Method of viscosity reduction and cold production of shallow oil reservoir

Abstract

The invention relates to the technical field of thickened oil development, and discloses a method of viscosity reduction and cold production of a shallow oil reservoir. The method is carried out by the first step, firstly confirming that the oil reservoir has the following characteristics: the ground crude oil viscosity is 50 mPa.s-20000 Mpa.s when the temperature is 20 DEG C, the acid value of the thickened oil is 0.6 mgKOH / g-2.3 mgKOH / g, the reservoir thickness is more than 5 m; the bury depth of the heavy oil reservoir is less than 800 m, the reservoir porosity is more than 15%; the permeability is more than 50x10<-3> mu m2; the reservoir is a reverse rhythmic stratum. Compared with the steam driving method, the development cost of the shallow oil reservoir by the method is reduced by 28-36%; for the shallow oil reservoir is developed without using the steam driving and other methods, the problems of steam channeling at post period of development, serious 'over-coating' phenomenon, and low gas injection utilization efficiency at post period are also not existed; meanwhile, high-temperature steam is also not produced without fuel gas; therefore, boiler explosion, high-temperature scalding and other safety accidents cannot be happened; greenhouse gases are not generated; compared with the steam driving development, the output is further improved.

Description

technical field [0001] The invention relates to the technical field of heavy oil development, and relates to a method for reducing viscosity and cold recovery of heavy oil in shallow oil reservoirs. Background technique [0002] The traditional method of shallow heavy oil development is steam huff and puff or steam flooding, and the core of its technology is to heat the oil layer to reduce the viscosity of crude oil and improve the fluidity of crude oil. After years of research and field practice, steam huff and puff or steam flooding technology has become increasingly mature, but there are common problems such as high investment, high development cost, serious steam channeling and "overlapping" phenomenon in the later stage of development, and low utilization efficiency of steam injection in the later stage. The use of steam flooding and other methods to develop oil reservoirs is prone to safety accidents such as boiler explosions and high-temperature burns, and gas is also...

AI Technical Summary

Problems solved by technology

[0003] The present invention provides a method for viscous reduction and cold recovery of heavy oil in shallow reservoirs, which overcomes the above-mentioned deficiencies in the prior art, and can effectively solve the problem of shallow reservoirs with a viscosity less than 20,000 mPa.s developed by steam stimulation or steam flooding. High investment, high development cost, serious steam channeling and "overlapping" phenomena in the later stage of development, low utilization efficiency of steam injection in the later stage, and high safety risks in the development process