Method of improving recovery rate of oil deposit by indigenous microbial combination flooding

Abstract

The invention belongs to the technical field of tertiary oil recovery, and in particular relates to a method of improving recovery rate of an oil deposit by indigenous microbial combination flooding.The method comprises the specific steps of screening a test oil deposit; carrying out oil-water separation on an output liquid of the test oil deposit; pre-treating formation water; preparing an activator; injecting the activator on-site; and evaluating an on-site test effect. The metabolism velocity and activity of the indigenous microorganisms are improved by a physical action of impulse waves,crude oil degradation of hydrocarbon oxidation bacteria is accelerated, aerogenesis of methanogens is promoted, and a producing biogenic surfactant for producing biogenic surfactant bacteria is promoted, so that in situ degradation and viscosity reduction of crude oil in a formation and plug removal of the formation are realized. Therefore, the recovery rate of the crude of the test oil deposit isimproved greatly. Thus, the method can be widely applied to a production increasing process of the oil deposit.

Description

technical field [0001] The invention belongs to the technical field of tertiary oil recovery, and in particular relates to a method for increasing oil recovery by endogenous microbial compound flooding. Background technique [0002] Microbial oil recovery refers to the comprehensive action of microorganisms and their metabolites with reservoir rocks and fluids to improve the oil-water mobility ratio, thereby achieving the purpose of enhancing oil recovery. Microbial oil recovery technology has the advantages of low investment cost, no pollution to the environment and a wide range of reservoir adaptation, so it has broad field application prospects. The endogenous microbial oil recovery technology is a technology that injects activators into the oil reservoir to activate the endogenous microorganisms in the oil reservoir, and utilizes the comprehensive effects of the microorganisms themselves and their metabolites to enhance oil recovery. [0003] After literature search, pa...

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Problems solved by technology

[0003] After literature search, patent number: "CN103114833A", patent name: "A microbial oil recovery method for activating functional flora in deep reservoirs", discloses a method of preventing the injection of functional flora in the near wellbore zone by injecting biological inhibitors. The problem of excessive consumption of activator, so that the activator can reach the depth of the oil reservoir to activate functional bacteria, the disadvantage of this method is: (1) a large number of inhibitors used in this method lead to a sharp increase in the cost of field tests; (2) the cost of a large number of inhibitors The use leads to increased difficulty in the treatment of produced water; (3) It is difficult to control the amount of biological inhibitors injected into the reservoir, and excessive use may inhibit the endogenous microorganisms in the deep reservoir

However, the disadvantage of this method is that usually the same oil layer corresponds to multiple water injection wells or the same water injection well corresponds to multiple oil layers with different permeability, and it is difficult to ensure that the activator systems of high, medium and low permeability oil layers are respectively injected into the corresponding oil layers , therefore, to a certain extent, it affects the field test results

However, this method has the following problems: the activators are all injected from the water well at the same time, and the injection of production differentiation is not realized according to the level of the oil layer permeability, resulting in the waste of biosurfactant functional bacteria or activators injected into the high permeability oil layer, and at the same time Functional microorganisms or activators injected into low-permeability reservoirs to produce biopolymers cause plugging of low-permeability reservoirs, which further aggravates the degree of heterogeneity of the reservoir, thereby affecting the effect of field tests to a certain extent