Method based on testing and assessment of sensitivity to alkali of hydrocarbon reservoir

Abstract

The invention discloses a method based on testing and evaluating the alkali sensitivity of oil and gas layers. The preparation of brine with different pH values ​​should start from the pH value of formation water and increase the pH value step by step according to the actual situation. The value can be set as 12. The selected core is evacuated and saturated with the first-stage brine, and soaked for 20-24 hours. Under the condition of lower than the critical flow rate, the stable permeability K1 of the core is measured with the first-stage brine, and injected into the second stage. Second-level brine, soak for 20~24h, under the condition of lower than the critical flow rate, use the second-level brine to measure the stable permeability K2 of the core, and change the level of injected brine until the last level of brine is used to measure the permeability of the core. Stable permeability Kn. The method obtains accurate values ​​by testing the alkali sensitivity of the oil and gas layers, which can prevent the high pH value fluid from entering the oil and gas layers, which will cause structural damage of clay minerals and siliceous cement in the oil and gas layers, thereby causing blockage of the oil and gas layers The problem of damage occurs.

Description

technical field [0001] The invention relates to a method, in particular to a method based on testing and evaluating the alkali sensitivity of oil and gas reservoirs. Background technique [0002] Oil and gas is the gas that comes out of oil wells with oil, and its main components are methane, ethane, etc. Used as fuel and chemical raw materials. Oil and gas generation has the following conditions. First, it depends on the amount of organic matter in the oil source layer, which is usually called "organic matter abundance". Mainly measure the residual organic carbon content in order to determine whether there are oil-generating layers in an area and how many oil-generating layers there are, and divide them into good, medium and poor oil-generating layers according to certain standards for classification and evaluation. Second, it depends on the quality of organic matter in the oil source layer, which is usually called "organic matter type". According to the biological sourc...

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Problems solved by technology

[0003] The purpose of the present invention is to overcome the problem that these damages are not tested in the above-mentioned existing production process, causing oil and gas reservoirs to be exploited for a period of time after damage occurs, so that the production efficiency is affected. The method, the method obtains accurate values ​​by testing the alkali sensitivity of the oil and gas layers, and can prevent the high pH value fluid from entering the oil and gas layers, which will cause the structural damage of clay minerals and siliceous cement in the oil and gas layers, thereby causing oil and gas Blockage and damage of oil and gas layers; a large number of hydroxides combined with some divalent cations will form insoluble matter, resulting in the problem of blockage and damage of oil and gas layers

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