Oil layer wax-condensing type oil reservoir mining method

Abstract

The invention discloses an oil layer wax precipitation type oil resource exploitation method which is progressed cyclically by the following steps: 1. 0.1-500 tons of pour point and viscosity depressant are injected into oil layers through an oil well; 2. 1-10000 tons of thermal fluids mixed with 30-400 DEG C of pour point and viscosity depressant are injected into the oil layers through an oil well; in the thermal fluids mixed with pour point and viscosity depressant, the weight proportion of the thermal fluids and the pour point and viscosity depressant is 100:0.001-10; 3. the oil well is closed, reacting for 2-240 hours when the well is closed; 4. a mixture of oil and water is sprayed through the oil well; 5. the oil is produced normally by a pumping unit. The exploitation method can effectively exploit the oil layer wax precipitation type oil resource, which greatly reduces the production cost, prolongs the production cycle of the oil well, improves the oil well production and increases the final recovery rate of the oil resource. Moreover, the exploitation method has the advantages of easy operation, safety and reliability and significant economic benefits.

Description

technical field [0001] The invention relates to a crude oil extraction method, in particular to an oil chromatography wax type oil reservoir extraction method. Background technique [0002] At present, in crude oil production and exploitation, oil tomographic waxy reservoirs are unavoidably exploited. The main feature of this type of waxy oil reservoir is that the temperature of the oil layer (reservoir) is higher than the freezing point of the crude oil in the reservoir, lower than the wax melting temperature of the crude oil, or close to the wax precipitation temperature of the crude oil. It can flow in the oil layer (reservoir), but it is easy to produce and precipitate wax crystals in the oil layer, so it is very easy to cause blockage near the oil layer or oil well, or cause its own viscosity to increase, affecting the normal production of the oil well. If no effective process is adopted, This type of oil tomographic waxy reservoir is extremely difficult to exploit, an...

AI Technical Summary

Problems solved by technology

This method has the following defects when it is directly applied to oil layer analysis wax-type reservoirs: first, it is difficult to inject steam due to the serious constraints of oil layer geological conditions and reservoir pressure; It is difficult to use a large amount of high-temperature and high-pressure steam in oil reservoirs that are highly heat-sensitive and waxy; third, waxy oil reservoirs must be kept at a temperature much higher than the waxing temperature of crude oil or even the waxing temperature of crude oil during the entire oil production process. In terms of temperature, a large amount of steam needs to be consumed for this, resulting in high oil recovery costs; fourth, the process is complex, and the control of steam temperature, dryness and reservoir temperature field is difficult, and oil production accidents such as condensation pipes and wax stuck are prone to occur; At present, it is still in the experimental stage, and it is difficult to be practical and large-scale application

The direct application of this method to oil tomographic wax-type reservoirs has the following defects: First, the ability of organic solvents to dissolve wax crystals is limited, and the ability to reduce the pour point and viscosity of crude oil in wax-type oil reservoirs is limited, so it is difficult to effectively solve the problem of oil tomographic wax-type reservoirs. The waxing problem of deep crude oil; the second is that its pour point and viscosity reducing ability has a strong timeliness, that is, with the continuation of time, the organic solvents in the waxy oil reservoir crude oil gradually reduce the pouring point and viscosity reducing ability of the crude oil. If it weakens or disappears, the freezing point and viscosity of the crude oil will gradually increase until it returns to its original state, resulting in the reappearance or recovery of wax precipitation, so it is difficult to provide sufficient production time for the oil recovery process and fail to meet the practical requirements of production; the third is its safety Fourth, the large amount of it used leads to high oil recovery cost, and it is difficult to be practical for oil tomographic waxy reservoir development

Since this method cannot effectively solve the problem of wax precipitation of crude oil in waxy reservoirs of oil chromatography and is difficult to inject, it is difficult to directly use it in the production of waxy reservoirs of oil chromatography in China at present.

[0014] In a word, the comprehensive effects of the above-mentioned methods in the production of oil tomography waxy reservoirs are not ideal