and effectively developing the heavy oil reservoir are achieved.

Description

technical field [0001] The method belongs to the technical field of oil field recovery, and in particular relates to a method for improving the SAGD development effect by using ammonia gas. Background technique [0002] Heavy oil reservoirs refer to reservoirs with a degassed crude oil viscosity greater than 100mPa·s at the reservoir temperature. At present, thermal recovery technology is widely used in the development of domestic heavy oil fields. Currently, the widely used development methods include: steam-assisted gravity drainage, steam Huff and puff, steam flooding and other technologies. [0003] Steam Assisted Gravity Drainage (SAGD) technology was invented by Dr. Butler in 1978. After more than 30 years of continuous development and improvement, a mature application technology for commercial mining has been formed. It has been successfully applied in the development of oil sands in Canada, and the development of ultra-heavy oil reservoirs in my country's Liaohe Oi...

AI Technical Summary

Problems solved by technology

Utilizing the properties of gas with small thermal conductivity and non-condensable gas, a heat insulation layer is formed to reduce the heat transfer rate of steam to the overlying rock layer, reduce heat loss, and improve thermal efficiency; at the same time, the non-condensable gas distributed in the upper part of the steam chamber can maintain The system pressure not only pushes the crude oil downward, but also slows down the steam’s upward overburden velocity, strengthens the lateral expansion capability of the steam chamber, and increases the steam’s lateral swept volume; The non-condensable gas affects the steam injection ability. During the operation, it is found that when the non-condensable gas is injected at the same time, the steam injection rate is reduced by about 30% due to the obvious increase in the steam chamber pressure.

Secondly, the injected gas only has the effect of heat insulation and viscosity reduction, so it can only increase the oil recovery rate, but the effect on improving the oil displacement efficiency is not obvious

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