Method for improving oil recovery efficiency through microbial oil displacement

Abstract

The invention discloses a method for improving oil recovery efficiency through microbial oil replacement and belongs to the technical field of microbial oil recovery. The method specifically comprises the following steps of performing in-situ sampling on a test site and detecting indigenous microorganisms, wherein the detected indigenous microorganisms are composed of aerobic, facultative and anaerobic microorganisms; performing oil displacement on oil reservoir through the aerobic microorganisms, filling the aerobic microorganisms or the activator of the aerobic microorganisms and air into the oil reservoir, and detecting the aerobic microorganisms inside the output liquid of the oil reservoir; performing oil displacement on oil reservoir through the facultative microorganisms, filling the facultative microorganisms or the activator of the facultative microorganisms and air into the oil reservoir, and detecting the facultative microorganisms inside the output liquid of the oil reservoir; performing oil displacement on oil reservoir through the anaerobic microorganisms and filling the anaerobic microorganisms or the activator of the anaerobic microorganisms and air into the oil reservoir. According to the method for improving the oil recovery efficiency through the microbial oil replacement, the activators are abundant in sources, low in price and free from damage to stratums. The method for improving the oil recovery efficiency through the microbial oil replacement is simple in process, high in pertinence and operability and good in in-situ testing effects and improves the recovery efficiency of in-situ tests by larger than 10.0%, thereby being capable of being widely applied to in-situ tests for improving the recovery efficiency through microorganisms.

Description

technical field [0001] The invention belongs to the technical field of microbial oil recovery, in particular to a method for improving crude oil recovery by microbial 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. Microbial oil recovery is divided into two types: endogenous microbial oil recovery and exogenous microbial oil recovery according to the source of microorganisms. Among them, the endogenous microbial oil recovery technology injects activators into the oil reservoir to activate the endogenous microorganisms in the oil reservoir, using the microorganisms th...

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Problems solved by technology

[0004] At present, the main process adopted in the field test of endogenous microbial flooding to enhance oil recovery is to inject the selected activator and air into the water wells in the test block at a certain injection rate continuously or in a slug manner. Currently, the injected activator is large. Some are quick-acting, such as: glucose, starch, corn steep liquor dry powder, diammonium hydrogen phosphate. These activators can quickly activate aerobic microorganisms near the well, but the problem is that the consumption rate is too fast, and the injected activator It is consumed in a large amount near the wellbore, and the amount that can migrate to the deep part of the reservoir is small, which leads to the inability to fully activate the facultative and anaerobic bacteria in the deep part of the reservoir, thus affecting the field test results to a certain extent

[0005] 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 the activator, so that the activator reaches the depth of the oil reservoir to activate the functional bacteria, the disadvantage of this method is: (1) the inhibitor used in this method inhibits the aerobic or facultative endogenous microorganisms in the oil reservoir, It can only activate anaerobic microorganisms in the deep part of the oil reservoir, and the activated functional flora is relatively single, which affects the field test results to a certain extent; (2) the use of a large number of inhibitors increases the difficulty of produced water treatment; (3) oil It is difficult to control the amount of biological inhibitors injected into the reservoir, and excessive use may inhibit anaerobic microorganisms in the deep reservoir

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