Experimental device and method for simulating single-node blocking and unblocking process of polymer injection well

Abstract

The invention discloses an experimental device and method for simulating a single-node blocking and unblocking process of a polymer injection well. The experimental device comprises a constant pressure air pump, N intermediate containers used for containing a working fluid and a sand filling pipe used for filling a porous medium, wherein N is greater than or equal to 2; the constant pressure air pump is connected with the air inlet of the intermediate container, and the outlet of the intermediate container is connected with one end of the sand filling pipe through a control valve; the other end of the sand filling pipe is connected with a liquid collecting device; a constant-temperature heating sleeve for controlling the temperature of the intermediate container is arranged outside the intermediate container; the sand filling pipe is arranged in the thermostatic bath; and the device further comprises an electronic balance used for measuring the mass of the liquid collecting device; and the device further comprises an automatic control and data acquisition system connected with the constant pressure air pump, the control valve and the electronic balance. The device and the method have important guiding significance on optimization of a plug removal system, and can simulate a blockage removal condition of a plug removal working solution in a porous medium migration process under a field underground condition; automatic control and data acquisition can be realized, personal errors can be reduced, the experimental period is short, and the efficiency is high.

Description

technical field [0001] The invention relates to the technical field of oil and gas field development, in particular to an experimental device and method for simulating a single-node blockage and blockage removal process of a polymer injection well. Background technique [0002] With the continuous development of oilfields, more and more oilfields have entered the medium-high water cut stage, and the production decline is obvious. Therefore, many oilfields have adopted chemical flooding to enhance recovery. Polymer flooding is the main means of enhancing oil recovery and has been widely used. However, with the wide application of polymer flooding, due to the viscoelasticity of polymers and the presence of residual insolubles, polymers are adsorbed and retained in the near-wellbore area. , coupled with the polymer solution wrapped inorganic scale, oil, etc., resulting in blockage of the wellbore of the polymer injection well / production well and the near wellbore area, resultin...

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Problems solved by technology

However, this method has the following deficiencies: 1) It cannot quantitatively evaluate the dynamic situation of the plugging over time; in fact, the reaction rate between the plugging agent and the plugging is very important for the design of the plugging removal process, and there is a lack of plugging kinetics experiments. The data will be difficult to effectively evaluate the actual effect of the plugging agent; 2) The blockage retrieved from the site contains water, and this method uses drying and weighing methods, and the calculation error of the final "dissolution rate" of the blockage is relatively large; In line with the actual process of plugging removal, poor guidance

This method has the following disadvantages: 1) There are large differences in the permeability and microscopic pore structure of different cores, and the repeatability is poor, resulting in poor experimental regularity; 2) The plugging simulation is realized by directly injecting high-concentration polymers. The clogging is caused by long-term accumulation and large-volume injection. The indoor simulation method is very different from the actual situation, resulting in a large difference between the simulated clogging degree and the actual clogging degree of the polymer injection well, which cannot simulate the on-site clogging situation; 3) The experiment is more complicated, the preparation work is more, the experiment period is long, and the cost is high

The plugging removal system obtained by this evaluation method has the problem of incomplete removal of blockages, which leads to a short effective period of plugging removal and repeated plugging of the main channel soon

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