Method for realizing water plugging of immovable string of high-water-cut oil well

Abstract

The invention relates to the technical field of petroleum exploitation, in particular to a method for realizing water plugging of an immovable string of a high-water-cut oil well. The method comprises the following steps that (1) a first slug is injected into an oil reservoir with constant flow and different concentration; (2) a second slug is front arranged and injected into the deep part of the oil reservoir; (3) a third slug is a plugging agent main plug, and is injected into the middle deep part of the oil reservoir; (4) a fourth slug is a high-strength agent and a cracking agent, and the injection pressure of the high-strength agent is 6-10 MPa; and (5) after the completion of slug injection, the well is closed for 5 days, and when the injected slugs are stabilized, the well is pened for production. The operating cost is low, the maintenance cost is low in a later stage, and the chemical agents have large spread space and are easy to inject into a target layer to come into play.

Description

technical field [0001] The invention relates to the technical field of petroleum production, in particular to a method for realizing water shutoff without moving a pipe string in a high water-cut oil well. Background technique [0002] Oil well water production is an important phenomenon in the process of oil well production, and it is a common problem in the process of oil and gas field development. In the late stage of oil production or when there is a lot of water injection in the surrounding area, the water in the oil well production fluid accounts for more than 90%, which seriously affects the oil recovery efficiency. Oil well shutoff refers to the use of mechanical or chemical methods to shut off water in flooded oil wells to reduce oil well water output and increase crude oil production. [0003] Chemical water plugging uses a specific chemical agent as a water blocking agent, which is injected into the high-permeability layer of the formation to reduce the water pha...

AI Technical Summary

Problems solved by technology

It is suitable for sealing a single water layer or a high aquifer; however, it has disadvantages that a packer needs to be lowered, and the operation cost is high, and the post-maintenance cost is high

Selective chemical water plugging: choose appropriate chemical agents to block the water layer or change the interfacial tension between oil, water and rock, reduce the water phase permeability of the same layer of oil and water, and have little effect on the oil phase permeability, but there are disadvantages. The chemical agent spreads to a small space, and it is difficult to inject into the target layer to play a role

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