Selective chemical water plugging method

Abstract

The invention discloses a selective chemical water plugging method, and belongs to the technical field of oilfield development drilling. The selective chemical water plugging method comprises the following steps that a temporary plugging agent and a water plugging agent are provided; the temporary plugging agent is injected into an oil sleeve annulus of an oil well; after first setting waiting time, the temporary plugging agent is cured and coagulated; in the curing period of the temporary plugging agent, the water plugging agent is injected into the oil sleeve annulus; well shut-in operation is carried out on the oil well; and after the second setting waiting time, the water plugging agent is solidified and coagulated. According to the selective chemical water plugging method, before the water plugging agent is injected into the oil sleeve annulus, an oil outlet layer is protected by the temporary plugging agent, and the temporary plugging agent can be degraded and recover the infiltration capacity of the oil outlet layer within a certain time after entering the oil outlet layer, so that water plugging is effectively and selectively carried out on the oil well, the water plugging operation procedure is simplified, the cost is saved, the water plugging operation efficiency is improved, and the water plugging effect is guaranteed.

Description

technical field [0001] The disclosure belongs to the technical field of oil field development and drilling, in particular to a selective chemical water plugging method. Background technique [0002] Oil well water plugging is a process to control oil well water production, and oil well water plugging is an indispensable and important adjustment measure in the middle and late stages of oilfield development. In order to control the output of water from the oil well, it is necessary to plug the high-permeability aquifer layer. Generally, the water plugging methods selected include mechanical water plugging and chemical water plugging. Chemical water shutoff is a method of injecting a certain chemical material (water shutoff agent) into the oil well, and using the product of the physical and chemical reaction between the water shutoff agent and the oil layer to seal the oil layer. According to the different properties of water blocking agent, it can be divided into non-selectiv...

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Problems solved by technology

[0004] However, with the above-mentioned selective chemical water shutoff, since the production layer includes the water-producing layer and the oil-producing layer, and there is a formation pressure difference between the water-producing layer and the oil-producing layer, generally speaking, the pressure of the water-producing layer is high and the pressure of the oil-producing layer is low.

Therefore, general injection of water shutoff agent into the production layer will cause the water shutoff agent to preferentially enter the low-pressure oil production layer, which will inevitably cause greater pollution to the oil layer, and the water shutoff selectivity effect is poor

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