Retrievable frac packer

Abstract

A retrievable frac packer is provided which allows frac operations to be conducted with a single, retrievable tool, with the capability of providing positive zone production indications during production testing.

Description

FIELD OF THE INVENTION [0001] The invention relates to frac packers which can be used in downhole environments, retrieved, and reconditioned for further use rather than requiring the time and expense to drill out, and thus destroy, the tool after use. BACKGROUND OF THE INVENTION [0002] To “frac” a well involves the introduction of media, typically containing a proppant, into a zone surrounding the wellbore to create flow conduits in the surrounding earth. In the interest of cost reduction, it is desirable to carry out such an operation as quickly as possible, and with as few trips up and down the wellbore as possible. For frac operations, it is necessary to introduce a seal in the wellbore to prevent the frac fluid from travelling further downhole than the desired frac zone. [0003] However, wells often have multiple production zones as well as multiple zones where performing the frac operation is desirable. Therefore, the seal which is introduced into the wellbore must be, or is cer...

AI Technical Summary

Benefits of technology

[0013] At the desired depth, the tool is set by wireline control, hydraulic pressure, mechanical means, or a combination of these techniques to compress and engage the circumferential seal with the inner wall of the surrounding casing. Compression pressure is applied to the seals by an upper compression member in slidable engagement with the annular body of the tool, and by a lower compression member in slidable engagement with the annular body of the tool. Downward travel of the lower compression member may be resisted by mechanical stops. However, in the preferred embodiment, the lower compression member is biased upward by mechanical means, such as a spring, to provide improved sealing force and to assist in the release of the tool after the frac operation. If the tool is to be utilized in wells in which multiple tools will be retrieved simultaneously, such a mechanical biasing is necessary to insure that the tools will release properly and move further down the wellbore to retrieve a deeper set frac packer, and retrieve properly.

[0019] In the preferred embodiment, the downhole end of the annular body of the tool is provided with a grip capable of latching onto the uphole end of another of such tools. Thus, when frac operations are completed in a wellbore with multiple zones, each tool may be released in turn, then moved downhole to latch onto and release the next lower tool. In this way, multiple tools may be retrieved simultaneously, reducing the number of trips required to clear the tools from the wellbore.

Problems solved by technology

However, these tools require expensive surface support equipment in order to be drilled out after the frac operation is completed.

Drilling out such tools is time consuming, and therefore expensive, and can result in undesirable damage to the inside of the wellbore.

Further, tool cost using this approach is driven up because the tools themselves must be considered as expendable.

However, such an approach requires two separate tools to perform a single task, adding cost and complexity to the process.

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