Multi-element thermal fluid auxiliary gravitational displacement process

Abstract

The invention provides multi-element thermal fluid auxiliary gravitational displacement process for extracting ultra-thick or super-thick oil reservoirs. The multi-element thermal fluid auxiliary gravitational displacement process includes arranging a horizontal injection well on the upper portion of a thick oil reservoir and arranging a horizontal production well on the lower portion of the thick oil reservoir; and injecting multi-element thermal fluid from the injection well after circularly preheating the injection well and the production well, and then extracting thick oil from the production well. Crude oil viscosity break mechanism and oil extracting power of the multi-element thermal fluid auxiliary gravitational displacement process are rich, accordingly the use level of steam and steam and oil ratio in an extraction process are reduced, and thermal efficiency and economic benefit are improved.

Description

technical field [0001] The invention relates to the field of oil recovery technology, and in particular to a multi-element thermal fluid assisted gravity displacement process for developing super-thick or extra-thick heavy oil reservoirs. Background technique [0002] Steam-assisted gravity drainage (SAGD for short) is considered to be the thermal recovery method with the greatest potential to replace steam stimulation. From the perspective of oil recovery mechanism, SAGD uses steam as a heat source, combines heat conduction and heat convection, and relies on the gravity of crude oil and condensate to recover heavy oil, and the recovery rate can reach 50% to 70%. Super heavy oil production method. At present, SAGD technology has been successfully commercialized in Canada and Venezuela, and more than 20 pilot test areas of gravity drainage have been carried out in different types of oil fields, and 5 commercial oil fields have been built. In 2005, China's Liaohe Oilfield an...

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Problems solved by technology

[0003] However, many problems have been encountered in the conventional SAGD production process: (1) For medium-deep ultra-heavy oil reservoirs, due to the high steam injection pressure / temperature, the loss along the wellbore is large, and the dryness of bottom-hole steam is difficult to guarantee; (2) For Reservoirs with top water / edge and bottom water may easily cause top water / edge and bottom water breakthrough during SAGD production, resulting in the collapse of the steam chamber; (3) in the SAGD production process, when the steam chamber expands to the top of the reservoir , will heat the overlying rock strata, resulting in ineffective waste of heat; (4) SAGD produces a large amount of water, especially in the later stage, the water content is above 80%, and the high-temperature output liquid treatment costs are high

[0005] But above-mentioned improvement still has some problems, as its viscosity reduction mechanism of patent CN101592028A is single, needs to configure special nitrogen making equipment simultaneously; It will suddenly rise, but the temperature rise in the place far away from the well is not obvious; the second is that the heat transfer to a certain range between the two wells requires a lot of electricity, and a large amount of electricity will cause the temperature of the well to be very high

If the temperature of the well is too high, it will cause damage to the well and evaporation of formation water, and the water in the communication channel is the medium that provides the conduction path for the electric current. Once the water is evaporated, the electric current will stop, so the heating effect will be ineffective. up

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