A Method for Enhanced Reservoir Recovery by Endogenous Microbial Compound Flooding

Abstract

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. The specific steps of the method are as follows: screening of test reservoirs; oil-water separation of produced fluid in test reservoirs; pretreatment of formation water; preparation of activators; field injection of activators; evaluation of field test effects. The invention improves the metabolic rate and activity of endogenous microorganisms through the action of the pulse wave physical field, promotes the crude oil degradation of hydrocarbon oxidizing bacteria, the gas production of methanogenic bacteria and the biosurfactant production of biosurfactant bacteria, and realizes In-situ degradation of crude oil, viscosity reduction and formation plugging removal, thereby greatly improving the recovery of crude oil in test reservoirs. Therefore, the present invention can be widely applied in the production stimulation technology of oil reservoir.

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