Determination method for alternate injection opportunity of gel/polymer flooding

A determination method and polymer technology, which can be used in earth-moving drilling, sealing/packing, wellbore/well components, etc., which can solve the problem of alternate injection timing that has not been reported in literature.

Inactive Publication Date: 2016-09-28
CHINA NAT OFFSHORE OIL CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although research on alternate injection has been carried out in domestic onshore oilfields, the research has only been carried out on the length of slugs and the frequency of alternation, but the timing of alternate injection has not been reported in the literature.

Method used

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  • Determination method for alternate injection opportunity of gel/polymer flooding
  • Determination method for alternate injection opportunity of gel/polymer flooding

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0021] The experimental methods used in the following examples are conventional methods unless otherwise specified.

[0022] The materials and reagents used in the following examples can be obtained from commercial sources unless otherwise specified.

[0023] The variation of the slug split rate with the injection volume of a single polymer concentration is as follows: figure 1 As shown, before chemical flooding, water flooding is carried out first, and when the water content in the produced fluid reaches 40-100%, the gel is re-injected, and the timing of re-injection is Alternate Timing 1; The shunt rate in the medium is in an oblique L-shape that first drops sharply and then rises slowly. When the injection volume of the gel is 0.05-0.3PV, it is the alternation timing 2. At the alternation timing 2, the polymer aqueous solution is injected; the polymer aqueous solution is at high The split rate in the permeability layer continues to rise, and when the polymer injection rate...

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PUM

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Abstract

The invention discloses a determination method for alternate injection opportunity of gel / polymer flooding. According to the determination method, alternate opportunity 1, alternate opportunity 2 and alternate opportunity 3 are determined according to the output liquid moisture content and injection quantity of oil displacement systems. The alternate opportunity 1 is the opportunity corresponding to the time when the output liquid moisture content reaches a certain value. The alternate opportunity 2 is the opportunity corresponding to the time when the injection quantity of the oil displacement system 2 is 0.05-0.3 PV. The alternate opportunity 3 is the opportunity corresponding to the time when the injection quantity of the oil displacement system 3 is equal to the difference value of 0.45 PV and the injection quantity of the oil displacement system 2. The viscosity, obtained through change injection in the alternate opportunity 1, of the oil displacement system 2 is larger than the viscosity, obtained through prior injection, of the oil displacement system 1. The viscosity, obtained through change injection in the alternate opportunity 2, of the oil displacement system 3 is smaller than the viscosity of the oil displacement system 2. Through the determination method, heterogeneous oil reservoirs conducting chemical flooding can obtain different oil displacement effects, and thus the usage degree of a low permeable layer is improved.

Description

technical field [0001] The invention relates to a method for determining the alternate injection timing of gel / polymer flooding, which belongs to the technical field of petroleum development. Background technique [0002] For reservoirs with strong heterogeneity, the injection mode of the single flooding system 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 alternate injection of different viscosity flooding systems can significantly improve the polymer flooding effect in heterogeneous reservoirs and increase the production of low-permeability layers with the same or even reduced oil displacement agent dosage. degree. 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 t...

Claims

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Application Information

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IPC IPC(8): E21B43/22E21B33/13
CPCE21B43/16E21B33/13
Inventor 薛新生王姗姗康晓东张健胡科李强唐恩高李宜强杨光赵文森
Owner CHINA NAT OFFSHORE OIL CORP
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