Casing leakage plugging small workover operation method

Abstract

The invention relates to a casing leakage plugging small workover operation method. The method sequentially comprises the following steps that (1) a position of a casing leakage breaking section is determined; (2) a bridge plug is arranged below the casing leakage breaking section; (3) the position above a rubber plug is filled with a quartz sand protective layer; (4) an oil pipe is run and cementpaste is injected to the position above the leakage breaking section; (5) after the tubing string is tripped out to a safe distance, a wellhead, is closed, pressing is performed to squeeze the cementpaste into a leakage layer, and it is guaranteed that the cement paste is still higher than the top of a leakage section; (6) a well is closed under pressure, and waiting on the cement paste is performed for 36 hours or longer; (7) the tubing string is tripped out, and a cement drilling tubular column runs in hole to drill and grind a cement section; (8) oil pipes are additionally connected one by one, and the cement drilling tubular column is downwards advanced until the cement section is completely drilled off; (9) pressure testing is performed to confirm whether a leakage point is successfully blocked or not, and then the oil pipe is detached one by one until the cement drilling tubular column is completely tripped out of the wellhead; and (10) if the leakage point is not successfullyblocked, the step (4) is re-executed. And if the leakage point is successfully blocked, a quartz sand protection layer is flushed, and the rubber plug is fished out. According to the operation method,a casing can be repaired under the condition that a small casing is not hung.

Description

technical field [0001] The invention relates to a workover operation method, in particular to a casing leakage plugging small workover operation method, and belongs to the technical field of oil and gas workover. Background technique [0002] Oil and natural gas are exploited through the wellbore formed by drilling construction. The wellbore casing string in the wellbore is formed by screwing the casing one by one through the thread. The construction operation of injecting cement into the annular space between the wellbore and the casing is called well cementing. As the production time of oil and gas wells increases, the downhole environment becomes harsher, the casing is prone to damage, and leakage occurs between the formation and the inner cavity of the casing. [0003] There are many methods of workover operations after casing damage, such as hanging a small casing inside the original casing, cementing again, and so on. For wells with less serious casing damage, it is ...

AI Technical Summary

Problems solved by technology

[0004] In addition, after milling and milling the casing, when the pipe string is lifted, the well flushing fluid in the pipe string is taken out of the ground, resulting in wellhead pollution, deteriorating the wellhead environment, and not meeting environmental protection requirements

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