A single-well huff and puff recovery method for high-temperature, high-salt, high-wax oil wells

Abstract

The invention belongs to the technical field of tertiary oil recovery and particularly relates to a method for single-well huff and puff oil recovery of a high-temperature, high-salt and high-wax-oil-content well. The method specifically comprises the following steps: screening a testing oil well; selecting a single-well huff and puff process; and carrying out a field test. The method has the characteristics of simple process, pertinence and long period of validity; meanwhile, wax formation of the high-temperature and high-salt well can be effectively controlled and oil increasing effect is realized. Therefore, the method can be widely applied to wax removal and paraffin inhibition and single-well production increasing processes of a wax-oil-containing well.

Description

technical field [0001] The invention relates to a method for tertiary oil recovery, in particular to a single well huff and puff oil recovery method for high-temperature, high-salt, high-wax oil wells. Background technique [0002] The internal cause of waxing in oil wells is that crude oil contains wax, and the more wax content, the more serious the waxing. Under the condition of the oil layer, the wax is dissolved in the crude oil due to the high temperature of the medium. When the crude oil flows from the oil layer to the bottom of the well, and then rises from the bottom of the well to the wellhead, the solubility of the wax in the crude oil decreases due to the decrease of the pressure and temperature. And precipitated. [0003] The wax dissolved in the formation crude oil will gradually precipitate from the crude oil, crystallize and deposit on the surface of the tubing as the temperature and pressure decrease during the production process, resulting in wax formation ...

AI Technical Summary

Problems solved by technology

When the oil layer pressure is low, a large amount of well washing water will enter the formation to cause clay expansion, block the oil layer, and pollute the formation. In addition, thermal wax removal will also cause backflow of the well washing fluid, affecting normal production

During the process of thermal wax removal, the heat loss on the wellbore is large, and it will also make it difficult to remove the wax at the bottom of the wellbore; mechanical wax prevention has high labor intensity, energy consumption is also large, and the cost is high; chemical wax prevention has a validity period Shortcomings, high cost and poor safety and environmental performance; at the same time, the above method can only solve the problem of wax deposition in the wellbore of the oil well

[0005] Through literature search, the patent number "ZL03156478.x", titled "The Method of Steam Injection Thermal Recovery for Waxy Low Permeability Reservoirs", introduced a method of producing waxy low permeability reservoirs by combining steam huff and puff and steam flooding. The disadvantages of this invention are: (1) The cost of steam injection thermal recovery is high and the risk is high; (2) The corrosion and maintenance costs of the pipe string are high; (3) Due to the low permeability of low permeability reservoirs and the poor fluidity of crude oil, steam injection Thermal recovery has a low rate of enhanced recovery, and the effect is limited; (4) The selection conditions for oil reservoirs are relatively strict, especially for the thickness and depth of oil reservoirs.