Wellhead pressure monitoring method and control system

Abstract

The invention relates to a wellhead pressure monitoring method and a control system. The method is used for multilayer oil reservoir polymer flooding profile reversal recognition, and comprises the following steps that the polymer injection well variable flow test is designed and implemented by adopting a variable flow well test principle; the wellhead pressure change is monitored in stages; accurate pressure and flow data is obtained during the test period, and the variable flow well test can be performed under the well opening condition; the wellhead pressure is converted into the well bottom pressure by considering the well tube friction and the polymer rheological property and using a converting module; the wellhead pressure is monitored for many times, and the converted well bottom pressure data is subjected to well test explanation by combining the actual pressure monitoring data and using an anisotropic multilayer oil reservoir polymer flooding model to obtain the formation conductivity of high-permeability and low-permeability layers; and the data is converted into the conversion condition of the fractional flow rate of the low-permeability layer for recognizing the profile reversal according to the obtained formation conductivity of each formation. A wellhead pressure test monitoring method is used, so that the limitation that a pressure meter of a pipe column structure cannot enter the well is avoided; and meanwhile, the pressure test cost is reduced.

Description

technical field [0001] The invention relates to the field of pressure measurement and monitoring for exploration and development of oil and gas fields, in particular to a wellhead pressure monitoring method and a control system for the reversal identification of poly-flooding profiles in multi-layer oil reservoirs. Background technique [0002] At present, polymer flooding technology has been widely used in domestic oil fields, and has made great contributions to enhancing oil recovery. During the process of polymer flooding, the change of the liquid absorption profile of the polymer injection well can intuitively show the further development of the reservoir. At the same time, the degree of improvement of the liquid absorption profile of the middle and low permeability layers by polymer flooding will directly affect the effect of polymer flooding . At the initial stage of polymer injection, the higher permeability layer absorbs a lot of liquid, and even a single layer brea...

AI Technical Summary

Problems solved by technology

[0003] In actual production, due to the strong vertical heterogeneity of offshore oilfield reservoirs and the large spacing between injection and production wells, as polymer flooding enters the middle and late stages, the blocks with relatively serious reservoir heterogeneity will have high permeability layers. The so-called "absorption profile inversion" phenomenon, which seriously affects the oil enhancement effect of polymer flooding, makes offshore polymer flooding more challenging

At present, there is no effective system and method for judging the reversal of the suction profile

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