Degradable temporary plugging agent for workover and preparation method thereof

Abstract

The invention belongs to the field of workover operations, and particularly relates to a degradable temporary plugging agent for workover and a preparation method thereof. The degradable temporary plugging agent comprises the following components in parts by mass: 5-7% of acrylic acid, 15-21% of acrylamide, 5-15% of inorganic mineral soil, 0.002-0.005% of a polymerization inhibitor, 6-12% of a degradation promoter, 0.02-0.1% of a crosslinking agent, 0.6-1.0% of an initiator, 7-10% of corn flour and the balance of water. The degradable temporary plugging agent for workover disclosed by the invention has good degradation performance and does not need to add an additional degradation process; for high-water cut oil wells, water wells and the like, the degradable temporary plugging agent can be degraded by itself and resume operation and production only under the condition of a reservoir (under the condition of 90 DEG C, the 48-hour degradation rate can reach more than 90%).

Description

technical field [0001] The invention belongs to the field of well workover operations, and in particular relates to a degradable temporary plugging agent for well workover and a preparation method thereof. Background technique [0002] Workover fluid loss is one of the biggest problems encountered in the workover operation, which not only makes the workover operation impossible, but also causes oil layer damage due to the workover fluid intrusion into the reservoir. Even if the workover operation is carried out smoothly, the oil well after operation The production recovery period is long, and even the production of oil wells cannot be restored to the production before operation. Targeted implementation of temporary plugging technology is one of the effective ways to solve such problems. [0003] At present, the widely used temporary plugging agents can be classified into water-soluble temporary plugging agents, oil-soluble temporary plugging agents, acid-soluble temporary pl...

AI Technical Summary

Problems solved by technology

However, with the development of oil fields, the water content of oil wells in most onshore oil fields in my country has gradually increased. Taking Dagang Oilfield as an example, the average water content of oil wells is above 70%, and some oil wells have water content above 90%. The degradation rate of oil-soluble temporary plugging agent Obvious reduction

[0004] In addition, the pressure between the various layers of the water injection well is unbalanced. During the workover, well killing, sand washing and other operations, the fluid leakage into the well is serious, and many wells cannot be killed and circulated normally, resulting in the uncontinuity of the operation process and seriously affecting The operation and normal production of the water well will be affected, and it will also cause damage to the formation. Some measures for water injection wells also need to apply temporary plugging technology

[0005] The currently used gel-type plugging materials such as bulky particles are variable elastic materials, and their plugging effect is good, but because they cannot degrade by themselves, they often need to be removed by oxidizing agents or acid solutions, which not only poses certain safety hazards , and increase the construction cost

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