Low-injury sandstone acid used for acidification technology of oil well

An oil well acidification and sandstone technology, applied in the directions of chemical instruments and methods, drilling compositions, etc., can solve the problems of high corrosion near the wellbore, and achieve the effects of less formation damage and improved permeability

Inactive Publication Date: 2010-07-28
XI'AN PETROLEUM UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The current conventional ordinary acidizing has the problem of excessive corrosion to the near-wellbore zone

Method used

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  • Low-injury sandstone acid used for acidification technology of oil well

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] A low-harm sandstone acid for oil well acidizing process, its components include: hydrochloric acid accounts for 2% of the total weight, compound phosphonic acid accounts for 8%, citric acid accounts for 1%, acidification corrosion inhibitor accounts for 5%, water accounts for 84%.

Embodiment 2

[0030] A low-harm sandstone acid for oil well acidizing process, the components of which include by mass ratio: hydrochloric acid accounting for 8% of the total weight, compound phosphonic acid accounting for 12%, citric acid accounting for 0.5%, acidifying corrosion inhibitor accounting for 5%, additive aqueous solution Accounted for 74.5%.

[0031] The components of the additive aqueous solution are as follows: the mutual solvent accounts for 0.5% of the weight of the additive aqueous solution, the demulsifier accounts for 0.1% of the weight of the additive aqueous solution, and water accounts for 99.4% of the weight of the additive aqueous solution.

Embodiment 3

[0033] A low-damage sandstone acid for oil well acidizing process, its components include: hydrochloric acid accounts for 11% of the total weight, ammonium bifluoride accounts for 3%, compound phosphonic acid accounts for 9%, citric acid accounts for 2%, acidification corrosion inhibitor Accounted for 5%, additive aqueous solution accounted for 70%.

[0034] The components of the additive aqueous solution are: the mutual solvent accounts for 5% of the weight of the additive aqueous solution, the demulsifier accounts for 5% of the weight of the additive aqueous solution, the clay stabilizer accounts for 30% of the additive aqueous solution, and water accounts for 5% of the additive aqueous solution. 60% by weight of components.

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Abstract

The invention relates to a low-injury sandstone acid used for the acidification technology of an oil well. The low-injury sandstone acid comprises the compositions according to the mass percentage: 2-15% of hydrochloric acid, 0-10% of ammonium bifluoride, 0-10% of hydrogen nitrate, 0-8% of acetic acid, 8-18% of composite phosphonic acid, 0.5-5% of citric acid, 5-15% of acidulate corrosion inhibitor and 70-84% of water or additive water solution, wherein the additive water solution comprises the compositions according to the weight percentage: 0.5-5% of mutual solvent, 0.1-5% of demulsifying agent, 0-30% of clay stabilizer and 60-99.4% of water. The sandstone acid has the characteristics that the permeability of the oil well can be improved, the speed of reaction is slow and uniform, and the corrosion of the sandstone acid to the area near the oil well is nearly the same as that of the clean water.

Description

technical field [0001] The invention relates to a preparation for oil layer plugging removal and enhanced oil recovery, in particular to a low-damage sandstone acid for oil well acidizing process. Background technique [0002] The mixed acid of hydrochloric acid and hydrofluoric acid, that is earth acid, is usually used for acidizing sandstone reservoirs of oil wells. Conventional earth acid is prepared according to the ratio of HCI:HF 12:3%. Usually, ammonium difluoride can be dissolved in HCI to prepare HF, such as 15% HCI and 5% NH 4 HF 2 Generate HF soil acid plugging solution. However, recent studies have shown that to reduce potential fluoride salt precipitation, the ratio should be at least 6:1, preferably 9:1. Foreign BJ Service Company has developed a new HF mixture, which is to replace HCI hydrolysis fluoride salt with chelating acid complex. This acid has 5 hydrogen ions, called "HV acid", HV acid and hydrofluorination Ammonium (NH 4 HF 2 ) produces complex ...

Claims

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Application Information

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IPC IPC(8): C09K8/72
Inventor 王俊奇屈展盖海防陈军斌
Owner XI'AN PETROLEUM UNIVERSITY
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