Hydraulic fracturing isolation methods and well casing plugs for re-fracturing horizontal multizone wellbores

摘要

A method for hydraulically isolating a portion of a multizone wellbore by providing a plug proximate the portion of the wellbore. The plug may be a proppant combined with a polymer. The proppant may be an ultra-lightweight proppant and the polymer may be cross-linked. The polymer may be a superabsorbent polymer or a hydrophobically modified polysaccharide. The plug may be formed by placing a pill of proppant and polymer within the wellbore and slowing pumping fluid down to cause the pill to bridge off and form a plug. The pill may also include a lightweight filler. The plug may be used to hydraulically isolate a portion of the wellbore during a fracturing or re-fracturing process. Multiple plugs may be placed along the wellbore to hydraulically isolate portions of the wellbore during the fracturing or re-fracturing process.

主权项

1. A method for re-fracturing a location of a formation of a multizone horizontal wellbore, the method comprising:
hydraulically isolating a first location from a portion of the multizone horizontal wellbore uphole from the first location, the first location having been previously hydraulically fractured at least once; hydraulically re-fracturing the first location; providing a first plug within the wellbore proximate to the first location after the first location has been hydraulically re-fractured; pumping fluid down the wellbore to bridge off the first plug within the wellbore to hydraulically isolate the re-fractured first location from the multizone horizontal wellbore uphole of the first location, wherein the first plug comprises proppant combined with crystalline silica hydraulically isolating a second location from a portion of the multizone horizontal wellbore uphole of the second location; hydraulically fracturing the second location; providing a second plug within the wellbore proximate to the second location after the second location has been fractured; and pumping fluid down the wellbore to bridge off the second plug within the wellbore to hydraulically isolate the second location from a portion of the multizone horizontal wellbore uphole of the second location, wherein the second plug comprises proppant combined with crystalline silica.