Claims
- 1. A method for simultaneously acid fracturing two spaced apart zones of a carbonate containing formation comprising:
- a) injecting a lower density fracturing acid into an upper zone of said formation via an annulus of a perforated wellbore communicating with said upper zone which fluid is injected at a pressure sufficient to initiate and propagate a first fracture within said upper zone; and
- b) simultaneously injecting with the fracturing acid of step a), a higher density fracturing acid into a lower spaced apart zone of said formation via a tubing string within the perforated wellbore that communicates fluidly with said lower zone which acid is injected at a pressure sufficient to simultaneously initiate and propagate another fracture within said lower zone which does not contact the first fracture thereby obtaining complete fracture growth that is confined to each zone while acidizing in each zone.
- 2. The method as recited in claim 1 where the lower and upper zones are spaced about 50 to about 200 feet apart.
- 3. The method as recited in claim 1 wherein the density of the higher density fracturing acid is about 0.5 pounds per gallon heavier than the lower density fracturing acid.
- 4. The method as recited in claim 1 where the tubing string is open-ended above perforations which fluidly communicate the wellbore with said lower zone.
- 5. The method as recited in claim 1 where the lower and higher density fracturing acids do not co-mingle while fracturing the zones.
- 6. The method as recited in claim 1 where the lower and higher density fracturing acids are different acids.
- 7. The method as recited in claim 1 where the lower and higher density fracturing acids are different acids and are selected from a member of the group consisting of hydrochloric, formic, acetic, and oxalic acid.
- 8. The method as recited in claim 1 where hydrochloric acid is directed into a zone of the formation which is most reactive to an acid while an organic acid selected from a member of the group consisting of formic, acetic, or oxalic acid is directed into a less acid active reactive zone.
Parent Case Info
This invention is a continuation-in-part of Ser. No. 08/057,132 which was filed on May 3, 1993.
US Referenced Citations (11)
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
057132 |
May 1993 |
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