Method for determining alternating injection time of polymer flooding

A method of determination and alternate injection technology, which is applied in earth-moving drilling, production of fluids, wellbore/well components, etc., which can solve the problem that the timing of alternate injection has not been reported in the literature.

Active Publication Date: 2016-08-17
CHINA NAT OFFSHORE OIL CORP +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Although research on alternate injection has been carried out in domestic onshore oilfields, the research has only been carried out o

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  • Method for determining alternating injection time of polymer flooding
  • Method for determining alternating injection time of polymer flooding

Examples

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Embodiment Construction

[0025] The experimental methods used in the following examples are conventional methods unless otherwise specified.

[0026] The materials and reagents used in the following examples can be obtained from commercial sources unless otherwise specified.

[0027] The variation of the slug split rate with the injection volume of a single polymer concentration is as follows: figure 1 As shown, before polymer flooding, water flooding is carried out first, and when the water content in the produced fluid reaches 40-100%, polymer flooding is performed by injecting polymer aqueous solution, and the timing of injection is alternate timing 1; The diversion rate of the aqueous polymer solution in the hypertonic layer is in a V-shape that first falls and then rises. The timing corresponding to the turning point of the decline and rise is the alternation timing 2. At the alternation timing 2, the polymer aqueous solution with a lower viscosity than before is injected ; The diversion rate of...

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Abstract

The invention discloses a method for determining alternating injection time of polymer flooding. The method comprises the step of determining injection time 1, injection time 2 and injection time 3 according to the changes of moisture content and shunt rate of an oil-displacement system in a high-permeability layer, wherein the injection time 1 is a corresponding period when the moisture content of output liquid reaches a certain value, the injection time 2 is a corresponding period when the shunt rate of the oil-displacement system in the high-permeability layer is suddenly changed, and the injection time 3 is a corresponding period when the shunt rate of the oil-displacement system in the high-permeability layer is in a rising trend and becomes flat. According to the method, the viscosity of a new oil-displacement system corrected to be injected in the injection time 1 is larger than that of the injected oil-displacement system, the viscosity of a new oil-displacement system corrected to be injected in the injection time 2 is smaller than that of the oil-displacement system corrected to be injected in the injection time 1, and the viscosity of a new oil-displacement system corrected to be injected in the injection time 3 is smaller than that of the oil-displacement system corrected to be injected in the injection time 2; and different oil replacement effects of chemically flooded heterogeneous reservoirs can be achieved, and the development degree of a low-permeability layer is improved.

Description

technical field [0001] The invention relates to a method for determining alternate injection timing of polymer flooding, which belongs to the technical field of petroleum development. Background technique [0002] For reservoirs with strong heterogeneity, the injection mode of a single polymer slug will reverse the profile, so that the reservoirs with relatively low permeability (hereinafter referred to as low-permeability layers) have more remaining oil. Studies have shown that the alternate injection of different viscosity flooding systems can significantly improve the polymer flooding effect in heterogeneous reservoirs and increase the production degree of low permeability layers with the same or even reduced polymer dosage. . In order to determine the best effect of alternation, it is necessary to select a suitable oil displacement system and the influence of parameters such as injection velocity, slug length, and injection timing according to the viscosity of the oil d...

Claims

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Application Information

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IPC IPC(8): E21B43/22
CPCE21B43/16
Inventor 张凤久
Owner CHINA NAT OFFSHORE OIL CORP
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