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Retarded crosslinked gel and preparation method thereof

A technology for cross-linking gels and working fluids, used in gel preparation, chemical instruments and methods, colloid chemistry, etc., and can solve problems such as increased pressure and too fast cross-linking time

Inactive Publication Date: 2017-05-10
泰伦特生物工程股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in the process of profile control and flood control, it is required that the injection fluid is not cross-linked before entering the well, and cross-linked into a semi-solid polymer gel (a semi-fluid substance formed by the cross-linking of polyacrylamide and metal ions) after being injected into the formation, resulting in Profile control and flood control effect, but at present, the cross-linking time of conventional agents is too fast (only a few hours), and the pressure continues to rise during the injection process.

Method used

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  • Retarded crosslinked gel and preparation method thereof
  • Retarded crosslinked gel and preparation method thereof
  • Retarded crosslinked gel and preparation method thereof

Examples

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Effect test

preparation example Construction

[0030] The preparation method of the above-mentioned profile control working fluid is the same as that of the control and flooding working fluid, specifically: including the following steps:

[0031] ⑴ Add polyglutamic acid to water (can be injected water) under stirring (speed 150-200rpm);

[0032] (2) Observe after stirring for 10 minutes, when there is no flocculent insoluble matter, slowly add anionic polyacrylamide, and continue stirring for 40-60 minutes;

[0033] ⑶ Add sodium dichromate after no obvious fish eyes (polyacrylamide is completely dissolved), and finally add sodium sulfite to make the finished product.

[0034] The pressure of profile control working fluid and control and flooding working fluid will not increase during the injection process, and the cross-linked viscosity after injection into the formation can produce profile control (control and flooding) effects. The data comparison is shown in Table 1:

[0035]

[0036]

[0037] Table 1: The detect...

Embodiment 1

[0040] The daily water injection volume of a water injection well in Dagang Oilfield is about 80m 3 , the water injection pressure is 1.0MPa, and the comprehensive water cut of the surrounding oil wells reaches more than 80%. It is judged that there are obviously large water flow channels inside the oil layer, and profile control operations are required.

[0041] The construction site is two 10m 3 The mixing tank is used for chemical preparation, and the plunger pump is connected to the water injection wellhead to inject into the oil layer to produce profile control effect.

[0042] Working fluid formula: anionic polyacrylamide 0.3%, polyglutamic acid 0.02%, sodium dichromate 0.1%, sodium sulfite 0.1%, local water injection 99.48%.

[0043] Preparation process: a 10m 3 Inject about 8 cubic meters of local water into the mixing tank, start stirring, add polyglutamic acid at 0.02%, stir for about 10 minutes, add polyacrylamide to a final concentration of 0.3%, continue stirrin...

Embodiment 2

[0047] The comprehensive water content of the well group in a block of Huabei Oilfield is close to 90%, and the profile control operation has been performed many times, but the profile control effect is getting worse and worse, the validity period is short and the oil increase effect is not ideal. The analysis reason is that the crude oil viscosity in this area Higher (viscosity 10-20mPa*s at 50°C), resulting in poor effect of water flooding after profile control.

[0048] Therefore, in order to improve the oil displacement effect and increase the viscosity of water injection, the oil displacement test was carried out by using the regulating and flooding working fluid containing polyglutamic acid.

[0049] Well group status: This well group includes 1 water injection well, surrounded by 4 beneficial oil wells, with a daily water injection volume of 120m 3 , water injection pressure 2.5MPa.

[0050] Working fluid formula: anionic polyacrylamide 0.2%, polyglutamic acid 0.04%, s...

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Abstract

The invention relates to a retarded crosslinked gel, which is prepared from the following raw materials of anionic polyacrylamide, a polyglutamic acid, sodium bichromate, sodium sulfite and water. According to the retarded crosslinked gel, hexavalent chromium ions are firstly complexed with the polyglutamic acid to form a molecular group with certain stability; free hexavalent chromium ions are reduced into trivalent chromium ions by the sodium sulfite; the trivalent chromium ions are crosslinked with the polyacrylamide to form the gel of a mesh structure. The crosslinking rate of the trivalent chromium ions and polyacrylamide is controlled through a dissociation rate of the hexavalent chromium ions in a complexed state, so that retarding the final gelling time. In addition, the polyglutamic acid has a very strong water locking function, so that the gel is not easily bled or broken, the stability of the gel is strengthened, obvious crosslinking reaction is not generated in the production process; the injection pressure is not obviously improved; a working solution is still crosslinked into a semi-flow state polymer gel after being injected into a stratum to generate a profile modification (profile control and displacement) effect.

Description

technical field [0001] The invention belongs to the technical field of improving the gelation time of working fluids for profile control, control and flooding, in particular to a slow cross-linking gel and a preparation method thereof. Background technique [0002] As the water injection development of the oilfield enters the later stage, the heterogeneity of the oil layer leads to the emergence of obvious water flow channels, and the water content of the produced fluid is getting higher and higher. In order to solve this problem, the oilfield often uses profile control and flooding operations to relieve the water injection from passing through the channels too early The problem of reduced oil recovery effect due to oil production. Profile control refers to the operation of plugging high-permeability layers from water injection wells. It can adjust the water absorption profile of the water injection layer and reduce the water production of oil wells. Profile control is to se...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J13/00C09K8/588
CPCB01J13/0052C09K8/588
Inventor 赵艳辉王永芝孙鹏龙张雪峰
Owner 泰伦特生物工程股份有限公司
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