Determination Method of Separate Injection Sections in Separated Water Injection Wells

Abstract

The invention discloses a determination method for a separate injection interval of a separated-zone injection well. Technical main points are that: according to permeability of a water injection wellperforated layer, the perforated thickness of the water injection well perforated layer, a stratum start-up pressure difference of the water injection well perforated layer, the oil reservoir mid-depth of the water injection well perforated layer, the number of benefited wells, the sum of injection-production well spacing of the benefited wells, the sum of the permeability of the benefited wells,the sum of the perforated thicknesses of the benefited wells, the sum of the daily fluid production rate of the benefited wells, and a cumulative injection-production ratio of a single sand layer andten water injection index parameters related to determination of the separate injection interval, a separate injection coefficient of each of small layers in each of separate injection intervals is calculated, and then a grade difference of the separate injection coefficient of each of the separate injection intervals is calculated and obtained; according to water absorption profile test data, afunctional relationship expression between the grade difference of the separate injection coefficient and a percentage of water absorption thickness of a block in which the separated-zone injection well of a to-be-determined separate injection interval is obtained; and according to the functional relationship expression, the determination for the separate injection interval of the separated-zone injection well is scientifically and reasonably guided, thereby improving the producing degree of oil reservoirs, and the recovery efficiency of oil fields is improved.

Description

technical field [0001] The invention relates to the technical field of water injection development in oilfields, in particular to a method for determining separate injection layers of a layered water injection well. Background technique [0002] Water injection development is the most economical and effective technical method in the process of oil exploitation. However, as the reservoir enters the stage of high water cut development, due to the dispersion of remaining oil, the problems of low efficiency and ineffective circulation of injected water become more and more prominent. Layered water injection of water injection wells is an important means to alleviate the conflict between layers, realize effective water injection, and improve the production degree and recovery rate of oil layers. How to scientifically and reasonably determine the intervals of separate injection is the key to realize effective layered water injection. [0003] In the prior art, the judgment is ma...

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Problems solved by technology

[0004] In the process of realizing the present invention, the inventors have found that there are at least the following problems in the prior art: the existing injection intervals determined based on the static geological parameters of the reservoir are not accurate enough, resulting in the degree of production of the oil layer and the recovery factor of the oil field not reaching ideal value

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