Injection-production two-trip pipe string balanced well killing control method

Abstract

The invention provides an injection-production two-trip pipe string balanced well killing control method. The method comprises the following steps of: (1) calculating productivity and formation pressure during the flow period of a multiple thermal fluid huff-puff well; (2) determining the well killing time; (3) calculating the bottom hole pressure during well killing; (4) calculating the density of well killing fluid and selecting the well killing fluid; (5) calculating the using quantity of the well killing fluid; and (6) determining the well killing way. According to the method provided by the invention, the multiple thermal fluid huff-puff well can be timely converted from oil flow production to mechanical oil production, and the energy in the injection formation can be fully utilized; and simultaneously, the time effectiveness of the well intervention operation can be minimized, the pollution of an oil layer and the heat loss of the formation can be reduced to the greatest extent, and the high-speed and high-efficient development of an offshore heavy oil field can be kept.

Description

technical field [0001] The invention relates to a matching process technology for thermal recovery of heavy oil, in particular to a method for controlling balanced well killing of two injection-production strings when the stage of heavy oil thermal recovery is changed from self-injection oil recovery to mechanical oil recovery. Background technique [0002] The multi-element thermal fluid stimulation technology is an efficient thermal recovery technology for heavy oil, which mainly uses the multi-element thermal fluid generator to burn the injected fuel (diesel or natural gas) and oxidant (air) in the combustion chamber, relying on the generated high temperature The high-pressure gas vaporizes the mixed water to produce high-temperature and high-pressure thermal fluid, and then adds chemical agents (foaming agents or viscosity reducers) to form multi-component thermal fluid according to technical needs, and injects the formed mixture into the oil layer together, relying on th...

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Problems solved by technology

[0004] In the existing thermal recovery wells, the injection and production strings are killed in two trips. The well killing operation is carried out when the oil well is self-flowing and there is basically no production, and then the pump is put into production. The energy injected into the formation cannot be fully utilized when injection oil production is transferred to mechanical oil recovery; at the same time, the well killing operation takes a long time, which easily increases the pollution and damage of the well killing fluid to the formation, reduces the temperature of the oil layer, and reduces the thermal recovery effect

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