Foam plug flow diverting acidification technique

Abstract

The invention provides a foam plug diversion and acidification technology. The method is that: a high permeable layer is temporality blocked by injecting foam plug and utilizing the diversion ability of the foamed fluid, then the acid liquid is converted to a low permeable layer and then the uniform acidification with different permeability is realized and thus, the acid-soluble blockage of the reservoir is effectively solved; at the same time, the high carrying capacity of the foamed fluid and the expansion of the nitrogen can back-drain the acidified solid particles and the residual acid, which can decrease the secondary injury. The invention is especially suitable for solving the acid-soluble injury of the heterogeneous stratum.

Description

Technical field: [0001] The invention belongs to a reservoir acidification production increase technology in the petroleum development process. Background technique: [0002] In the development of oil and gas fields, sandstone or carbonatite formation matrix acidizing technology is an important measure to remove plugging and increase production. By injecting acid liquid into the formation, dissolving soluble substances in the reservoir, restoring and improving the permeability of the near-wellbore area, so as to achieve the purpose of increasing production. [0003] For heterogeneous oil and gas reservoirs with great disparity in injection capacity, the acid liquid will follow the principle of natural selection during conventional acidizing, that is, the acid liquid will preferentially enter the high-permeability zone, which will inevitably cause the low-permeability layer or the seriously damaged layer to be unable to enter the acid or too little acid. As a result, the amo...

AI Technical Summary

Problems solved by technology

[0003] For heterogeneous oil and gas reservoirs with great disparity in injection capacity, the acid liquid will follow the principle of natural selection during conventional acidizing, that is, the acid liquid will preferentially enter the high-permeability zone, which will inevitably cause the low-permeability layer or the seriously damaged layer to fail to enter the acid or too little acid. As a result, the amount of acid designed according to the multi-layer acidification mainly enters the high-permeability layer, so that the high-permeability layer absorbs too much acid, and the excessive dissolution of the rock will inevitably lead to the collapse of the reservoir and cause secondary damage to the reservoir.

At the same time, the acidizing solution cannot enter the low-permeability layer according to the design requirements, so that the low-permeability layer cannot be improved, and the purpose of acidizing and plugging removal cannot be achieved.