Well re-fracturing method

Abstract

A method of re-treating a well with pre-existing fractures which includes: displacing a tool in a well, leaking off motive fluid to an open fracture zone passed by the tool to diminish the rate of displacement, and locating the open fracture zone above the tool.

Description

CROSS REFERENCE TO RELATED APPLICATION(S)[0001]None.BACKGROUND[0002]Re-fracturing a well is a challenging operation, the success of which is in part dictated by the often unknown state of the well and associated formation at the start of the re-fracturing treatment. Often, the initial or previous fracturing treatment(s) has been designed to place several fractures along the wellbore. In the time between the fracturing treatment and the subsequent re-fracturing treatment, many parameters of the well may have changed, and / or parameters at the time of the fracturing may be otherwise unavailable, resulting in a number of unknown parameters which may impact the success of the re-fracturing treatment.[0003]Examples of typical unknown parameters that affect the design and execution of a re-fracturing treatment may include the number and location of open fractures along the wellbore at the start of the re-fracturing treatment, pore pressure and its distribution profile, and stress variation...

AI Technical Summary

Benefits of technology

The patent is about methods for re-fracturing a well with pre-existing fractures. The methods involve deploying a tool connected to surface by a cable, pumping a motive fluid into the well to displace the tool, leaking off the motive fluid into open fracture zones above the tool, and treating the open fracture zones. The methods can be used to selectively leak off the motive fluid in order to decrease the displacement of the tool. In some embodiments, the method includes tensioning the cable to selectively leak off the motive fluid into the open fractures. The technical effect of the patent is to provide a way to re-fracture a well with pre-existing fractures without the need for excessive drilling and equipment costs.

Problems solved by technology

Re-fracturing a well is a challenging operation, the success of which is in part dictated by the often unknown state of the well and associated formation at the start of the re-fracturing treatment.

In the time between the fracturing treatment and the subsequent re-fracturing treatment, many parameters of the well may have changed, and / or parameters at the time of the fracturing may be otherwise unavailable, resulting in a number of unknown parameters which may impact the success of the re-fracturing treatment.

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